Heh... I see the above question a lot here, and I've heard a number of good responses:
All good ideas, but speaking as someone who's pulled v8 engines out of two boats, they're all too much trouble to do on a regular basis. If I need to get to the underside of the engines or service the transom kit (like replacing the trim hoses) then it's a major problem to arrange to get the engine out, and an expense I don't need.
- Use the header on your garage door and a chain hoist
- Rent an extra large engine hoist
- Use a nearby tree and a chain hoist
- Use a regular engine hoist if you've got a small boat
- Put a regular engine hoist inside a big boat and move the engine out of the way as much as possible
- Have a friend with a skid loader or backhoe come over and lift it out
- Have the local boat shop take it out of the boat and put it back in, while you do the rest of the work
Plus I have need to lift things other than engines, like the windshield assembly on my 21 footer, the sterndrive, or even lift the whole boat off the trailer to fix the support structure (adjust tongue weight or whatever).
So, here's my own solution to the problem.
I have a TIG welder which I'm getting practice with and getting decent at welding steel (still working on aluminum). So I decided to make a hoist. I went to discount steel and aluminum here in downtown minneapolis and bought some tubing. I wanted a super heavy duty hoist, plus I was going to make it tall, so I wanted at least 4x3 rectangular tubing with a 1/4 inch wall.. basically heavy duty trailer tubing.
I got 5x3 5/16 tubing since that was what they had in stock. I bought enough to make the vertical post, the horizontal base, and I also got some 3x2 tubing for a "foot" on one side. I picked up some 5/8 plate for making hydraulic mounting points.
The hydraulic ram I got from harbor freight... it's a standard generic model they and Northern Tool both sell, 8 ton long ram air/hydraulic cylinder with mounting loops:
I also used a pile of scrap metal I had from various things... my neighbor's garage clean-out, a boat trailer I scrapped, etc.
The fasteners used are farm type pins.. the main pivot is a 1 inch forged hitch pin, the bolts on the vertical are 3/4" grade 8, U bolts on the hook are trailer axle attachments. The hydraulic pins are 5/8" forged trailer pins. The hook is a cast steel towing hook from a truck bumper.
I sat down to several nights with the welder. I didn't take pics of the assembly for various reasons, mostly because I didn't want to take the time, and frankly seeing how it went together is boring in this case.
(apologies for the blurriness) That's my 21 footer on the left.
The hard parts were figuring out a design to hold the weight I wanted, designing it so I could insert an extension section to make it taller as needed, and finding casters that would work for it. The frame itself can hold up to 8-10 tons easily, but the casters are too small for that. The ones on there can maybe handle 1 ton total max, they're a temporary solution. This thing isn't too useful if I can't move it around.
I did buy some heavy duty casters from a surplus place, but didn't think through the size... they're about a foot tall, which would make this thing even more unwieldy. I'm going to make some roller type casters out of aluminum or nylon that can take the weight. I also have planned from the start to weld a spare axle I have onto the rear of the hoist so I can use the tires to help move it, and I'll also weld a hitch onto the rear of the horizontal beam so I can tow the thing anywhere I need. I'm not sure if I have to license it as a trailer, though I suppose I'll find out.
Here's a pic of my first test:
The "air" part of the hydraulics is nice. I can use a 5 gallon tank of 120PSI air for one lift, saves some arm movement. It works better attached to a compressor.
At some point I may replace the ram with a 24" hydraulic cylinder, and a 12 volt power unit and battery. That would extend the range of lift and also add some power.
Right now it can lift either of my friends' RIB boats off their trailers completely (20 footer and a 17) but needs some extra fold-out legs to be completely stable (gonna add those too).
As you can see it picked up my truck front end ok, and I did some nasty things to test the stability, like pushing the whole truck sideways with my foot in the air. The hoist flexed a little but didn't creak or bend.
It can lift loads from 9 1/2 feet in the air and put them down to 5 feet, which is perfect for removing my engines. The 4 foot extension should let it pick up engines out of the 30 footer a friend of mine owns while it's on the trailer, once I get those support legs installed.
Total cost in metal: About $250
Total time to build: 8 hours
Hydraulics cost: $90+ tax
Total weight of the unit: about 400 lbs
height: 7' 6"
lift capacity: 2 tons at end of arm, 8 near the ram
lowest lift: 5 feet
highest lift: 9' 6"
welder: TIG, DC, 15 cfm 100% argon, 3/32 and 1/8" thoriated tungsten, 3/32 and 1/8" filler rod, 200 amp setting
I went through 3 80 cf argon tanks while doing this because my welder has a leak and I forgot to turn off the gas twice, which sucked. $45 a tank fill cost later I'm remembering to turn off the tank valve and learning to conserve gas while welding.
Rental of the big engine hoist I was using was costing me about $75 a day, so it'll pay for itself in about one year, plus I can pull fenceposts up, fix trailers more easily, and more safely work on large objects around my house (no more dislocated bones while working on trailers).