dingy hoist block & tackle?

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OffLeash

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C Dory Year
2007
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255 Tomcat
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OffLeash
I am fabricating a hoist to make loading my inflatable (58 lbs) on our Tomcat a little easier. I have seen some great examples many of you have.
For those of you who have a hoist,

1. What combination block system use? 2 and 3 block or a 2 and 2 block set up. Also what size line.
2. I know that 1/4 inch line is strong enough but is it too small to pull on for your hands?
3. Does your hoist interfere with your radar transmission?
Any thoughts would be appreciated.
Thanks
 
The Garhauer davit uses 3 blocks on the bottom and dead eye, 2 blocks and then a change of direction block--so ratio is 6:1. The line is 60' of 5/16 dacron double braid. The blocks are works of art, with very smooth roller bearings, and fairly large race, to decrease the friction. This is easy for me to use, even as an 81 year old. Sometimes we lift the boat with Torqeedo in it, and that brings the weight close to 100#..

LD6-1S%20(A)_final.jpg



They will customize at least the height of the two sections--not sure if they customize the length of the arm, but I suspect unless you have a machine shop, it would be hard to beat the utility and cost. They fold down to the point that they fit in the side pockets of both the 22, 25 and Tom cat.

It does not make much difference if they do not reach to the mid point of the boat--once the dinghy is on the top, it will swing/slide in place very easily.
I feel that a use of a spreader bar makes the whole thing a lot easier. Mine is at the balance point:

DSC01575.sized.jpg


One could put the D rings a little lower on the boat, but my lifting point is just an inch or two above the top of the pontoon. If you use a bridle, it will put the lifting point attachment to the moving block much higher, and you will need a longer support tube. (dinghy and floor were not fully inflated for the "demo" photos.)
 
This is exactly what I am working on right now, have already ordered the longer lower piece of pipe for the garhauer hoist and when it arrives I will install. Will post pictures.
 
Thanks Bob.
I love you idea on the cross beam on the Dingy! I have already fashioned one based on your design. On my Zodiac the balance point is exactly on the front of the oar lock so I can use a line attachment through the oar lock and not have to glue on an attachment ring.

I have two set ups for the lifting arm I am experimenting with. Both came from mostly aluminum or stainless steal parts I had lying around for other projects.
The aluminum one looks similar to the Garhauer you have and is adjustable and can be removed.
The other uses 1" stainless steel and is mounted only on my radar arch
so it does not affect the side deck. I am not sure about the 1 inch tubing even though it is supported like Garhauer. I have not tried it yet.

The 5/16 line is nice size to handle but I was trying to keep things small that is why I was curious about any experience with the 1/4 line set up and if I could get away with a 2/2 block. The 2/3 blocks are not much more money but it does add more line.
Also if I leave the arm attached to the dink will the aluminum or stainless steal affect the radar.
 
Not sure how strong the attachment for the socket of the oar lock is--I have had similar appearing to your Zodiac oar locks. Sort of a plastic tab which holds it in place. You do want the spreader bar as low as possible.

I looked at your photo album--not sure how you are going to attach to radar arch--but that should be OK. You don't want it slipping. You want the lead of the line to your hand, handy--and you want to be able to brace yourself on the boat with the other hand. I like the Jam Cleat on the Garhauer, because it will hold the line, while you swing the dinghy in place or to clear some obstruction.

I have found that a "spine" often is necessary when using pipe (is it pipe, and what schedule, or tubing?) for a davit:

example below:

pipe3.jpg

If not then a brace under, as the Garhauer has, or as I have in the aluminum pipe davit at our home:

2007_08_26_004.jpg

The 1/4" line will be harder on your hands, and the less purchase you have on the blocks (4:1 vs 6:1) will be harder. You may want to try with gloves. I usually like to use 3/8 to 1/2" line.

The spreader bar, or the davit arms should not affect your radar.
 
Hey Bob thanks for the additional conversation on this.

I agree using the plastic oar lock peg is probably a bad idea. On my model zodiac, there is no safety or grab lines and where the line goes through your oar lock mine is open. I was thinking of several ways to run small line through that tube for attachment to keep it as close to the tubes as possible and not involve the plastic parts. I was hoping not to have to add lower attachment but I guess I won't know until I get the whole system together.
I am still worried about radar interference if I leave the arm attached to the dink.

Both of the designs I have been messing with require an under braces similar to the Garhauer for support. On the Arch mount version. I have had to fabricate some mounts and while it looks good and leaves the side ledge open it does not have a natural line track like the side deck pole mount with a jam cleat on the pipe. Both have a longer arms and I am hoping that I can raise the dingy without having to push it out. Then I can step on the ledge and simply swing it over to the rooftop dingy mounts. I will try and get some pictures up when it find what works.

Since I am an old sailor I should know that 1/4 line is difficult to handle and that 3/8's at a minimum is probably best. Just trying to push the limits a little.





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I have mounted radars on the front side of aluminum masts which were as "thick" as 12" and no attenuation of the radar signal. Same with one on a mizzen and an aluminum main mast in front. by 25 or so feet. If you have a flat aluminum plate such as the motor mount on the dinghy it might cause some issue. But the thin pipes of the davit are close enough that the wave guide of your radar is far wider, and the microwaves will just ignore it.
 
Thanks...That would be an advantage for the Aluminum version.
 
OffLeash":2771u4qf said:
Thanks...That would be an advantage for the Aluminum version.
Click to expand...
Aluminum and SS will be the same as far as radar beams. The SS will be stronger (more resistant to bending) than the equivalent aluminum pipe. Of course some depends on the alloy used in both cases.
 
I am no longer using the Garhauer on Dessert 1st (sold the kayak), so if someone is interested, contact me. Very good price for the major components. Local (close to FL) would be best as mailing would be a PITA.
Best,
Casey
602-418-8267
 
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