Soggy sandwich

[ArthurWood]

Have spent a few days trying to find where rainwater is entering the fwd cabin at the decorative bolster which runs around the head of the bed. From there it exited on the floor at the foot of the bed, fortunately without wetting the bed.
I think I finally figured it to be coming from a leaking hatch over the bed, although it wasn't apparent till I really hosed it and it came in at the hatch itself. The water was entering at the hatch, running through the coachroof "sandwich" and into the boat around the level of the rubrail, under the lining of the cabin and out at the bolster around the bed.
Upon removing the hatch, I find some rot in the sandwich material in the coachroof. At one point it extends back about 2" I would estimate. I've dug out all the nasty stuff, but I have three questions:

- how do I ensure it dries out from that point to the side of the boat where it entered the cabin?

- should I treat the sandwich material to prevent any further rot?

- what should I use to fill the void?

Thanks in advance.

 

[Nautorius]

Hi Arthur,

Sorry to hear of this bad luck! Water creep is to Sandwich Hulls what Rust is to steel ones! I had a similar Issue on my Regal. I removed the Ports, dug out some of the accesable damp area and then set up a fan heater to blow warm air into the gap. I left it going quite a while and had a de-humidifier on it.

Do not know how well it worked, but it felt a lot drier. Then re-sealed with lots of silkaflex. It is also good if you can open up some of the area around where the water exited and blow up through the hull as the air will rise out taking some of the moisture with it. The only sure way is to rip all out, but that is not likely!

A real painful Job, and you can now only limit the damage as it can not really be repaired (practically and cosy wise).

Cheers

Paul /forums/images/graemlins/laugh.gif

 

[boatmike]

Condolences Arthur. This is a pretty difficult question. It is in fact very unlikely that the water is travelling through the balsa itself as end grain block balsa does not "wick", the grain actually being vertical. It is more likely that the deck sandwich has delaminated from the balsa giving a route for the water to travel between the GRP and balsa. Looking at your bio, you live in Florida where the hot sun on the deck could well have caused delam of areas not properly bonded in the first place. Unfortunately not uncommon.
Lets imagine the boat being built.
The deck moulding is upside down and the outer GRP skin has been moulded. The next stage is to cover the GRP with a bonding resin or adhesive. This probably has no more than 40 minutes pot life. Then the balsa is pressed into place and held down while the resin cures by either weights or vacuum applied under a plastic sheet. There are therefore all kinds of opportunity for either taking too long, or not doing the job properly resulting in voids, and incomplete bonding. The inner skin is laminated over the balsa by direct application so in this case it is unlikely to have poor bonding so the suspect areas are on the outside skin not the inner.
Now when the boat is new all appears OK. Then it gets cooked in the Florida sun...
The temperature of the deck can reach very high levels which causes the resin to soften and those areas of poor bond to break meaning that there are large areas where the skin is not attached. Then if water gets in you really have trouble because in the heat steam can be produced blowing the outer skin away from the balsa still further. Bad news I am afraid.
The solution is to find a good composite technologist who can first of all determine the extent of the problem. This might entail ultrasonic testing of the whole deck. Then it is likely that a solution can be found by injecting high temperature epoxy through small 1/8" holes in the outer skin locally. If its extensive the same can be done applying vacuum from one hole or more around the area while introducing resin from another central to them . The edges of the laminate must be sealed with sikaflex or something before hand though for this to work. I have personally supervised about 8 laminate repairs like this and it can produce a lasting solution.
Anything less can be a problem in itself. Whatever you do don't just seal up around the edges. If there is still water there it has to be able to escape.
Sorry to be depressing but there is no quick fix..... /forums/images/graemlins/frown.gif

 

[sarabande]

[ QUOTE ]
The temperature of the deck can reach very high levels which causes the resin to soften

[/ QUOTE ]

Boats that dissolve in the tropical sun ? No wonder there are so many disappearances in these Round The World voyages !

I wonder if embrittlement occurs when the temp goes below zero, as well ?

I'd stick with wood (rots ?) or steel (rusts?) or ferro (rusts/ alkaline degeneration ?) or ... /forums/images/graemlins/grin.gif

 

[Rivers & creeks]

Go with aluminium, no known problems there.

 

[ArthurWood]

Boatmike and Nautorious - thanks for your very useful, if depressing responses. Oh, b&^gger is all I can say at the moment.

 

[Salty John]

Arthur,
you might want to get a copy of the Gougeon Brothers, Inc's(West System epoxy people) booklet "Fibreglass Boat Repair and Maintenance". It addresses the repair of delamination.

 

[Searush]

[ QUOTE ]
Go with aluminium, no known problems there.

[/ QUOTE ]

I presume you are being sarcastic then? /forums/images/graemlins/tongue.gif

 

[rhumlady]

I had problems of wet core on my foredeck a few years ago. IThe balsa was shot and wouldn't dry out. I had to drill from the under side after tapping with a screwdriver to find the extent of the problem and then remove the section of laminate to get at the balsa. Having removed the core I replaced it with balsa and then redid the laminate on the under side. I hate working above myself at the best of times but using resin was awfull. Not a nice job at all.

 

[ArthurWood]

Thanks, John. I'll go to one of our two local West Marine stores this p.m. and have a browse.

 

[ArthurWood]

John,
The book you mentioned was not to be found but there was another one which described the process for repair - much like Rhumlady describes. Went to the boat and tapped the area of the deck with a screwdriver handle, but couldn't find any "funny" spots. I'm going to wait until Monday to see the SeaRay service guy who has had experience of this type of thing. Good weather, in the 70sF, is forecast for the next few days, so no chance of it getting any wetter.

 

[BrendanS]

Good luck Arthur, I hope it's a localised problem (or should I say localized, just for you /forums/images/graemlins/laugh.gif)

 

[ArthurWood]

Thanks, Brendan. The other problem is that I had just paid a 50% deposit on a $7K+ interior refurb job on the boat. But after all, it's only money and still cheaper than a new boat /forums/images/graemlins/smile.gif

 

[Rivers & creeks]

[ QUOTE ]
Quote:
Go with aluminium, no known problems there.



I presume you are being sarcastic then?

[/ QUOTE ]

Um....yes /forums/images/graemlins/smirk.gif