Hull Structure and Arrangement for the
Classification of Cargo Ships less than 65 m
and Non Cargo Ships less than 90 m
NR 600
AMENDMENTS
July 2015
These sheets contain amendments within the following Sections of July 2014 issue of the
Rules for Hull Structure and Arrangement for the Classification of Cargo Ships less than 65
m and Non Cargo Ships less than 90 m.
These amendments are effective from July 1st, 2015.
Chapter
Section / Appendix
Chapter 1
Sec 1, Sec 3
Chapter 2
Sec 3
Chapter 3
Sec 1, Sec 2, Sec 3, Sec 4
Chapter 4
Sec 3, Sec 4, Sec 5, Sec 6, Sec 7, App 2
Chapter 5
Sec 1, Sec 2, Sec 4, Sec 5
Chapter 6
Sec 2,
NR 600 DT Amd 001 E July 2015
MARINE & OFFSHORE DIVISION
GENERAL CONDITIONS
ARTICLE 1
1.1. - BUREAU VERITAS is a Society the purpose of whose Marine & Offshore Division (the "Society") is
the classification (" Classification ") of any ship or vessel or offshore unit or structure of any type or part of
it or system therein collectively hereinafter referred to as a "Unit" whether linked to shore, river bed or sea
bed or not, whether operated or located at sea or in inland waters or partly on land, including submarines,
hovercrafts, drilling rigs, offshore installations of any type and of any purpose, their related and ancillary
equipment, subsea or not, such as well head and pipelines, mooring legs and mooring points or otherwise
as decided by the Society.
The Society:
• "prepares and publishes Rules for classification, Guidance Notes and other documents (" Rules ");
• "issues Certificates, Attestations and Reports following its interventions (" Certificates ");
• "publishes Registers.
1.2. - The Society also participates in the application of National and International Regulations or Standards, in particular by delegation from different Governments. Those activities are hereafter collectively referred to as " Certification ".
1.3. - The Society can also provide services related to Classification and Certification such as ship and
company safety management certification; ship and port security certification, training activities; all activities and duties incidental thereto such as documentation on any supporting means, software, instrumentation, measurements, tests and trials on board.
1.4. - The interventions mentioned in 1.1., 1.2. and 1.3. are referred to as " Services ". The party and/or its
representative requesting the services is hereinafter referred to as the " Client ". The Services are prepared and carried out on the assumption that the Clients are aware of the International Maritime
and/or Offshore Industry (the "Industry") practices.
1.5. - The Society is neither and may not be considered as an Underwriter, Broker in ship's sale or chartering, Expert in Unit's valuation, Consulting Engineer, Controller, Naval Architect, Manufacturer, Shipbuilder, Repair yard, Charterer or Shipowner who are not relieved of any of their expressed or implied
obligations by the interventions of the Society.
ARTICLE 2
2.1. - Classification is the appraisement given by the Society for its Client, at a certain date, following surveys by its Surveyors along the lines specified in Articles 3 and 4 hereafter on the level of compliance of
a Unit to its Rules or part of them. This appraisement is represented by a class entered on the Certificates
and periodically transcribed in the Society's Register.
2.2. - Certification is carried out by the Society along the same lines as set out in Articles 3 and 4 hereafter
and with reference to the applicable National and International Regulations or Standards.
2.3. - It is incumbent upon the Client to maintain the condition of the Unit after surveys, to present
the Unit for surveys and to inform the Society without delay of circumstances which may affect the
given appraisement or cause to modify its scope.
2.4. - The Client is to give to the Society all access and information necessary for the safe and efficient
performance of the requested Services. The Client is the sole responsible for the conditions of presentation of the Unit for tests, trials and surveys and the conditions under which tests and trials are carried out.
ARTICLE 3
3.1. - The Rules, procedures and instructions of the Society take into account at the date of their
preparation the state of currently available and proven technical knowledge of the Industry. They
are a collection of minimum requirements but not a standard or a code of construction neither a
guide for maintenance, a safety handbook or a guide of professional practices, all of which are
assumed to be known in detail and carefully followed at all times by the Client.
Committees consisting of personalities from the Industry contribute to the development of those documents.
3.2. - The Society only is qualified to apply its Rules and to interpret them. Any reference to them
has no effect unless it involves the Society's intervention.
3.3. - The Services of the Society are carried out by professional Surveyors according to the applicable
Rules and to the Code of Ethics of the Society. Surveyors have authority to decide locally on matters related to classification and certification of the Units, unless the Rules provide otherwise.
3.4. - The operations of the Society in providing its Services are exclusively conducted by way of random inspections and do not in any circumstances involve monitoring or exhaustive verification.
ARTICLE 4
4.1. - The Society, acting by reference to its Rules:
• "reviews the construction arrangements of the Units as shown on the documents presented by the Client;
• "conducts surveys at the place of their construction;
• "classes Units and enters their class in its Register;
• "surveys periodically the Units in service to note that the requirements for the maintenance of class are
met.
The Client is to inform the Society without delay of circumstances which may cause the date or the
extent of the surveys to be changed.
ARTICLE 5
5.1. - The Society acts as a provider of services. This cannot be construed as an obligation bearing
on the Society to obtain a result or as a warranty.
5.2. - The certificates issued by the Society pursuant to 5.1. here above are a statement on the level
of compliance of the Unit to its Rules or to the documents of reference for the Services provided for.
In particular, the Society does not engage in any work relating to the design, building, production
or repair checks, neither in the operation of the Units or in their trade, neither in any advisory services, and cannot be held liable on those accounts. Its certificates cannot be construed as an implied or express warranty of safety, fitness for the purpose, seaworthiness of the Unit or of its value
for sale, insurance or chartering.
5.3. - The Society does not declare the acceptance or commissioning of a Unit, nor of its construction in conformity with its design, that being the exclusive responsibility of its owner or builder.
5.4. - The Services of the Society cannot create any obligation bearing on the Society or constitute any
warranty of proper operation, beyond any representation set forth in the Rules, of any Unit, equipment or
machinery, computer software of any sort or other comparable concepts that has been subject to any survey by the Society.
ARTICLE 6
6.1. - The Society accepts no responsibility for the use of information related to its Services which was not
provided for the purpose by the Society or with its assistance.
6.2. - If the Services of the Society or their omission cause to the Client a damage which is proved
to be the direct and reasonably foreseeable consequence of an error or omission of the Society,
its liability towards the Client is limited to ten times the amount of fee paid for the Service having
caused the damage, provided however that this limit shall be subject to a minimum of eight thousand (8,000) Euro, and to a maximum which is the greater of eight hundred thousand (800,000)
Euro and one and a half times the above mentioned fee. These limits apply regardless of fault including breach of contract, breach of warranty, tort, strict liability, breach of statute, etc.
The Society bears no liability for indirect or consequential loss whether arising naturally or not as
a consequence of the Services or their omission such as loss of revenue, loss of profit, loss of production, loss relative to other contracts and indemnities for termination of other agreements.
6.3. - All claims are to be presented to the Society in writing within three months of the date when the Services were supplied or (if later) the date when the events which are relied on of were first known to the Client,
and any claim which is not so presented shall be deemed waived and absolutely barred. Time is to be interrupted thereafter with the same periodicity.
ARTICLE 7
7.1. - Requests for Services are to be in writing.
7.2. - Either the Client or the Society can terminate as of right the requested Services after giving
the other party thirty days' written notice, for convenience, and without prejudice to the provisions
in Article 8 hereunder.
7.3. - The class granted to the concerned Units and the previously issued certificates remain valid until the
date of effect of the notice issued according to 7.2. here above subject to compliance with 2.3. here above
and Article 8 hereunder.
7.4. - The contract for classification and/or certification of a Unit cannot be transferred neither assigned.
ARTICLE 8
8.1. - The Services of the Society, whether completed or not, involve, for the part carried out, the payment
of fee upon receipt of the invoice and the reimbursement of the expenses incurred.
8.2. - Overdue amounts are increased as of right by interest in accordance with the applicable legislation.
8.3. - The class of a Unit may be suspended in the event of non-payment of fee after a first unfruitful
notification to pay.
ARTICLE 9
9.1. - The documents and data provided to or prepared by the Society for its Services, and the information
available to the Society, are treated as confidential. However:
• "Clients have access to the data they have provided to the Society and, during the period of classification of the Unit for them, to the classification file consisting of survey reports and certificates which
have been prepared at any time by the Society for the classification of the Unit ;
• "copy of the documents made available for the classification of the Unit and of available survey reports
can be handed over to another Classification Society, where appropriate, in case of the Unit's transfer
of class;
• "the data relative to the evolution of the Register, to the class suspension and to the survey status of
the Units, as well as general technical information related to hull and equipment damages, may be
passed on to IACS (International Association of Classification Societies) according to the association
working rules;
• "the certificates, documents and information relative to the Units classed with the Society may be
reviewed during certificating bodies audits and are disclosed upon order of the concerned governmental or inter-governmental authorities or of a Court having jurisdiction.
The documents and data are subject to a file management plan.
