To balsa core or not to balsa core?

[jzk]

Actually, I mean the Gulfstar 60 has a balsa core below the waterline. If these 1982 boats are dry, however, then things must have been done ok I would assume.

[Tropic Cat]

All cored boats are dry to begin with. It's what happens to them after they are delivered that causes problems. You're right in that a well maintained cored hull boat is probably fine.

Unfortunately delamination issues sometimes get by surveyors. I reference the Bumfuzzle Wildcat, where a well renown surveyor missed it completely.

Why take a chance if you don't have to?

[cat man do]

Originally Posted by rickm505

Why take a chance if you don't have to?

Cored panel construction = stiffer stronger lighter boat (generaly)

Lighter boat = performance



Dave

[cat man do]

Originally Posted by 44'cruisingcat

Yes, 80% isn't as good as 100% you would think. Still, if you're trying to do something on the cheap, near enough might have to be good enough I guess.

If you stopped buying that expensive ATL resin and purchased epoxy from someone else you may find that epoxy and Vinyl arent that far apart in price

Genkem Fiberglass Epoxy Resins Core Adhesives and Gelcoats

Dave

[ssullivan]

Originally Posted by jzk

Actually, I mean the Gulfstar 60 has a balsa core below the waterline. If these 1982 boats are dry, however, then things must have been done ok I would assume.

Ahh... sorry.

Yes, things seem to have been done well, as we had no moisture in our core either.

I mean really... the only places things can get screwed up are through hulls or other attachments to the hull. I guess that's the saving grace of laminates below the waterline. There isn't a lot of harware to make leaking points.

The Gulfstar (ours anyway) had an encapsulated keel, so no chance of getting water in there either.

[ssullivan]

Originally Posted by cat man do

Cored panel construction = stiffer stronger lighter boat (generaly)

Lighter boat = performance



Dave

As I'm too painfully aware, you're right, Dave.

[44'cruisingcat]

Originally Posted by cat man do

If you stopped buying that expensive ATL resin and purchased epoxy from someone else you may find that epoxy and Vinyl arent that far apart in price

Genkem Fiberglass Epoxy Resins Core Adhesives and Gelcoats

Dave

Yes, most of what ATL sells is pretty pricey, but not all of it. You just have to know what to ask for, and who to ask...

[BigCat]

"The Gulfstar (ours anyway) had an encapsulated keel, so no chance of getting water in there either."

I'd be amazed if the keel weren't solid (no core,) laminate, assuming that your ballast keel isn't bolted on. Assuming that the through hulls were mounted properly, ie. in a thick section of solid laminate slightly bigger than the hardware, you shouldn't have hull problems unless you hit something kind of small or pointy.

The problem with core laminates is that they are good with well distributed loads but not so resistant to puncture by point loads. That is why I, and many others, don't use core, especially balsa core, below or near the waterline. This increases my structure weight by about 9%, but I consider this a worthwhile trade-off in a cruising boat that will be getting close to a lot of coral heads.

I like balsa and am using it, so this isn't a slam at balsa.

[ssullivan]

Originally Posted by BigCat

"The Gulfstar (ours anyway) had an encapsulated keel, so no chance of getting water in there either."

I'd be amazed if the keel weren't solid (no core,) laminate, assuming that your ballast keel isn't bolted on. Assuming that the through hulls were mounted properly, ie. in a thick section of solid laminate slightly bigger than the hardware, you shouldn't have hull problems unless you hit something kind of small or pointy.

The problem with core laminates is that they are good with well distributed loads but not so resistant to puncture by point loads. That is why I, and many others, don't use core, especially balsa core, below or near the waterline. This increases my structure weight by about 9%, but I consider this a worthwhile trade-off in a cruising boat that will be getting close to a lot of coral heads.

I like balsa and am using it, so this isn't a slam at balsa.

At least using no coring low, your 9% weight is down where it should be.

Sorry... sometimes I end up replying a little quickly. I definitely didn't have a core around the keel. ha ha I was trying to say the keel was encapsulated, which is good and means that no matter how far down the coring went, there aren't any keel bolts to worry about moisture getting into the laminates from the bilge or the outside.

I need to hire an editor.

[BigCat]

"I had one bolt break on an inner forestay. Just one bolt... and by the time I discovered it and repaired it, balsa core damage was already done." IHMO, if there was balsa under a bolt that held a forestay, the boat wasn't built right to begin with. Should have been solid glass under that spot. I am having some trouble visualizing this-if you had lost your forestay you would have noticed right away, and that is what would usually happen if you lost a bolt holding a forestay-

[Tropic Cat]

Originally Posted by BigCat

I am having some trouble visualizing this-if you had lost your forestay you would have noticed right away, and that is what would usually happen if you lost a bolt holding a forestay-

No, I didn't lose a forestay. When walking the foredeck one day I noticed small gel coat cracks radiating out from one of the 4 bolts holding my baby stay. I immediately set out to remove the bolts and have a look. In doing so, I discovered that one of the 4 bolts was broken. It was in place, and looked OK, but had sheered off 1/2 inch into the hole. I have no idea how this could happen. The other 3 bolts holding the forestay were fine. Water ingress from the broken bolt entered the core.

Like I said, all it took was one broken bolt to cause damage. On my boat the foredeck is the only core on the boat. The rest is solid fiberglass.

[BigCat]

"but had sheered off 1/2 inch into the hole." I'm thinking maybe it was over-torqued when it was installed, and had been broken all along, or at least cracked when it was installed, and then crevice corrosion finished it off.

I'm sure you were glad not to lose your whole mast. This is what I like about unstayed masts-no crevice corrosion problems can threaten your mast.

[delmarrey]

Originally Posted by rickm505

Like I said, all it took was one broken bolt to cause damage. On my boat the foredeck is the only core on the boat. The rest is solid fiberglass.

In another words, a bad installation!

[Tropic Cat]

Originally Posted by delmarrey

In another words, a bad installation!

I dunno..it took 22 years to go bad

[Joli]

Not a bad install but poor execution. A highly loaded are like a shroud base should not be fastened to a core. The area should have been manufactured with no coring in that area but builders cut corner all to often.

Joli

Originally Posted by delmarrey

In another words, a bad installation!