# G10 backing plates



## sailordave (Jun 26, 2001)

New to me sailboat. Bow and stern cleats are backed w/ nothing but fender washers! But hey, they've worked for 20 years.

My plan is to replace them w/ G10 epoxied to the underside of the deck structure and then use longer bolts and fender washers to beef things up. 
Boat is 36', 13000#
My QUESTION is.... .25" or .50" G10. 

My guess is .25" will be sufficient, but I want to hear from the resident "experts" on this.


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## Maine Sail (Jan 6, 2003)

sailordave said:


> New to me sailboat. Bow and stern cleats are backed w/ nothing but fender washers! But hey, they've worked for 20 years.


Mine are too. Our cleats have survived 32 years, five hurricanes and too many Nor' Easters to count. If done right with good old fashioned THICK fender washers they can be fine so long as the deck is solid and dry.



sailordave said:


> My plan is to replace them w/ G10 epoxied to the underside of the deck structure and then use longer bolts and fender washers to beef things up.
> Boat is 36', 13000#
> My QUESTION is.... .25" or .50" G10.
> 
> My guess is .25" will be sufficient, but I want to hear from the resident "experts" on this.


Perhaps 90% of the boats out there have cleats backed with fender washers and while they can, on occasion pull out, they are often associated with wet core when they do. I have seen fender washer backed cleats fail before the cleat pulled through the deck.. Remember they are not being pulled straight up..

If you feel this is necessary then 1/4" G10 would be a decent choice as would 3/8" or 1/2" or......


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## olson34 (Oct 13, 2000)

*G10 = strong*

It's been a few years, but I dimly recall using 5/16 or 3/8 under all of our stanchions and pulpits when rebedding and improving. Backers were about 6 X 8 inches, IIRC, and set in epoxy mush; the deck above is like a rock in those places. G10 is stout stuff.
FWIW, all of our factory cleats are backed up with 1/4 aluminum.

LB


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## asdf38 (Jul 7, 2010)

Do you need anything special to cut G10?


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## overbored (Oct 8, 2010)

I used 3/16" thick G 10 for all backing plates and that is more then double the thickness of the glass that it is reinforcing. anything more is just a waste of money. this stuff is very strong and will break the bolts or tear the surrounding deck before the g10 will break. you will have to cut the stuff and the 3/16" is easy to do with a carbide edge saw blade.


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## MedSailor (Mar 30, 2008)

olson34 said:


> FWIW, all of our factory cleats are backed up with 1/4 aluminum.
> 
> LB


Mine too. I would go this route. Cheap and easy to work the material with regular tools. Available everywhere.

MedSailor


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## sailordave (Jun 26, 2001)

Maine Sail said:


> Mine are too. Our cleats have survived 32 years, five hurricanes and too many Nor' Easters to count. If done right with good old fashioned THICK fender washers they can be fine so long as the deck is solid and dry.


Yours are this way b/c mine are too. Or vice versa. B/c I just bought a CS Merlin!

The cleats probably ARE okay this way but I just want to back them properly and then move on to sealing the deck core and rebedding all the deck gear.

There also is one small area where the core did not bond to the deck but is not wet. I'm going to put a big ass backing plate under the genoa turning block JUST TO BE SURE. (per the survey rec's)

I was pretty sure .25" would be sufficient.

Yes, AL is easy to work and all but just want to keep more metal out of the boat.


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## Ajay73 (Jun 13, 2011)

Quarter inch would be fine. Aluminum is what is normally used and a lot cheaper than G10. I am using G10 when I replace some seacocks and through hulls but I will epoxy it in place.


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## pdqaltair (Nov 14, 2008)

sailordave said:


> New to me sailboat. Bow and stern cleats are backed w/ nothing but fender washers! But hey, they've worked for 20 years.
> 
> My plan is to replace them w/ G10 epoxied to the underside of the deck structure and then use longer bolts and fender washers to beef things up.
> Boat is 36', 13000#
> ...


I figure this is a trick question. There simply is not enough information, unless the responder has done surgery on this specific boat (some may have).

What is the existing deck lay-up? Cored or solid?

On my boat the deck varies from cored with thin skins, to thicker skins, to very thick solid lay-up, depending on the area. The cleats and winches were mounted in areas with NO CORE, specifically for this reason. So, without knowing, we are just guessing. But most quality manufacturers will build without core in the bow cleat areas.

