Hydraulic bowthruster RPM

[Stillbuilding]

Does anyone know usual RPM for a 12" bowthruster? Just curious.

[Lurvio]

http://www.usthrusters.com/hthrusters.asp

Hard to say, what the prop shaft rpm is, as the gear ratio is not specified, but hydr.motor rpm is around 3000 rpm (57 liters/min, 19.5 ccm).

Edit: Model SP 300 Hyd

Lurvio

[Stillbuilding]

Presumably a geroter motor is used in most cases providing some sort of reduction gearing. No guesses for the thruster prop RPM?

[Adler]

Dear,

More or less a 12" Dia-Ducted propeller(eff 0.65-0.67) of a thruster absorbs 25kW Hyd.Power at 1350-1450 rpm. (more speed , reduces the propeller's efficiency when the cavitation appears on blades' tip).
Most of these systems use piston motors (because of the better efficeincy than the orbit or gerotor type motors) and reduce the motor's speed through the L drive gears by a ratio 1.3 to 1.5.
If you consider all these above you need a Hyd.Motor to operate at 250 bars (continuous mode - able to achieve 350 bars) with a displacement 40-45 cm3/rev. and top speed never less than 2500rpm.

I hope all these help you regarding the case.

[Stillbuilding]

Adler, Thanks very much for that. All very clear. Will help with my plans.