fitting davits

[Phoenix of Hamble]

Having twin aft cabins, locker space is at a premium, and the inflatable currently fills at least 60% of one of these lockers.... on top of this, I am making a rigid tender that will also sport a sail, so that we can go dinghy sailing with the kids, plus row more easily...

All of this suggest that davits make sense, especially now we have a boat that they won't look out of place on....

However...

I'm not really sure how best to fit them..

Here's our transom...

As you can see, we have plenty of space vertically, but the horizontal bit on the bathing platform has lockers in it, so neither strong enough, or sensible to mount them on here... the bit of transom behind the pushpit is sloped, and doesn't have any horizontal area at all...

We can only afford the plastimo davits... these ones...

And so, I need to work out how I get them modified to fit...

Current thoughts are:

get a crank welded into them, and mount them on the vertical surface ie

this however, will prevent them from being able to swivel inwards, and will require their full removal to reduce LOA, plus i'm not sure about the loadings

alternatively, I could get a box made up ie

but this puts a largish stainless 'lump' onto the transom either side.... which may or may not be a problem... the base plate on the davits is 150mm dia, so the box will extend by 20cm or so....

last, but not least, I could get the davits modified so that the mounting plate is angled to match the profile of the sloped part of the transom behind the pushpit ie

This does require carefull checking to see if the davits clear the pushpit neatly, and also has the disadvantage of putting them quite a long way forwards, and thus reducing the reach out over the stern..

Any thoughts, observations, ideas anyone?

 

[DaveS]

I fitted the Plastimo davits and, like you, had insufficient horizontal surface to take the sockets. I made up two GRP boxes which I bolted to the transom - a bit like your idea no. 2, but "squarer" in shape with all edges radiused. They've worked well: 5 years so far with no problems.

 

[Phoenix of Hamble]

What sort of thickness of material did you use?

 

[philip_stevens]

Your profile 2 is what we had to have made for our Konsort Duo. The transom curves in 3 different directions, and the fabricator had to make 3 different templates to accurately follow the transom curves.

If you are still at a loss as to what to do, I will take some photos of our arrangement when we go to the boat at the weekend.

 

[DaveS]

I can't now remember exactly, but quite a few layers of glass went in - probably about 10 mm in total. I have a drawing somewhere, which I'll look for when I'm back home.

 

[Phoenix of Hamble]

Thanks guys...

drawings and piccies would be much appreciated

 

[Phoenix of Hamble]

One other thought.... if I get a plate made up that the 'box' slides into, then I could also make the box removable...

ie, something like this.....

 

[pyrojames]

You might find that the expense of making up the adapters, and buying the plastimo davits is about the same as having something custom made from scratch.

 

[Phoenix of Hamble]

Yup....

i'll be checking with a fabricator for the price of the adaptors... AND, the price of a custom build!

 

[DaveS]

I have now found my drawing lying on the loft floor! Here it is (cross section also showing the angled transom and the davit socket):

Looking at it I see that I actually used a sandwich construction with GRP each side of a plywood rectangle for each face. I made up a screwed together (and thus dismantleable) mould from melamine faced chipboard with plasticine and masking tape fillets. The bottom of the GRP box is open, and I (later) also drilled a small hole in the socket to drain rain water.

The W and R refers to white and red gelcoat respectively: I tried to be clever and used bi-coloured gelcoat to match the hull. This did not work out so well in practice since (a) I somehow cocked up the measurements, and the dividing line on the boxes is 25 mm different to that on the hull /forums/images/graemlins/blush.gif , also the gellcoat was a bit too thin with a number of voids between it and the GRP - which are now filled with 'poxy putty. Eventually I'll get round to dismantling, sanding down and painting them, but meanwhile they're soundly functional if a bit unsightly.