Motorsailer with pilothouse in front

[YuriB]

Fast Fred, the propulson engine is in project, it is however difficult to plan anything now, because the hull has two large diameter low noise (technology stolen from USA ) screws in nozzles. They look nice but absolutely useless on sailing ship. We plan either remove them at all and cut in deadwood tube in the middle or just leave one (left) prop shaft and attach smaller diameter screw on it.

[FAST FRED]

You will have to do something , no sail plan will overcome that huge drag aft.

A single CPP prop on centerline would be best , but would increase draft , and is EXPEN$IVE.

Perhaps coupling the gen set to a hyd pump would allow you to free wheel the props with small hyd motors.

The prop speed would be matched to the boat speed , just overcoming the huge drag from the props , and nozzels , but not necessarily creating added thrust. Although going to windward some extra thrust would help the course held higher .

FF

[YuriB]

We will put more ballast in front to lift stern a bit, for reducing drag.
I expected to have some drag from the prop. And will hook DC generator on the shaft-i will loose 1-2knots because of the drag but will have free electricity source on the boat. Hyd motor could be good idea but those who create good torque are not small at all. Biggest i could go with makes 1400HM, which is not enough torque for 30-35" diameter prop.(and its weight 70kg ).

[FAST FRED]

which is not enough torque for 30-35" diameter prop

Remember simply turning the prop at a speed that matches the water flow requires no power for propulsion.

You simply want to cancel the drag , make the props "invisible" as drag , and cancel the drag of the stuffing box and bearings .

Not that much power.

FF