hull to deck leaks

[markxengineerin]

I have always had leaks which drip off the 18-8 through bolts. Rain and seawater both. They're slowly driving me mad, ruining electronics, and rotting wood in inaccessible areas that Pacific Seacraft failed to add drainage to.

From literature

The hull-deck joint is at the 4″ tall bulwark. The 3/8″ deck flange overlays the inward oriented 5/16″ hull flange and the two are bedded in 3M 5200 and secured with 1/4″ stainless steel bolts and backing plates located on 4″ centers. Additional structural support is provided by a 13/16″ teak caprail bedded in polyurethane and fastened with #10 stainless steel screws on 8″ centers. We doubt this joint will leak or deteriorate except in the event of a heavy collision.

1) Is this normal/inevitable for a 30 year old boat? It's hard for me to imagine that much surface area of adhesive developing a leak, but maybe this happens to all fiberglass boats with age?

2) Odds of fixing the leak by digging out as best possible and re-caulking the toe rail to deck joint? I did the outboard side already, no difference, could also re-do the inner one as a last ditch band-aid.

3) If the toe rails are coming off, can they ever be re-used?

4) Suggestions for toe rail alternatives? I am fed up with leaks and while I prefer the look of a teak toe rail, I don't see myself spending $10K+ or whatever it would cost to make or buy new ones. It's too much work and not the enjoyable kind for me.

5) Is there any reason to remove all the 18-8 bolts, or is ok/better to just glass over them? Glassing is certainly less work. Why isn't this done in the first place?

[Ballsnall]

Originally Posted by markxengineerin

1) Is this normal/inevitable for a 30 year old boat? It's hard for me to imagine that much surface area of adhesive developing a leak, but maybe this happens to all fiberglass boats with age?

Yes, very common.

2) Odds of fixing the leak by digging out as best possible and re-caulking the toe rail to deck joint? I did the outboard side already, no difference, could also re-do the inner one as a last ditch band-aid.

Zero chance.

3) If the toe rails are coming off, can they ever be re-used?

Yes, should not be a problem if you are very patient with them. A heat gun is you friend to soften 5200. Go slow, be patient, use lots of wedges, gently.

4) Suggestions for toe rail alternatives? I am fed up with leaks and while I prefer the look of a teak toe rail, I don't see myself spending $10K+ or whatever it would cost to make or buy new ones. It's too much work and not the enjoyable kind for me.

Reuse

5) Is there any reason to remove all the 18-8 bolts, or is ok/better to just glass over them? Glassing is certainly less work. Why isn't this done in the first place?

The leaks are most likely through the bolt holes mostly.
If they are accessible then re-bed them then glass over.
If not accessible just glass over.

Cost.

[Bowdrie]

The construction method that the diagram shows is probably the most used method of hull/deck mating, and dates to the beginnings of fiberglass boats.
It's always been a contentious issue.
There have been a few production boats that used a bonded interface, (the Alajuela 38 comes to mind,) but the accuracy needed for the tooling of the plugs/molds, and bulkhead installation is much more critical, (it's a vertical interface joint).
The "hat" type, horizontal joint, (as per the diagram,) if bonded, requires countless amounts of labor to grind off the gelcoat both on the deck part and the hull, then when the bonding and glass work overlay is done a lot of fairing and re-gel coating is required.
It's a cost driven issue, bolts and 5200 are quick and easy, as the deck is already supported on the flange.

[gonesail]

if it is the scupper drain that passes thru the toe rail .. you might be able to concentrate on that. but it sounds like you have multiple leaks.

[Bowdrie]

Addendum; No matter how good it sticks, 5200 is a polyurethane and has a lot of flexibility.
Over the years the constant wracking/flexing of the hull/deck joint gradually breaks the bond around the bolts, (the horizontal flanges of the mating surfaces slide around on each other due to the flexibility of 5200).
Because 5200 does not have the greatest adherence to metal the bond around the bolts weakens.
The different expansion/contraction rates of fiberglass vs bolts do not help matters either.

[markxengineerin]

Thanks, so i guess I'm hoping the leaks are the red one and not the blue


My plan to thinly glass the yellow surface may not work if it's the blue, even if I try to get right up to the edge. Wrapping glass around all the way onto the hull would not be easy, for cosmetic reasons. Any other ideas to stop the blue?

What should the rig tension be during this job?

[Shanachie]

In one of Hal Roth's early books many years ago, he described being so aggravated by hull-deck leaks that he removed the toe rail, glassed over everything and installed a different type of toe rail.


He said he was perfectly satisfied with how it worked out, but I don't remember all of the details. I believe he had SS fittings made, installed them on the desk and then bolted the toe rail to them.

[markxengineerin]

Does a toe rail have any structural purpose? It seems that everything attached to it is also bolted through the deck/hull flange, which seems pretty strong by itself. It does act as a bit of a rub-rail because it protrudes slightly, but any other purpose?