ARTICLE 10
10.1. - Any delay or shortcoming in the performance of its Services by the Society arising from an event
not reasonably foreseeable by or beyond the control of the Society shall be deemed not to be a breach of
contract.
ARTICLE 11
11.1. - In case of diverging opinions during surveys between the Client and the Society's surveyor, the Society may designate another of its surveyors at the request of the Client.
11.2. - Disagreements of a technical nature between the Client and the Society can be submitted by the
Society to the advice of its Marine Advisory Committee.
ARTICLE 12
12.1. - Disputes over the Services carried out by delegation of Governments are assessed within the
framework of the applicable agreements with the States, international Conventions and national rules.
12.2. - Disputes arising out of the payment of the Society's invoices by the Client are submitted to the Court
of Nanterre, France, or to another Court as deemed fit by the Society.
12.3. - Other disputes over the present General Conditions or over the Services of the Society are
exclusively submitted to arbitration, by three arbitrators, in London according to the Arbitration
Act 1996 or any statutory modification or re-enactment thereof. The contract between the Society
and the Client shall be governed by English law.
ARTICLE 13
13.1. - These General Conditions constitute the sole contractual obligations binding together the
Society and the Client, to the exclusion of all other representation, statements, terms, conditions
whether express or implied. They may be varied in writing by mutual agreement. They are not varied by any purchase order or other document of the Client serving similar purpose.
13.2. - The invalidity of one or more stipulations of the present General Conditions does not affect the validity of the remaining provisions.
13.3. - The definitions herein take precedence over any definitions serving the same purpose which may
appear in other documents issued by the Society.
BV Mod. Ad. ME 545 L - 7 January 2013
NR600
Amendments to NR600
Ch 1, Sec 1, [1.2]
Replace requirement [1.2.2] by:
1.2.2 Service notation or additional feature
The assignment of any service notation as defined in NR467
Steel Ships, Part A is subject to compliance with the general
rule requirements laid down in the present Rules and especially, for some service notations, with the additional
requirements laid down in Ch 5, Sec 4.
Ch 1, Sec 1, [2.2]
Delete requirement [2.2.2].
Ch 1, Sec 1, [3.1]
Replace requirement [3.1.1] by:
3.1.1 The navigation coefficient n which appears in the
formulae of the present Rules are defined in Tab 2 depending on the assigned navigation notation defined in NR467
Steel Ships, Pt A, Ch 1, Sec 2, [5.1].
Ch 1, Sec 1, [3.2]
Replace requirement [3.2.1] by:
3.2.1
For the service notations sea going launch and
launch as defined in NR467 Steel Ships, Pt A, Ch 1, Sec 2,
[4.11.2], the navigation coefficient n which appears in the
formulae of the present Rules, are defined in Tab 3.
Ch 1, Sec 1
Replace Table 2 and Table 3 by:
T1 :
Table 2 : Navigation coefficient n
Navigation notation
T2 :
Navigation coefficient n
Table 3 : Navigation coefficient n
Service notation
Navigation coefficient n
0,65 + 0,008 Lw ≤ 0,80
unrestricted navigation
1,00
sea going launch
summer zone
0,90
launch
tropical zone
0,80
Note 1:
0,80
Lw
:
Lw = 0,5 (LWL + LHULL)
where:
LWL
LHULL
:
:
Length at waterline at full load, in m
Length of the hull from the extreme forward to
the extreme aft part of the hull, in m.
coastal area
sheltered area
Amendments July 2015
0,65
Bureau Veritas
0,65
3
NR600
Ch 1, Sec 1, Table 6
Add the following rows in Table 6:
T3 :
Table 6 : Plans and documents to be submitted depending on service notations
Dredger
Transverse sections through hoppers, wells, pump rooms and dredging machinery spaces
Structural arrangement of hoppers and supporting structures
Closing arrangements, if any
Connection of dredging machinery with the hull structure
Hopper dredger
Hopper unit
Transverse sections through hoppers, wells, pump rooms and dredging machinery spaces
Structural arrangement of hoppers and supporting structures including:
• location, mass, fore and aft extent of the movable dredging equipment, for each loading condition
• calculations of the horizontal forces acting on the suction pipe and on the gallows
Closing arrangements, if any
Connection of dredging machinery with the hull structure
Split hopper dredger
Split hopper unit
Transverse sections through hoppers, wells, pump rooms and dredging machinery spaces
Structural arrangement of hoppers and supporting structures, including:
• location, mass, fore and aft extent of the movable dredging equipment, for each loading condition
• calculations of the horizontal forces acting on the suction pipe and on the gallows
Closing arrangements, if any
Connection of dredging machinery with the hull structure
Superstructure hinges and connections to the ship’s structure, including mass and location of the superstructure centre of gravity
Structure of hydraulic jack spaces
Deck hinges, including location of centre of buoyancy and of centre of gravity of each half-hull, mass of
equipped half-hull, half mass of spoil or water, supplies for each half-hull and mass of superstructures supported by each half-hull
Hydraulic jacks and connections to ship’s structure including operating pressure and maximum pressure of
the hydraulic jacks (cylinder and rod sides) and corresponding forces
Longitudinal chocks of bottom and deck
Transverse chocks
Hydraulic installation of jacks, with explanatory note
Ch 1, Sec 3, [2]
Replace sub-article [2.1] by:
2.1 Global hull and local strength
2.1.1
General
As a rule, the global hull girder strength and the local
strength are examined independently in the present Rules,
as follows:
• the longitudinal scantling of the hull girder and the
transversal scantling of the platform of catamaran are
examined on the basis of a maximum permissible stress
and a buckling check of elements contributing to the
global strength in the cases listed in Ch 4, Sec 2, [1.1.3]
• the local scantling is examined on the basis of local permissible stresses defined in relation to the type of local
loads applied and the type of structure element.
2.1.2 Particular case
When the global stress, in N/mm2, calculated according to
Ch 4, Sec 2 (excluding the cases of additional specific wave
hull girder loads defined in Ch 3, Sec 2, [6]) is greater than
0,35 Ry , where Ry is defined in Sec 2, [2.1.5] for steel structure and in Sec 2, [3.1.3] for aluminium structure, global
and local stresses are to be combined to check the structure
scantlings.
As a rule, the following requirements are to be fully applied:
• NR467 Steel Ships, Chapter 7, dedicated for ships
greater than 65 m, or
• Ch 4, App 2 of the present Rules.
For ship built in composite materials, a combination with
the global hull girder stresses for the local scantling analysis
may be carried out when deemed necessary by the Society,
on a case by case basis.
Delete sub-article [2.2].
4
Bureau Veritas
Amendments July 2015
NR600
Ch 2, Sec 3, Symbols
Delete the definition of σVM and replace the definition of R by:
: Minimum yield stress value, in N/mm2 to be
taken equal to:
• for steel structures: Ry as defined in Ch 1,
Sec 2, [2.1.5]
• for aluminium structures: Ry as defined in
Ch 1, Sec 2, [3.1.3].
R
Ch 2, Sec 3, [1.2]
Replace requirement [1.2.1] by:
1.2.1 General
As a rule, the global hull girder stresses and the local
stresses are examined independently.
However, according to the global stress level, the hull structure under local stresses may be checked taking into account
the global hull girder stresses (see Ch 1, Sec 3, [2.1.2]).
When a three dimensional model, simultaneously loaded
by global external loads and by local loads, is submitted to
the Society by the designer, the checking criteria are to be
in accordance with [2.3].
Ch 2, Sec 3
Replace Article [2] by:
2
• for analyse through a three dimensional structure
beam or finite element model: σvmam
Steel and aluminium alloy structures
2.1
2.1.1
where:
Permissible stresses under global loads
σlocam , τlocam : Local permissible stresses, in N/mm2,
defined in (new) Tab 4
General
When the global hull girder strength is examined as
required in Ch 4, Sec 2, [1.1.3], the permissible global
stresses for platings, secondary and primary stiffeners, and
the safety factors for the buckling check of the structure submitted to global loads are defined in (new) Tab 1.
2.2
2.2.1
When finite element model is used, typical mesh size is
to be equal to spacing of secondary stiffeners.
Permissible stresses under local loads
Plating and secondary stiffeners
b) Buckling of associated plating of primary stiffeners
Primary stiffeners
a) Bending and shear stresses of primary stiffeners
The primary stiffeners check submitted to local loads, in
relation to the type of structure element and the type of
local loads, is to be carried out taking into account the
following permissible stresses:
• for analyse through an isolated beam calculation:
σlocam and τlocam
Amendments July 2015
: Local permissible Von Mises equivalent
stresses, in N/mm2, defined in (new) Tab 4.
When very fine mesh is used, criteria defined in NR467
Steel Ships, Pt B, Ch 7, Sec 3, [4.4.3] may be used, taking into account σMASTER equal to the local permissible
σvmam.
The permissible local stresses for platings and secondary
stiffeners check submitted to local loads, in relation to the
type of structure element and the type of local loading, are
defined in (new) Tab 2 and (new) Tab 3.
2.2.2
σvmam
Bureau Veritas
Depending on the compressive stress level in the
attached plating induced by the bending of primary stiffener under local loading cases, it may be necessary to
check the buckling of the attached plating along the primary stiffener span.
