Mooring Equipment

Question 1

What markings (in tonnes) should be on all mooring fittings?

Answer 1

SWL (Safe working load) for mooring

TOW (Minimum towing load) for fittings designed for towing

Question 2

What should the SWL of mooring fittings be?

Answer 2

Whichever is the highest of

1. The intended maximum towing load (static bollard pull)
2. Minimum breaking load of the mooring line

Question 3

What is TOW?

Answer 3

Safe Towing load

Question 4

What is the safe towing load?

Answer 4

80% of the design load of the fitting

Question 5

Where can i find information about the vessel mooring and towing capability?

Answer 5

The ships towing and mooring arrangements plan

Question 6

What must be included on the towing and mooring arrangements plan?

Answer 6

1. Location on the ship
2. Type of fitting
3. SWL/TOW
4. Purpose (Mooring/normal towing/other towing)
5. Method of applying load/load angle at fitting
6. Arrangement of mooring lines
7. MBL of mooring lines
8. Length of mooring lines
9. Type and diameter of mooring lines
10. Maximum environmental conditions for design loads

Question 7

What are the three mooring line types used on a mooring arrangement?

Answer 7

1. Breast line - perpendicular to the ship
2. Spring line - parallel to the ship
3. Head/Stern line - 45 degree angle to secure fore/aft and athwartships movement

Question 8

What is the maximum beam wind speed for design load of moorings?

Answer 8

25 m/s between 2000m2 and 4000m2 windage area for passenger ships and car carriers and all other ships

21 m/s over 4000m2 windage area on passenger ships and car carriers

Question 9

Where are the best places to find mooring guidance?

Answer 9

OCIMF Effective Mooring publication

Standard club and other P and I club best practise

COSWOP

Question 10

What angle to the quay should mooring lines be kept at?

Answer 10

Spring lines - Max 10 degrees

Breast lines - Max 25 degrees
30 degrees = 87% efficiency

Question 11

How should mooring loads be balanced ?

Answer 11

1. Mooring lines at as close to horizontal as possible
2. Mooring ropes of equal type and diameter used together
3. Mooring lines as close to fore and aft line and perpendicular to ship as possible
   4 Mooring lines as long as possible
   (a 30m line will stretch twice as much as a 15m line so can absorb more force)

Question 12

What should the mooring winch brake holding power be set at?

Answer 12

Between 60 and 80% of the MBL of the mooring line so that the winch renders before the line breaks.