Using old boat trim/tilt hydraulics on a tractor.

[arkydog]

Hey everyone. I was wondering if anyone had, or thought about using an inboard/outboard Mercruiser outdrive hydraulics from a boat that are 12v activated to run say an upper grapple arm on a front loader bucket instead of tapping into the tractors hydraulics? It would seem that it should work because i think everything is there. The two cylinders for opening and closing the grapple, the releif valve, the hydraulic pump, and the motor. the hydraulic hoses would probably have to be made longer, but that shouldn't be much of a problem. I'm thinking that there wouldn't need to be all that much pressure to hold the brush in the bucket unless you were trying to hold tree trunks, at which time you could chain the trunk on. This all works to open and close the grapple.

The pump and motor are all in one unit and could be mounted on the grapple mount with only the wires running back to the dash with a quick connect electrical plug near the pump.

Any ideas either pro or con?

Thanks Rob

 

[davesl708]

It would be slow operating due the flow rate of the boat pump. Also I don't think the pump will be built to withstand the pressure of loaded cylinders on your tractor during operation.

 

[J_J]

I have a small hyd systems for boats that am using.

I use it on my pull behind scraper blade to raise and lower the blade for transport.

 

[zzvyb6]

It would be slow operating due the flow rate of the boat pump. Also I don't think the pump will be built to withstand the pressure of loaded cylinders on your tractor during operation.

Loads encountered during trailering (bumps) and object encounters are much higher than you'd ever generate on a slow moving tractor.

 

[davesl708]

Loads encountered during trailering (bumps) and object encounters are much higher than you'd ever generate on a slow moving tractor.

I would disagree. Outboard motors are near balance on the transom. Load on the hyd. cylinders would not be that great. Stern drives do not have that much weight out past the cylinders. My cruiser's tilt trim and lift cylinders are powered by the same pump. The pump is very light duty with plastic hoses operating the cylinders not high pressure lines. The cylinders on boats are very small volume. The pump may put out 1/4 gal. per minute and a few hundred pounds of force.

The force applied against the grapple cylinders will be high when a log is off balance and you hit a bump. The twisting force would be much more than a boat motor on a trailer with springs and sometimes shocks.

 

[zzvyb6]

I would disagree. Outboard motors are near balance on the transom. Load on the hyd. cylinders would not be that great. Stern drives do not have that much weight out past the cylinders. My cruiser's tilt trim and lift cylinders are powered by the same pump. The pump is very light duty with plastic hoses operating the cylinders not high pressure lines. The cylinders on boats are very small volume. The pump may put out 1/4 gal. per minute and a few hundred pounds of force.

The force applied against the grapple cylinders will be high when a log is off balance and you hit a bump. The twisting force would be much more than a boat motor on a trailer with springs and sometimes shocks.

Not quite. He has an I/O outdrive system. And, just because an outboard is somewhat balanced at the dock. the thrust vector from the prop at a 3, 4, or 5 to 1 leverage arm on a 6,000 lb boat at 50 knots is VERY large and must be contained by the electrohydraulic system at ALL outdrive angles. This includes actually lifting the transom weight when the drive is at full droop at a WOT launch event.

For example, my OUTBOARD bass boat (3500# dry weight) trim system can actually lift my boat and trailer off the ground with a block of wood under the skeg when tied down to the trailer. And it must handle a thrust vector capable of pushing us 50 knots across the swamp with a couple of guys, 15 gallons of gas, two dogs and fish wells full of water.

Now we're not sure what unit this guys has, how big his logs are, or how much travel he needs. But if the unit is on hand (free), I'd try to make it work. Junk yards around me are full of boat trim units, snow plow pumps and cylinders, and old farm scrapola. You pay by the pound going out the door, not by what it used to be. I'm used to taking more out of a scrapyard than bringing stuff in. That's a BAD habit. But, I like this particular idea very much.

 

[davesl708]

Not quite. He has an I/O outdrive system. And, just because an outboard is somewhat balanced at the dock. the thrust vector from the prop at a 3, 4, or 5 to 1 leverage arm on a 6,000 lb boat at 50 knots is VERY large and must be contained by the electrohydraulic system at ALL outdrive angles. This includes actually lifting the transom weight when the drive is at full droop at a WOT launch event.

For example, my OUTBOARD bass boat (3500# dry weight) trim system can actually lift my boat and trailer off the ground with a block of wood under the skeg when tied down to the trailer. And it must handle a thrust vector capable of pushing us 50 knots across the swamp with a couple of guys, 15 gallons of gas, two dogs and fish wells full of water.

Now we're not sure what unit this guys has, how big his logs are, or how much travel he needs. But if the unit is on hand (free), I'd try to make it work. Junk yards around me are full of boat trim units, snow plow pumps and cylinders, and old farm scrapola. You pay by the pound going out the door, not by what it used to be. I'm used to taking more out of a scrapyard than bringing stuff in. That's a BAD habit. But, I like this particular idea very much.

The trim cylinders on my 26ft cruiser are plastic with 3/8" steel rods. The cruiser displaces 6500lbs. The drive trim cylinders are the same size but have steel cylinders. The boat on the water weighs 6500lbs but moving it through the water requires much less force. The trims are only lifting part of the weight. The same is true with the drive trims. They only have partial weight of the boat due to riding on top of the water.

arkydog can sure give it a try. I wouldn't put to much money or effort into it. The junkyard will probably have a more robust system to work with.

I agree on the junkyards. Could easily bring home more stuff than I have room for.

 

[PILOON]

While at 60 MPH water is harder than you think, once adjusted to position those tilt cylinders do not take all that much abuse.
On a grapple you'd be tempted to clamp with max forces and I suspect you'd be disappointed .

 

[Sprinklerman]

Great idea . I think I have a old merc set up in the shed

 

[Leejohn]

The stern drive unit work just fine, just a little slow. If you use only one cyl. it would double the speed. The power unit well pump up to 2200 psi if I remember right. I could check that for you if you need the info. The older units have 1" piston in them, there are also built in relief valves in the piston. The relief works if you pull the rod out they open and when pull isn't there anymore there is a check valve to let it bleed back to where it was. There is a floating piston in the cyl that let the piston to be able to return back to where it was. Over loading when pushing rod in it could bend the rods or bust the outer housing of the cyl. By the way the rods are 3/4 ". I would give it a shot if the speed doesn't bother you.