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Old 22-06-2016, 19:57   #1
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Hanging dinghy from davits

Trying to figure out what is the best way to do this off the back of my cat.

Specifically, I have a small inflatable, about 9', not rib, but air bottom, weighs about 80lbs and a 4hp motor about 40 lbs.

The dink has wooden transom with 2 holes that I am going to put eyebolts in. I have purchased and glued on hanging hooks on the topside of the pontoons midway between bow and middle.

So I need to make 2 bridles, obviously one for each davit.

Can someone recommend type of line and size for the bridle?

Off my davits I put 2 snap shackles that I am going to attach to the bridles. Should the shackles attach directly to the bridles on the line, should it attach to a metal shackle (metal on metal), should I make a loop in the line so the shackle attaches direct to the line?

Is there a premade kit for hanging the dink?

Thanks for any help.
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Old 22-06-2016, 20:06   #2
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Re: Hanging dinghy from davits

The key is actually to trice under the dingy. Any attachment to the tubes will be stressful and unstable when the dingy loses pressure, which it will someday.



You will also need a spreader for the glue-on patches or the pull force will be ridiculous. The photo shows a hard bottom, but same idea. 1" aluminum square tube is good.



As for line, 3/8" is enough, 1/4" for the tackles.
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Old 22-06-2016, 20:13   #3
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Re: Hanging dinghy from davits

thanks for the quick reply. i was thinking of putting a line under. Is this line separate or part of the line on the top? And would you know what size and type line this is?
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Old 22-06-2016, 20:52   #4
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Re: Hanging dinghy from davits

On the bow of the boat I would bolt an eye strap through one of your floor boards. The forces up there are almost zero. Make sure you keep your tubes inflated otherwise you may get some chafe. Also make sure the inflatable is well secured from swinging while on the davits. Worked for us.


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Old 23-06-2016, 10:33   #5
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Re: Hanging dinghy from davits

The line under the tubes is likely to chafe the tubes and/or the line over time if you do any significant sailing.
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Old 23-06-2016, 11:00   #6
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Re: Hanging dinghy from davits

These pictures should help you see what other cruisers have done with dinghy lifting bridles.

https://www.google.com/search?q=ding...w=789&bih=1067
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Old 23-06-2016, 11:04   #7
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Re: Hanging dinghy from davits

Defender sells a dinghy strap set pre-made that we use for our soft bottom inflatable to hang from the davits.
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Old 23-06-2016, 11:25   #8
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Re: Hanging dinghy from davits

Quote:
Originally Posted by jbinbi View Post
Trying to figure out what is the best way to do this off the back of my cat.

SNIP

Thanks for any help.
Probably need more information to answer your question. A lot depends on the reasons you want to put the inflatable on the davits. If you are on a ball or dock the system you use would be different than if you are circumnavigating and keeping the inflatable on davits almost all the time. There is normally little movement of a boat at a dock to cause problems with an inflatable on davits compared to what goes on in blue water. In fact most folks who are even doing a short hop like from Florida to the Bahamas will take the outboard off the inflatable, remove everything from inside the inflatable, and secure it to to a greater degree than if the trip is a simple day sail.

To answer some of your specific questions I would go some what oversize in selecting line and base it more on how easy it is to handle the line, with or without gloves, as opposed to how strong it needs to be to lift the inflatable and motor.

I agree with the post about running supports under the inflatable in addition to the bridle and snap shackles above it for long term storage or passages; but I have been using straps for this purpose instead of rope. Not sure where I got them but here is a link to a harborfreight product that will give you an idea of what I am talking about. I know you can get stuff like that from other sources that is probably better quality.

I also have not only used pulleys to raise the inflatable but have a pulley dedicated to raising the outboard and a bracket to secure the outboard on.

