Artificial Seaweed Frond Mattresses
Pipeline Scour Control
Structure Stabilisation
Coastal Protection
Subsea Protection Systems
SPS
is the world leader in the design and supply of a comprehensive range of products for
the Stabilisation, Protection, and Scour control of subsea pipelines, cables and structures.
SPS is proud of its acknowledged worldwide reputation it has established with its clients.
Since the company’s inception in 1994, it has become one of the world’s leading suppliers of
specialist subsea pipeline protection systems to oil and energy producers and offshore
contractors. Our capability and reputation for quality, reliability and fast action response
quickly permeated the worldwide oil and energy industries.
SPS provides to its clients:•
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Experience
A range of proven products
Engineering and design
A Commitment to Quality, Health and Safety and the Environment
Delivery and Performance
SPS Artificial Seaweed Frond Mattresses
What is Scour?
Scoured Pipeline
The displacement of sand, silt and soil on the seabed is known as scour. The forces of nature
are relentlessly at work worldwide reshaping beaches, rivers and seabeds. Currents, tides
and storms work adversely within these environments causing erosion. This problem allows
currents to increase in velocity locally, with the supporting sediment around structures
eroding creating stress points. In time the effect of this scour will result in the possible
collapse or breakage of such structures.
Subsea Protection Systems
The Solution
SPS have over 15 years of experience supplying the offshore industry with products that
support and protect pipelines and umbilicals that stretch across the seabed of the worlds
oceans. One such product is the SPS Artificial Seaweed Frond Mattress; this product is an
economically tried, tested and proven solution for preventing scour around sub sea
structures. The mattress is constructed of polyethylene strands, these strands are known as
fronds. The fronds are approximately 1.2m in height and when installed on the seabed will
naturally float vertically to resemble natural sea grass or seaweed. As local currents
transport sediment through the frond mat strands, velocities decrease thus encouraging sand,
silt, or soil to be deposited onto the mat. The deposited material is then compacted by the
motion of the strands; this immediately begins to build up on the frond mattress, forming a
permanent, natural, fibre reinforced sand bank to protect the area in question.
Diagram (left) shows the
initial installation of a
frond mattresses.
Diagram (right) shows a
frond mattress after a sand
bank has formed.
Picture (left) Shows the end result
after a year, a fully developed sand
bank formed over fronds
Subsea Protection Systems
Technical Details
The SPS Artificial Seaweed Frond Mats comprise of lines of polyethylene fronds that are
attached to a framework of webbing that extends around the periphery of the mat and
crosses at regular intervals. These mats are retained on the seabed by anchors that have a
retention strength of 1 tonne per anchor as witnessed by Bureau Veritas. The anchors are
attached to the webbing framework by 1 metre long webbing straps, these anchors are then
driven into the seabed to a depth of 1 metre by using a standard hand hydraulic gun. Secure
stabilisation of the artificial seaweed frond mat is critical at the early stages.
Picture (left) shows an
example of installed
frond mat.
Picture (Right) shows
an Anchor
Mat Size
(Length x Width)
Frond
Height
Number of
Fronds per mat
Specific
Gravity
Frond Material
Number ofAnchors
per mat
5 x 2 metres
1.2 metres
5,000
.90
Polyethylene
8
5 x 4 metres
1.2 metres
10,000
.90
Polyethylene
12
The frond mattress’s are available in standard sizes and can also be made to suit customer
requirements. The mats are designed to be diver-friendly; they can also be supplied on a
SPS concrete fleximat or a specially designed spindle for ease of installation.
A
B
C
Picture A shows a frond mat on an installation spindle.
Picture B shows an Anchor fitted to a Hydraulic Gun.
Picture C shows an Anchor driven into the seabed.
Subsea Protection Systems
In its field SPS has a track record of applying its innovation and experience to provide
solutions for its clients. This can include modification of a standard product, to developing
and designing a whole concept to specific problems.
All SPS standard and purpose built products are engineered and manufactured to be fit for
purpose and to the appropriate international technical standards, typically considering:•
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Design Criteria
Design Life
Environmental Conditions
Lifting and Deployment
Safety considerations and experience underwrite all of this.
Quality Assurance
SPS has ISO 9001 accreditation and is members of Achilles and First Point. Quality
Assurance, Quality Control, Certification and all the associated activities and documented
essential to comply with these International Standards.
Subsea Protection Systems Ltd
SPS House,
Yarmouth Business Park,
Thamesfield Way,
Great Yarmouth,
Norfolk,
NR31 0ER,
United Kingdom
Telephone : +44(0)1493 600700
Fax: +44(0)1493 651327
E-Mail: [email protected]
Web: www.sps.gb.com