Ship's derricks

• Pages: 72-76

7. Ship's derricks

7.1. Rigging plans

7.1.1. Every ship should carry adequate rigging plans showing

at least

the correct position of guys;

the resultant force on blocks and guys;

the position of blocks;

their identification marking; and

arrangements for union purchase.

7.2. Slewing guys

7.2.1. Slewing guys should be designed for operation of the

derrick with the ship having a list of not more than 5° and a trim of

not more than 2° with the derrick at its maximum outreach.

7.3. Span winch

7.3.1. (1) A derrick other than one that has its own power-

operated topping winch should be provided, whenever this is

reasonably practicable, with a span winch complying with the

relevant requirements of Chapter 8.

(2) Where this is not reasonably practicable, a span chain joined

to the span rope by means of a monkey or a delta plate should be

employed.

7.4. Temporary stopper

7.4.1. No derrick should be rigged and adjusted for angle

otherwise than by its own power-operated topping winch or by a

span winch complying with the relevant requirements of Chapter 8.

It should be prohibited to use a short length of chain shackled to the

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