John,Yes, I understand but my point is, one horsepower isn't much power for a sub and isn't not difficult to control with an on off switch. You'll find that you don't need fine controls for your thrusters as you would if you were using them on a land vehicle. To illustrate my point, I bet you could maneuver your boat quite well with it's present engine if you just used it at five horsepower, neutral and reverse by pulsing it on and off when required.
I have two 3/4 Hp thrusters with toggle on and off switches also reverse, and one variable speed 3Hp rear thruster on my sub. I can control the sub with either system just as well. The mass of the sub allows me to pulse on and off as required the 3/4 Hp thrusters and move as slowly and precisely as I want.
Don't forget, with hydraulics you still have to seal the motor shaft so you don't get water forced into the hydraulic reservoir. The existing seals on a hydraulic motor aren't high pressure seals. They only hold back pressure on the low pressure side of the motor, the tank side, and even then aren't installed in the direction to keep out pressure. You can pressure compensate the reservoir mechanically, or locate it outside the pressure hull. In that case you have to seal the pump seal so it doesn't blow out. It's only made to seal against back pressure in the drain line.
Of course you could place the entire hydraulic system outside of the pressure hull and run wires to it through through hull fittings. Not much of a savings there either.
What your testing should work on your boat just fine but be sure it's sealed for the pressure of the depth your planning to use it.
HMMmmmmm.......... A one Hp log splitter? It would split logs, but not fast!
Dan H.----- Original Message ----- From: "John Gaertner" <jgaertner1@earthlink.net>
To: <personal_submersibles@psubs.org> Sent: Tuesday, October 25, 2005 7:51 AM Subject: Re: [PSUBS-MAILIST] Hydraulic thrusters
Hi Dan,Well I guess we will see... I just ordered my "test" 1 HP motor and pump and am going to bread board the system before coming to any final conclusions. (Once the system is up and running I am going to mount it underneath a small boat of mine for testing) But my submersible design is much like the Soucoupe, I have no propellers and they would probably not work in my case for the designed shape of the submersible.A 1 HP electric motor turning an efficient hydraulic pump can push a whole lot of water through two vectored thrust nozzles I have learned from my research and calculations. The noise problem, if it exists, can be solved through sound proofing the motor mount and motor housing. The hydraulics have the advantage of being easily throttle able and require only a small hull pass through as I have mentioned.Plus I am interested in the concept... But experimentation will tell. If it does not work at the bread board stage, then I have all the parts for a great log splitter!John -----Original Message----- From: "Dan H." <jmachine@adelphia.net> Sent: Oct 24, 2005 8:59 PM To: personal_submersibles@psubs.org Subject: Re: [PSUBS-MAILIST] Hydraulic thrusters John, Is it really going to be that worth while to go with hydraulics? You must be planning a really small system if your total power input is only onehorsepower. You have some power lost to heat in the hydraulic system also.Then you have the noise of the pump to listen to. For a total of one horsepower, wouldn't it be much easier to just use electric motors in pods with a pump shaft seal? Dan H.----- Original Message -----************************************************************************ ************************************************************************ ************************************************************************ The personal submersibles mailing list complies with the US Federal CAN-SPAM Act of 2003. Your email address appears in our database because either you, or someone you know, requested you receive messages from our organization. If you want to be removed from this mailing list simply click on the link below or send a blank email message to: removeme-personal_submersibles@psubs.org Removal of your email address from this mailing list occurs by an automated process and should be complete within five minutes of our server receiving your request. PSUBS.ORG PO Box 311 Weare, NH 03281 603-529-1100 ************************************************************************ ************************************************************************ ************************************************************************
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