Another thing to consider is once the outboard and everything else has been removed from the inflatable there may be a better way to secure it for long term storage and long passages. I have two securing points shaped like a squared off U below the davits. I turn the inflatable 90 degrees from the way it floats and put the squared off Us between the inflatable tubes and bottom. Then I secure it with the straps I linked to above. Here is a pix, the Us are on the tube at the top of the seats.

Seawind Cockpit - View from salon of cockpit Cruisers & Sailing Photo Gallery
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Old 23-06-2016, 11:35   #9
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Re: Hanging dinghy from davits

Not sure why you want to hang the center and dinghy stern rather than the bow. Many inflatables have a fixture below the bow that should work well. You want the bridal to lifting line attachment to not move to prevent a stray wave from shifting the dinghy to hang one side down. You might also be aware that you need to pull the drain plug whenever you hang the dinghy. Water weighs a lot and your rig will probably will fail if you accumulate significant rain water.
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Old 23-06-2016, 11:35   #10
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Re: Hanging dinghy from davits

Whatever you choose, don't forget to put drain holes in the transom of the dinghy and leave it hanging stern-down, as a shower of rain can ruin all your calculations.....
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Old 23-06-2016, 12:09   #11
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Re: Hanging dinghy from davits

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Originally Posted by jbinbi View Post
thanks for the quick reply. i was thinking of putting a line under. Is this line separate or part of the line on the top? And would you know what size and type line this is?
The tricing lines are separate from the lifting tackle. They run from the tips of the davits to the base of the davit. Yes, in theory, webbing will chafe less than rope, but I've used the rope for 20 years (1997 dinghy) and there are no marks. I keep the ropes tight (no movement--very tight off-shore), the dinghy hoists very close to the davits (the inside tube is tight to the transom and davit tubes) and they probably bear different places each time. Few passages, but lots of miles, over 15,000. If the dingy hangs far below the davits and there is swing, you have to stop that swing and probably hoist higher. Much depends on specific design elements. Pictures?

The blue lines are dock lines.

The reason for the small line on the tackle is because the tackle is small. But it is 6:1 and a child can pull it. And wear gloves. NEVER over size a rope in tackle.

Personally, I believe removing the engine defeats the purpose of having davits. I've never heard an explanation that made sense to me. The transom and motor are generally very easy to secure. The only exception might be if the lower unit is catching water; mine does not, other than a few splashes in near gale conditions.

Store on deck in bad weather? Depends on the boat, on mine I am quite sure that is worse (I've done it). But it is something you should investigate, so you know. Since the pics were taken I have lengthened the transoms, making the davit location even better.
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Old 23-06-2016, 13:02   #12
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Re: Hanging dinghy from davits

Use 2inch yellow webbing for the trice lines. Buy it for peanuts at Home Depot, in a ratchet strap. You may be able to use the ratchet buckles to tighten up, but they rust quickly in salt.
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Old 23-06-2016, 13:07   #13
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Re: Hanging dinghy from davits

The weight is in the stern. You have the right approach there with the two eyehooks. The other end using the bow eye /loop is likely enough. Or like someone mentioned, a strap under is good. I liked using webbing/strap for all the bridles but doesn't have to be. You will also want a fender + tie to keep the motor from banging on the hull as the dingy wants to wobble side to side between the cat hulls.
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Old 23-06-2016, 18:39   #14
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Re: Hanging dinghy from davits

Don't rely on hanging your dink from the hoisting tackles. The line will chafe through and it will not be at a convenient time or place. When the dink is hoisted in stowage position, hang it from a chain (metal to metal) with a snap shackle and slack the falls. My falls chafed through at 2 am in a thunderstorm between Bermuda and Horta. Captain Fred
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Old 23-06-2016, 18:45   #15
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Re: Hanging dinghy from davits

another vote for ratchet straps under the dink. I put them diagonally so they immobilize it. I got them on line from a truckers site (Cargo control maybe?) that advertised them as "impervious to road salt". That is a bit of an exaggeration but they are way better than the Home Depot kind
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