In this case, the buckling of the attached plating is to
comply with:
σc > SFbuck σac
where:
σc
: Critical buckling stress of associated plating
as defined in Ch 4, App 1, [2]
5
NR600
σac
: Actual compressive stress in the associated
plating induced by local loads, to be taken
equal to:
• for external sea pressures and internal
loads and for flooding loads calculation:
σac + 0,1R for primary stiffeners not
contributing to the global stress
σac + 0,35R for primary stiffeners
contributing to the global stress
• for the other loading cases: σac
R
: Minimum yield stress value of material as
defined in Ch 2, Sec 3
SFbuck
: Safety factor defined in (new) Tab 4.
2.3
Checking criteria
It is to be checked that the stresses deduced from the model
are in compliance with the following criteria:
R
σ VM ≤ -----SF
σ c ≥ SF buck σ
where:
σVM
: Von Mises equivalent stresses, in N/mm2,
deduced from the model
σc
: Critical buckling stresses of associated platings,
in N/mm2, calculated as defined in Ch 4, Sec 1,
[2]
Permissible stresses of primary stiffeners under global and local loads
2.3.1
2.3.2
σ
: Actual compressive stress in the associated platings in N/mm2, deduced from the model calculation
SF
: Safety factor to be taken equal to 1,25
SFbuck
: Safety factor defined in (new) Tab 4.
General
The requirements of this Article apply to the structure check
of primary stiffeners analysed through a three-dimensional
structural beam or a finite element model, loaded simultaneously by global loads (as defined in Ch 3, Sec 2, [4] and
Ch 3, Sec 2, [5]) and by local loads induced by external sea
pressures and internal loads (as defined in Ch 3, Sec 3, [2]
and Ch 3, Sec 3, [3]).
As a rule, dynamic loads defined in Ch 3, Sec 3, [3], testing
loads and flooding loads defined in Ch 3, Sec 4, [5] and
Ch 3, Sec 4, [6] need not be taken into account when combining local and global loads.
When finite element model is used, typical mesh size is to
be equal to spacing of secondary stiffeners.
When very fine mesh is used, criteria defined in NR467
Steel Ships, Pt B, Ch 7, Sec 3, [4.4.3] may be used, taking
into account σMASTER equal to the permissible σVM defined
above.
Ch 2, Sec 3
Replace Table 1 and Table 2 by the following Table 1 to Table 4:
T4 :
Table 1 : Permissible global stresses and buckling safety factors for platings,
secondary and primary stiffeners under global loads
Type of structure element
Type of stress and
safety factor
Material
Steel
Aluminium
Plating
Secondary stiffeners
Primary stiffeners
σglam (1)
0,60 R
τglam (1)
0,40 R
Plating
SFbuck (2)
1,35
1,35
Secondary stiffeners
SFbuck (2)
1,45
1,30
Primary stiffeners
SFbuck (2)
1,25
1,15
(1)
(2)
6
Permissible stresses may be increased by 15% for:
• high speed ship when the actual global stresses are calculated with the moment in planing hull defined in Ch 3, Sec 2, [6.1]
• swath when the actual global stresses are calculated with the moment acting on twin-hull defined in Ch 3, Sec 2, [6.2.2]
Permissible buckling safety factor may be decreased by 15% for:
• high speed ship when the actual global stresses are calculated with the moment in planing hull defined in Ch 3, Sec 2, [6.1]
• swath when the actual global stresses are calculated with the moment acting on twin-hull defined in Ch 3, Sec 2, [6.2.2].
Bureau Veritas
Amendments July 2015
NR600
T5 :
Table 2 : Permissible local stresses for platings under local loads
Permissible value σlocam
Type of loading
Type of plating
Type of framing
Plating not contributing to the global
strength
transverse
Plating contributing to the global
strength
0,70 R
transverse
0,50 R
0,45 R
longitudinal
0,60 R
0,65 R
0,75 R
0,75 R
Flat forward bottom plating
0,90 R
0,90 R
all type of framing
transverse
0,75 R
longitudinal
0,85 R
transverse
0,60 R
0,45 R
longitudinal
0,70 R
0,70 R
Collision bulkhead
all type of framing
0,70 R
0,70 R
All platings
all type of framing
0,85 R
0,90 R
Plating contributing to the global
strength
Testing loads
0,70 R
All type of plating
Plating not contributing to the global
strength
Flooding loads
Aluminium
structure
longitudinal
Local external and internal pressures
Bottom slamming for high speed ship,
or bottom impact pressure for flat bottom forward area, or side shell impact
Steel
structure
0,80 R
Note 1: Platings contributing to the global strength are continuous platings located between 0,3 L and 0,7 L and continuous platings
located in platform of multihull.
T6 :
Table 3 : Permissible local stresses for secondary stiffeners under local loads
Type of loading case
Local external and internal pressures
Bottom slamming for high speed ship,
or bottom impact pressure for flat bottom forward area, or side shell impact
Flooding loads
Type of structure element
Type of stress
Permissible value
Stiffener contributing to the global strength
σlocam
0,55 R
Stiffener not contributing to the global strength
σlocam
0,80 R
All stiffeners
τlocam
0,45 R
σlocam
0,75 R
τlocam
0,50 R
σlocam
0,90 R
τlocam
0,55 R
Stiffener contributing to the global strength
σlocam
0,60 R
Stiffener not contributing to the global strength
σlocam
0,85 R
All stiffeners
τlocam
0,45 R
σlocam
0,65 R
τlocam
0,40 R
σlocam
0,85 R
τlocam
0,50 R
All stiffeners
Flat forward bottom stiffener
Stiffener on collision bulkhead
Testing loads
All stiffeners
Note 1: Stiffeners contributing to the global strength are continuous longitudinal stiffeners located between 0,3 L and 0,7 L and continuous transverse stiffeners located in platform of multihull.
Amendments July 2015
Bureau Veritas
7
NR600
T7 :
Table 4 : Permissible local stresses for primary stiffeners under local loads
Type of loading case
Type of structure element
Bottom and side girders contributing to the
global strength
Local external and internal pressures
Other primary stiffeners contributing to the
global strength
Primary stiffener not contributing to the
global strength
Bottom slamming for high speed ship, or
bottom impact pressure for flat bottom
forward area
All primary stiffeners
Primary stiffener on collision bulkhead
Flooding loads
Primary stiffener contributing to the global
strength
Primary stiffener not contributing to the
global strength
Testing loads
All loading cases
All primary stiffeners
Associated plating of primary stiffeners
Type of stress and
safety factor
Permissible value
σlocam
0,45 R
τlocam
0,40 R
σvmam
0,45 R
σlocam
0,55 R
τlocam
0,45 R
σvmam
0,55 R
σlocam
0,80 R
τlocam
0,45 R
σvmam
0,80 R
σlocam
0,90 R
τlocam
0,50 R
σvmam
0,90 R
σlocam
0,70 R
τlocam
0,50 R
σvmam
0,70 R
σlocam
0,60 R
τlocam
0,50 R
σvmam
0,60 R
σlocam
0,85 R
τlocam
0,50 R
σvmam
0,85 R
σlocam
0,90 R
τlocam
0,50 R
σvmam
0,90 R
SFbuck (steel)
1,45
SFbuck (aluminium)
1,30
Note 1: Primary stiffeners contributing to the global strength are primary continuous stiffeners located between 0,3 L and 0,7 L and
primary continuous transverse stiffeners located in platform of multihull.
Ch 2, Sec 3, [3.1.1]
Replace the beginning of requirement [3.1.1] by:
3.1.1
Principle of design review
The design review of composites structures is based on
safety factors defined as the ratio between:
• the theoretical breaking stresses of the elementary layers
of the full lay-up laminates (defined in NR546 Composite Ships, Section 5), and
• the critical buckling of the whole laminate (defined in
NR546 Composite Ships, Section 6),
and the applied stresses (calculated on the basis of the
present rules).
8
Bureau Veritas
Amendments July 2015
NR600
Ch 3, Sec 1, [3.1.1]
Replace the definition of p, in the 2nd item of the bulleted list in item a), by:
• p = pint − 10 (TB − h1 − z)
with:
TB − h1 − z ≥ 0
Ch 3, Sec 2, Symbols
Replace the 2nd paragraph in the definition of CB by:
As a rule, the value of CB is to be taken at least
equal to 0,4 in the present Section
Ch 3, Sec 2, [4.1.4]
Add the following item c) at the end of the alphanumeric list in requirement [4.1.4]:
c) Hogging and sagging conditions for catamaran and
swath considered as cargo ship
For catamaran and swath considered as cargo ship for
which the global strength in head sea condition is examined according to Ch 4, Sec 2, [4.2.1], the values of
bending moments and shear forces calculated according
to item a) and item b) are to be reduced by 50%.
Ch 3, Sec 2, [5.2]
Replace requirement [5.2.1] by:
5.2.1 Wave loads in head sea condition
The bending moments and shear forces induced by wave in
head sea condition are calculated according to [5.2.3], considering the following hypotheses:
• the forward and aftward perpendiculars of the hull are
on the crest (sagging conditions), or
• the forward and aftward perpendiculars of the hull are
on the trough (hogging conditions).
