Using the boom as a crane - sliding track

[jwcolby54]

Has anyone ever seen a block on a sliding track attached to the underside of the boom? Would this work?

I see a lot of "we tied a loop over the boom" kinda threads but what about screwing a track to the underside of the boom and allowing the block to slide along the length of the boom? That would sure make moving things out from the deck to over the water (or dock) much simpler.

For example I want to pick up a dingy with small motor attached and get it over the deck. I can pick it up with the boom, but then have to swing the boom and the dingy would end up over the cockpit, not over the deck.

With a slide rail, I could pick it up from alongside the boat, and then holding the boom in place, slide the block towards the boat and over the deck.

[ctl411]

You can accomplish the same by using two sets of tackles. One at the outboard end to lift one at the gooseneck to pull the first inboard. We also use the halyard to lift the boom a bit this give more options.
We don't usually use the inboard tackle, just main halyard and the end tackle.

[ryon]

There are so many variations of boom, boom tackle, boom lift, halyard, outhaul, and tag line that are much simpler.

[RaymondR]

You could do it and it would work but would look a bit ugly and may be hard to control as the boat lists.

[Terra Nova]

Originally Posted by ryon

There are so many variations of boom, boom tackle, boom lift, halyard, outhaul, and tag line that are much simpler.

This. A track is simply unnecessary.

[Cheechako]

How would you swing past the stays? Just use a halyard forward....

[cabo_sailor]

In the past I've detached the motor at the stern using a motor hoist that is part of my wind generator pole. I then used my spinnaker halyard attached to a three point harness to lift the dinghy, a 10.5 ft Achiles, onto the foredeck.

I've also seen people attach a block and tackle to the end of their whisker pole.

[jheldatksuedu]

If you use the halyard to lift the end of the boom and hang the weight you are lifting from the end there is little chance of damaging the boom. Supporting a weight from the center of the boom would risk bending the boom. To move the weight closer to the mast you lift with the halyard, use a block and tackle to lift the weight connected at the end of the boom and it doesn't change distance from the mast. Swing the boom to move it in and out, 2 preventers from the end of the boom to somewhere on deck controls boom position. You can see this on my card, and also on the first picture on my website, as well as many other places on there. I use this system so much that it accidentally ended up as the picture of my boat that I have on my card.

[sailon46]

By the time you spend the $$$ and mess up your boom, what I did was pay Defender about $300.00 the sold me a Forespar dingy motor hoist and I mounted to the stern of my boat. Where this system earns every penny I paid is in rolly anchorages in the Carrib where it is difficult to hoist the outboard any other way without hurting yourself or the boat.

[sailon46]

As far as the dingy is concerned I lifted out of the water onto the deck with my spinnaker halyard. The routine goes very easy without messing ups so far.

[FamilyVan]

I've seen a Stay sail boom rigged to make a crane, no track as I recall, just a snatchblock with a hook. It was used for lifting dinghy's.

I lift my dinghy just with my main halyard, I don't use the boom at all. No motor though.

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[jwcolby54]

I just see the boom being used as a big, heavy duty crane. But a real crane can move payloads in and out along the boom. Like the ones that build buildings in a city. We have everything except the track.

The track changes it from "pick it up and swing it anywhere on a fixed arc" to "pick it up and swing it anywhere within a fixed arc area". Fundamentally very different. Even more so as the boom gets longer.

I started by looking at the little "cranes" but they are little. Max about 30" extension. Max about 220 lbs. Only on a circular track. Yea, it works, as long as you only need to pick up no more than 200 lbs, no more than 30" out from the boat, and only need to deposit the payload within 30" of the post. And not very high lift either by the way.

Or you do this one piece with the (little) crane, and this other piece with a halyard.

Understand that I may very well end up doing exactly that, but not without grumbling. I am going to single hand most of the time. I don't have a "mate" to grind a winch while I hold the motor stead standing down in the dink. Etc. No "inside the box" solutions are working very well for me.

But building a real crane (with track) on the bottom of the boom isn't trivial either. Having done so however you get a long crane boom, and a huge arc area available to place the load in. All the way aft in the cockpit, or up alongside the mast, or anywhere in between.

My grandfather was a bee keeper. He built the entire thing to use to hoist stands of bees up onto a flatbed truck. Once built, it worked a treat. One could pick up four boxes of bees, hoist them from ground level to shoulder height, slide them anywhere along either edge or back of the flatbed, and set them onto the bed of the truck.

I would be starting with the boom. Track on the bottom. Motor to wind the tackle up and down.

Just blue sky stuff.

Never been done before obviously so no where to go to see it in action.

[FamilyVan]

Originally Posted by jwcolby54

I just see the boom being used as a big, heavy duty crane. But a real crane can move payloads in and out along the boom. Like the ones that build buildings in a city. We have everything except the track.

The track changes it from "pick it up and swing it anywhere on a fixed arc" to "pick it up and swing it anywhere within a fixed arc area". Fundamentally very different. Even more so as the boom gets longer.

I started by looking at the little "cranes" but they are little. Max about 30" extension. Max about 220 lbs. Only on a circular track. Yea, it works, as long as you only need to pick up no more than 200 lbs, no more than 30" out from the boat, and only need to deposit the payload within 30" of the post. And not very high lift either by the way.

Or you do this one piece with the (little) crane, and this other piece with a halyard.

Understand that I may very well end up doing exactly that, but not without grumbling. I am going to single hand most of the time. I don't have a "mate" to grind a winch while I hold the motor stead standing down in the dink. Etc. No "inside the box" solutions are working very well for me.

But building a real crane (with track) on the bottom of the boom isn't trivial either. Having done so however you get a long crane boom, and a huge arc area available to place the load in. All the way aft in the cockpit, or up alongside the mast, or anywhere in between.

My grandfather was a bee keeper. He built the entire thing to use to hoist stands of bees up onto a flatbed truck. Once built, it worked a treat. One could pick up four boxes of bees, hoist them from ground level to shoulder height, slide them anywhere along either edge or back of the flatbed, and set them onto the bed of the truck.

I would be starting with the boom. Track on the bottom. Motor to wind the tackle up and down.

Just blue sky stuff.

Never been done before obviously so no where to go to see it in action.

No need for a fixed arc. Snatch block on end of boom with its own purchase for lifting, topping lift to the boom raises and lowers the boom giving you full control over the size of the arc. Raise boom, reduce size of arc, lower boom, increase size of arc. Ever seen an old- pre hydraulic boom lift, like on a boom truck, or union purchase for handling cargo on an old ship? That's the principal they work on.

Hope I'm explaining myself well enough.

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[Stumble]

Take a look at the Harken access rails. You would have to screw the track to the underside of your boom and install the car, but it wouldn't take more than an afternoon to install.

Loads on the boom may be an issue if you try to swing to much weight, but presuming your dinghy doesn't weigh more than you do, and you are ok sitting on your boom, I don't see any major issues.

[Terra Nova]

Van--good post.

54--you don't need a track's added complexity/cost/issues.