Use ball bearing blocks (cheek or swivel) with a minimum sheave diameter of 45mm. It is advantageous if cheek blocks are secured to the decks. Then, route 7mm diameter, flexible, non-stretch lines to wheel / tiller.
It is essential that the lines run squarely off the wheel, using either swivel or cheek ball bearing blocks. These should also run squarely to the Neptune power arm.
230 mm dia – For vessels with approx 3.5 turns lock to lock
310 mm dia – For vessels with approx 2.5 turns lock to lock
350 mm dia – For vessels with approx 1.5 turns lock to lock
440 mm dia – For vessels with approx 1.2 turns lock to lock
For installations, where a small movement of the wheel does not significantly alter the ship’s course, it is recommended that a wheel, one size smaller than those recommended above, is selected.
Although not as critical, for best performance, it is also preferable for the lines to run square off. They should also run squarely to the Neptune power arm.