The values obtained are to be applied along the ship from
0,25 L to 0,75 L.
When deemed necessary by the Society, a distribution of
the bending moments and shear forces as defined in NR467
Steel Ships, Ch 5, Sec 2, [3] may be considered.
Ch 3, Sec 2, [5.2.3]
Replace the formulae of MWH, QWH, MWS and QWS by:
MWH = 0,20 n CW LW2 BWL CB
MWS = − 0,25 n CW LW2 BWL CB
QWH = 0,65 n CW LW BWL CB
QWS = − 0,75 n CW LW BWL CB
Ch 3, Sec 2, [5.3.2]
Replace the formulae of MWQH, QWQH, MWQS and QWQS by:
MWQH = n CWQ LW2 BWL CB
MWQS = − n CWQ LW2 BWL CB
QWQH = 1,60 n CWQ LW BWL CB
QWQS = − 1,60 n CWQ LW BWL CB
Amendments July 2015
Bureau Veritas
9
NR600
Ch 3, Sec 2, [6.1.1]
Add the following paragraph at the end of requirement [6.1.1]:
As an alternative to items a) and b), the Society may accept
the values of hull girder bending moment induced by still
water plus wave loads plus impact loads in the fore body
area derived from direct calculation or obtained by model
test.
Ch 3, Sec 2, [6.2.1]
Replace the formula of F’ in item b) of the alphanumeric list by:
1, 8 gΔdA
F' = ---------------------------p ⋅ n
δ1 + δ2
Replace the formula of F’ in item c) of the alphanumeric list by:
1, 5 gΔ ( 0 , 2L WL )A p
-⋅n
F' = -----------------------------------------------δ1 + δ2
Ch 3, Sec 3, [2.2.1]
Replace the second formula of PS in item “for side shell structure:” by:
0, 8B
P S = ρg  T + ----------------1 sin A R – z


2
Replace the definition of Pdmin and h2 and add the definition of B1 as follows:
Pdmin
h2
-
: Minimum sea pressure on exposed deck, in
kN/m2, as defined in [2.2.2], in the considered
section, with ϕ1 and ϕ3 taken equal to 1,00
h2 = 0
with:
: Parameter, in m, equal to:
• for monohull:
BWL
: Waterline breadth, in m, at full load
waterline at considered section (see
Fig 2)
Bi
: Distance, in m, between internal
side shells at waterline considered
transverse section (see Fig 2)
h2 = 0
• for catamaran:
-
for bottom, internal side shell and platform bottom:
B WL ( T + h 1 )C B
h 2 = -----------------------------------Bi
B1
: Reference breath to be taken equal to:
• BWL
for monohull
h2 = 0
• BE + BWL
for catamaran
• for swath:
• BE + BST
for swath
-
-
for external side shell:
for bottom, internal side shell and platform bottom:
B ST ( T + h 1 )C B
h 2 = ---------------------------------Bi
10
for external side shell:
Bureau Veritas
with:
BWL , BE , BST : Breaths defined in Ch 1, Sec 1,
[4.2] or in the considered Section
when deemed necessary.
Amendments July 2015
NR600
Ch 3, Sec 3, [2.2.2]
Replace the definitions of ϕ2 and pdmin by:
ϕ2
: Coefficient taken equal to:
pdmin
L WL
- ≥ 0, 42
ϕ 2 = --------120
: Minimum sea pressure on deck, in kN/m2,
equal to:
• from aft part to 0,70 LWL:
pdmin = 17,5 n ϕ1 ϕ2 ϕ3 > 5
• from 0,70 LWL to fore part:
pdmin = 19,6 n ϕ1 ϕ2 ϕ3 > 7
Ch 3, Sec 3, [3.1.1]
Replace the second paragraph of requirement [3.1.1] by:
These impacts are considered as locally distributed like a
water column of 0,6 m diameter and is to be applied above
the minimum draught operational for:
• the side shell and bulwarks: on all the length of the ship
• the lowest tier of side walls of superstructure, where the
side wall is in the plane of the side shell.
Ch 3, Sec 3, [3.1.3]
Replace the definition of Ci by:
Ci
: Dynamic load distribution factor defined in
Tab A
Add the following Note 1 at the end of requirement [3.1.3]:
Note 1: When the platform of multihull is extended up to the fore
float, the fore areas 5 and 6 are to be considered as area 7 (see
Fig 3).
Ch 3, Sec 3
Insert the following Table A:
T8 :
Table A : Dynamic load distribution factor Ci
for catamaran
Areas
(see Fig 3)
from T to
(T + 1) m
from ( T + 1) m
to (T + 3) m
above
(T + 3) m
Area 5
80
60
30
Area 6
80
60
30
Area 7
120
90
50
Amendments July 2015
Bureau Veritas
11
NR600
Ch 3, Sec 3, [3.2.3]
Replace the bullet list in item a) of [3.2.3] by:
• general case:
• non propelled units:
T Fmin
119 – 2300 ----------L WL
C 1 = ----------------------------------------T Fmin
78 + 1800 ----------L WL
T Fmin
119 – 2300 ----------L WL
- + 0, 09
C 1 = ----------------------------------------T Fmin
156 + 3600 ----------L WL
with 0 < C1 ≤ 1
with 0 < C1 ≤ 0,59
where:
TFmin
: Minimum forward draught, in m
Ch 3, Sec 3, [3.3.3]
Add the following Note 1 at the end of the definition of Sr :
Note 1: For catamaran, Δ is to be taken as half of the total displacement.
Ch 3, Sec 3
Replace Table 3 by:
T9 :
Table 3 : Value of K1
Location
K1
from aft part to 0,25 LWL
0,60
from 0,25 LWL to 0,70 LWL
0,90
from 0,70 LWL to 0,85 LWL
1,00
from 0,85 LWL to fore part
0,75
Ch 3, Sec 4
Replace Table 2 by:
T10 :
Table 2 : Value of KV
Location
KV
from aft part to 0,25 LWL
1,00
from 0,25 LWL to 0,70 LWL
1,20
from 0,70 LWL to 0,85 LWL
1,55
from 0,85 LWL to fore part
1,85
Ch 4, Sec 3, Symbols
Replace the definition of λ by:
λ
12
: Corrosion coefficient taken equal to:
• λ = 1,10 for steel plating
• λ = 1,05 for aluminium plating
Bureau Veritas
Amendments July 2015
NR600
Ch 4, Sec 3, [1.2]
Delete requirement [1.2.3].
Ch 4, Sec 3, [2.2]
Replace requirements [2.2.2] and [2.2.3] by:
2.2.2
• bottom impact pressure for flat bottom forward area and for bottom slamming pressure for high speed ship in planning hull:
General case
As a rule, the thickness of plating subjected to lateral pressure is to be not less than the value obtained, in mm, from
the following formula:
p
t = 22, 4 λn p μs -------------σ locam
2.2.3
where:
p
: • local pressures (wave loads and internal
loads), in kN/m2, as defined in Ch 3, Sec 3
and Ch 3, Sec 4, or
• bottom impact pressure for flat bottom forward area, in kN/m2, as defined in Ch 3, Sec
3, [3.2], or
• bottom slamming pressure for high speed
ship with planning hull, psl, in kN/m2, as
defined in Ch 3, Sec 3, [3.3]
np
: Coefficient to be taken equal to:
np = 0,77 for transversely framed steel
plating
-
np = 1,00 for aluminium plating, whatever the frame system
-
np = 0,85 for aluminium plating.
Plating on side shell under impact pressure
p ssmin
t = 22, 4 C f λn p μs ------------σ locam
where:
pssmin
: Impact pressure on side shell and, for multihull,
on platform bottom, in kN/m2, as defined in
Ch 3, Sec 3, [3.1.2] and/or Ch 3, Sec 3, [3.1.3]
Cf
: Coefficient equal to:
• if  ≤ 0,6 (1 + s):
Cf = 1
• if  > 0,6 (1 + s):
np = 0,67 for longitudinally framed steel
plating
-
np = 0,77 for steel plating
As a rule, the thickness of the side shell plating subjected to
impact pressure is to be not less than the value obtained, in
mm, from the following formula:
• local pressures (wave loads and internal
loads in tanks):
-
-
Cf = (1 + s)−1/2
np
: Coefficient to be taken equal to:
• np = 0,77 for steel plating
• np = 0,85 for aluminium plating.
Delete requirement [2.2.5].
Ch 4, Sec 4, Symbols
Replace the definition of λ by:
λ
: Corrosion coefficient to be taken equal to:
• steel structure:
- λ = 1,1 for stiffener located in a dry
compartment
- λ = 1,2 for stiffener located in a liquid
compartment
• aluminium structure:
λ = 1,05.
Amendments July 2015
Bureau Veritas
13
NR600
Ch 4, Sec 4, [1.3]
Replace requirement [1.3.1] by:
1.3.1
General case and attached plating width
As a rule, the inertia, section modulus and shear section of
secondary stiffeners are to be determined by direct calculation.
