Tayana 37 hull flexure question - will it flex?

[markkopyc]

Hi,

I recently recored the side decks of my Tayana 37, using balsa core and vinylester and CSM.

I cut the top 'skin' about 3 inches from the outboard (near bulwark) edge and 3 inches from the coachhouse and removed the center in largeish sections (6 per side) to do the cleanout and new core/new resin. I then reused the 'old' top skin and put it back where it had came from.

Question is, I didn't use glass cloth to 'bind' the existing 3" flanges to the underside of the replaced original skin.

A surveyor is telling us (the buyer and I) that when the hull flexes due to immersion in water, that the top skin joint will break due to flexure. He used the analogy of a tupperware container with a lid on it being squeezed, and the lid flexing or popping up or off.

Those that know Tayana 37's.. Is this true, or is the T37 built so heavily that this isn't a concern?

Thanks so much everyone,

Mark

1983 Tayana 37 'Reverie', Hull #369, West Bath Maine

[neilpride]

I think I understand reading your post that you did not cover the seams with FG, in that case your surveyor may be right, if you are unlucky enough to find yourself in a good storm you will find out, the deck is not a 100% rigid element.

[tkeithlu]

General principle - If you've disconnected a structural member you need to use as much or really more of a patch to reconnect it, because you can't get the patch truly in the same place with the same strength. The designer was counting on those flanges for rigidity. Your assuming that without them that the hull is still adequately rigid is going to be suspect. Sorry to say it, but you have a difficult job ahead of you.

[Randy Bogardus]

Sorry to say that your surveyor is correct. I would not take this setup into a seaway.

[chaggart]

Hi Mark
I own a Tayana 37 and re-cored my side decks a few years ago. I reused the top skin and bevelled 3 inches and layed down 3 layers of bi axle cloth, ground that down and faired the deck and applied non skid. You have to mechanically reattach the top skin together otherwise any flexing will create cracks. The deck will have to be redone IMHO.

Charles
T37 #268

[cr180]

Don’t have a Tayana 37, but have observed flexing on other fiberglass hulls of that vintage. My Gulfstar for example was built with hand layed up heavy cloth resulting in a thick hull. See flexing only when hauled though, not in the water.

Think your deck repair method is widely used. And the deck also has an underside fiberglass member still intact. And the cut joint is outboard of the radius from cabin house to deck (3”). And the new balsa is now bonded to old at the cut joint (keep in mind without the core, the fiberglass would surely crack). So it is unlikely that the joint would crack. And way better than if not repaired (with spongy deck). But to win an argument with a Surveyor is an uphill battle. And the insurance companies now default to the Surveyor and want everything fixed.

[markkopyc]

Thanks everyone,

I guess the consensus and reading between the lines here, is not Redo the entire deck, but grind 12:1 ratio and add 1708 glass over the joints from above and bond with VE. Then fix the cosmetics.


Total aside: Yeah I hate some surveyors, some just aren't practical and want everything 'just so' or scrap the boat, because they don't know any better. Some want too much 'belt and suspenders'. Some are used to nearly-new boats with minimal issues and unlimited budgets and don't know how to deal with a 40year old boat.
One "surveyor" gave me Horrible advice about how to fix something, and said I'm be better off 'parting out the boat'. Frankly I don't trust them, so I'm always looking for confirmation about what they say. As soon as the lawyers and insurance underwriters get involved, it's all screwed up..

[cr180]

Originally Posted by markkopyc

Thanks everyone,

I guess the consensus and reading between the lines here, is not Redo the entire deck, but grind 12:1 ratio and add 1708 glass over the joints from above and bond with VE. Then fix the cosmetics.


Total aside: Yeah I hate some surveyors, some just aren't practical and want everything 'just so' or scrap the boat, because they don't know any better. Some want too much 'belt and suspenders'. Some are used to nearly-new boats with minimal issues and unlimited budgets and don't know how to deal with a 40year old boat.
One "surveyor" gave me Horrible advice about how to fix something, and said I'm be better off 'parting out the boat'. Frankly I don't trust them, so I'm always looking for confirmation about what they say. As soon as the lawyers and insurance underwriters get involved, it's all screwed up..

Or wait for another buyer and Surveyor.

Edit: Better yet take it out sailing hard on the wind and see what happens.

[Cheechako]

Are you saying you only 'tapered and glassed' the outside?
"I didn't use glass cloth to 'bind' the existing 3" flanges to the underside of the replaced original skin."
That would be pretty much normal procedure as you cant do the inside effectively. Ditto for a lengthy hull repair where you cannot do the inside due to cabinetry etc. The bonding strength is dictated by the length of the taper, not whether it's new glass or bonded old glass, it's the joint area that matters either way..

