MTC
Anchor
Planning:
Goal Descibe the goal. When do we have to be ready.
Collect data – check systems
What What to do to reach the goal
Who Delegate tasks – make sure everybody knows who are responsible for each task
How Make job descriptions, descripe standard procedures, make risk assessment
When When do the tasks need to be finished?
Prioristising of tasks
Be ready to correct the plan as necessary
Have status meetings
Work as a team
Keep the leader informed
Goal, example: |
Be ready for anchor handling at POLARIS |
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Water depth 500 meter |
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Retrieve anchors No 1, 4, 5 and 6 |
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Move rig to position: |
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Run anchors No 4, 6 and 3 |
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Collecting data: |
Rig move report |
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Anchor type |
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PCP, length, chaser type |
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Chain / Wire combination |
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Chain, length and size |
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Wire, length and size |
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Winch drum capacity |
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Load calculations, maximum weight of system, how much |
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force can I use on engines |
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Power consumption |
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Communications: |
Contact persons |
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Charts and drawings |
VHF channels |
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M:\ANCHOR HANDLING\Course Material\Training Manual New\Chapter 04\1.0 Planning and RA.doc
MTC
Anchor
What to do: Prepare deck: Which drums
Check correct spooling of wires Chain wheel size – correct size Shark Jaws size – correct size Chain lockers
Prepare engine room: Defects, out of order, limitations
Power consumption
Ships stability
Ballast, bunkers, trim
Make risk assessment on each job
Voyage planning: |
Precautions when: |
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Approaching, |
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Working alongside |
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Moving off / on location |
Prepare checklists |
Contingencies |
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Brief crew of coming job – ToolBox Meeting
Who: Make sure all know their job
Make sure all know the difficult / risky part of the operation
How: Prepare job descriptions and safe job analysis Use standard procedures as far as possible Apoint responsible person for each job
When: Time consumption for each job Time schedule
Alternative plans
Do status, can we reach the goal on time The leader to stay on top of the sistuation
M:\ANCHOR HANDLING\Course Material\Training Manual New\Chapter 04\1.0 Planning and RA.doc
MTC
Anchor Handling Course
Planning and Risk Assessment
Job:________________________________________________________
Working process / |
Hazard |
Consequence |
Probability |
Action to |
What to do, |
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Plan |
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eliminate / avoid risk |
if risk cannot |
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be avoided |
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M:\ANCHOR HANDLING\Course Material\Training Manual New\Chapter 04\1.0 Planning and RA.doc
Chapter 04 Page 6
ANCHOR HANDLING CALCULATIONS
The 5 steps to success
in
Anchor Handling
ANCHOR HANDLING CALCULATIONS
The TASK :
600 Meters water depth
10 T Anchor
3” Wire / Chain
3000’ = 914 Meter Dead Man Wire
Can we run and retrieve the anchor ?
Can we deck the Anchor ?
ANCHOR HANDLING CALCULATIONS
Planning
APM-Procedure:
Deep-water A/H. 15, 266
ANCHOR HANDLING CALCULATIONS
STEP 1 : Wirelength
Wirelenght 1.5 in shallow water, but less in deep water (>300 Meter)
600 x 1.1 = 660 Meters
600 x 1.2 = 720 Meters
600 x 1.3 = 780 Meters
ANCHOR HANDLING CALCULATIONS
STEP 2 : Winch Capacity
Connection on drum you maybe loose 30-50 meters
A
D |
B |
C
Winch Capacity = AxCx¶x(A +B)
dxd
B = 1020 mm, C = 1300 mm, D = 2650 mm, d = 76 mm
A = (D-B) / 2 = (2650-1020) / 2 = 815 mm
CAPACITY = |
815 × 1300 × π × (815 + 1020 ) |
= 1030M |
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77 2 |
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ANCHOR HANDLING CALCULATIONS
STEP 3 : Winch Max. Pull
(Max pull 1.) * B = K * (Actual diam.) Max pull 1. = 260 T
K = (260*1020)/2560 = 100 T (Dynamic)
The static holding force (Bandbreak) is bigger. Probably 30-50 %
ANCHOR HANDLING CALCULATIONS
STEP 3 : Winch Max. Pull
Quadratic equation.
Ax2 + Bx + C = 0
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X = -B ±√ B2-4AC
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2A
Capacity on drum = A * C * 3.14*(A+B) d d
914000 = A * C * 3.14*(A+1020) |
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77 |
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914000*77*77 =A2 + 1020A |
(-C = Ax2 + Bx) |
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3.14*1300 |
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ANCHOR HANDLING CALCULATIONS
STEP 3 : Winch Max. Pull
(Ax2 + Bx + C = 0)
A=1 B=1020 C=-1327561,5
A2+1020A-1327561,5 = 0
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A = -1020 ±√ 10202-4*1*(-1327561,5) 2*1
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A= -1020±√ 6350645,9 2
A= -1020 ± 2520,0 2
A = 750 MM
ANCHOR HANDLING CALCULATIONS
STEP 3 : Winch Max. Pull
(Max pull 1.) * B = K * (Actual diam.) Max pull 1. = 260 T
K = (260*1020)/1020+(2x750) = 105 T (Dynamic)
ANCHOR HANDLING CALCULATIONS
STEP 4 : SYSTEM WEIGHT
Chain : |
126 kg/m 3” |
Wire : |
25 kg/m 3” |
Weight |
600 M |
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600 * 0,126 |
= |
75,6 T |
Anchor + ?? (10 + 5) |
= |
15,0 T |
Totalt: |
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90,6 T |
Incl. Bouyancy 90,6 * 0,85 |
= |
77,0 T |
Bouyancy = 15 % Density iron = 7,86
Must only be used as safetyfactor |
1000kg Iron = 1 / 7,86 = 0,127 M3 |
According to proc. 15,266, |
1000kg-(127Lx1,025kg/L)= 872,7 kg |
ANCHOR HANDLING CALCULATIONS
STEP 4 : SYSTEM WEIGHT
Decking the anchor
Weight without bouyancy
600 * 0,126 |
= |
75,6 T |
Anchor + ?? (10 + 5) |
= |
15,0 T |
Totalt: |
= |
90,6 T |
To deck the anchor you maybe need another 30-50 T
It can be necessary to make a crossover to a drum with less wire on and therefore closer to the center
ANCHOR HANDLING CALCULATIONS
STEP 5 : Bollard Pull
200 M
ANCHOR HANDLING CALCULATIONS
STEP 5 : Bollard Pull
43 T
600 m
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43 T |
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43 T |
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88 T |
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99 T |
77 T |
90 T |
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Probably using 40% pitch on Maersk Trainer = 43 T Bollard Pull