The width bp , in m, of the attached plating to be taken into
account for the inertia and section modulus calculations are
to be taken equal to the spacing between stiffeners, or half
the spacing between stiffeners when the plating extends on
one side only.
Ch 4, Sec 4, [2.2.2]
Replace the formula of Z in the 1st item of the bullet list by:
2
ps
Z = 1000λC t ------------------mσ locam
Replace the formula of Z in the 2nd item of the bullet list by:
2
p 1 s
Z = 1000λC t --------------------m 1 σ locam
Replace the definition of Ct by:
Ct
:
Reduction coefficient defined as follows:
• for wave loads and internal pressure cases:
• for the other loading cases:
Ct = 1,00
s
C t = 1 – -----2
Ch 4, Sec 4, [2.2]
Delete requirement [2.2.6].
Ch 4, Sec 5, Symbols
Replace the definition of λ by:
λ
: Corrosion coefficient taken equal to:
• λ = 1,10 for steel structure
• λ = 1,05 for aluminium structure.
Ch 4, Sec 5, [1.2.2]
Replace item d) of the alphanumeric list by:
d) Checking criteria
It is to be checked that the equivalent stresses σVM
deduced from the model are in compliance with Ch 2,
Sec 3.
Ch 4, Sec 5, [1.3.1]
Add the following paragraph at the end of requirement [1.3.1]:
It is to be checked that the equivalent stresses σVM deduced
from the finite element model calculation are in accordance
with the permissible stresses defined in Ch 2, Sec 3.
14
Bureau Veritas
Amendments July 2015
NR600
Ch 4, Sec 5, [2]
Replace the title of Article [2] by:
2
Primary stiffener scantling analysed
by isolated beam calculation under
local loads
Ch 4, Sec 5, [2.1]
Replace requirement [2.1.1] by:
2.1.1 Scantling
The local primary stiffener scantling is to be carried out as
defined for the secondary stiffener scantling in Sec 4,
excepted otherwise specified, considering successively the
different loads sustained by the primary stiffener defined in
[1.2.1], item b) and the relevant permissible stresses defined
in Ch 2, Sec 3.
The corrosion coefficient λ considered in the formulae of
section modulus and shear area is to be taken equal to the
value given in the present section.
The minimum section modulus for secondary stiffeners
defined in Sec 4, [2.2.1] is not applicable to primary stiffeners.
Ch 4, Sec 5, [2.1.2]
Replace the last paragraph of item a) in the alphanumeric list by:
The buckling of the attached plating is to be checked
according to the criteria defined in Ch 2, Sec 3.
Ch 4, Sec 5, [3.3]
Replace requirement [3.3.2] by:
3.3.2 For steel structure, the moment of inertia I, in cm4,of
stiffeners of web of primary supporting members is to be not
less than the value obtained from the following formula:
tw
: Web thickness, in mm, of the primary supporting member
ReH
: Minimum yield stress, in N/mm2, as defined in
Ch 1, Sec 2, of the material of the web of primary supporting member.
R eH
I = 11, 4 st w ( 2, 5  – 2s ) --------235
2
2
where:

s
: Length, in m, of the web stiffener (see Fig 5)
: Spacing, in m, of web stiffeners (see Fig A)
For aluminium structure, the moment of inertia I, in cm4,of
stiffeners of web of primary supporting members is to be as
defined in NR561 Aluminium Ships, Sec 4, [4.3].
Ch 4, Sec 5
Insert the following Figure A:
Figure A : Web stiffeners for
primary supporting members
s
Amendments July 2015
Bureau Veritas
15
NR600
Ch 4, Sec 6, [4.1.1]
Replace the three formulae of tb by:
Sf 1 σ 1
t b = -----------------------0, 4h 2 R eH
Sf 2 σ 2
t b = -----------------------0, 4h 1 R eH
tb = Min (t1 ; t2 )
Replace the definition of Sf1 , Sf2 and σ1 , σ2 by:
Sf1 , Sf2 : Flange sections, in mm2,of member 1 and member 2, respectively
σ1 , σ2
: Actual normal stresses, in N/mm2, in member 1
and member 2, respectively
Replace the definition of Ry by the following definition of ReH :
ReH
: Minimum yield stress, in N/mm2, as defined in
Ch 1, Sec 2, of the material of the web of primary supporting member.
Ch 4, Sec 6, [4.1.2]
Replace the formula of tb by:
Sf 1 σ 1
t b = -----------------------0, 4h 2 R eH
Add the following definition of ReH :
ReH
: As defined in [4.1.1].
Ch 4, Sec 7, [2.1.1]
Replace the definition of σE by:
σE
: Euler column buckling stress of the pillar, in
N/mm2, to be obtain by the following formula:
I
σ E = π 2 E ---------------2- 10 –4
A ( f )
Ch 4, Sec 7, [2]
Insert the following sub-article [2.3]:
2.3
Pillars in tanks
2.3.1 Where pillars are submitted to tensile stress due to
internal pressure in tank, the tensile stress in the pillar and
the shear stresses in the connection elements between the
pillar and the supported structure of the tank are to be lower
than the permissible stresses defined in Ch 2, Sec 3, [2.2.2].
As a rule, brackets are to be provided at the connection of
the pillar ends with the tank structure.
Doubling plate are not to be used at pillar ends.
Pillars in tanks are not to be of hollow profile type.
Chapter 4
Add the following Appendix 2:
16
Bureau Veritas
Amendments July 2015
NR 600, Chap 4, App 2
APPENDIX 2
HULL SCANTLING CHECK WITH LOCAL AND
GLOBAL STRESSES COMBINATION CRITERIA
Symbols
R
P
σA
μ
: Minimum yield stress of the material, in N/mm2,
used for the scantling criteria as defined in
Ch 1, Sec 2
: Local pressures and forces defined in:
• for external pressure: Ch 3, Sec 3, [2]
• for internal pressures: Ch 3, Sec 4, [3] and
Ch 3, Sec 4, [4]
: Actual overall stress, in N/mm2, calculated
according to Sec 2 for hull girder loads defined
in Ch 3, Sec 2, excluding the additional specific
wave hull girder loads defined in Ch 3, Sec 2,
[6]
: Aspect ratio coefficient of the elementary plate
panel, equal to:
s 2
s
μ = 1 ,21 1 + 0 ,33  -- – 0 ,69  

m
1
2
Plating scantling
2.1
2.1.1 The plating thickness under local loads, in mm, is to
be greater than the minimum value defined in Sec 3, [2.2.1]
and the following value:
P
t = 22, 4λμsn p ------σ ad
where:
s
: Length, in m, of the shorter side of the plate
panel
np
: Coefficient to be taken equal to:
• Steel:
without being greater than 1.
: End stiffener condition coefficient, defined in
Ch 4, Sec 4, [1.4].
General
-
plate transversely framed: np = 0,77
-
1.1.1 The requirements of this Appendix apply for the
check of hull structure element, built in steel or aluminium
material, where overall stresses and local stresses are combined according to Ch 1, Sec 3, [2.1.2].
λ
Local stresses
: Corrosion coefficient to be taken equal to:
λ = 1,1
• for aluminium plating: λ = 1,05
: Permissible stress, in N/mm2, as given in Tab 1.
Table 1 : Permissible stress, in N/mm2
Plate longitudinally
framed
Aluminium
(1)
Bureau Veritas
Plate transversely
framed
σ ad = 0, 75λ LT R
Steel (1)
1.3.1 The local stresses to take into account in the present
Appendix are those induced by the local pressures and
forces defined in:
• for external pressure: Ch 3, Sec 3, [2]
• for internal pressures: Ch 3, Sec 4, [3] and Ch 3, Sec 4,
[4]
Amendments July 2015
Whatever the frame system: np = 1
• for steel plating:
σad
Overall stresses
1.2.1 The actual overall stresses are to be determined
according to Sec 2 for hull girder loads defined in Ch 3, Sec
2, excluding the additional specific wave hull girder loads
defined in Ch 3, Sec 2, [6].
As a rule, the values of the still water bending moments to
take into account for the calculation of the actual overall
stresses are to be given by the designer.
1.3
plate longitudinally framed: np = 0,67
• Aluminium:
1.1
1.2
-
σ ad =
2
2
0, 55R – ( 1, 1σ A )
σ ad = 0, 75R – σ A
For plate longitudinally framed:
λ LT =
σ 2
σ
1 –  -----A- –  0, 25 -----A-
 R 
R
For plate transversely framed:
σ
λ LT = 1 –  -----A-
 R
17
NR 600, Chap 4, App 2
3
Secondary stiffener scantling
3.1
3.1.1 The section modulus of secondary stiffener under
local loads, in cm3, is to be greater than the minimum value
defined in Sec 4, [2.2.1] and the following value:
s
: Spacing, in m, of the primary stiffener under
consideration

: Span, in m, of the primary stiffener under consideration
σad
: Permissible local scantling stress, in N/mm2, to
be taken equal to:
• for bottom and side girder: σad = 0,80R − σA
2
1000λC t Ps
Z = --------------------------------mσ ad
• for other primary stiffeners: σad = 0,85R − σA
where:
λ
The shear are Ash, in cm2 is to be not less than the values
defined in Sec 5, [2].
