Backing plate material

[RogerFoxTerrier]

What's a good, cost effective material for backing plates for cleats and winches etc? I'm surprised to see on our FoxTerrier 22 there are none for any of the winches. There's no sign of wear or damage to guess the GRP is strong enough.

There's a large centre bow cleat, and this is backed with what looks like a bit of old wooden skirting board!

I'm shocked at the price of plates for cleats - almost the price of the cleats themselves. On various photos online I've seen what looks like kitchen chopping boards!

Any suggestions or advice please? As we've removed all the deck fittings for painting, I want to re-fix them as robustly as possible.

Thanks

 

[Sandy]

Kitchen chopping boards are cheap and can be cut to almost any shape.

 

[RogerFoxTerrier]

Kitchen chopping boards are cheap and can be cut to almost any shape.

Apart from the marble ones !!! tee hee...

 

[Tranona]

Plywood is the most common. Chopping board (HDPE) is not good as it creeps and compresses.

 

[Kwik Decision]

If you need the backing plates to spread the load, personally I'd want something rather stronger than plastic chopping board. I'd use either marine ply, 1/2" or 3/4", or aluminium plate, 1/4", off eBay.

 

[Goldie]

Many years ago, PBO experimented to find the answer to your question. After trying various materials singly and in combination, the conclusion was ply with an aluminium plate IIRC.

 

[Sandy]

Apart from the marble ones !!! tee hee...

I find them difficult to cut.

Looking at the above answers, what sort of loads are people working with in a 10 - 15 metre sailing boat?

 

[PCUK]

6mm mild steel. Epoxy coated. Cheap from scrap yard and massively strong.

 

[Boathook]

I use ply 12mm or thereabouts coated with GRP. Don't forget to chamfer the edges at 45 degrees which allows any 'deflection'. I bed the ply in place with epoxy or a structural adhesive / sealant.

 

[rogerthebodger]

I find them difficult to cut.

Looking at the above answers, what sort of loads are people working with in a 10 - 15 metre sailing boat?

Easy with an angle grinder and a concrete cutting disk

I have cut big holes in a ferro boat with such kit

 

[rogerthebodger]

6mm mild steel. Epoxy coated. Cheap from scrap yard and massively strong.

I agree with this approach painted with any metal paint

I have done this on my old ferro boat

 

[IanCC]

G10 perhaps.

 

[doug748]

What's a good, cost effective material for backing plates for cleats and winches etc? I'm surprised to see on our FoxTerrier 22 there are none for any of the winches. There's no sign of wear or damage to guess the GRP is strong enough.

I think you answer your own question, almost anything will do a stronger job.

I would use plywood, just check it has multiple veneers, no obvious voids and is bonded with waterproof adhesive. You might varnish and bed them as well, just for extra panache.
Use washers and all will be good, the deck will lift before the bolts pull through. Simple, easy, cheap.

.

 

[Neeves]

Buy your self a small sheet of 10mm marine ply, say 1m square, and it will 'cover' all the backing plates you might need (check your stanchion bases).

Make them neatly, varnish them and they will enhance the interior. I always bedded such on sealant.

Jonathan

 

[zoidberg]

I've used stainless steel sheet, in various thicknesses and cut with an angle grinder. I've also used 13mm frp sheet in combination - as I had some of both.
See example pics.

I've found it helpful to pre-drill holes in reinforcing plates for the fitting's bolts and glue on Nylock nuts using JB Weld. This facilitates single-handed fitting.
Others will drill and tap thick aluminium - which is also effective if one has the right taps.

Of course, I use thickened epoxy as gap-filling bond material. I have also used C-Tec 'Power Grab and Bond' to position and hold plates in place 'up-under', where the gunk has sufficient initial hold to remain while I go above to locate/drive fittings' bolts.

I was advised by a shipwright that the use of marine ply as backing pads - even if coated in epoxy resin - can rot within a few years and is then often very difficult to remove and replace.

 

[dancrane]

I was shocked to find a chunk of what I believe had started as 18mm plywood, spreading the load under the deck where my forestay was attached. The forestay's original 'tang' was rooted into the stem, but had rusted and I replaced that, too. But the previous attempt to secure the rig had been the piece of ply, which had compressed substantially, I'd never seen such deformation.

Granted, loads on the forestay are enormous, but I wouldn't use ply as backing for winches either.

I replaced it with a slab of acetal from eBay. I've no idea what the chemical composition is, for all I know it may be a more expensive form of chopping board, but it is reasonably easy to scrape/cut into a shape to suit, if the location in question isn't just flat glassfibre, as was the case for me.

Acetal seems to be extremely robust and resistant to marine conditions (unlike ply in many uses).
.

 

[zoidberg]

Chopping boards are made, I believe, of a nylon-type material which is 'plastic'.... in that it deforms and flows under compressive load.
Looks good initially, and is cheap and easy to work. However.....

 

[vyv_cox]

What's a good, cost effective material for backing plates for cleats and winches etc? I'm surprised to see on our FoxTerrier 22 there are none for any of the winches. There's no sign of wear or damage to guess the GRP is strong enough.

There's a large centre bow cleat, and this is backed with what looks like a bit of old wooden skirting board!

I'm shocked at the price of plates for cleats - almost the price of the cleats themselves. On various photos online I've seen what looks like kitchen chopping boards!

Any suggestions or advice please? As we've removed all the deck fittings for painting, I want to re-fix them as robustly as possible.

Thanks

My Sadler 34 has no backing plates for the genoa winches that were originally Lewmar 40 non-ST. We intended to upgrade to Lewmar 43 ST but at the chandlery we found a pair of Gibb 50s, very reasonable as they had just gone out of business. They have been extensively used for well over 30 years with absolutely no evidence that they need any backing plates whatsoever. The layup is quite thick here and loading is in shear, needing no reinforcement.

 

[Ammonite]

G10 / FRP sheet is ideal as it's easy to work with and doesn't rot but it's expensive which is why most builders use plywood. You can minimise the chances of it rotting by drilling slightly oversize holes, filling with epoxy and redrilling to the correct size but most don't. Whatever material you opt for you should countersink the holes in the deck so that the sealant (I always use a dome of butyl tape around the studs / bolts) doesn't get squeezed out.

 

[Trident]

G10 FR4 is perfect as its super strong and last forever - its is expensive but you can buy small sheets quite cheaply on eBay which should be perfect for most backing plates . Then you just drill the holes you need through it, put it in place and forget it forever