Mechanical Clutch Needed To Engage Belt - Powering Compressor Off Boat Motor

[cadmus]

My steering hydraulics drive off of a massive belt driven pump off of the port engine. They are cooled using waste raw water off of the starboard main engine. The heat exchanger is quite small, so I don’t expect that there is a lot of churn in the system. Reservoir is 2 gallons.

My bow thruster hydraulics (since removed) are clutch driven off of the generator, and the oil is not cooled (intermittent use) and the reservoir is massive. About 15 gallons.

On my last boat, the steering pumps were direct drive off of both port and starboard engines, the reservoir was 35 gallons, and the oil was not cooled.

Depending on compressor size and motor HP, you can get away without cooling, but a little cooler isn’t expensive not hard to mount, and eliminating a big hydraulic tank is priceless….

Remember, a hydraulic pump and a hydraulic motor are the same thing….

Thanks for this response.
My sailboat is small. Nor'Sea27. 10,000lbs +/-1500. My entire fuel tank is 30 gallons plus two 5 gallon jerrys. My steering is powered with a wooden tiller attached to a barndoor of a rudder. My bowthruster is a long oar. (i hope that was taken as funny)

I was using a 1980s Yanmar 2gm (13hp) which shared the front end of a tractor engine, a hydraulic pump could have meshed into the cogs of the cam shaft. I intended to run a WW2 kidde (which are by original design hydraulic) off that pump. Jim Sheldon advised not to do it using hydraulics. I should have asked why in detail, I hate to bother him in his retirement so long after. I see other great advantages of hydraulics, especially a windlass to preserve my spine and a manual backup engine start system (accumulator+handcrank+enginestarter). If you want to suggest some texts or videos on the topic please do. It was originally my plan and I abandoned it.
We will likely be repowering to a Yanmar 3ym20, Beta20, Yanmar 3ym30 or Beta25 (in order of preference). I rebuilt the engine bed to take either and the decision will be driven largely by what accommodates the compressor best.

 

[cadmus]

A consideration would be how many HP the clutch can handle. My big belt driven hydraulic pump is about 2.5 HP. When looking at other belt driven applications, it seems that 5 Hp with V-belts is about the limit....

The compressor is dinky. A Bauer Varius. I am told it has a wider range of RPM than most but the best feature is the really small size. I doubt it needs more than 2hp even at startup. Not sure how to determine for sure (EDIT: Planned to examine amp draw when powered by the existing electrical motor but not sure that will translate perfectly to a mechanical system).
Knowing a belt will slip or a clutch will fail above 2hp is reassuring as the engine is the more valuable asset.

 

[100days-a-year]

We used a 12volt a/c clutch off of a car for the pto on both washdown pumps and hydraulic pumps for the compressor.
Belt off the flywheel freewheels on the clutch pulley unless the clutch is energized.
About a $100.
On my personal boat I did direct drive off a 10 hp Yanmar. Rough estimate is 1cuft per min per hp.

 

[100days-a-year]

You'll need to size your pulleys appropriately for rpm when using direct drive. And they really don't like varying rpm as mentioned. We used timing lights to tune compressor rpm.

 

[cadmus]

We used a 12volt a/c clutch off of a car for the pto on both washdown pumps and hydraulic pumps for the compressor.
Belt off the flywheel freewheels on the clutch pulley unless the clutch is energized.
About a $100.
On my personal boat I did direct drive off a 10 hp Yanmar. Rough estimate is 1cuft per min per hp.

Clarification if you will kind sir: 10hp yanmar was powering the compressor only, right? not the prop and the compressor? and what was the compressor model/size/brand?

Do you recall the brand and model of your electromagnetic pulley clutches and how long lived were they in marine environment.

 

[cadmus]

You'll need to size your pulleys appropriately for rpm when using direct drive. And they really don't like varying rpm as mentioned. We used timing lights to tune compressor rpm.

I planned to use a bike odometer.... but i like the strobe idea if I can find one.

 

[Wookie]

I planned to use a bike odometer.... but i like the strobe idea if I can find one.

Hand-held tachs and strobotachs on ebay are a must for the small boat mechanic.

 

[100days-a-year]

Yanmar was strictly for the compressor.
Sorry, I have no recollection of the model numbers for the a/c clutch but they needed to fit the shaft of the pump being driven. Lasted several years in a relatively dry bilge.

 

[Gone for diving]

What's wrong with mouning a pulley on the front of the eng, and a over center, idler that tensions the belt,
Like some lawnmowers use...
When you don't need it, belt comes off...

 

[tbone1004]

undefined | undefined | KOHLER

kohlerpower.com

something like that solves the fuel problem and probably isn't that big of a delta in price. It's basically 1cf in volume, not big at all.