Backing pads

[zoidberg]

I have several 'improvements' to make to the various mooring cleats mounted around the deck, and am querying the optimum backing material - and why.

These new cleats are substantialy larger than originals and will carry anchoring and trot-mooring loads into the solid GRP structure on a 3-ton boat. I have available to me 2" teak planking, 1" oak plank, 30mm marine ply, and 12mm woven grp sheet.

Thots?

 

[Little Dorrit]

All would be ok. I think 2" teak and 30mm ply might be unnecessarily thick, my preference would be grp sheet.

 

[Blueboatman]

Alright
12mm ply pad set on fibreglass ‘pug’ then nip up the through bolts . And tighten when cured
Plenty strong for 3 ton
Your deck underside may even have camber not obvious to the eye until you offer up the backing pad.( use generous pug)
Round over the edges of the ply a bit too- no stress lines

 

[jwilson]

If you have it I'd use GRP sheet, bedded onto wet resin.

 

[geem]

If you have it I'd use GRP sheet, bedded onto wet resin.

Absolutely. No rot, ever! Stronger than wood. Bed on thickened epoxy. Snipe the edges so you don't create a hard point at the edge of the backing plate.

 

[Beneteau381]

I have several 'improvements' to make to the various mooring cleats mounted around the deck, and am querying the optimum backing material - and why.

These new cleats are substantialy larger than originals and will carry anchoring and trot-mooring loads into the solid GRP structure on a 3-ton boat. I have available to me 2" teak planking, 1" oak plank, 30mm marine ply, and 12mm woven grp sheet.

Thots?

The backing pads on my big std Beneteau 381 are SS penny washers.

 

[geem]

Mine are stainless or aluminium plate glassed in place. I found them under mooring cleats, genoa tracks and mizzen sheet block. They aren't visible under the deck. They effectively form a composite panel.

 

[zoidberg]

Thanks, all.

I do have some 'spare' epoxy with resin I could use for 'pug' and for flo-coating, should I go that way.

 

[Neeves]

The backing pads on my big std Beneteau 381 are SS penny washers.

So were ours. I replaced the lot with a combination of aluminium 4mm backing plates or GRP sheet. The choice was dictated by what actually fitted most easily. Used Sika and Duralac with the aluminium plate.

Penny washers are a disgrace

Jonathan

 

[john_morris_uk]

I’m just about to make several for through hull fittings. (Generator inlet, water discharge outlet, exhaust out, water maker inlet and brine discharge) and I’m making then from decent plywood, edge rounded over with a router ad then flow coated with epoxy. I’ll bed them on thickened epoxy gloop and put Sikaflex on the skin fitting. The ply is an off cut of Robbins Elite Marine ply which is some of the best quality hardwood ply I’ve ever worked with. That’s my technique FWIW and I’d do the same for deck fittings.

Is your deck sandwich construction? I’m sure you know to extract the balsa core and to cast epoxy plugs to stop the deck being crushed by the fastenings etc.

 

[Beneteau381]

So were ours. I replaced the lot with a combination of aluminium 4mm backing plates or GRP sheet. The choice was dictated by what actually fitted most easily. Used Sika and Duralac with the aluminium plate.

Penny washers are a disgrace

Jonathan

Why? Beneteau, one of the biggest manufacturers of boats in the world. No headlines saying my cleats pulled out.

 

[jwilson]

Jeanneau use a lot of "penny washers" but usually they are quite thick - about 1.5mm to 2mm, and are under a well reinforced layup section designed in from the start. My only complaint is that whilst the bolts/screws/fittings seem decent S/S, these chunky penny washers are a lower grade S/S and develop surface rust in a few places like under the bow roller fitting in the anchor locker.

 

[Neeves]

Why? Beneteau, one of the biggest manufacturers of boats in the world. No headlines saying my cleats pulled out.

If you are happy I am happy.

You implied your stanchions, deck fittings, cleats, winches were all reinforced with penny washers. Personally I don't think it is good enough. I offered my view. Its really not a difficult upgrade. I assume you have no crazing in the gel coat round the attachment points of your stanchions, cleats etc. Your faith is thus well placed.

