Anchor windlass fitting II- further advice sought

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RobBrown

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In process of fitting a manual windlass. As there is a bow well, from earlier advice on here have now got a 3" block of Iroko to raise the windlass on and have a 3mm Al backing plate to help spread the load under the deck (Moody 29 so GRP, not balsa or foam cored).
Queries- what fixative/sealant to use - Sikaflex 291 or something else? Presumably between base of windlass & woodblock & between that & deck? Any between deck & internal backing plate? Is it necessary to glass in the backing plate?

Windlass is also Ally and fitting with A4 SS bolts- have nylon bushes made up for the windlass bolt holes as would have been supplied by S/L from new, but would it be sensible to use Duralac as well?

Have treated Iroko with teak oil and boiled linseed. Is this sufficient weather proofing?

Any other words of wisdom?!
 
G'day Rob,

Will the well hold any water? OK, I will own up, I'm not a fan on timber on decks and not sure it is the best material.

Now that you have decided to place the winch in the well. is a good opportunity to fill it, thus avoiding ponding and strengthening the deck at the same time.

I suspect the backing plate would be stronger if made of Stainless steel, as this will be a high load application. When locating the plate you should cover it with resin and micro-fibres, this will ensure the load is spread over the full plate, no need to glass it in if this is done. Also glad you did not choose ply as a backer.

Sealing should only be required around any penetrations and sika should be fine, though when you place the micro fibres will get a thru deck seal, just don't tighten them up for a day or two.

Adding some Duralac will do no harm but save you later.

If you must use timber in the well, I would advise you epoxy coat it several times, then prime and paint as the epoxy is not UV stable.

Hope this helps.

Avagoodweekend......
 
Brian

Thanks very much for your helpful comments. The bow well is self draining- port & starboard drains at the back end of the well. No anchor locker, just a chain locker below via a hawse (navel?) pipe. It is evidently an Angus Primrose quirk- as other Moodys designed by him have it, such as the 33. Odd, but reassuring when you're at the pulpit in a blow.

I already have purchased the wood block and ally plate & all now cut & pre-drilled, so I guess I will run with these, but will use resin & microfibres as you suggest.

Sorry if a dumb question., but re the plate, do you mean cover/paint with epoxy after fitting/bolting up (ie just the lowest face ie that seen from inside the forepeak, or the whole plate before fitting, so it would bond with the underside of the deck? You mention the microfibres giving a through deck seal- - do you suggest I put epoxy in the deck drill holes immeditely prior to fitting the windlass?

I am surprised over minimal use of Sikaflex, as I assumed adhesive as well as sealant, so I was going to use it liberallly on all above deck meeting surfaces as well as in the four drill holes (ie the four M10 mounting bolts are intended to pass through the windlass, wood mounting block, deck and underdeck backing plate).

I haven't done this type of work before, so please don't assume much prior knowledge (or ability)!- what I planned is only on the basis of info I've found on here and generic advice in one or two windlass fitting instruction leaflets I've located on the web. Any further advice/suggestions gratefully received.

Rob
 
When we fitted our Hydrovane we used teak pads - didn't treat them as teak is naturally oily and boats with teak decks often have no treatment at all and last 20 years or more.
We used Sikaflex on the Hydrovane (and on the through-hulls below the waterline when we replaced those) - we are about to install an anchor windlass too and I will be using sikaflex for this - a ring around the base of the windlass, and some around the top of each bolt, maybe a little in the hole before I push the bolts through, and a ring around the washer where it meets the underside of the deck. This will make it watertight.

Re the plate - I would bond this to the underside of the deck with sikaflex as I am installing the unit (ie cover the back of the plate with sikaflex, and put into position, then bolt the unit up quite quickly so you can still move the plate before the Sikaflex goes off).

