Reinforcement

[Ammonite]

I'm not sure you understand how those legs work. There is no bolting and un-bolting involved. Once the fitting is mounted, the pin on the leg is inserted and held in place by the prongs of the u-bolt as seen in my pic.

Once installed, the ply backing will never be touched or disturbed again unless you are t-boned by a freighter.

I'm not sure why entire boats and interiors may be built in ply, but it is not permissible to use a ply backing plate sealed with epoxy. The Gougen brothers must be a ripe pair of fools. Maybe the OP should use titanium bolts as well?

I haven't looked at my ply pads in 11 years, should I panic now or save it for when I try out my legs again?

My response was not in relation to or as a reply to your post so please do not take offence. If plywood works for you so be it. It was meant more as a general comment in relation to through bolted backing plates. To my mind G10 is a much better solution for cleats, through hulls or anything else attached in this way as it completely eliminates the risk of a backing plate turning to mush. Other than a slight difference in cost why take the risk if you can't be 100% sure that sealant you've used will not fail at some point.

Besides if you are a fan of epoxy you should love G10

 

[anoccasionalyachtsman]

I'm not sure you understand how those legs work. There is no bolting and un-bolting involved. Once the fitting is mounted, the pin on the leg is inserted and held in place by the prongs of the u-bolt as seen in my pic.

Once installed, the ply backing will never be touched or disturbed again unless you are t-boned by a freighter.

I'm not sure why entire boats and interiors may be built in ply, but it is not permissible to use a ply backing plate sealed with epoxy. The Gougen brothers must be a ripe pair of fools. Maybe the OP should use titanium bolts as well?

I haven't looked at my ply pads in 11 years, should I panic now or save it for when I try out my legs again?

You can do whatever you like. As will I.

 

[Laminar Flow]

My response was not in relation to or as a reply to your post so please do not take offence. If plywood works for you so be it. It was meant more as a general comment in relation to through bolted backing plates. To my mind G10 is a much better solution for cleats, through hulls or anything else attached in this way as it completely eliminates the risk of a backing plate turning to mush. Other than a slight difference in cost why take the risk if you can't be 100% sure that sealant you've used will not fail at some point.

The ply backing plates for the seacocks on our boat are over forty years old. They are still rock solid and have outlasted the seacocks. To effect rot or deterioration in wood requires an environment that sustains the fungus. Any coating, but especially penetration by epoxy prevents that. Same goes for wood deterioration caused by the acids from galvanic processes i.e. "nail sickness".

 

[Ammonite]

The ply backing plates for the seacocks on our boat are over forty years old. They are still rock solid and have outlasted the seacocks. To effect rot or deterioration in wood requires an environment that sustains the fungus. Any coating, but especially penetration by epoxy prevents that. Same goes for wood deterioration caused by the acids from galvanic processes i.e. "nail sickness".

Forgive me if I bow out of this particular argument

 

[anoccasionalyachtsman]

Forgive me if I bow out of this particular argument

Me too. I've got some rotted epoxy coated ply to attend to tomorrow so have some packing to do.

 

[Laminar Flow]

Me too. I've got some rotted epoxy coated ply to attend to tomorrow so have some packing to do.

As you said, each to their own.

 

[zoidberg]

Maybe the OP should use titanium bolts as well?

Er, actually I AM looking for some titanium bolts as well - but that's for a completely different reinforcement project....

.... for these deckeyes. ( Or they, at a pinch, could be steel. )

They really ought to be 1/2" diameter, as the maker is one of those outdated little old engineering works in the middle of Mid-America that hasn't heard of 'SI' and 'Metric'.

Then there are nuts......

 

[Laminar Flow]

Er, actually I AM looking for some titanium bolts as well - but that's for a completely different reinforcement project....

.... for these deckeyes. ( Or they, at a pinch, could be steel. )

They really ought to be 1/2" diameter, as the maker is one of those outdated little old engineering works in the middle of Mid-America that hasn't heard of 'SI' and 'Metric'.

Then there are nuts......

Nicely finished parts. My boat has gradually shifted into the undefined no man's land between the old imperial and metric systems and which can make sourcing parts a bit confusing.

Make certain you only use carefully tapered carbon fibre/ kevlar (YBW approved) laminate pads to avoid any potential stress risers in the adjacent material. Also, I'm sure there are quite a few aviation and space program bone yards in the US Midwest, where one could source some technically exquisite and exotic materials to more properly equip any average cruising yacht to be better prepared for the next major crossing of the Solent.
I, for my part, am not adverse to dumpster diving in boat yards or fishing ports for that matter, as a source for any number of excellently useful nautical bits (Dumpsters in Fishing harbours are a veritable treasure trove, btw, and you can get any amount of high quality marine grade ply backing pads and for free at the trash bin of your neighbourhood boat yard).
Jus' sayin'...

 

[zoidberg]

I sense we may be 'kindred spirits'.

The Southern English equivalent of 'dumpster diving' was probably doing a visit to old John Foulkes' Chandlery Barge at Bursledon Bridge. He's gone to Fiddler's Green, alas, but I frequently dropped in of a rainy morning when passing, and often traded a couple of chocolate biscuits for a mug of his coffee....