Jonathan

 

[TSB240]

I have just fitted a windlass to a friends Centaur. I spent half an hour neatly cutting out the clearance hole and drilling a plastic chopping board for a solid under deck backing plate.
Jig saw needs a very coarse blade operating slowly or you just melt the cut line.
No need for any paint or fibreglassing.
Sealed with OB1 from toolstation to under deck. Butyl rubber used to seal windlass to deck.
Wife happy as she has a brand new chopping board for £1.99!

 

[Beneteau381]

If you are happy I am happy.

You implied your stanchions, deck fittings, cleats, winches were all reinforced with penny washers. Personally I don't think it is good enough. I offered my view. Its really not a difficult upgrade. I assume you have no crazing in the gel coat round the attachment points of your stanchions, cleats etc. Your faith is thus well placed.

Jonathan

Its 23 years old, still going strong, one of the forward cleat nuts had come loose a few months back, the cleat hasnt moved. I tightened it up. No cracking etc. You imply you are better qualified than Beneteau engineers? My faith in my boat is well placed.

 

[ghostlymoron]

Chopping board

I have just fitted a windlass to a friends Centaur. I spent half an hour neatly cutting out the clearance hole and drilling a plastic chopping board for a solid under deck backing plate.
Jig saw needs a very coarse blade operating slowly or you just melt the cut line.
No need for any paint or fibreglassing.
Sealed with OB1 from toolstation to under deck. Butyl rubber used to seal windlass to deck.
Wife happy as she has a brand new chopping board for £1.99!

Chopping board is easy to use and cheap but it creeps under pressure which is something you don't want in a backing pad. (IMG)

 

[geem]

My experience of cleats and backing pads, etc is that 99% of the time they are strong enough. Occasionally you get caught out. You are in a harbour or marina and a storm comes through. Cleats are now getting loaded like never before because there is a big swell and surge. The manufacturer might not have designed for such eventuality. If you know you are going to be cruising to new places and spending time sheltering from storms in unfamiliar harbours, it may well be worth uprating cleats, etc.
Mine have never needed uprating. They are already beefed to oblivion. The builder made the boat super strong from the outset.

 

[TSB240]

Chopping board
Chopping board is easy to use and cheap but it creeps under pressure which is something you don't want in a backing pad. (IMG)

Not worried at all about using a plastic backing pad for a low profile vertically driven windlass on a Centaur as it is unlikely to be under great pressure.

The majority of strain on the mounting bolts is shear not compression or tension.

The chopping board on the deck underside will not be subjected to either high compression loads or significant thermal cycling which are the major cause of creep in plastics.
I am sure an annual tweak with a 13mm spanner will be enough regular maintenance!

I certainly wouldn't do the same for a more traditional horizontally driven windlass where there are much higher tensile/compressive loads on the mountings due to the leverage caused by the mounting arrangement.

This is why a chain stopper or chain hook needs to be used to relieve any snatch loading at anchor.

I still have a great supply of Tufnol which offers a much better non metallic solution for load spreading.

 

[zoidberg]

Mine have never needed uprating. They are already beefed to oblivion. The builder made the boat super strong from the outset.

Tell me a little more about the boat.....

 

[geem]

Tell me a little more about the boat.....

Trintella 44 designed by Van da Start. Airex foam core composite hull and deck. Encapsulated lead keel and skeg hung rudder. Deck and hull glass together. The outer 300mm edge of deck is solid glass where the deck to hull joint is glassed together. Within this deck perimeter are glassed in reinforcing for cleats (stainless steel backing pads) and genoa tracks (aluminium backing pads). The aluminium toerail is bolted through the deck to hull joint with M8 bolts every 75mm. 400 bolts in total. The extrusion is so beefy you could easily lift the boat from it. All deck fittings are big. Everything is equivalent of what you would find these days on a 60/70ft boat. Its stood the test of time.
The cheeks on the substantial bow roller are 12mm plate. Yesterday we saw a guy with a Grand Soleil of about 50ft bashing his bow roller straight with a hammer. You couldn't bend ours with a sledge hammer.