Re: [PSUBS-MAILIST] Water nozzle propulsion

[RiskEverything21@aol.com]

I wonder what would be more energy efficient, in terms of Amps. 4 electric motors direct-driving props, or two electric motors each driving 1 hydro pump, with each pump driving two props?

 

Also, I've been thinking about gearing and props. An elecric motor driving a shaft to a ring-and-pinion gear which turns a large, multi-bladed prop. Exchanging torque for speed, since we shouldn't need fast-spinning props on slow-moving subs. I'd be thrilled if I had a sub that went 5 knots even. I'd be terrified of currents, of course. I've been in currents that were considerably greater than 5 knots while out on the boat.

 

In a message dated 4/10/2006 5:32:39 PM Eastern Daylight Time, ojaivalleybeefarm@dslextreme.com writes:

I would say just generally,  that every time you have to go from one type of power transmission to another you will have a certain amount of power loss due to the coefficient of friction for that particular device.  The most direct and efficient transmission of power would be a electric motor going directly to a prop turning in the water.  If you are going to, first a electric motor to a hydraulic pump and then second, from a hydraulic pump to a hydraulic driven water pump you will be adding many steps which will absorb energy every step of the way which will manifest it self in terms of heat to each device. 

 

Brian