Fiberglass-Balsa Deck, Surprising Find

MatthewM · #1 (**permalink**) 10-11-2011

Hello Everyone,

I had a surprising discovery this evening. We purchased a 1979 Nor'West 33 about two months ago. I was told the deck was balsa cored, and have been working under that assumption. The deck was sounded at survey with no soft spots.

Tonight I was removing the forward headliner to inspect the underside of some deck hardware. There are many deck fittings that are not through bolted all the way through the headliner, and I am trying to access the bottom side of all of them.

Well, After pulling down a small section of the headliner I see balsa wood. I scratch my head for a second and remember a picture I saw in the original boat brochure.

So, it turns out that my deck is not balsa-cored, but rather is balsa wood sandwiched between fiberglass topside, and plywood headliner below. I have not heard of this, but I haven't really been looking either. I don't really know what to think. It makes inspecting the balsa a breeze, at least compared to cored decks. But it also seems like it would not be as strong.

Anyone else have a boat like this, or any thoughts on the matter? Maybe there are many boats like this and I just didn't know.

Matthew

Faster · #2 (**permalink**) 10-11-2011

From the illustration in the link it looks like a conventional FRP/Balsa core sandwich arrangement... was the balsa actually bare wood? If the underside of the deck was not painted or gelcoated you would see the balsa sections through the essentially clear fiberglass...

If it had been as you described with the headliner as the bottom 'layer' it would have been very difficult to remove...

MatthewM · #3 (**permalink**) 10-11-2011

After some more thinking, I think you must be right Faster. I didn't get the headliner all the way out and it was a little dark. I feel a little silly now, but I guess that is what internet forums are for, making yourself feel silly. Thanks for the reply, and if I am wrong I will let you all know.

denverd0n · #4 (**permalink**) 10-12-2011

Read what the brochure says...

"The deck and internal cabin headliner sandwich end grain balsa..."

Sounds to me like a description of fiberglass on top, plywood on the bottom (the headliner), and balsa in between. The picture is just vague enough so that you really can't be certain if the balsa is completely encased in fiberglass or not.

On the other hand, this is a 30+ year old boat that has held up well and has no soft spots. If it were inherently weak, significant problems would have become apparent by now. Though it is a little unconventional, it appears that Nor'west put it together well. Frankly, I wouldn't worry about it.

Faster · #5 (**permalink**) 10-12-2011

Quote:

Originally Posted by denverd0n

Read what the brochure says...

"The deck and internal cabin headliner sandwich end grain balsa..."

Sounds to me like a description of fiberglass on top, plywood on the bottom (the headliner), and balsa in between. The picture is just vague enough so that you really can't be certain if the balsa is completely encased in fiberglass or not.

On the other hand, this is a 30+ year old boat that has held up well and has no soft spots. If it were inherently weak, significant problems would have become apparent by now. Though it is a little unconventional, it appears that Nor'west put it together well. Frankly, I wouldn't worry about it.

The balsa would have to encapsulated for the cored structure to have the necessary strength... if the lower skin was indeed plywood, I suspect the OP would have had considerable difficulty separating it from the core. Since this boat seems to be in good condition and well built I think the confusion may lie in the builder using the term 'headliner' for the inner skin...

... but anything is possible, of course...

CharlieCobra · #6 (**permalink**) 10-12-2011

If the balsa was overlaid dry onto the ply, I could see this happening. I sure wouldn't want to deal with deck leaks on that boat though...