Using old boat trim/tilt hydraulics on a tractor.

arkydog · Oct 21, 2015

i appreciate all the replies! i'm only going to build the upper part of a grapple for my 54" bucket hopefully with the boat hydraulics built on the grapple frame. just 2-3 wires ran from a 2-way switch. i broke my ankle and getting together everything for this build when it heals. I have a lot of brush to clear and came up with this. thanks. rob

muddstopper · Oct 22, 2015

Interesting concept I hadnt thought of before. Probably plenty of old boat hydraulics laying around if one wishes to look for them. Someone said the pumps would put out 2200psi. No mention of flow rates. Still, 2200psi can supply a lot of clamping force. With a big enough cylinder you could crush a car. As long as speed isnt an issue I dont see why the boat hydraulics couldnt work. Post some pics when you get the grapple built.

Leejohn · Oct 22, 2015

I don't recall the flow rate and I'm not for sure if it's even posted in the service manuals. I do know the gears are just a little larger then a dime and a hair thicker then a nickel.

arkydog · Oct 22, 2015

it will be a while, broke my ankle couple months back and being type one diabetic i heal slow, about twice or 3 times as long. this winter i will start cutting and building this grapple. just wanted to see if my idea might work and sound like if it will. thanks rob

4570Man · Oct 22, 2015

zzvyb6 said:
Loads encountered during trailering (bumps) and object encounters are much higher than you'd ever generate on a slow moving tractor.

You haven't seen me use my grapple.

arkydog · Oct 23, 2015

i'm old and disabled, had stroke last year and almost fully recovered so speed is no issue. cost is slightly important. more interested is the challenge.

davesl708 · Oct 23, 2015

arkydog said:
i'm old and disabled, had stroke last year and almost fully recovered so speed is no issue. cost is slightly important. more interested is the challenge.

Good luck with the project. Get well soon. Broken bones stink.

4570Man · Oct 23, 2015

The boat cylinders have a 1" bore, but only have a 1/2" ram. The 1/2 ram couldn't stand up to the abuse my poor grapple takes. 2200 psi on a 1" cylinder isn't going to be very much force. It would probably be adequate for clamping brush, but not stumps, logs, and rocks.

aczlan · Oct 23, 2015

4570Man said:
The boat cylinders have a 1" bore, but only have a 1/2" ram. The 1/2 ram couldn't stand up to the abuse my poor grapple takes. 2200 psi on a 1" cylinder isn't going to be very much force. It would probably be adequate for clamping brush, but not stumps, logs, and rocks.

Ayep. Most grapples use at least a 1" ram for that very reason.
Its not so much the closing of the jaws that will bend it as the driving around with stuff hanging out the sides and bumping into things.

Aaron Z

ishiboo · Oct 23, 2015

For light brush it should work fine. At 2500 PSI, that is 1900 lbs of force on a 1" cylinder. Some trim pumps only produce 600psi in the "down" stage which is the grapple retraction. Since you have less surface area on that side of the piston with the rod being in the way, that will be exacerbated by even less retraction force. So you could have times where you get stuck in something and have a hard time retracting.

IMO, this is a pointless waste of time. It takes so little money and effort to add a diverter valve when you already have a FEL, it's not even funny.