I'm guessing--so is everyone else so I might as well--that even a thin layer of reinforcement that is well bonded to the underside will add far more strength than you realize. Anything beyond 1/4-inch would be silly and 1/8-inch is probably very suitable. By bonding the FRP it should act as a part of the laminate, not as a fender washer, and far less is needed. Taper the edges at least 5:1 to avoid a hard spot. Use plain--not fender washers--as they are thicker and will better transfer force to the G10. Fender washers will just dish (not enough to see) and will only apply force on the very edge of the new stiffer laminate.


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## mitiempo (Sep 19, 2008)

Fender washers are available thin or thick as are standard washers.


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## pdqaltair (Nov 14, 2008)

mitiempo said:


> Fender washers are available thin or thick as are standard washers.


Very true.

When thick, they very nearly are backing plates. For most loads, even quite large, they are very adequate. Still, I often fabricate aluminum or FRP backing plates when substantial fender washers would do as well; if I'm in the shop, scrap is free, the time is minimal with a drill press, band saw and grinder at hand, and it makes for a neater job with fewer parts and less cost.

When thin, far more common, they give only a false impression of security when the load becomes extreme.


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## rugosa (Aug 30, 2011)

*fender washers*

I was deck assembly lead hand on 27, 33, 36T for 4.5 years and we never cut corners because Raymond Wall (designer) and Matt Sterling (plant manager) kept tight control. You should expect factory installed deck hardware on your Merlin to be bolted through solid frp or areas cored in plywood. Thick fender washers were standard also. The factory standard continued into the Tony Castro designs too. May not be the case where an owner or yard has added hardware.


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## Maine Sail (Jan 6, 2003)

rugosa said:


> I was deck assembly lead hand on 27, 33, 36T for 4.5 years and we never cut corners because Raymond Wall (designer) and Matt Sterling (plant manager) kept tight control. You should expect factory installed deck hardware on your Merlin to be bolted through solid frp or areas cored in plywood. Thick fender washers were standard also. The factory standard continued into the Tony Castro designs too. May not be the case where an owner or yard has added hardware.


And THANK YOU !!! Over 80% of our boats deck hardware is un-rebedded and none of it leaks or has leaked in 32 years (almost 33 now)! . Even when I pulled the chain plates at year 31 they were still bone dry.. You guys built a hell of a product..! Probably could have saved some money on fasteners on the hull deck joint...

Genny track at year 32 and hull /deck joint in the background... Overkill is good!









P.S. Do you have any pics from the factory from when you were there? I'd love to see some layup and assembly pics...


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## rugosa (Aug 30, 2011)

Thanks for the compliment Maine Sail - sorry, no pics from the factory unless they are at the bottom of a trunk full to the top with photos & negatives. Do have some pics from working on Canada One and True North.

Butyl was the tried and true bedding material for almost everything except ports, phenolic main hatch slides, aluminum mast collar ring, few other things. I bet the Beckson ports leak on most of them after a while, tried all sorts of sealants. The optional Gebo fixed ports (I think most of them went to Europe) with tempered glass were bedded in butyl too. BTW, we rigged two 36T's as cutters with club foots. One went to Vancouver, still in touch with one of the owners although she is now back on Lake Ontario.

What year is your 36? How long yours? Any major problems? Email [email protected] if you like. Cheers!


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## SloopJonB (Jun 6, 2011)

Ajay73 said:


> Quarter inch would be fine. Aluminum is what is normally used and a lot cheaper than G10. I am using G10 when I replace some seacocks and through hulls but I will epoxy it in place.


+1 on the aluminium. I have been using 1/4" aluminium for years and it works great. Very easy to work - cuts with wood tools for the most part. You don't get fiberglass itch when working it either. It's a lot cheaper than G10 if you get some scrap sheet at a metal recycler. I got a 3' X 2' hunk for $8 and I've still got some left after 2 boats. If you take some care making them - rounded corners and edges and buff them before installing them, they look very nice as well - if you appreciate the "mechanical" look.

One factor often overlooked is that it takes shorter fasteners than thick G10 or plywood backers - long fasteners are much more expensive and can even be hard to come by.

I still use fender washers between the nuts and the backing plate.


