Hydraulic Drive Ideas

[Cheechako]

[QUOTE=forsailbyowner;1099614]

Originally Posted by Lake-Effect

less efficient? less reliable than the hurth?

Dpnt know efficiency of hurth. Hydraulic ad states 95% efficiency.

Hurth is described as 1000 hour transmission at cost of $1000 to rebuild. Pita to remove and reinstall.

Hydraulic drive rated for 1000 rpms continuous duty in industrial or agriculteral setting. Would be very simple to remove and replace. Cost around $300 so carry a spare or two.

Not sure where you are hearing this, My 47 footer and my 44 footer both had Hurth transmissions, bought used, ran many hours and not one issue. By my way of thinking, anything without a Hurth is suspect! The cost to rebuild a Velvet Drive is $4500 I hear! OUCH!
I've wondered about Hydraulic motors also. (The engine no longer has to be anywhere near the output shaft!) and it's been done, but never seems to come out well from what I've heard... kinda crazy though, as most fishing vessels have hydraulic operated winches, pullers etc... so they must be reliable. Must be something about the aplication that doesnt work well...???

[glenn.225]

Well to sum it up:

Cons - Heat, weight, efficiency, maintenance, cost, complexity

Pros – flexibility, torque at low RPM

I banged around the idea of small hydraulic drive off-road 6x6 machine (Argo type), every way I looked at it gears and shafts made more sense. hve also thought about hydraulic marine drive but electric may be better.

[sailvayu]

Forsalebyowner it sounds to me like you have made up your mind and now you are trying to convince others it is a good idea. In my experience it is a bad idea, inefficient messy, expensive and will have no resale value. Oh and noisy to boot! If you really want to do away with a normal transmission why not run a generator with an electric drive. you still can power your windlass, winches and what ever with electric and be cleaner and more efficient and take advantage of solar and wind while sailing. Anyway just my thoughts sounds like you already have made your mind up, damn the torpedoes full speed ahead! lol good luck hope it works for you. keep us posted.

[Sailmonkey]

Vetus makes just what you're looking for.......but charge a lot more than the parts are worth. They do need to pay their engineering staff.

Power Hydraulics | Vetus Products | UK

[JRM]

Originally Posted by RabidRabbit

Also most electric boats suck because they lack a diesel genny big enough to run them at full throttle all day.

Most electric boats lack a diesel genny, period. And yet they don't suck. Quite the opposite actually. But don't let other's experience get in the way of your ignorance.

If you're just looking to ditch the tranny then electric, I think, would be better than hydraulic. Mostly because I converted our last boat to electric and would do our current one in a second if I had the funds (and the punch list wasn't ten pages as is) and my hydraulic experience is limited to calling the mechanics at work when they blow. Go with what you know ... It's not cheap, but maintenance wise the savings over hydraulic would be extreme.

What you can do is ditch the tranny, and slap an electric drive on the propshaft. Then adapt an identical motor onto the diesel drive shaft as a generator. If you've got an 18HP diesel now (unless I've crossed threads), you could easily run with a Mars ME0913. You can get those full kits for about $2K, figure another couple hundred for mounts and belt drives from McMaster-Carr. The genny portion probably run $1500. Since the motors and controllers are the same, if you desire spares only one of each is required. Heh, imagine carrying an entire spare engine...

The real sticker shock will be the battery bank. Probably should sit down before you start pricing them out. They're usually the deal killer on electric conversions.

Whole thing soup to nuts probably cost you around $6,000 to $8,000 plus labor. That's a lot of transmission rebuilds...

JRM

[forsailbyowner]

Ok I've been hearing estimates of up to 10k for the system. So I connect the $300 pump to the $250 motor, put a direction control inline for $90 so add a reservior/cooler some hydraulic lines, teleflex cable and lever for shift control, mount to bell housing, dampner(w/machinework) for attaching to flywheel, what's left? I'm a hydraulics novice what am I missing?

[Saltyrope]

Parker Hannifen seem to be a lot more efficient with the set ups that I have read about. I am considering a hydraulic drive and lack of efficiency was a concern. Some claim 20 to 30 % losses, others that it can be as low as 10 to 12 % in losses as compared to around 7 % for a regular transmission. I guess it depends on hose length, cooling, friction losses etc. Here is an interesting read. Anglian Diesels opts for Parker drives on Hong Kong ferry

[Saltyrope]

Originally Posted by forsailbyowner

Ok I've been hearing estimates of up to 10k for the system. So I connect the $300 pump to the $250 motor, put a direction control inline for $90 so add a reservior/cooler some hydraulic lines, teleflex cable and lever for shift control, mount to bell housing, dampner(w/machinework) for attaching to flywheel, what's left? I'm a hydraulics novice what am I missing?

Have a look at the Beta UK site (may be on the US one as well) under Inland Waterways as there is a picture of the componetry. Looks like a pump on the back of the engine (no gearbox) tank full of hydraulic fluid, control valve for forward and reverse, hydraulic motor for the prop, oil cooler for the hydraulic oil, hoses of course and an engine powerful enough to allow more loss in transmission than with a standard gearbox. See my other post for the water taxis. Cheers, John,
Beta Marine | Marine Diesel Propulsion Engines and Generating Sets

[Saltyrope]

This from Beta.

Key points for this system are as follows:
ProsCons• The engine and hydraulic pump unit can be sited anywhere in the boat and this maximises the use of space.
• The engine can be sited away from the steering position to give a quieter running ship.
• Very flexible speed control is available at low rpm.
• Transmission power losses can be between 20 to 30% or more, depending upon the hydraulic pipe run lengths; so the system is on average about 20% less efficient than a conventional engine and gearbox combination where the losses are approximately 7%.
• Generally a hydraulic solution will cost more than a standard mechanical drive.

[boatpoker]

[QUOTE=Cheechako;1102299][The cost to rebuild a Velvet Drive is $4500 I hear! OUCH!
QUOTE]

Suggest you get your hearing checked ..... that price would buy me two rebuilt velvet drives.

[Saltyrope]

[QUOTE=Cheechako;1102299][The cost to rebuild a Velvet Drive is $4500 I hear! OUCH!
QUOTE]

Suggest you get your hearing checked ..... that price would buy me two rebuilt velvet drives.

What has money got to do with it? You own a boat don't you? Tee Hee, JB