DRILLSAFE MEETING
ADELAIDE JUNE 2004
DROPPED STINGER INCIDENT
Actual Level 1 / Potential Level 4
Atwood Eagle - 20 April 2004
The Incident
• What?
– A crane whip line “stinger” assembly weighing 40 kg fell to the main
deck.
• Where?
– Atwood Eagle
• When?
– 20th April 2004
• Outcome
– There were no injuries to personnel however the incident had the
potential for serious injury or fatality.
BHPB Australia Drilling
16/06/2004
Page 2
Incident Key Learnings
• Enquiries determined this type of event has occurred
numerous times in the industry and we are failing to
capture learning by these incidents
• High potential incident but very simple solution
– the hook below the whip line is able to be removed entirely
from the assembly configuration with minimal operational
impact
• Always look at work systems to identify better
solutions.
BHPB Australia Drilling
16/06/2004
Page 3
Incident Description
• The starboard crane had a stinger attached to the whip
line hook (Type BK 22-8 Gunne XN2).
• After landing a load, the crane with stinger attached
(with no load) was being slewed round to the boom
cradle when the stinger fell ~15 metres and landed on
top of the riser sections racked on the pipe deck.
• No persons were in the vicinity nor was there any
property damage.
Note: The stinger assembly weighs ~40kg and consisted
of a gather (or master) ring connected to a BK 22-8 Gunne
XN2 hook with a 5-metre wire sling below and a BK
hook/shackle fitting on the bottom.
BHPB Australia Drilling
16/06/2004
Page 4
Incident Causes and Contributory Factors
• The hook opened when the safety
latch of the Type BK 22-8 Gunne XN2
hook fitted to the whip line swung
back against its own frame
Safety Latch
Mechanism
(unprotected)
• Design of Type BK 22-8 Gunne XN2
hook in service did not protect the
latch locking mechanism from impact
events.
• Uncontrolled swinging of whip line
without load.
BHPB Australia Drilling
16/06/2004
Page 5
Solution
• The absolute solution to prevent recurrence is to remove the hook
fitted to the whipline
• BHPB have identified two possible methods of removing the hook
BHPB Australia Drilling
16/06/2004
Page 6
Corrective Actions
BHPB WWD Policy
Regarding Configuration of
Assembly
Gather
ring
Gather
Ring
•Remove the hook from the whip
line immediately under the
headache ball
•Connect the Gather (or Master)
ring directly to the whip line fitting
under the headache ball with
stinger attached (see photo-1)
Whip line
under
Whip line
headache
ball
under
headache ball
Top of
Stinger
Top of stinger
Photo-1
Safety
Safety
Latch
Latch
•All Hooks to be used in WWD to
have protective safety latch
guards to prevent inadvertent
opening (see photo-2)
Latch Guards
Photo-2
BHPB Australia Drilling
16/06/2004
Page 7
Corrective Actions (cont.)
Alternative Solution
• Crane manufacturer have advised they can provided a
longer pennant wire under the headache ball (thus
completely eliminating the need for an an extension
stinger)
• Atwood have ordered for trial and will be installed on
both cranes on the Atwood Eagle early-July
BHPB Australia Drilling
16/06/2004
Page 8
Corrective Actions (cont.)
Hook Manufacturer Consultation
• Discussions with manufacturer revealed that the hooks are capable of enduring
dynamic load conditions during normal lifting operations (such dynamics being
induced by slewing or wind effects during lifting).
• The statement in the BK (Gunnebo) documentation that snatch loading of their
hooks must be “avoided at all times” raised some concerns particularly that the
risks associated with boat transfers may not be widely understood even though
these hooks are in routine use.
• The above issue is being addressed in the North Sea by Sparrows in a
collaboration with industry. BHPB WWD will monitor the progress of this activity
and will report on any findings when the study is completed.
BHPB Australia Drilling
16/06/2004
Page 9
BHPB Australia Drilling
Page 10 16/06/2004