[markkopyc]

[from a marine architect] Hey Mark, your surveyor is correct, if you reused the old top solid skin, you will have problems.
My advice was to totally rebuild a top skin with new cloth, always bonding back to the perimeter flanges. If that is not done then you have lost any advantage of rebuilding the deck structure, and consequently you basically have only the strength of the bottom skin attached to the flanges.
The old top skin cut line will always Crack and will be a source for water ingress into the new core.
I suggest that you bond the old topskin to the flanges,with a healthy overlap of at least 3 to 4 inches, and run it across the flange and up the bulwark. Use a biaxiale ( +-45°)24 oz cloth with a mat down on a well ground surface. Preferably 2 layers and finish with a 3oz CSM.
You can make the lap edge a defining detail with paint,so that it looks like it's meant to be.
I hope this helps.
Grant.

[Lee Jerry]

Originally Posted by markkopyc

Hi,

I recently recored the side decks of my Tayana 37, using balsa core and vinylester and CSM.

I cut the top 'skin' about 3 inches from the outboard (near bulwark) edge and 3 inches from the coachhouse and removed the center in largeish sections (6 per side) to do the cleanout and new core/new resin. I then reused the 'old' top skin and put it back where it had came from.

Question is, I didn't use glass cloth to 'bind' the existing 3" flanges to the underside of the replaced original skin.

A surveyor is telling us (the buyer and I) that when the hull flexes due to immersion in water, that the top skin joint will break due to flexure. He used the analogy of a tupperware container with a lid on it being squeezed, and the lid flexing or popping up or off.

Those that know Tayana 37's.. Is this true, or is the T37 built so heavily that this isn't a concern?

Originally Posted by markkopyc

I guess the consensus and reading between the lines here, is not Redo the entire deck, but grind 12:1 ratio and add 1708 glass over the joints from above and bond with VE. Then fix the cosmetics.

It is unclear (to me) exactly how you put it back together. A more detailed description (and maybe sketch) could be helpful if you want better advice (from everyone). Not exactly sure where / how you used it, but CSM is not a good structural material. If the edges of the skin were simply cut (square) to remove and then just replaced and the kerf filled with resin, that is not good.

The best option is to rebuild the entire skin as your NA described.

But it is possible to reuse the old skin if the proper steps are used (and its condition is acceptable). These would include:
1- gluing the old skin (after cleaning) to the new core. There might be an appropriate adhesive available (in caulk tube), or old school is coat both surfaces (core and bottom of skin) with neat resin, then add some thickened resin to bed and fill gaps, then "clamp" skin (weigh down) until cured. This should be the same / similar to how you glued the new core in.
2- beveling the edges (of both skin and flange) and secure with glass tape (or cloth) of decreasing width, of appropriate weight and number of layers to rebuild the thickness.

Did you do either of these, let alone both? If you did #1 but not #2, you may be able to salvage as you've described. If you didn't do #1, I think you have to start over (and probably do new whole skin).

Total aside: Yeah I hate some surveyors, some just aren't practical and want everything 'just so' or scrap the boat, because they don't know any better. Some want too much 'belt and suspenders'. Some are used to nearly-new boats with minimal issues and unlimited budgets and don't know how to deal with a 40year old boat.
One "surveyor" gave me Horrible advice about how to fix something, and said I'm be better off 'parting out the boat'. Frankly I don't trust them, so I'm always looking for confirmation about what they say. As soon as the lawyers and insurance underwriters get involved, it's all screwed up..

Surveyors are like any other profession - there are good ones and bad ones, fewer very good ones and very bad ones, with most somewhere in the middle. When possible, recommendations are the best option, either to use or to avoid.

[c.K.]

Originally Posted by markkopyc

Hi,

I recently recored the side decks of my Tayana 37, using balsa core and vinylester and CSM.

I cut the top 'skin' about 3 inches from the outboard (near bulwark) edge and 3 inches from the coachhouse and removed the center in largeish sections (6 per side) to do the cleanout and new core/new resin. I then reused the 'old' top skin and put it back where it had came from.

Question is, I didn't use glass cloth to 'bind' the existing 3" flanges to the underside of the replaced original skin.

A surveyor is telling us (the buyer and I) that when the hull flexes due to immersion in water, that the top skin joint will break due to flexure. He used the analogy of a tupperware container with a lid on it being squeezed, and the lid flexing or popping up or off.

Those that know Tayana 37's.. Is this true, or is the T37 built so heavily that this isn't a concern?

Thanks so much everyone,

Mark

1983 Tayana 37 'Reverie', Hull #369, West Bath Maine

Hey mark
I had core rot in the front peak and cut out the inside and reused the fg I had taken out