hull recore options

i have been reading on how wood below the water line is bad ., as a balsa core will rot when water finds it and it usually does i have a 1977 imp x250 and the core is gone rotted out all the way to the bow . what are my options on fixing this right , from what i read foam does not rot but the balsa seams to be the strongest , there are composite materials but how long will they last, how well do they really hold to the fiberglass. what are the options for no core . either way it would have to be put in a cradle to get it straight so is it wort it being 25 by 8 , i figured i could do it for around 2500 , but loots of work and again is it worth it .
thanks jason

 

The stories about core below the waterline being bad are not based in fact. Proper construction and maintenance will avoid problems. Recoring a hull and keeping it fair is not easy. All cores have good and bad points. On first thought, the hull is not worth the trouble.

 

Typically a recore for a large area is never worth the price. Even if the initial estimate might make it seem reasonable (though I have never seen this), if there is a problem in one area of the boat it is likely that others suffer from the same problem. Meaning that as you get into the project it gets bigger and bigger.

On a boat your's age and value I just can't see the justification for undertaking this. Buying something newer for the same money and parting the rest of the boat would be my thought.

 

Yes there have got to be better boats to work on BUT if you are a enthusiast and love the boat you got i would say just do it .
Interest and enthusiasm along with learning and the love of boats in general is most important at the end of the day .

 

I second with Gonzo and Stumble. Basicly for boats that age, and with these kind of problems, in the current market there is no place for them. Ditch it, sell off the good parts, and buy something else. This will get you on the water cheaper and faster.

However, if you like the work, expenses and trouble (something mostly referred to as "hobby") then I would opt for either 80 kg/m3 or 100 kg/m3 foam (5 or 6 lb/ft3) in scrim cloth.
You will need to decide which side of the sandwich construction has to go. Usually the outside is cheaper, as long as the interior is still usable.

Start in the front, with a section some 3-4 ft wide. Remove the outer skin, remove the core, clean up and feather edges, apply an extra layer of glass (multiaxial) preferably with vinylester (or epoxy), and install the foam. Foam is to be installed in a proper bedding compound, using (light) vacuum to press them firmly into the bedding compound. more on this can be found on this forum.
Then sand smooth, and apply a layer of glass, and peelply.
Work your way back, until you have done all. Now you can apply more glass, fair and paint.

I have no idea of the amount of glass needed, as I do not know what you are working on. Try and match the skin you took off.

Have fun...

 

Heres a contradiction in perception if ever I saw one.

Kelsall has been building with Airex cores for 25 years with never a problem, but I have read a number of really juicy stories of catastophic failure, mostly in balsa below the waterline.

Its alright saying proper maintenance will avoid the problem, buts these are boats after all.

 

I would dare to say that proper construction is way more important than proper maintenance. A properly engineered and constructed boat can have balsa below the waterline without any problem.

There are numerous boats with balsa core that will never see a problem. However, as soon as a builder starts cutting corners, things go haywire. This is the same for balsa, PVC or single skin.

Do it right, and you do it for a lifetime. Do it wrong, and you will run into problems.