: Corrosion coefficient to be taken equal to:
• for steel structure:
4.1.2
-
1,1 for stiffener located in a dry compartment
-
1,2 for stiffener located in a liquid compartment
• for aluminium structure: 1,05
s
Ct
Buckling check of the associated plating
The associated plating of the primary stiffener is to be
checked according to the following criterion:
σc ≥ SF (σA + σloc)
where:
: Spacing, in m, of the secondary stiffener under
consideration
σc
: Reduction coefficient defined as follows:
σloc
: Critical buckling stress of the associated plating,
in N/mm2, calculated as defined in Sec 1, [2]
: Actual local stress in the associated plating, in
N/mm2
s
C t = 1 – -----2
SF

: Span, in m, of the secondary stiffener under
consideration
σad
: Permissible local scantling stress, in N/mm2, to
be taken equal to:
• for steel structure:
1,45
• for aluminium structure: 1,30
4.2
σad = 0,85R − σA
: Safety factor to be taken equal to:
Primary stiffener checked by three
dimensional structural model
The shear are Ash, in cm2 is to be not less than the values
defined in Sec 4, [2.2].
4.2.1
4
For primary structure analysed under local loads by three
dimensional structural model, it is to be checked that the
Primary stiffener scantiling
Checking criteria
equivalent Von Mises stress σVM, in N/mm2, is to comply
4.1
4.1.1
Primary stiffener checked by isolated
beam calculation
with the following criterion:
σVM ≤ R/SF
Section modulus
where:
The section modulus of primary stiffener under local loads,
in cm3, is to be greater than the following value:
: Corrosion coefficient to be taken equal to:
λ = 1,2
• for aluminium: λ = 1,05
18
2
N/mm2
where:
• for steel:
2
( σ A + σ loc ) + 3τ loc
σloc, τloc : Actual local bending and shear stresses, in
2
1000λPs
Z = ---------------------------mσ ad
λ
σ VM =
SF
: Safety factor to be taken equal to 1,25.
4.2.2
Buckling check of the associated plating
The associated plating of the primary stiffener is to be
checked according to [4.1.2].
Bureau Veritas
Amendments July 2015
NR600
Ch 5, Sec 1, Symbols
Replace the definition of μ by:
μ
: Aspect ratio coefficient of the elementary plate
panel, equal to:
s 2
s
μ = 1 ,21 1 + 0 ,33  -- – 0 ,69 - ≤ 1
 

Ch 5, Sec 1 [2.2.1]
Replace the definition of f by:
f
: Coefficient equal to:
f = 0,076 LWL − 0,6
Ch 5, Sec 1
Replace Table 4 by:
Table 4 : Minimum lateral pressure
for superstructures and deckhouses
T1 :
Type of wall
Unprotected front
wall
Location
lower tier
x/LWL ≥ 0,70
21 n
x/LWL < 0,70
15 n
upper tiers
10 n
lower tier
Protected front wall
10 n
second tier
7n>5
5 (1)
upper tiers
lower tier
Side walls
x/LWL ≥ 0,70
19,6 n ϕ2
x/LWL < 0,70
17,6 n ϕ2
second tier
7n>5
5 (1)
upper tiers
Unprotected aft wall
Protected aft wall
Note 1:
n
:
ϕ2
:
lower tier
pmin
x/L ≤ 0,25
10 n
x/L > 0,25
7n>5
upper tier
5 (1)
anywhere
5 (1)
Navigation coefficient defined in Ch 1, Sec 1,
[3.1.1] or Ch 1, Sec 1, [3.2.1]
Coefficient taken equal to:
L WL
- ≥ 0, 42
ϕ 2 = --------120
(1)
pmin may be taken equal to 2,5 kN/m2 when:
z > T + 0,5 B AR + h1
with:
z
: Z co-ordinate, in m, of the calculation
point as defined in Ch 3, Sec 1, [4]
T
: Moulded draught, in m, as defined in Ch 1,
Sec 1, [4.4]
h1
: Ship relative motion, in m, in the considered longitudinal part of the ship as
defined in Ch 3, Sec 3, [2.2.1]
: Roll amplitude, in rad, as defined in Ch 3,
AR
Sec 4, [2.1.7].
Amendments July 2015
Bureau Veritas
19
NR600
Ch 5, Sec 1, [2.2]
Add the following requirement [2.2.2]:
2.2.2 In addition to [2.2.1], the side shell impact is to be
determined according to Ch 3, Sec 3, [3.1] for the lowest
tier of side walls of superstructure, where the side wall is in
the plane of the side shell.
Ch 5, Sec 1, [3.2]
Replace requirements [3.2.1] and [3.2.2] by:
3.2.1 As a rule, the thickness t of plating, in mm, is to be
not less than the following value:
p
t = 22, 4 λn p μs -------------- ≥ t min
σ locam
where:
p
: Lateral pressure, in kN/m2, as defined in [2.2.1]
np
: Coefficient to be taken equal to:
• np = 0,67 for longitudinally framed steel
plating
• np = 0,77 for transversely framed steel plating
• np = 1,00 for aluminium plating, whatever
the frame system
λ
: Corrosion coefficient taken, in the present Section, equal to:
: Minimum thickness as defined in [3.2.2].
tmin
For the lowest tier of side walls of superstructure, where the
side wall is in the plane of the side shell, the thickness of
side wall plating is also to be not less than the value given
in Ch 4, Sec 3, [2.2.3].
For decks sheathed with wood, the thickness t may be
reduced by 10%.
3.2.2
Minimum thickness
As a rule, the minimum thickness tmin , in mm, is to be taken
equal to:
• for steel structure: tmin = 2,6 + 0,045 LWL k1/2
• for aluminium structures: tmin = 1,35 LWL1/3 k1/2
• λ = 1,05 for steel plate
• λ = 1,00 for aluminium plate
without being less than 3,5 mm for rolled products and
2,5 mm for extruded products.
Ch 5, Sec 1, [4.2.1]
Add the following paragraph at the end of requirement [4.2.1]:
For the lowest tier of side walls of superstructure, where the
side wall is in the plane of the side shell, the section modulus of side wall ordinary stiffeners is to be also not less than
the value given in Ch 4, Sec 4, [2.2.3].
Ch 5, Sec 1, [4.2]
Replace requirement [4.2.2] by:
4.2.2
Minimum section modulus
As a rule, the minimum section modulus Zmin , in cm3, of
secondary stiffeners calculated according to the present
Section is to be taken equal to:
• for steel stiffener: Zmin = 3,5 + 0,15 LWL k
• for aluminium stiffeners: Zmin = 1,7 LWL1/3 k
20
Bureau Veritas
Amendments July 2015
NR600
Ch 5, Sec 1, [5.1.1]
Insert the following paragraph after the 1st paragraph in requirement [5.1.1]:
For the lowest tier of side walls of superstructure, where the
side wall is in the plane of the side shell, the check of primary stiffeners under side shell impact need not be carried
out.
Ch 5, Sec 1, [7.3.2]
Replace the first paragraph of requirement [7.3.2] by:
The windows and sidescuttles scantling assessment methodology defined in this sub-article is equivalent to Standard
ISO 21005:2004.
Ch 5, Sec 1, [7.3.4]
Replace the definition of Rm by:
Rm
: Guaranteed minimum flexural strength, in
N/mm2, of material used specified by the manufacturer.
When this value is not available, Rm may be
taken, at a preliminary design stage, equal to:
• for glass thermally tempering (toughened):
• for glass chemically toughened:
Rm = 200 N/mm2
• for polymethacrylate (PMMA):
Rm = 100 N/mm2
• for polycarbonate:
2
Rm = 80 N/mm2
Rm = 150 N/mm
Ch 5, Sec 2, [8.1.1]
Insert the following paragraph after the 1st paragraph in requirement [8.1.1]:
For rudder built in aluminium alloys, the material factor k1
to be taken into account in the scantling formulae is to be
taken equal to:
235
k 1 = ---------Ry
where:
: Minimum yield stress of aluminium, in N/mm2,
Ry
defined in Ch 1, Sec 2, [3.1.3].
Delete “in aluminium alloys or” in the last paragraph of requirement [8.1.1].
Ch 5, Sec 2, [12.1.2]
Replace the formula of z and the formula of Ash for the case “if s < 0,6” and the definition of ps in item
b) of the alphanumeric list by:
-
if s < 0,6:
ps
600sp ssmin (  – 0, 3 )
z = ------------------------------------------------σ locam
-
: Sea pressure on side shell as defined in Ch 3,
Sec 3, [2.2.1], in kN/m2, calculated at midheight of the stay
if s < 0,6:
6sp ssmin
A sh = ------------------σ locam
Amendments July 2015
Bureau Veritas
21
NR600
Ch 5, Sec 4, Table 1
Insert the row “Ship for dredging activity” and add the row “Offshore patrol vessel” in Table 1, as follows:
Table 1: List of articles in relation to the
service notation or additional service feature
T2 :
Service notation or
additional service feature
Ship for dredging activity
Offshore patrol vessel
Reference
of Article
Reference
Chapter in
NR467, Part D
(new) [13]
13
[22]
21
Ch 5, Sec 4
Insert the following Article [13]:
b) Hopper dredgers and hopper units floors
13 Ship for dredging activity
The scantling of floors of ships with open wells fitted
with bottom doors is to be obtained from a direct calculation according to:
13.1 Application
13.1.1 General
Ships for dredging activity as defined in [13.1.2] are to comply with the requirements of the present Article and with the
requirements of NR467 Steel Ships, Pt D, Ch 13, Sec 1,
where applicable.
