[DG] [DG] Rotary Drive selection

[Derek - Raymarine - Moderator]

HI Hg1
Thankyou for your enquiry.

Given the vessel displacement, for offshore work a T2 Rotary drive would be the best option as it would give plenty of power in a heavy sea, where the T1 would struggle and need to have the mainsail reefed and helm load eased.

The T2 rotary drive would require an ACU400, although the control unit, rudder reference unit and EV would remain unchanged.

The gear ratio will need to be changed, the calculation is achieved by measuring the turns of the steering gera shaft at the point the rotary drive is going to be connected to from hard port to hard starboard. Once you know how many turns you need - this is referred to as the Driven shaft.

I have attached a graph that can be used to now identify the correct reduction ratio required based on the number of turns of the driven shaft and the T2 Drive. this will identify the correct reduction ratio and the size of sprockets required.

I hope this helps?

Regards

Derek