my janky 80 Jib crane plan...will it work? (1 Viewer)

[HardyDanger]

OK team.

Because I really don't like my money, I bought as used boat. Don't get me wrong, it's a great thing. However, I need to replace the steering cable in my new yacht, and to do that, I need to lift the motor to remove the dang cable. Really, it's a 1.5 repair, but the dang motor is in the way.

So, while I could find a fork lift, or drive my self to a crane, or rent an engine hoist...that's all fine, but why not do it myself with the help of the mighty 80???

below is the Janky 80 Jib crane "technical" drawing, it all seems to measure out....the question is, will it hold? Easy test is for me and a buddy to hang off the end of it... oh, and the motor has a lift eye on the block, so no straps around the cowling needed. In reality, I only need to lift the motor about an inch or two to get clearance for the replacement cable to go into the tilt tube.

sexy boat pic below.

release the hounds....

 

[80t0ylc]

It might work, as long as the doesn't hop in the LC to head out shopping in the middle of your project...

 

[ppc]

Not a smart move. The "beam" will need to extend off the roof rack 2, 3 or more feet from the pivot point of the rear most part of the rack acting as a lever. At one foot that will be 260 pounds of force, two feet: 2 x 260 = 520 lbs, and 3 feet: 3 x 260 = 780 lbs. I don't think that your roof or roof rack will fair well under that load. Find a big tree, build something from lumber or find a place that has a hoist and pay a few bucks or gift them a case of beer.

 

[NorCal97]

Ditto above...not worth risking a rack, or a roof, or both.

Recently had to do similar work on my boat's outboard, twice. It has a 90hp Mercury on it...just under 300 lbs.

First time (for a transom repair), slung a 1.5" pipe across several rafters in the garage, then used a come-along between the pipe and the engine. Worked great.

Second time (for steering cable replacement), I just removed the thru-transom bolts, loosened the transom clamps, and manually shifted the engine to the left (ahem...port) to gain clearance. Did this all by my lonesome. Had to use sailor words, of course.

Good Luck!

 

[greentruck]

Looks OK to me, presuming the rack is in good shape. The tie in to the ARB is what fixes things. Yeah, if t6he beam only stuck off the back and no counterforce up front it would be seriously unbalanced. If rigged per the drawing, then what you get on the rack, distributed along the length of the board, is the 260 lbs. Even the stock rack, pitiful thing it was, was rated at something like 200 lbs? Prinsu gotta be at least that, so as long as it's not rusted out or something drastic, and it's distributed along the drip edge, much better than on the roof itself.

It's a lightweight in relative term among outboards, too.

 

[cjmoon]

This is what 800lbs of pipe does on a gutter mount roof rack. I’m guessing the factory one would have been toast.

 

[greentruck]

Ouch, that's ugly. Too much weight there, but might have been OK if load was better balanced front to rear - or if you'd had plush shocks on? Plus I presume that was driven home and this will be a static lift.

 

[ppc]

Looks OK to me, presuming the rack is in good shape. The tie in to the ARB is what fixes things. Yeah, if t6he beam only stuck off the back and no counterforce up front it would be seriously unbalanced. If rigged per the drawing, then what you get on the rack, distributed along the length of the board, is the 260 lbs. Even the stock rack, pitiful thing it was, was rated at something like 200 lbs? Prinsu gotta be at least that, so as long as it's not rusted out or something drastic, and it's distributed along the drip edge, much better than on the roof itself.

It's a lightweight in relative term among outboards, too.

Tying off the front to the ARB does stabilize the load but does nothing to reduce the force on the rear of the rack that acts as a fulcrum. The force on the front would be in the upwards direction.

 

[I Lean]

Do you have a winch in that ARB bumper? Actually, even if you don't you could build a version of this idea:

 

[greentruck]

Tying off the front to the ARB does stabilize the load but does nothing to reduce the force on the rear of the rack that acts as a fulcrum. The force on the front would be in the upwards direction.