The items pictured above came from one of his bins. How he came by them, no-one now knows - for he wouldn't tell me. There was a hoard of other Harken/Barbarossa 'Big Boat' gear, mostly unused, which came my way. Most of this is still in my loft....

"What on earth am I to do with a titanium runner block with an 8" sheave....?"

Or one of these....??

 

[Laminar Flow]

I sense we may be 'kindred spirits'.

The Southern English equivalent of 'dumpster diving' was probably doing a visit to old John Foulkes' Chandlery Barge at Bursledon Bridge. He's gone to Fiddler's Green, alas, but I frequently dropped in of a rainy morning when passing, and often traded a couple of chocolate biscuits for a mug of his coffee....

The items pictured above came from one of his bins. How he came by them, no-one now knows - for he wouldn't tell me. There was a hoard of other Harken/Barbarossa 'Big Boat' gear, mostly unused, which came my way. Most of this is still in my loft....

"What on earth am I to do with a titanium runner block with an 8" sheave....?"

Or one of these....??

Very pretty. Perhaps something for the glass showcase in the living room, next to Aunt Gwendoline's Wedgewood and Meissen collectibles, or a conversation piece for the "man cave" if Mrs. Zoidberg objects?

'Fraid, best of my booty pales by comparison: a nice, super heavy 9" bronze mushroom vent though, just needed to have the paint removed and a bit of cleaning up done, a 200m spool of 2.5 mm SS cable, oh and a fully functional VHF radio - all from the Fisherman's dumpster and all of which eventually found a new seagoing home.

 

[DownWest]

I sense we may be 'kindred spirits'.

The Southern English equivalent of 'dumpster diving' was probably doing a visit to old John Foulkes' Chandlery Barge at Bursledon Bridge. He's gone to Fiddler's Green, alas, but I frequently dropped in of a rainy morning when passing, and often traded a couple of chocolate biscuits for a mug of his coffee....

The items pictured above came from one of his bins. How he came by them, no-one now knows - for he wouldn't tell me. There was a hoard of other Harken/Barbarossa 'Big Boat' gear, mostly unused, which came my way. Most of this is still in my loft....

"What on earth am I to do with a titanium runner block with an 8" sheave....?"

Or one of these....??

Takes me back even further When Foulkes was in Walthamstow... Static lines that were unpicked for dinghy toe straps and D rubber for trailer side supports. Treasure indeed..

It was Thomas then, presume the same family?

 

[Iliade]

Zoidberg, are you fabricating the legs as well? I'm looking for ideas for my long keel Evasion 32 which already has the sockets from new.
I'm thinking of allu scaff, joined in the middle to allow onboard stowage but having only seen pics of dried out boats, wary!

I'm about to make/have made a pair for my Evasion 34.
I wonder if there are any quantity discounts to be had? Thus far I know the sockets' thread is M20 and I'm looking at something considerably bigger than ally scaffolding... PM if interested.

 

[Laminar Flow]

I'm about to make/have made a pair for my Evasion 34.
I wonder if there are any quantity discounts to be had? Thus far I know the sockets' thread is M20 and I'm looking at something considerably bigger than ally scaffolding... PM if interested.

Since we are talking about this particular subject here are a few numbers. I chose Iliade's boat for illustration (interesting layout btw)
There are a few assumptions that I made:
Firstly, the displacement of 5500kg quoted in Sailboatdata is quite likely incorrect. I chose 8000kg instead which is far more probable.
Secondly, I assumed the C of G to be at the waterline. That is probably optimistic in spite of a ballast/displacement ratio of 40%, regardless, it makes little difference.

I guess the Evasion would need a leg of 8' in length. A heavy wall pipe of 2.75" OD with a wall thickness of 1/4" and a length of 8' would support a load of 7521kg (Euler).

A M20 pin will hold 9013 kg in shear.

So what is the expected load at varying angles of list for an 8ton boat?
5 degr - 83.8kg
10 degr - 334.8 kg
15 degr - 736 kg
20 degr - 1291 kg

The normal range of list will not likely exceed 10 degr. . 15 and 20 degr. are rather extreme and still the 2.75" pipe would easily support that load. The biggest risk at, say 20 degr., would be the ground compacting and giving way, causing a further list and eventual collapse of the tube at much more extreme angles when it subjected to a bending component.

For all intents and purposes the 22.8 safety margin would, in normal use, provide plenty of safety, even considering dynamic loading, for example, while refloating in swell conditions.

The Yachtleg brackets use two M16 studs to secure, that has less to do with required strength as to do with providing sufficient bearing surface against the GRP.

At 83 kg and 334kg respectively for loading in normal conditions, one could also use papier machè for backing pads and quite likely get away with it.

Hope this helps, LF

 

[geem]

For myself....
Ply is more stable.
Grind and key the hull grp
Round off all the edges if you like on the ply block then pug it down on a polyester pug mix, nicely filleted radii, once it has set up in place laminate over it to the hull with grp and cloth , feathering outwards with the layers , jobsa good un.

I wouldn’t bother with epoxy, myself ..but each to their own

One can so easily overthink these things

Polyester is rubbish at bonding to polyester. Epoxy works so much better on polyester. As stated in another post, shamfering the edges of the ply to avoid a hard spot and potential cracks in external gelcoat is advisable