7. Ship's derricks
7.1. Rigging plans
7.1.1. Every ship should carry adequate rigging plans showing
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
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