Fixing a windlass to curved deck

[asj1]

I have purchased a horizontal axis elecric windlasss. This all fits on deck with minimum neccessary cut -outs (chain and cabling).

I was intending to fix it with a stout pad of hardwood circa 25/30 mm thick between it and the deck with the windlass through bolted.

My problem, which I am sure is quite common, is that the deck is slightly curved in this area. Therefore the hardwood pad needs to have a slight concave shape to it in order that it fits properly on the deck . This will be difficult to do ! Possible solutions that come to mind are;

1) Shape it as best I can and then bed it down onto sikaflex - probably the most straightforward solution , bit will it be firm enough?
2) try and make a flat bed from polyester resin by making a small frame and pouring the resin in to naturally find its own flat level. This would tehn not require any shaping of the hardwood pad. - will this actually work? does polyester resin 3-4 mm thick actually set properly?
3) work at getting a very good concave shape onto the hardwood pad so that the through bolting provides a good rigid fitting with only ordinary sealant round the edges - very difficult to achieve I think.

Any commenst from the forum/experiences to share?
What tool could I use to try and make a concave shape into a hardwood pad.

Regards

 

[Channel Ribs]

Option 1 is not a good one.

Option 2 will make for a very brittle base and windlasses do need some flexing to absorb some of the shock load.

Option 3 is going to be time consuming and tricky to pull off.

How about putting a skirt around your pad? IE Cut out two lots of wood and cut a large hole in the second.

 

[2nd_apprentice]

Buy a cheap contour gauge and go for option #3

 

[sailorman]

Align the block on the deck with wedges then scribe/ mark around the base with a piece of wood n pencil ( piece of wood height to be size of largest gap under block ) shape to mark & fit to deck.
if you can get a Lump-o-teak it is quite easy to work as opposed to some hardwoods

 

[FrankieJ]

Follow Sailorman's instructions for marking out, then try a angle grinder with a suitable disc for wood removal ( I have seen these discs somewhere,but unfortunately I can't remember where. It must have been on the 'net' ). Alternately, you can make a series of saw-cuts down to the scribed lines, spaced about 12mm.apart and remove the rest with a good sharp chisel.
I personally would use a router, but I think if you had one,and knew how to use it,you wouldn't be posting the question.
( unless this is a test)

 

[Billjratt]

Shape it, without a doubt. Finish by sticking sandpaper onto the deck and rubbing the wood on it to see where the highs are. make it nice and big (fore and aft) to spread the torsion.

 

[ningcompoop]

West epoxy, bless their cotton socks, describe how to cast a base using epoxy with 404 high density filler ("For maximum physical properties...where high cyclical loads are anticipated.") in their user manual (free), and in a bit more detail in their guidebooks (cheap). I know its very tough, and an absolute bugg3r to sand smooth if you don't get it right. (Can be softenned and removed using heat.) Do you prefer working with wood, or, err, goo? /forums/images/graemlins/wink.gif
Oh, and do you need a backing plate?

 

[Clyde_Wanderer]

Cover the deck area with plastic sheet, make a plywood frame, then laminate a bed using woven roven and epoxy resin to a substantial thickness finnishing with a flat top surface, making it aprox 12-15mm bigger than base of windlass inside the wood frame, lift off when hard and tidy it up.
You will struggle to find a stronget base so easy to make.

 

[oldsaltoz]

G'day Andrew,

ningcompoops post has to be the best solution (he just beat me to it). Not having timber as a support is good in that epoxy resin will not rot or warp and will give very good support for many years.

Simple to do, prepare the area under winch by washing with some acetone to remove all polish, silicon and other contaminants, then give it a light sand and was again as above; then just mix the filler to a toothpaste thickness and apply to the deck, install fixing bolts with a little glad wrap covering the threaded area only and secure it with the nuts finger tight and check the levels and alignment, clean up any material that has squeezed out with acetone leaving a neat finish.

You will need a backing plate also, Your local scrap yard or engineering works should be able to supply a plate of 316 stainless of 8 or 10mm, just make sure the corners have at least a 75mm or more radius and both top and bottom edges are rounded.

To ensure the load is evenly spread over the entire backing plate, coat it with the same high density mix used under the winch, do up the bolts to squeeze out any excess and clean up, fully tighten after 24 hours when curing has completed.

Finally, you need to protect the filler from UV light, a simple coat of paint the same colour as the winch will finish the job.

Hope this helps.

Avagoodweekend.

 

[asj1]

Interesting idea to use an angle grinder - will try and get a thick grinding blade to use. I do have a very cheap router, but I've never used it and it would actually be quit difficult on this smallish piece of wood.
thanks for your help

 

[asj1]

The advice is fairly evenly split between using epoxy or similar to even up the deck and shaping the hardwood pad accurately. I will try the latter, and if I'm not successful will revert to the former.

Regards

 

[john_morris_uk]

[ QUOTE ]
Follow Sailorman's instructions for marking out, then try a angle grinder with a suitable disc for wood removal ( I have seen these discs somewhere,but unfortunately I can't remember where. It must have been on the 'net' ). Alternately, you can make a series of saw-cuts down to the scribed lines, spaced about 12mm.apart and remove the rest with a good sharp chisel.
I personally would use a router, but I think if you had one,and knew how to use it,you wouldn't be posting the question.
( unless this is a test)

[/ QUOTE ]I agree with the router use - its the way I would do it. Rout a series of grooves at the correct depth. Cut the islands away with a sharp chisel and then sand smooth. Finish with Sandpaper stretched across the deck itself to give an accuracte contour 'in situ'.

However the suggesting to cast the base in epoxy is possibly better (and easier).

 

[pampas]

Dont use a thick grinding wheel on wood. Buy a flexible backing pad and use 24 grit disc rough out then go to 60 grit, with practice it will not take long to make a small pad.

 

[FrankieJ]

Just remembered where I saw the wood grinding disc,
try http://www.machinemart.co.uk/shop/product/details/pro-4-wood-grinding-disc-kit

 

[somerset]

If you go for the shaped wood as per option (3) - one way of ensuring a good fit is to colour in the relevant area of the deck with coloured chalk and then place the roughly shaped piece of wood on the deck and then gently rub it on the deck.The chalk that transfers to the wood indicates the 'high' spots on the wood which can then be skimmed back a little.Re-chalk any bare patches on the deck and repeat until you reach a point where the chalk is all over the wood.You then know that you have a near perfect fit.Its a method known as a 'Rub Joint'.Its slow but you will get a near perfect fit.