Bureaucrat, staff, administrator
4,335
edits
Changes
m
→Bow Thrusters
Consult your designer about putting an eyebrow fairing in front of the tube, or a scallop behind the tube, to reduce drag. Don’t put fine grids over the openings, as they clog up. Paint the inside of the tunnel with [https://en.wikipedia.org/wiki/Anti-fouling_paint antifouling paint].
Bow thrusters come with either single or twin propellers. Each has its advocates. The efficiency of one versus the other is unclear. Twin propeller designs contra-rotate and are more complex. Propellers are usually square-bladed, made of [http://dupont.com/ Dupont ] [http://www.dupont.com/products-and-services/plastics-polymers-resins/thermoplastics/brands/delrin-acetal-resin.html Delrin® ] or [http://www.dupont.com/products-and-services/plastics-polymers-resins/thermoplastics/brands/zytel-nylon.html Zytel® ] plastic, and designed to be efficient in both turning directions.
The thrust required is a function of displacement, waterline length, lateral water resistance, wind on the superstructure, the forward thrust of the stern, and the turning point on the hull (usually the transom). Some manufacturers’ recommendations are given below. Be sure to consult your designer/builder about the appropriate size for your boat.