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30-03-2016, 11:42
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#16
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Registered User
Join Date: Nov 2007
Location: Cruising in the SUN! Now hauled out in Malta for the winter.
Boat: 37' Oldenziel cat
Posts: 461
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Re: Hydraulic drive for Catamaran?
I have a one-off Bob Oldenziel (of Holland) designed cat with one 34hp Lombardini diesel engine in the starboard hull and twin hydraulic drives (pumps) which in turn drive two electric pumps to operate the shaft / propellers which are folding props. This system's set-up works just as two engines, I can turn on a dime. I have a twin wheels setup and can operate the propellers from each wheel though I can only change the revs from one wheel station.
Overall I would say that I like this system, it has saved some weight and enabled me (as only one engine is installed) to utilise the saved space to create a dining area in the port aft cabin which convert to a double bunk when needed.
But to answer the original question, I do not know of this kind of system being offered by any cat manufacturer.
__________________
Roger
Catamaran "Burnout"
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30-03-2016, 13:02
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#17
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Registered User
Join Date: May 2013
Location: Treasure Island, FL
Boat: Island Packet 35
Posts: 478
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by smj
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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The hydraulic drives were awful in that boat.
Great to have one in front to buddy boat with, though. You could just follow the sheen in the water.
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30-03-2016, 13:37
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#18
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Registered User
Join Date: Apr 2007
Location: Australia
Boat: Island Packet 40
Posts: 6,432
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Re: Hydraulic drive for Catamaran?
There are a number of technologies available with which to implement a hydraulic drive system.
The oldest is probably one using gear pumps and motors with flow through control valves. This is also the noisiest with a fairly high pitched whine from both pumps and motors. Whether of not one experiences slow down or speed up of motors depends upon how independent each of the drives is. If a double stage pump and independent control valves are used to implement two independent hydraulic circuit slow down and speed up should not be a problem.
The quietest, most precisely operated system and least power wasteful would be one implemented using axial piston, reversible, variable displacement pumps. In this system two separate pumps which have reversible fluid flow are used to drive the props through either gerotor or axial piston motors. There are no valves in the hydraulic system the amount and direction of flow being controlled by the movement of a swashplate in the pump. Since there is no throttling of fluid in the operation of the system very little waste heat is generated and power losses in the system tends to be generated by fluid friction which can be mitigated by generously sizing the flow conduits. Unfortunately these pumps and motors tend to be the more expensive although there are savings on the rest of the system. They can be very quiet in operation and possibly less noisy than a mechanical drive system.
Hydraulic systems are advantageous where one needs to transmit lots of power through compact transmission components to serve a number of functions.
Whilst having just a single engine may be appealing in some instances I tend to the opinion that for reliability through redundancy reasons and the average multihull being such a poor windward boat the two engine, mechanical drive is the best solution and that this is why hydraulic drives are not offered by many manufacturers.
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30-03-2016, 15:45
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#19
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Registered User
Join Date: Apr 2007
Location: Marina del Rey, California
Boat: President 43 Sportfish
Posts: 4,105
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Re: Hydraulic drive for Catamaran?
RR--good post.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
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31-03-2016, 08:16
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#20
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by boatpoker
Google " Fisher catamaran images" They built 28' 34' and 37' cats with hydraulic drives from a single Pathfinder diesel.
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I forgot about the Catfishers. Have you ever heard how they sail?
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31-03-2016, 08:39
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#21
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Hydraulic drive for Catamaran?
On a smaller boat, an outboard (diesel outboard if you are outside the states), makes more sense. Ours being tied in with the rudders is almost as good as our old twin engine power boat once we learned how to use her. With directional thrust you can do a lot. Twin engine is still better but not by a lot.
If you are really intent on an inboard diesel, using a single engine with outdrive is an option but our experience is they do take more maintenance. Properly functioning, they are as maneuverable as the outboard.
If you are set on two propellers in the hulls and twin diesels are out of consideration, I would really think a diesel/electric option would make more sense as it could also feed house loads.
I know people will say they don't have to leak but I've yet to see a hydraulic system that didn't leak within 6 months. To my knowledge, no manufacturer is offering them and none are toying with them.
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31-03-2016, 08:57
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#22
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,483
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Re: Hydraulic drive for Catamaran?
I've often wondered why this isn't done in sailboats in general. Fishing boats use hydraulic drives for all there peripheral gear. Tractors etc do it in lieu of gear drives. Heavy equipment uses it. The engine doesn't have to be anywhere in particular with a hydraulic drive. Of course my maintenance manager in industry had a saying "if it aint leaking, it aint hydraulic"!
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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31-03-2016, 09:03
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#23
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by valhalla360
On a smaller boat, an outboard (diesel outboard if you are outside the states), makes more sense. Ours being tied in with the rudders is almost as good as our old twin engine power boat once we learned how to use her. With directional thrust you can do a lot. Twin engine is still better but not by a lot.
If you are really intent on an inboard diesel, using a single engine with outdrive is an option but our experience is they do take more maintenance. Properly functioning, they are as maneuverable as the outboard.
If you are set on two propellers in the hulls and twin diesels are out of consideration, I would really think a diesel/electric option would make more sense as it could also feed house loads.
I know people will say they don't have to leak but I've yet to see a hydraulic system that didn't leak within 6 months. To my knowledge, no manufacturer is offering them and none are toying with them.
