Balsa Core

[hjubyhavn]

I did post this under Freedom but no one else have used the section yet.

I have been looking at used Freedoms (80's) but have found that the builder did not seal any through-core/through-hull fittings. This becomes a problem as the boats age because it is usually the exterior caulking that gives up first and start leaking, and the interior does not leak until the core is good and wet.

How much damage is acceptable around a through hull before the whole thing has to be torn open and what is an industry wide rule of thumb for determining at what point the hull is permanently weakened by a "peel-back" repair (I will sail or ship across the Atlantic at some point) ???

[sailingfool]

Originally Posted by hjubyhavn

....
How much damage is acceptable around a through hull before the whole thing has to be torn open and what is an industry wide rule of thumb for determining at what point the hull is permanently weakened by a "peel-back" repair (I will sail or ship across the Atlantic at some point) ???

Boy, that sounds like pretty dumb construction.

I don't feel there's any reason to think that a peel-back-repair done by a reputable yard doesn't produce a boat as solid as new, as long as you don't balk at the $3-400/foot cost.

If by how much damage is acceptable, you mean how much wet core in the hull, I'd say simply none is acceptable, due to the risk of properly identifying the limits of what damage in fact exists. I don't think there's like a lot of scientific research on the subject...You could read up on what Mr. Pascoe has to say on the problems of wet core, and the problems of surveying same: Boat Hulls - Cores and Structural Issues: Online Articles by David Pascoe, Marine Surveyor .

Given what you state, should you proceed with a purchase of a Freedom I would include the removal of all through hulls, at owner's cost, for core inspection during the survey. If you buy the boat, you can have the core surrounding the hull holes properly sealed, reinstall everything and pay the owner the cost of the through hulls removal.

[lans0012]

I own a cored hull but the boat was in good shape and very cheap so I don't care if it gets to a point where there is a lot of work to do because I'll just get rid of the boat. I also live in Florida and there isn't a freeze thaw here and even if the core is wet there may not be delamination for quite some time.

I noticed you're from Minnesota. I grew up in Minneapolis and have owned cored speedboats there and the freeze thaw speeds up the delamination rapidly. I pulled the core out of a hydrostream viper speedboat one winter. The 1/4" core was mostly dust but in some spots the wet core was still very much laminated and strong. The pounding of the boat causes the water to squirt around in there and peel the layers off too. The high stress areas were toast and the low stress areas were wet but fine.

If it is cored around the throughhull then water intrusion could have spread into a great area. The best way to fix it is to take off the INNER skin and gouge out the wet core and rebed and relaminate. I wouldn't fix from the outside because when you layup the new fiberglass there will only be a physical bond and not a chemical bond like you need especially if you are on the great lakes or ocean. Cruising around the whitefish chain or on mille Lacs no prob.

Note that fiberglass repair is very expensive, and time consuming, hazardous to your health and a pain in the A$$. Find a non cored boat or one without coring by the throughhulls.

Many of the older boats are still in the water. I wonder if we will see boats built in the cored age last 40plus years like we have seen some of the first gen fiberglass boats.

[tommays]

The TPI boats Jboats, Freedom ,ect are more or less one of the best PRODUCTION boats made

A solid hull is no sure thing as a bad day of layup can lead to a life time of blister problems


SO any old boat needs a carefull survey to be sure it does not have a big problem

[r.furborough]

Well how annoying, post in one forum section and then repeat in another!!

As I connot put a link here as my post count is less than 10, here is a duplication of that post.

Tillotson-Pearson made the Freedom hull and currently make the J-Boats. They are a very reputable company, pioneers in the use of cored hulls and are known for making excellent boats.

I have a Freedom 32 and have recently replaced several thru-hulls and every one I replaced had had the coring material cut out and the coring sealed, on my boat, a 1985 model I have no significant problems with moisture in the hull or deck coring except for an area around an aft cablin opening port where the sealant used has failed.

I would suggest what you are finding is bad maintenance. sealants used in manufacturing do not last the lifetime of the boat as pointed out in your own posting, exposed deck fittings are expected to be removed and resealed. It is also possible the addition of extra sail and line handling hardware added to the decks, as many boat have, was not installed correctly.

This applies to most boats as they generally all have cored decks.

What Freedoms of this era do suffer from is gel coat spider cracks that are caused by the gel coat being applied too thick and the use of an unstayed masts where the forces are transferred through the mast base and deck partners only and not via stays and shrouds as on conventionally rigged boats. Thick gel coat is not as flexible as thinner gel coat and crack rather than yields to the changing forces. This is more of a cosmetic problem as the cracks very rarely are deeper than the gel coat itself.

Regarding repairs. The extent of the repair and the effectiveness is not so relevent, it is the depth of the owners pockets. I am aware of whole decks being stripped back and re-cored, though not on Freedoms, this can be from above or from below when the original deck surfaces need to be retained for cosmetic reasons.

[CrazyRu]

I have a Freedom 28 CK. They are built like tanks. Outer skin of the sandwich is as thick as no-core skin of modern boats.
Yes, there can be wet core around fittings. Yas, it is a bad sign. However, typicaly, wet core isn't structural problem as long as there is no delamination or rot, and typicaly, it is not wide spread problem.
Solution - remove the fitting, remove inner skin and core around, and build a solid glass area.

Cored hulls have their huge advantage - they are solid, quet, worm and insulated...
I'm sitting in 40 degrees air and there is no single sight of condensate.

[sailingdog]

Ideally, if anyone installed a through-hull in the cored areas of the hull, they should have potted the area, replacing the core with thickened epoxy after removing the core material. The better builders generally only installed through-hulls in solid glass areas of the hull....often leaving a strip, that includes the keel, of solid glass down the center of the hull.