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## SloopJonB (Jun 6, 2011)

Maine Sail said:


> And THANK YOU !!! Over 80% of our boats deck hardware is un-rebedded and none of it leaks or has leaked in 32 years (almost 33 now)! . Even when I pulled the chain plates at year 31 they were still bone dry.. You guys built a hell of a product..! Probably could have saved some money on fasteners on the hull deck joint...
> 
> Genny track at year 32 and hull /deck joint in the background... Overkill is good!
> 
> ...


A trick I have used successfully for backing tracks or other rows of fasteners is to get an appropriate piece of aluminium channel - at least as wide as the track and at least as deep as the exposed fasteners. Cut to length - a bit longer than the track, taper the ends of the sides of the channel then clamp the track and channel together. Drill through the end mounting hole on the track and through the aluminium - voila, a perfectly aligned hole.  Bolt the two together temporarily to maintain the alignment and continue down the length of the track. A drill press is nice for this part of the job. I drop another bolt in periodically to ensure the alignment is maintained.

When all the holes are drilled, separate the track and channel - you now have a matched pair, a one piece backing plate, a recess for the fasteners to reduce scalp tearout  and a good looking, custom backing setup for your genny track. To make it REALLY pretty, polish it before installing it.


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## BigZ (Jan 3, 2001)

SloopJonB said:


> A trick I have used successfully for backing tracks or other rows of fasteners is to get an appropriate piece of aluminium channel - at least as wide as the track and at least as deep as the exposed fasteners. Cut to length - a bit longer than the track, taper the ends of the sides of the channel then clamp the track and channel together. Drill through the end mounting hole on the track and through the aluminium - voila, a perfectly aligned hole.  Bolt the two together temporarily to maintain the alignment and continue down the length of the track. A drill press is nice for this part of the job. I drop another bolt in periodically to ensure the alignment is maintained.
> 
> When all the holes are drilled, separate the track and channel - you now have a matched pair, a one piece backing plate, a recess for the fasteners to reduce scalp tearout  and a good looking, custom backing setup for your genny track. To make it REALLY pretty, polish it before installing it.


After installing a much longer adjustable track, I wanted to cover the bolts for aesthetic reasons and to reduce chance of nicking myself on the exposed bolts.
At appropriate distances I used longer bolts, then built some wood channels that would fit over the bolts, but had thru holes at the location of the long bolts. At the long bolt locations, I used barrel nuts (not exactly sure of the term, have seen them binned as blind nuts or sex bolts) to hold the channel in place. Due to the curvature of the track I made 3 channels, maybe could have gotten by with 2. Really just needed one barrel nut per channel, but ended up using one at each end. 
Had to cut the long bolts to length to allow the barrel nuts to tighten, but no big deal; they don't have to be super tight because they're only holding the channel in place, not the track. 
Turned out ok. The barrel nuts can be removed very quickly for inspection. 
The pics show the port side. The starboard side has a shelf much closer to the bolts where scratching is more likely to occur.


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## Parley (Jul 13, 2006)

G-10 makes great backing plate (6-8mm should suffice), however overkill. 1/8-1/4" aluminum is much cheaper , just as easy to work with and will do the same job. I typically lay up carbon plate and use G-10 rod as a compression post for ea. thru-bolt (drilled out for the bolt, of course).


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## RFBrownPE (4 mo ago)

Maine Sail said:


> And THANK YOU !!! Over 80% of our boats deck hardware is un-rebedded and none of it leaks or has leaked in 32 years (almost 33 now)! . Even when I pulled the chain plates at year 31 they were still bone dry.. You guys built a hell of a product..! Probably could have saved some money on fasteners on the hull deck joint...
> 
> Genny track at year 32 and hull /deck joint in the background... Overkill is good!
> 
> ...


No one ever regretted building stronger than necessary.


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## pdqaltair (Nov 14, 2008)

RFBrownPE said:


> No one ever regretted building stronger than necessary.


Maybe. There have been a lot of boats built overweight that were down on their lines. A mast that is heavier than required will make a tender boat. A big truck can carry lots, but it gets crap gas mileage and the strength has zero benifit just driving to work. Given a choice between a steel pipe wrench and an alloy handle wrench, I'll take the alloy wrench every time.

In fact, it is easy to build too strong. Building light and strong is much more difficult. Too strong is often just as wrong as not strong enough.


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