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I had bought an old dozer and an old tractor. Once I had new hoses made up never had to add a drop of fluid. Hydraulics need to leak is a myth.
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31-03-2016, 10:00
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#24
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by Cadence
I had bought an old dozer and an old tractor. Once I had new hoses made up never had to add a drop of fluid. Hydraulics need to leak is a myth.
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I've heard people online claim this...never seen it happen in real life.
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31-03-2016, 10:08
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#25
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Marine Service Provider
Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,974
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by Cheechako
I've often wondered why this isn't done in sailboats in general. Fishing boats use hydraulic drives for all there peripheral gear. Tractors etc do it in lieu of gear drives. Heavy equipment uses it. The engine doesn't have to be anywhere in particular with a hydraulic drive. Of course my maintenance manager in industry had a saying "if it aint leaking, it aint hydraulic"!
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Because typically sailboats don't always have an engine running when the hydrolic a need to be used. So you would need to use a battery driven hydrolic pump to generate the preassure for the consumer. It's just easier and more efficient to use electric directly.
Of course on super yacht sailboats you start to see hydrolic equipment but they always operate with at least a generator operating anyway.
__________________
Greg
- If animals weren't meant to be eaten then they wouldn't be made of food.
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31-03-2016, 10:13
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#26
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by valhalla360
I've heard people online claim this...never seen it happen in real life.
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What about hydraulic breaks on autos. Granted they are not pump driven. As I said I have seen no leakage if the pumped hydraulics are plumbed correctly.
I would like Carsten B's input on this.
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01-04-2016, 09:38
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#27
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Registered User
Join Date: Apr 2009
Location: Gulf Breeze, FL
Boat: Kelsall Kelly 42' Catamaran
Posts: 45
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Re: Hydraulic drive for Catamaran?
I have a Kelsall catamaran that was built in 1988 with a single Diesel engine and twin hyd drives. I did a complete refit, new engine, pump, motors, hoses, controls. Pumps and motors weight 65lbs each, all the hoses less than 100lbs, hyd oil 7 gallons (7.2lbs gal). I bought the vessel because of the hyd setup and only 1 engine. The Best thing about using hydraulic's is you can mount things in places other systems won't fit. As for leaks I have only had leaks that I caused by spilling it. Sure there is some whining noise and I have heard louder noise coming from a gearbox on some boats. Still only have the noise, maintenance and cost of 1 engine. There is the redundancy of 2 engines, but after all it is a sailboat and we use the wind as our primary propulsion. Cost of all the hyd system was lest than 1/2 the cost of the engine and way less work then installing a second engine and gearbox.
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01-04-2016, 11:06
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#28
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,208
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by rjdives
I have a Kelsall catamaran that was built in 1988 with a single Diesel engine and twin hyd drives. I did a complete refit, new engine, pump, motors, hoses, controls. Pumps and motors weight 65lbs each, all the hoses less than 100lbs, hyd oil 7 gallons (7.2lbs gal). I bought the vessel because of the hyd setup and only 1 engine. The Best thing about using hydraulic's is you can mount things in places other systems won't fit. As for leaks I have only had leaks that I caused by spilling it. Sure there is some whining noise and I have heard louder noise coming from a gearbox on some boats. Still only have the noise, maintenance and cost of 1 engine. There is the redundancy of 2 engines, but after all it is a sailboat and we use the wind as our primary propulsion. Cost of all the hyd system was lest than 1/2 the cost of the engine and way less work then installing a second engine and gearbox.
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Well said. If you want a motor sailor it may not be the ticket. If you want to get back to the dock having twin screws is nice.
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01-04-2016, 11:43
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#29
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Registered User
Join Date: Nov 2007
Boat: TRT 1200
Posts: 7,268
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by rjdives
I have a Kelsall catamaran that was built in 1988 with a single Diesel engine and twin hyd drives. I did a complete refit, new engine, pump, motors, hoses, controls. Pumps and motors weight 65lbs each, all the hoses less than 100lbs, hyd oil 7 gallons (7.2lbs gal). I bought the vessel because of the hyd setup and only 1 engine. The Best thing about using hydraulic's is you can mount things in places other systems won't fit. As for leaks I have only had leaks that I caused by spilling it. Sure there is some whining noise and I have heard louder noise coming from a gearbox on some boats. Still only have the noise, maintenance and cost of 1 engine. There is the redundancy of 2 engines, but after all it is a sailboat and we use the wind as our primary propulsion. Cost of all the hyd system was lest than 1/2 the cost of the engine and way less work then installing a second engine and gearbox.
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So the weight of the hydraulic system would pretty much equal a new Yanmar 3gm30 with saildrive. Our hydraulic system on our Cherokee was made by Volvo and was extremely expensive, but I'm sure there are better and less expensive alternatives.
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01-04-2016, 13:24
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#30
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Registered User
Join Date: Apr 2009
Location: Gulf Breeze, FL
Boat: Kelsall Kelly 42' Catamaran
Posts: 45
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Re: Hydraulic drive for Catamaran?
Quote:
Originally Posted by Cadence
Well said. If you want a motor sailor it may not be the ticket. If you want to get back to the dock having twin screws is nice.
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The system works great for motoring too, we have made 200nm crossings under power with no problems.
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