13.1.2 Type of ship for dredging activity covered by
the present Rules
a) The present Rules apply to ship for dredging activity
within the following maximum length:
• up to 90 m for service notation dredger
• up to 65 m for service notations hopper dredger,
hopper unit, split hopper dredger and split hopper
unit
b) Ship group
The ship group “cargo ships” or “non-cargo ships” is to
be assigned as defined in Ch 1, Sec 1, [1.1.2].
As a general rule:
• ships with the service notation dredger may be considered as non-cargo ships
• ships with one of the service notations hopper
dredger, hopper unit, split hopper dredger or split
hopper unit may be considered as cargo ships.
• Ch 4, Sec 5, [1.2] for two- or three-dimensional
beam model, or
• Ch 4, Sec 5, [1.3] for finite element model,
taking into account the assumptions defined in NR467
Steel Ships, Pt D, Ch 13, App 1, [2].
The permissible local stresses for primary structure
check are defined in Ch 2, Sec 3, [2.2.2].
c) Other primary elements of hopper dredger and hopper
units
Strong beams at deck level, brackets for trunks and girders supporting the hydraulic cylinder in the hopper
spaces are to comply with the requirements defined in
NR467 Steel Ships, Pt D, Ch 13, App 1, [3] to NR467
Steel Ships, Pt D, Ch 13, App 1, [5].
13.2.3 Specific arrangements
Arrangements relating to suction pipes, chafing areas, reinforcements for grounding and bolted structure are to comply with the requirements defined in NR467 Steel Ships,
Pt D, Ch 13, Sec 2, [2.4] to NR467 Steel Ships, Pt D, Ch 13,
Sec 2, [2.7].
13.3 Design loads
13.2 Structure design principles
13.2.1 General
The general structure design principles are to comply with
the requirements defined in NR467 Steel Ships, Pt D,
Ch 13, Sec 2, [2.1].
13.2.2 Structure members in the area of the hopper
well
a) General
Longitudinal and transverse ship structures in the area of
the hopper well are to comply with the requirements
defined in NR467 Steel Ships, Pt D, Ch 13, Sec 2, [2.2]
and NR467 Steel Ships, Pt D, Ch 13, Sec 2, [2.3].
22
13.3.1 General
Design loads are to be determined for the various load
cases in the following two situations:
• navigation situation, considering the draught T and the
navigation coefficient n defined in Ch 1, Sec 1, [3.1.1]
• dredging situation, considering the dredging draught TD
and the navigation coefficient nD defined in Tab 7.
For dredgers made of bolted structure, the Society may
require the hull girder loads calculated with the maximum
length of the unit when mounted to be applied to each individual element.
Bureau Veritas
Amendments July 2015
NR600
T3 :
a) Still water load conditions
Table 7 : Coefficient nD in dredging situation
Operating area
nD
Associated HS,
in m
dredging within 8 miles from shore
1/3
HS < 1,5
dredging within 15 miles from
shore or within 20 miles from port
2/3
1,5 ≤ HS < 2,5
dredging over 15 miles from shore
1
HS ≥ 2,5
Note 1:
:
HS
As a rule, the vertical still water bending moments in
dredging situation in hogging and sagging conditions
are to be defined by the designer and are to be combined to the vertical wave bending moment defined in
item b).
b) Vertical wave bending moments and shear forces
• In addition to the vertical wave bending moments
MWH and MWS in navigation situation defined in Ch 3,
Sec 2, the vertical wave bending moments in dredging situation at any hull transverse section are to be
obtained, in kN⋅m, from the following formulae:
Maximum significant wave height, in m, for operating area in dredging situation, according to the
operating area notation assigned to the ship (see
NR467 Steel Ships, Pt A, Ch 1, Sec 2 [4.6.3]).
-
hogging conditions:
MWV, H, D = 190 nD C L2 B CB 10−3
13.3.2 Hull girder loads
-
MWV, S, D = − 110 nD C L2 B (CB + 0,7) 10−3
Where the hull girder strength of the ship is examined in
accordance with Ch 4, Sec 2, [1.1.3], the hull girder loads
are to be considered as follows:
where:
nD
a) General
The still water loads are to be as defined in Ch 3, Sec 2, [4].
QW, D = 30 nD C L B (CB + 0,7) 10−2
The values of bending moments and shear forces are to
be applied along the ship from 0,25 L to 0,75 L.
b) Still water load conditions for service notations hopper
dredger, hopper unit, split hopper dredger or split hopper unit
• homogeneous loading at maximum dredging
draught if higher than the maximum service draught
• partial loading conditions
• any specified non-homogeneous loading condition,
in particular where dredgers are fitted with several
hopper spaces
• navigation conditions with hopper space(s) filled
with water up to the load line
: Coefficient defined in Tab 7 depending on
the operating area, without being taken
greater than the coefficient n defined in Ch 1,
Sec 1, [3.1.1].
• In addition to the vertical wave shear force QW in
navigation situation defined in Ch 3, Sec 2, the vertical wave shear force in dredging situation at any hull
transverse section is to be obtained, in kN, from the
following formula:
Calculation of the still water bending moment and shear
force for any loading case corresponding to a special
use of the ship may be required by the Society on a
case-by-case basis. In particular, in the case of stationary dredgers, the curve of the still water bending
moment, where the suction pipe is horizontal, is to be
submitted to the Society for approval.
In addition to item a), still water loads are to be calculated for the following loading conditions:
sagging conditions:
When deemed necessary by the Society, a distribution
of the bending moments and shear forces as defined in
NR467 Steel Ships, Ch 5, Sec 2, [3] may be considered.
13.3.4 Internal pressure for hopper well in dredging
conditions
The internal pressure to be taken into account for hopper
well, in kN/m2, is to be not less than the greater value of the
following formulae:
2
2
P = δ 1 d D ( g + a z + n D ) ≥ 22
P = δ 1 d D ( 10 + 4, 5n D ) ≥ 22
where:
δ1
: Coefficient equal to:
δ1 = δ
• working conditions at international freeboard with
the hopper space(s) filled with spoil
for δ < 1,4
δ1 = δ + (1,4 − δ) sin2α for δ ≥ 1,4
dD
: Vertical distance, in m, from the calculation
point to the highest weir level with the corresponding specific gravity of the mixture of sea
water and spoil
α
13.3.3 Hull girder loads for dredgers of more than
65 m
: Angle, in degrees, between the horizontal plane
and the surface of the hull structure to which
the calculation point belongs
az
The hull girder strength of the ship is to be examined taking
into account the following hull girder loads:
: Vertical acceleration in dredging condition, in
m/s2, defined in Ch 3, Sec 4, [2.2.1]
nD
: Coefficient defined in Tab 7.
• ballast navigation conditions, with empty hopper
space(s), if applicable.
c) Wave loads
The wave loads are to be as defined in Ch 3, Sec 2, [5].
Amendments July 2015
Bureau Veritas
23
NR600
c) Bottom plating
13.4 Hull scantlings
Where the bottom is longitudinally framed and the bilge
is made of a transversely framed sloped plate, the bottom is to be assumed as being transversely framed when
calculating the plating thickness.
The thickness of the bottom strake, to which the longitudinal bulkheads of the hopper space are connected, is
to be not less than bottom plating thickness increased
by 15%.
13.4.1 Hull girder strength for dredger, hopper
dredger and hopper unit
a) General
The hull girder strength of ships is to be checked according to Ch 4, Sec 1, [2.2] and Ch 4, Sec 2, taking into
account the load conditions defined in [13.3.2].
For dredger of more than 65 m in length, the hull girder
strength is to be checked taking into account the still
water load conditions and the vertical wave bending
moments defined in [13.3.3].
T4 :
b) Calculation details
Plating
In the determination of the midship section modulus
according to Ch 4, Sec 2, [3] or Ch 4, Sec 2, [4], as
applicable, account is to be taken of both 85% and
100% effectiveness of the sectional area of the cellular
keel.
However the 85% and 100% effectiveness of the sectional area of the cellular keel may be replaced by the
actual effectiveness of the cellular keel determined by a
three-dimensional finite element analysis.
Where cut-outs in the side shell are needed to fit the
suction pipe guides, a section modulus calculation not
taking account of the side shell plating may be required
by the Society on a case-by-case basis, if the structural
continuity is not fully achieved.