Jonny
 
Thanks Jonny. The wood block I sourced for this was Iroko, which was said to be the best teak substitute, but it did not seem naturally oily, which is why I used the teak oil & linseed. Just read the DavidPBO posts above re marine ply & coupled with oldsaltozs suggesions, i might try painting the wood with epoxy & varnishing before fitting- then at least keep the wood finish, which does look good.

I was going to put penny washers below the plate immediately before the nuts- are you fitting under the plate?

Rob
 
G'day Rob,

Re backing plate, the resin and micro fibre mix needs to be between the underside of the deck and the upper side of the plate, this will create a level surface between the load bearing plate and the underside of the deck.

Do Not Tighten, just get it into position with a gap between underside of deck and upper side of plate about 6 mm, make sure you have enough on the plate to cause it to squeeze out, this will ensure some has gone up around the bolts at the point they pass thru' the deck.

Clean up as soon as you are happy with the location and thickness because this stuff is hard to sand off after curing. try making a wedge shape tapering away from the plate out and up to the underside of the deck with a finger in a latex surgical glove.

Re use of Sikaflex, I suspect the freshly oiled timber will not be suitable for much of bond with Sika' or almost any other adhesive for some time. Even epoxy will not penetrate freshly oiled timber.

FWIW, I would keep the block as low as practical because raising the winch will put more stress on the deck, the higher you go the more stress, so keep the block as long as you can running fore and aft.

I hope this helps.

Avagoodweekend......
 
This all sounds fierce complicated. And I don't think the real loads have been addressed.

A windlass, like any other winch is subject to a horizontal force along the deck, not upwards through the deck. In other words you would expect failure to take the form of the sides of the bolts cutting through the deck material, rather than being pulled up through it. There will, of course, be some tilting force lifting the rear bolts and depressing the front of the windlass because the chain joins the windlass above the level of the bolts.

You need to ensure that the windlass cannot move forwards under load - which may mean that your backing plate, or your teak block, should be long enough to butt against a strong point on the boat forward of the windlass. Alternatively, the deck may already be strong enough to resist being deformed by any reasonably likely force on the windlass.


The loads on a windlass mounting are likely to be very different from a windvane.
 
[ QUOTE ]
The loads on a windlass mounting are likely to be very different from a windvane.

[/ QUOTE ]

Agreed. All I was trying to emphasize was the way in which we achieved a watertight fixing between the teak and the hull - apologies if this was not portrayed very well.

Jonny
 
Excellent help guys. Many thanks. I will try to incorporate as many of your suggestions as I can. A bu88er to hear about the problems with Sikaflex and oiled wood- I thought I was doing something sensible! I will try to leave it as long as possible to do the fitting, to give the wood some time to dry out and perhaps can treat the two mating surfaces with detergent or something similar to at least remove the surface oil?

I have kept the block as low as possible, just as you say to try and reduce the lever element, but it is 3" thick (x8x10), to give sufficient height for the fall from the bow roller to come down to about 15-20%, which a fellow YBW member said worked OK in his similar set up on a 33.

Regards

Rob

Posted before I got Robin2's post. I guess that both vertical and lateral components will be present,along with turning moment, given as I said above, the gypsy will still be below the bow roller. I'm sure the block isn't large enough to wedge against any strong points, but the ally plate may be. But this is a 1983 Moody and the lay up is very substantial (they were very cautious with GRP in those days!) , so I would certainly hope the deck in this area would be pretty strong.

R
 
I have a Moody 36 which has the same paddling pool at the bow, the drains though are not the silly wee things you find in modern bow lockers but cockpit sized drains so no prolems there.

I have an Anchorman manual windlass similarly mounted, and it seems to have survived the years quite well so there are no obvious potential problems.

The main forces are certaily shear so bonding the backing plate to the deckhead makes sense though there will be some tension in the rear mounting bolts, which if I was replacing with a similar windlass I would conteemplate hoping to reduce by extending the mounting system ahead of the windlass.
 
Again thanks to everyone for their input. I hope to do the job sometime this month and now have a reasonable expectation of arriving at something workable.

Cheers

Rob

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