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Cartop Dinghy Loader


Garry

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For something a bit mre complex, have a look at this one...

http://www.abc.net.au/tv/newinventors/txt/s1889951.htm

It is a way of car-topping a boat while towing something else, like a caravan, or another boat, and then taking it off the roof and quickly turning the frame into a trailer.

The video on the website explains it all...

Or, if you are into canoes and kayaks, have a look at the Tryak, a 3-piece sit-on kayak that is pulled together by a strap tensioned through a tube running through each piece. http://www.abc.net.au/tv/newinventors/txt/s1883861.htm

You could probably do something similar with nesting dinghys, perhaps with a strap each side rather than one in the centre....

Cheers, Peter

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I've been wrestling, myself, with the car-top issue (and the boat in question) for a few weeks now. My 11' long 4.5' beam Michalak Piccup Pram was to be my little launch-anywhere boat, but it came in at over a hundred pounds, and I need to be able to single-hand the whole process. I started out with just a couple of transverse 2X4s atop the rack on my Toyota minivan. Trying to get the beast up there endangered me, the boat and the car, and it scared me into making a sort of loading ramp by running a 2X4 by 8' rail from the ground to one end of each transverse piece. Now I tip the boat against these rails, get underneath the cockpit, and lift the boat up the rails from the inside. Still a lot of work and I continue to dent the car sometimes, but I don't always feel as if I'm teetering on the edge of disaster. I'm thinking some sort of tackle might be helpful, both the get the boat up there and to provide a way to hold the boat in place part way up when I want a rest. Technique still needs work.

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  • 2 weeks later...

I built my own version of the cartop dinghy loader as well as a strap on dolly. I am very pleased with how it worked out. Now its easy to move my 11 ft. Spindrift around and load it on the van by myself. And the loader folds up for easy storage and transportation.

Check it out at http://www.pbase.com/sailrosita/my_other_boats

If the image is too big, scroll to the bottom and select "medium."

79618146.jpg

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Gary, Thanks for posting the pictures of how you built your dobberish cartop loader. The idea to use hoops and hooks to hinge the lift is ingenious. One comment though, why not position the dolly nearer to the center of the boat? This will make it take much less effort to wheel it to the water or shelter.

Ed

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Garry, I'd like to try your idea--having committed enough errors of my own. A couple of questions: how do your lifting pieces hinge to the roof rack? My ramp bolts on, and that slows the procedure a bit. Oh, and what is the cleat for? Your excellent pictures make everything else clear to me.

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The roof rack beams (2x4s) have an eye screwed into each end (so I can load from either side). The lifting rack has a hook screwed into each end. I think I used 5/16" screw eyes and screw hooks. Much fast than bolt or slipping a pin in and out of hinges. And pletny secure.

I'm not sure what you mean by the cleat?

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Jeff,

I have added a detail drawing to answer some of the questions I've recieved about the pivot point, the cleat, and hinge points. This should answer your question about the cleat.

79730395.jpg

Roy,

This should work just as well with the dinghy nested. You may want to construct a larger gunwhale block to safely catch the gunwhale when rolling the dinghy onto the lifting rack. Maybe add a 2x4 on edge to the top of the gunwhale block that I show. I can't see any other problems that might arise.

I'm glad you guys find this design useful. I'm really pleased with how it works!

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Gary, one final(?) question, if I may: I would expect too much flex in supporting a 112lb boat with the lifting rack 2x4s laid flat, and am considering running them with broad sides vertical. The rack would also make a neater package this way, since the whole would be 3 2x4s laid flat against each other rather than edge-to-edge. I could maybe hinge the lifting legs and support leg by running a stout bit of rope through all three, leaving just enough slack in the rope to spread the legs in use. Or, if that rig was too insecure, I could use barn door hinges on the lifting rack as well as the support leg. Any thoughts?

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Jeff,

I'm sure you could do it that way and I like the idea of folding up more compactly.

But I assure you there is no concern about the weight. I don't know exactly, but I'm sure my boat is over 100 lbs. and there was no noticeable flexing. Remeber, the weight is spread out over the beam and two 2x4s. I'm sure there is plenty of safety factor there.

It would be easy to set up a test on a pair of sawhorses.

Garry

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I too was wondering about using the 2x4s on edge. This would also allow you to make the car to loader hinge such that when the loader it in its 'up' position the hinge is not exposed. This would make moving the boat onto the car a little less risky (eg minimal need to lift the boat when passing the rack/loader hinge joint.)

On the down side the attachment to to car is a little harder...

Ed

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Jeff and Ed,

I've thought more about the idea of making the lifting rack with the 2x4s standing up rather than laying flat. I don't think this is necessary for strength but I do like the idea of folding up into a more compact bundle. With the hook-and-eye connection at the rack, the 2x4s on the rack can still be flat. The attached sketch shows my idea bout how to make the hinge block for the three legs (two liftingrack legs and one support leg).

The only drawback that I can see is that the lifting patform is somewhat narrower. The dinghy contacts the lifting rack at four points. The two closer to the hinge end will be about 10" apart instead of 15" with the flat legs. However, the two contact points closer to the cargo rack will still be almost as wide so the dinghy should still be stable when lifting.

If you build one of these, please let us know how it works.

Rack on edge.pdf

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Interesting. Thanks. I would worry a bit about that strap hinge. It has to support quite a bit of weight when the rack is up. I would be tempted make the 'but' piece out of three pieces of 2x4 instead of one, putting the lifter hinge between the two outside pieces. I would then round the top of the lifter and drill a hole through all three pieces, insert a metal shaft (I) and cap the ends (+) .This would be a bit more work but would be less failure prone (the "."s are empty space where the lifter pivots).

You could probably get away with a wood shaft if you put a plywood top on the 'but' piece such that the lifter is in contact with the ply when lifting so the ply takes some of the load.

---+-------

....I....----

---+-------

I may be worrying for nothing? Comments?

Ed

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I like the idea of making the pivot block out of three pieces. I wouldn't worry too much about side loads on the support leg. The triangle shape of the lifting rack will ensure there is no sideways movement. And a heavy duty strap or butt hinge will certainly support more weight than I can lift.

I don't really like the idea of having all three pieces pivot on one axle. That would allow the two lifting legs to twist a little in relation with each other which could add a little instability into the lifting rack. I would prefer to have one solid triple-thick 'butt' block to which all three pieces are hinged. The triple thick block would allow the use of (what I call) a barn door hinge (one half like a butt hinge, one half like a strap hinge).

Here's a sketch.

80038984.jpg

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Started putting together a quick-and-dirty version of Gary's last design. After I had the leg and rack hinged to the 3-piece pivot block and hooks and eyes in the ends, I set the thing up to test the geometry and got a nasty surprise: the end of the rack can swing back and forth by almost 6" while the pivot block wiggles on its hinges. Gary might not have encountered this with his larger vehicle, but my roof rack is a rather short one, making the triangle it forms with the lifting legs a long, narrow one. The fact that the pivot block has 2 hinges parallel to each other allows this movement. I began to wonder why it needs two hinges in the first place: why not fix one lifting leg rigidly to the pivot block and let the other lifting leg do all the moving? That should reduce the wiggle considerably. I'm going to try it and see.

Oh, also, I decided that using 2x3s for the lifting let and a 2x2 for the support leg would lighten the load but still be plenty strong.

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