13.4.2 Hull girder strength for split hopper unit
The hull girder strength of split hopper units is to be
checked according to Ch 4, Sec 1, [2.2] and Ch 4, Sec 2,
taking into account:
• the load conditions defined in [13.3.2], item b)
5,3 + 0,036 L k1/2 + 4,5 s
Side
• below freeboard deck
• between freeboard deck and
strength deck
3,5 + 0,031 L k1/2 + 4,5 s
3,5 + 0,013 L k1/2 + 4,5 s
•
3,5 + 0,032 L k1/2 + 4,5 s
• dredging situation, considering the dredging draught
TD and the navigation coefficient nD defined in Tab 7.
b) Minimum thicknesses
The thickness of plating is to be not less than the greater
of the following values:
The thickness of the longitudinal bulkhead above the
deck or within 0,1 D below the deck is to be not less
than the thickness of the strength deck in way of the
hatchways.
The thickness of the transverse and longitudinal bulkhead of a dredge pipe well is to be determined as for the
side shell thickness.
b) Transversely framed bottoms
The scantlings of floors located inside large compartments, such as pump rooms, are to be obtained from a
direct calculation, according to Ch 4, Sec 5, [1.2.2], and
taking into account the following assumptions:
• floors are simply supported at ends
• local discontinuities in strength, due to the presence
of wells, are to be considered.
c) Specific element scantling for split hopper unit
Superstructure hinges, deck hinges, hydraulic jack connections and chocks and hydraulic jacks and associated
piping systems are to comply with the requirements
defined in NR467 Steel Ships, Pt D, Ch 13, Sec 2, [8] to
NR467 Steel Ships, Pt D, Ch 13, Sec 2, [10].
• thickness obtained from Tab 8.
24
4,2 + 0,034 L k1/2 + 4,5 s
a) Well bulkheads and cellular keel platings
The thickness of hopper well bulkhead plating and cellular keel plating is to be not less than the thickness
defined in Ch 4, Sec 3, considering the internal pressure
defined in [13.3.4].
• 6 mm
When no protection is fitted on the deck areas where
heavy items of dredging equipment may be stored for
maintenance, the thickness of the deck plating is to be
not less than the value obtained, in mm, from the following formula:
4,2 + 0,034 L k1/2 + 4,5 s
13.4.4 Specific hull scantlings
a) General
• navigation situation, considering the draught T and
the navigation coefficient n defined in Ch 1, Sec 1,
[3.1.1]
Strength deck
Hopper well
• transverse and longitudinal
bulkheads
• cellular keel plating
13.4.3 Hull scantlings
Hull scantlings are to be checked according to the
applicable requirements of Ch 4, Sec 3 to Ch 4, Sec 5
for the following two situations:
Minimum thickness,
in mm
Bottom
• the section modulus of the transverse section as defined
in Ch 4, Sec 2, [3.2], considering the both half-hulls
connected.
t = 6,1 + 0,040 L k1/2 + 4,5 s
Table 8 : Minimum thickness of plating
13.5 Rudders
13.5.1 General
The rudder stock diameter obtained from Sec 2, [8] is to be
increased by 5%.
Bureau Veritas
Amendments July 2015
NR600
13.5.2 Rudders for split hopper dredgers and split
hopper units
Each half-hull of ships with one of the service notations split
hopper unit or split hopper dredger is to be fitted with a
rudder complying with the requirements of Sec 2, [8].
13.6 Equipment
13.6.1 General
The equipment in anchors and chains is to be as defined in
NR467 Steel Ships, Pt D, Ch 13, Sec 2, [12].
An automatic system for synchronising the movement of
both rudders is to be fitted.
Ch 5, Sec 4, [18.4]
Add the following requirement [18.4.4]:
than the values defined in Ch 4, Sec 4, [2.2.2], taking into
account:
18.4.4 Scantling of deck secondary stiffeners
subjected to maximum allowable loads
defined by the Designer
For longitudinal secondary deck stiffeners contributing to
the global strength and subjected to maximum allowable
deck loads defined by the Designer, the section modulus Z,
in cm3, and the shear area Ash, in cm2, are to be not less
• deck pressure p, in kN/m2, calculated according to Ch
3, Sec 4, [3.2.1], with an acceleration coefficient η
taken equal to 0,85, and
• permissible stresses σlocam and τlocam as defined in Ch 2,
Sec 3, increased by 15%.
Ch 5, Sec 4
Add the following Article [22]:
22 Offshore patrol vessel
22.1 General
22.1.1 Attention is to be drawn on the possible additional
requirements of the flag administration, if any.
The number of persons on board is defined in NR467 Steel
Ships, Pt D, Ch 21, Sec 1.
Ch 5, Sec 5, [2.2.3]
Replace the definition of Shfr , Shar and Shlat by:
Shfr
Shar
: Front surface of hull and bulwark if any, in m2,
projected on a vertical plane perpendicular to
the longitudinal axis of the ship
: Aft hull transom surface and bulwark if any, in
m2, projected on a vertical plane perpendicular
to the longitudinal axis of the ship
Shlat
: Partial lateral surface of one single side of the
hull and bulwark if any, in m2, projected on a
vertical plane parallel to the longitudinal axis of
the ship and delimited according to Fig 1
Ch 5, Sec 5 [2.2.4]
Replace the title of requirement [2.2.4] by:
2.2.4
Static forces on superstructures and
deckhouses FSS
Replace “superstructures” by “superstructures and deckhouses” in the first sentence.
Replace “of a superstructure tier” by “of tier i (superstructure or deckhouse, including bulwark if any)”
in the definition of Ssfri , Ssari and Sslati .
Replace “for each superstructure tier.” by “for each tier i of superstructure or deckhouse.” at the end of
the definition of Csari .
Amendments July 2015
Bureau Veritas
25
NR600
Ch 6, Sec 2 [2.6]
Replace requirement [2.6.2] by:
2.6.2 Double continuous fillet weld location
As a general rule, double continuous fillet weld is to be
required in the following locations, as appropriate:
• watertight and oiltight connections
• main engine and auxiliary machinery seatings
• bottom structure of high speed ship in way of jet room
spaces
• structure in way of bilge keel, stabiliser, bow thruster,
cranes
• bottom structure in the vicinity of propeller blade
• primary and secondary stiffeners in way of end supports
(crosstie, pillars, brackets) and knees on a length extending over the depth of the stiffener and at least equal to
50 mm for:
-
web stiffener connection with the attached plating
-
flange stiffener with web of built-up stiffeners
• stiffeners in tanks intended for the carriage of ballast or
fresh water.
Continuous fillet weld may also be adopted in lieu of intermittent welding wherever deemed suitable, and is recommended where the length p, defined according to [2.6.5], is
low.
Where direct calculations according to [2.6.4] or equivalent
are carried out, discontinuous fillet weld may be considered
on a case-by-case basis.
Ch 6, Sec 2, [2.6.5]
Replace the definition of tT by:
tT
: Throat, in mm, of the double continuous fillet
weld, equal to:
tT = wF t
with:
wF , t
: As defined in [2.6.3]
Ch 6, Sec 2, Table 3
Replace footnote (2) in Table 3 by:
T5 :
Table 3 : Welding factor wF for the various hull structural connections
(2) The web at the end of intermittently welded stiffeners is to be continuously welded to the plating or the flange plate, as applicable,
over a distance d at least equal to:
• For secondary stiffeners:
- general: the depth h of the stiffeners, with 300 mm ≥ d ≥ 75 mm. Where end brackets are fitted, ends means the area
extended in way of brackets and at least 50 mm beyond the bracket toes
- floors: 20% of the span from span ends
- bulkhead stiffeners: 25% of the span from span ends
• For primary stiffeners:
Ends of primary supporting members means the area extended 20% of the span from the span ends. Where end brackets are fitted, ends means the area extended in way of brackets and at least 100 mm beyond the bracket toes.
26
Bureau Veritas
Amendments July 2015
NR600
Ch 6, Sec 2, [2.6]
Replace requirement [2.6.7] by:
Welding between secondary and primary
stiffeners
As a general rule, the resistant weld section AW , in cm2, of
the fillet weld connecting the secondary stiffeners to the
web of primary members is not to be less than:

2.6.7
k
b) Case of side shell impact:
a) General case:
AW
s
–3
A W = ϕsp ssmin  0, 6 – --- k10

4
s
–3
= ϕps  1 – ------ k10

2
where:
ϕ
: Coefficient as indicated in Tab 4
p
: Design pressure, in kN/m2, acting on the
secondary stiffeners
s
: Spacing of secondary stiffeners, in m
Amendments July 2015
: Span of secondary stiffeners, in m
: Greatest material factor of secondary stiffener and primary member, as defined in Ch
1, Sec 2
Bureau Veritas
where:
s
: Spacing of secondary stiffeners, in m, without being taken greater than 0,6 m
: Impact pressure, in kN/m2, acting on the
pssmin
secondary stiffeners as defined in Ch 3, Sec
3, [3.1.2].
27
Move Forward with Confidence
Marine & Offshore Division
92571 Neuilly sur Seine Cedex - France
Tel: + 33 (0)1 55 24 70 00 – Fax: + 33 (0)1 55 24 70 25
Marine website: http//www.veristar.com
Email: [email protected]
© 2015 Bureau Veritas – All rights reserved