Hydraulic propulsion system

[Guest-3-21-09-10-33]

Anyone know about a reliable hydraulic propulsion system powered by a single diesel engine/pump to a twin hydraulic motor suitable to power a displacement catamaran? We know just Vetus system. Could someone indicate a similar system/producer?

[fcfc]

Look http://www.boschrexroth.com/business_units/bri/en/products/index.jsp
You can find any size in hydraulic motor and pump.

But a 2x hp diesel engine + hyd pump + 2 hyd motors may cost more than two x hp diesel engines + gearboxes.

[Guest-3-21-09-10-33]

Look http://www.boschrexroth.com/business_units/bri/en/products/index.jsp
You can find any size in hydraulic motor and pump.

But a 2x hp diesel engine + hyd pump + 2 hyd motors may cost more than two x hp diesel engines + gearboxes.

Thanks for the precious link.
You are right but we suppose that 1 diesel/pump that give hydraulic power to two hydraulic motor (independents with valve controls) will cost less and allow us to fit the engine/pump on then boat center.
We intend to put single diesel engine on center of catamaran, on the beam connection.
But we just started to valuated costs.

[bilgeboy]

I had the same thought a year ago, but I don't know much about hydraulics.

I asked a friend in the hydraulic service industry, and he said the size of the hydraulic fluid tank would have to be enormous, and would prohibit a marine application.

Thats as far as I got. I am sure there would be a way around it ( like raw water cooling, etc ). Would certainly be many advantages over the typical engine/tranny/shaft alignment problems, and a single engine could certainly power two pumps, maybe save alot of weight.

Curious how far you have gotten with the idea.

Mike

[Guest-3-21-09-10-33]

here Vetus system but all parts are quoted quite double price compared with same parts used on land movers or similar hydraulic powered machines. In the picture the oil tank/reservoir.

[FAST FRED]

"here Vetus system but all parts are quoted quite double price compared with same parts used on land movers or similar hydraulic powered machines. In the picture the oil tank/reservoir."

AS an OEM , (Origonal Equippment Mfg) your trade discount should be 50%+10%.

In other words an item that "lists" for $100 will cost you $45.

WE have found Vetus to not be of very high quality , or worth their high prices, and never use them as a source.

The hyd system you need is very simple , but as noted the hyd fluid would need some type of cooler and the propulsion system would only be 85% as efficent as a shaft setup.

Of course the ability to shift into foward or reverse at any speed for manuvering might be worth the fuel / maintance costs.And a genset could give slow "gethome" or manuver on station power.

FAST FRED

[Guest-3-21-09-10-33]

...hey guys...I need some thecnical parameters to choose compenents for this system.....nobody can help me?
Boat specs are:
catamaran sailing boat kind hull with V shape
LWL 9,45 meters
LOA 9,5 meters
beam 5,25 meters
displacement 3750 kg
desidered speed 24 knots max, 20 knots cruise
supposed single diesel engine 140 hp Lomatec coupled with hydraulic pump
two hydraulic motors on each hull


HELP PLEASE...!!

[nero]

A few years ago, I too was interested in hydraulic propulsion. But it is not a viable way to go.

First up the system will be noisy. It will wine.

Second is the cooling problem. The fluid gets hot quickly.

Electric motors are a better way to go. Use a motor/generator to power it and you will have a quiter, more reliable system. Yahoo has a usergroup on this subject and it is quite active.