G10 backing plates

[sailordave]

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.

[Maine Sail]

Originally Posted by sailordave

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.

Originally Posted by sailordave

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......

[olson34]

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

[asdf38]

Do you need anything special to cut G10?

[overbored]

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.

[MedSailor]

Originally Posted by olson34

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

[sailordave]

Originally Posted by Maine Sail

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.

[Ajay73]

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.

[pdqaltair]

Originally Posted by sailordave

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.

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.

[mitiempo]

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