The force of the load would be, but I assume that the strap will be tightened to put a counteracting force on it. That is what will distribute the downward force along the length of the rack, spreading it out so the rear end of the rack doesn't become a fulcrum. Otherwise, you're right, things could end up like the pipe load.

Worst case, the weakest point in this is actually the crosswise part of the rack right at the rear. If not strong enough, that might bend in the middle. To protect against that possibility a 2x4 could be set on edge across the width of the rack to distribute the force more evenly there., but should be repeated along the length of the rack in order to spread the weight along it as before, if it's decided the rack requires that reinforcement.

Note that cjmoon's rack did not give there, but it looks pretty substantial. Load was centered on the truck cabin, but needed to be centered between the support points. The bulk of the load was on the rear support point, which is what crumpled things under a dynamic load. The Prinsu isn't that beefy, but might be up to the job, the key is to spread the weight evenly, plus has the advantage of being a static load.

 

[Dindu Nuffin]

If a piece of equipment already exists to safely perform the job you require, why not just do that? This is a one time thing and the goal is to replace the steering cable, not build some Sanford & Son rig, right? You're not going to be using whatever you contrive all day, five days a week, right? I'd just rent the engine hoist and move on with life. Like someone else said- I dont see it being worth risking your roof or rack.

 

[slow95z]

How many miles on the truck, what's the interior like? Once you crush the roof I might want to buy it to part it out

 

[yotakrawler]

Not a smart move. The "beam" will need to extend off the roof rack 2, 3 or more feet from the pivot point of the rear most part of the rack acting as a lever. At one foot that will be 260 pounds of force, two feet: 2 x 260 = 520 lbs, and 3 feet: 3 x 260 = 780 lbs. I don't think that your roof or roof rack will fair well under that load. Find a big tree, build something from lumber or find a place that has a hoist and pay a few bucks or gift them a case of beer.

I could be wrong but I don't think that is how a force calculation works. I think you are talking about torque which will be ft-lbs. The force will still be 260 lbs on the roof, the key will be distributing the load and not having it all at one point. In general I think many of us are putting more than 260 lbs on the roof with tents and 2 adults. Still not saying this is a good idea.

 

[gofast]

30-45 bucks rents you an engine hoist.

 

[Cruiserdrew]

This looks like a good excuse to buy an engine hoist. 260 pounds would be nothing for it.

 

[Cruzerman]

Nothing could possibly go wrong with that setup...

 

[Heckraiser]

Around here an engine hoist rents for about $40 a day. Or get a $60 chain hoist at harbor freight and hang it from a sturdy tree or tie together several rafters in your garage. Then sell the hoist when you're done. Don't risk body damage to the 80 when there are perfectly good alternatives at a similar cost to your wacky idea.

 

[JeepinPete]

Take your idea, but remove the roof rack from the equation. The frame of the truck extends beyond the rear of the body of the truck. The aluminum tread plate sits on top of the frame. Build a lumber A-frame, set it on top of the frame, and place your beam on the top of the A-frame. Tie the beam off to your front bumper as drawn. I would set it up so that it is an inch or so higher than the floor of the roof rack.

 

[BILT4ME]

Grow a pair and squat lift it from inside the boat.

Or, ask that neighbor you're always helping to help you for once and the two of you lift it and slide it over.

Or.....lower the front of the boat trailer. Block UNDER the boat engine. Raise the jack (or front) of the boat trailer to lower the rear of the boat and hence....lift the engine relative to the boat. Use the axle as the fulcrum.

 

[Lumpskie]

My idea, if you have a winch, would be 3 long tubes tied at the top and bracketed half way down... making a tripod. Hang a short chain with a snatch block from the center. Then use your winch to lift/lower the engine using soft strap. You could get fancy and make the tubes telescoping for easy storage and enabling different heights. Who knows what trouble you could get yourself into with a setup like that in the future!