Hydraulic drive for Catamaran?

[captlloyd]

Does anyone know of a Cat manufacturer who uses a hydraulic drive system utilizing a single diesel engine to drive the hydraulic motors. Other than only having one engine, I see a few advantages with this idea. Less cost for one less engine, and much cheaper drive motors. Less weight with again one less engine and hardware plus drive motors . Any opinions please?

[Iodine]

Originally Posted by captlloyd

Does anyone know of a Cat manufacturer who uses a hydraulic drive system utilizing a single diesel engine to drive the hydraulic motors. Other than only having one engine, I see a few advantages with this idea. Less cost for one less engine, and much cheaper drive motors. Less weight with again one less engine and hardware plus drive motors . Any opinions please?

Heavenly twins (older English cat builder) offered this as an option, no idea how common it was (I know of one with this set up, so there are some out there).

Maybe you can find some more info here:Heavenly Twins Catamarans

[smj]

Originally Posted by captlloyd

Does anyone know of a Cat manufacturer who uses a hydraulic drive system utilizing a single diesel engine to drive the hydraulic motors. Other than only having one engine, I see a few advantages with this idea. Less cost for one less engine, and much cheaper drive motors. Less weight with again one less engine and hardware plus drive motors . Any opinions please?

Our old Cherokee had this setup. If you figure the weight of the 3 hydraulic pumps, the hydraulic fluid and reservoir and the massive amount of hydraulic hoses and fittings that make this system work, you would probably save more weight having a second diesel. That and the fact that it is a terribly Inefficient setup. I know the cost of the system we had was far greater than a diesel to replace.


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[Stumble]

I doubt there would be any cost savings. But if you wanted to drive the two propulsion motors off of one diesel I am willing to bet that going electric would be far cheaper and easier.

As I have mentioned on DE threads I think this is a silly idea, but doing it with hydrolic would be even worse.

[UNCIVILIZED]

There was a cat in San Diego, which I believe Ian Farrier built, which had hydarulic drives. They had a Very high pitched whine, which you could literally hear for miles. It sounded just like a torpedo, & was as annoying as F**k. Even if you were 3nm away when they took the boat out.
She had a Really goofy layout too.

[boatpoker]

Google " Fisher catamaran images" They built 28' 34' and 37' cats with hydraulic drives from a single Pathfinder diesel.

[smj]

Originally Posted by boatpoker

Google " Fisher catamaran images" They built 28' 34' and 37' cats with hydraulic drives from a single Pathfinder diesel.

The Catfisher was built as a 28' and 32' catamaran. The 28'er had the single diesel with hydraulic drive set up. The 32 was a single diesel with Sonic outdrive. The 37'er was proposed but I don't believe ever built.


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[Huey2]

Hi Captlloyd, I have a Fisher catamaran 28' that has this set up & I love it. It has a 37.5 hp Kubota diesel with hydraulic pump that drives two hydraulic motors (a little bigger than a softball) that turn a shaft in each hull. It's like driving a zero turn lawn mower. I can turn it in it's own length. The burn rate is approx. 1 gallon per hour & I cruise around 6 mph. I have folding props on each shaft. The space savings allows for two forward staterooms, an aft 3/4 berth, a kitchen, a bathroom, both inside & outside steering, a large pilot house with map table, and electronics all with stand up headroom. It is more of a motor sailer. I would consider this a coastal cruiser, not a blue water boat. Send me a PM if you need extra information. I also have a Privilege 39 that does have an engine in each hull, so I know the difference.

[captlloyd]

Originally Posted by Huey2

Hi Captlloyd, I have a Fisher catamaran 28' that has this set up & I love it. It has a 37.5 hp Kubota diesel with hydraulic pump that drives two hydraulic motors (a little bigger than a softball) that turn a shaft in each hull. It's like driving a zero turn lawn mower. I can turn it in it's own length. The burn rate is approx. 1 gallon per hour & I cruise around 6 mph. I have folding props on each shaft. The space savings allows for two forward staterooms, an aft 3/4 berth, a kitchen, a bathroom, both inside & outside steering, a large pilot house with map table, and electronics all with stand up headroom. It is more of a motor sailer. I would consider this a coastal cruiser, not a blue water boat. Send me a PM if you need extra information. I also have a Privilege 39 that does have an engine in each hull, so I know the difference.

Thanks for all of your replies CF members.
As to your Fisher 28', how would you rate the noise level as ''Uncivilized'' has brought up one of my concerns, I to have a 54'' zero-turn mower and it does not seem to be that noisy. And thank you too.

[Huey2]

Mine isn't that loud. The prior owner routed the exhaust out behind the port hull which helped on noise issues also. Both hydraulic motors and the pump have been replaced on this 1978 model. The engine hatch should use good "sound deadening" material. We are going on some extended trips this summer so I'll let you know. I plan on downwind sailing and upwind motoring. You will lose approx. 15% efficiency using hydraulics however. Good luck

[Jeannius]

Originally Posted by captlloyd

Any opinions please?

First cat I ever skippered was a Star Twins 34 (from the designer of Heavenly Twins) It had a single diesel with twin hydraulic drive. It was fine except when manoeuvring in close quarters. With both at idle speed ahead you'd be trundling along nice and slowly but as soon as you brought one back to neutral prior to engaging astern, the one left forward would DOUBLE its speed. Very disconcerting and awkward. I suppose the correct method would have been to put both sides to neutral and then engage one forward and one astern at the same time but as I only had a weekend aboard I didn't work that out at the time.

[FSMike]

Drove a trimaran once that had one diesel and two hydraulically operated shafts/propellers. The really aggravating part was that you could not operate just one shaft with the other in neutral, it was either both or none.

[captlloyd]

Originally Posted by FSMike

Drove a trimaran once that had one diesel and two hydraulically operated shafts/propellers. The really aggravating part was that you could not operate just one shaft with the other in neutral, it was either both or none.

I would say that the vessel was most definitely plumbed wrong in that case. Skid loaders, zero-turns, track-hoes will all operate on one side or the other.

[Cadence]

Originally Posted by captlloyd

Does anyone know of a Cat manufacturer who uses a hydraulic drive system utilizing a single diesel engine to drive the hydraulic motors. Other than only having one engine, I see a few advantages with this idea. Less cost for one less engine, and much cheaper drive motors. Less weight with again one less engine and hardware plus drive motors . Any opinions please?

I saw one listed just recently. She was older but powered just that way. Wish I could remember the Mfg.. Seems she was 40'. and listed in the 60K range.

[Terra Nova]

I worked on a Buddy Ebsen PolyCon that had a single, air-cooled Yanmar diesel with twin hydraulic outdrives that tilted up completely clear of the water.