Dinghy on Davits

[harstonwood]

Question for the forum

Currently have. 2.6m dinghy with 4hp outboard hanging from Davits.
Lowering and recovery reasonably simple, but it's tight against transom and that makes things difficult. Can't really get it that high either

Any suggestions how to make it "hang" further out? (maybe 18 inches away from transom) guess I need some kind of offset spreader bar?

Would really like to keep the engine on.

Any thoughts?

 

[Bojangles]

Dont suppose the davitts extend out. Mines are Whittall and you simply loosen a type of wing nut and they extend out from within themselves?

 

[harstonwood]

They do extend out, but not where the winch lift cable is.
I guess the extending parts are to cater for wider dinghys


If there is a way of extending the lift point out that would be ideal

 

[Bojangles]

Had to have a look at a photo of mine and I see what you mean, the lifting point doesnt move, only the support cleats on the end move out. Maybe a rigging expert could advise on a set up that would help put some of the weight on the extending part mabye on the engine side only?

 

[harstonwood]

Maybe need a narrower dinghy!

 

[PCUK]

How about a pulley on the strop for lifting the dinghy and the other end of the wire attached to the outboard end of the extending part?
Basically making it a 2 to 1 lift. See diagram.

 

[Nick_H]

You could have a SS fabricator weld an extension piece onto the existing davit.

 

[neale]

Obviously putting the weight bearing point further out is going to increase the leverage on the davit fixing point. If you are well within the davits recommended capacity this should be no problem but if you are already on the limit it might be something to think about.

 

[miket]

Don't think so!

PCUK How about a pulley on the strop for lifting the dinghy and the other end of the wire attached to the outboard end of the extending part?
Basically making it a 2 to 1 lift. See diagram.
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You are then transferring some of the load from the stronger fixed part of the davit to the weaker extending piece?

 

[harstonwood]

Thanks guys
I think the extending part of the Whittal Davit is only for supporting the dinghy, as opposed to taking the load. I would probably do the pulley thing if it was just the dinghy, but with the engine and fuel it's a fair bit of weight

Think I may need to lift on one side of dinghy ( offset wire strops) which may move it out, though it will sit at an angle. Any probs with this idea ?

Thanks

 

[Nick_H]

Thanks guys
I think the extending part of the Whittal Davit is only for supporting the dinghy, as opposed to taking the load. I would probably do the pulley thing if it was just the dinghy, but with the engine and fuel it's a fair bit of weight

Think I may need to lift on one side of dinghy ( offset wire strops) which may move it out, though it will sit at an angle. Any probs with this idea ?

Thanks

Not quite understanding your idea, but as a matter of physics the CoG of the tender /engine combo will always sit vertically under the lifting point. If you make an offset cradle or use different length strops, then it'll sit in exactly the same place, just tilted at an angle. The idea may still work if you manhandle the dinghy as you lift it, as I guess it doesn't weigh that much. If you want the tender to lift with its CoG in a different place, then you need to move the lifting point somehow.

 

[harstonwood]

If the strop, which is attached to both sides of the dinghy, is say 6" and 18" to the the lifting ring, the short side will lift first, and the dinghy will sit further out, though will be with with one side lower than the other, as c of g will be closer to short strop side, or have I got it wrong ?

Actually i like this idea, as currently I have to push it of bathing platform after lowering, and perhaps offset may alleviate

 

[solitaire11]

a friend of mine has done like pcuk,s diagram and it's worked for years with no problems, and that is on a 3.2 metre avon rib with 25hp mariner.. no probs at all.

 

[harstonwood]

Thanks

Will have to have a look next time at the boat, and see how to fabricate

Some pics below of current arrangements, to assist with the ideas!! Sorry about size of pics!

 

[Nick_H]

If the strop, which is attached to both sides of the dinghy, is say 6" and 18" to the the lifting ring, the short side will lift first, and the dinghy will sit further out, though will be with with one side lower than the other, as c of g will be closer to short strop side, or have I got it wrong ?

No, the dinghy wont sit further out, it'll just tilt until the CoG is directly under the lifting point. Having the dinghy tilted could conceivably move the nearest tube further away from the boat (by triangulation), and this may achieve what you need if its just about clearing the bathing platform, but if you want it to hang horizontally, not tilted, and be further away from the main boat then you need to move the lifting point, either by the pully arrangement suggested, or some other modification to the davits

 

[harstonwood]

Thanks Nick am with you now. From the pics above, do you think the extending arms will take the load?

Cheers

 

[Nick_H]

Thanks Nick am with you now. From the pics above, do you think the extending arms will take the load?

Cheers

The extending arm looks strong enough, though obviously you can't see how it sits in the main arm. I'd pm solitaire11 to get a bit more detail about his mate's set up, as that seems to have worked well.

There's something to be said though for having the tubes of the tender tight against the davit stanchions and also for having the extending arms doing what they're supposed to, to stop the tender flapping about in rougher seas.

I guess the problem you have is getting on and off the boat with the tender stored? If so, have you considered a side boarding ladder that can be hung on either side, just in front of your rear cleats? You could easily fit a couple of deck sockets each side that it just drops into, and you could store it in the tender underway?

 

[harstonwood]

Hi Nick
Yes we do get on through the side, though currently do not have a ladder
I bought one but unfortunately the stand off arms touch the side in the area of the engine air intakes, so I need to modify, which is on my extensive to do list!

Will ask Solitaire to get me a pic sometime. Going to the boat later this week, wil have another study

Certainly would like to retain the Davits, it's great being able to keep the outboard on, which is not possible with the snap Davits

Thanks for your advice, much appreciated

 

[hlb]

Think I now see your problem. You need a rigging man to make up a short cable, and mount it low down in the dinghy, so the dinghy goes right up to the davits. I have a couple of blocks of wood, with a curved bottom, on the outboard end, so the dinghy is held firmly in position.

There is a slight snag, that you have to make sure, that the dinghy does not turn upside down, as it is lifted. Once up, it will never move, no matter the weather.

So, some sort of D hook thingy on each end of the strop and a ring in the middle, it must be tight and low down. Maybe your ring needs to be lower down on the bow of your dinghy as well.

It's not going to get the dinghy farther out, but higher up and much firmer and looking much more the part.

 

[longjohnsilver]

Think I now see your problem. You need a rigging man to make up a short cable, and mount it low down in the dinghy, so the dinghy goes right up to the davits. I have a couple of blocks of wood, with a curved bottom, on the outboard end, so the dinghy is held firmly in position.

There is a slight snag, that you have to make sure, that the dinghy does not turn upside down, as it is lifted. Once up, it will never move, no matter the weather.

So, some sort of D hook thingy on each end of the strop and a ring in the middle, it must be tight and low down. Maybe your ring needs to be lower down on the bow of your dinghy as well.

It's not going to get the dinghy farther out, but higher up and much firmer and looking much more the part.

And what were you doing in QAB? Did you get lost going home?