Michel, my boat is 1980, hull #10, one of few centerboards built.
On my boat balsa is not terminated prior to joints, except hull to deck joint and at very bottom of the hull.
So, I have another project to tackle. I had badly delaminated/rotted cabin top, because of centerboard block was compressing it. I did replace the laminate there, and I built a crossbeam to support the weight. However water was spreading inside and it got into sides of the cabin. I now have delaminated sides of the cabin too.
Also the water got into transom too, through the damaged area I’m fixing. there no separation of balsa at transom-to hull joint…
It’s the one I don’t sure yet how to fix. The area is small and it is structurally strong. I’m running out of time, so I can not talk myself into cutting transom too.
On a bright side - it seems like all thru-hulls are done properly, there is solid glass everywhere…
Have you thought about using any of the currently available subtitutes to balsa for core replacement, like coosa compsite panels?
Balsa though light is probably one of the least rot resistant woods available, kind of surprised it was used at all!
And when used why it was not epoxy impregnated, cost I guess.
Very interested in your progress.
Chandler
Hi, Chandler, how was survey of F33?
Yes, I thought about foams and I voted against them for several reasons.
Foams are not without problems too. They are weak, heat and cold sensitive, they don’t bond well. It is generalization, but you get my idea. In my catamaran racing days I cut many hulls to fit into dumpster and have seen how bad foam sandwich looks like after many years of stress…
If you look at coosa panels manufacturer’s website, you won’t find epoxy resin (or any resin) in the list of recommended glues. It must be glued with polyurethane glue (such as M5200).
Now we have a core 4 times more expensive, we have expensive glue and nobody really knows how this core will look like 30 years after.
At least with balsa I know what to expect. 2/3 of my boat is still dry after 30 years. I made sure that repaired area is protected from water intrusion. I may expect that my repair will last another 30 years, and nobody knows what else go sour on a boat in this time frame. So why pay 4-5 times more for materials?
Besides, wet core is not a structural problem. Sandwich with wet balsa is still very strong. Delamination, hollow composite is a problem. Delamination starts when balsa rots. Delamination is very easy to spot, just sound a boat with a hummer at haul out.
We own 30+ years old boats. I went to doctor at 43 fist time. Now I visit him regularly. I guess our boats have finite life spans too…
Crazy ru
The survey didn’t go that great, big section of the starboard side is quite wet. a gelcoat crack in the stern was visibly weeping water.
I think the only thing saving her is that she has been kept in the water for several years which minimized the freeze thaw cycle of the core. If we buy her we will be taking her to Maine where I’m afraid the cold weather may not be so forgiving. Haven’t given up hope yet.
Before starting with using balsa as a core material, Everett Pearson, founder of TPI, builder of many Freedoms, did extensive research. Here’s an article about his findings.
Pearson_Everett_Part 1.pdf (420 KB)
Michel
Interesting article.
Do you think it can be inferred from the aricle that any wet areas of a hull must be the result of compromised fiberglass, gelcoat, or through hull fastenings through out the wet areas?
Michel,
Amazing article! That work ethic and a devotion to the trade, wow, I’m blown away, thanks…Numbknots
I can think of other causes too; insufficient wetting of the end grain is one. Freedom is known for not sealing the balsa core when mounting hardware, thus compromising the core material. They must have thought it wouldn’t hurt.
Such an easy and inexpensive thing to do.
Michel. It is not just insufficient wetting of the balsa with resin.
I believe the story about making panel and submerging it. However, I’m sure that panel was made with whole piece of balsa inside. In our boat we are not having whole, monolithic balsa as a core. We have counter-core, which is many independent balsa “bricks”. In any curved panel the ridge between bricks allows for easy water migration anywhere within the composite. I know that because when I was cutting my cabin top, I was trying to get to dry balsa, which is hell of the job, by the way, trying to break wet but solid sandwich. I pealed outer skin inch by inch. I saw “streets and avenues” of wet lines. Centers of the “bricks” were dry, edges were wet…And all bricks were perfectly well glued to skins.
There is no way anyone can seal the gap between bricks, while building a boat. I tried to seal every brick in my repair, as you can see from my photos, however I pretty sure that there are many gaps left…
crazy RU
How’s your progress?
Do you think it would be possible to use a router set at the proper depth and get rid of the gelcoat glass and core all at one time?
RU,
When I recored my cabin top I used a router off a plywod template. I stepted the core down so as to add a “stair” in the build up that would help support the center board pend.
I used that honey comb material and then used solid mat and s-glass build up around the hole in cabin top for center board pendent. It is very solid now. I had to remove a 2X3 ft area as water had accumulated behind the fwd hatch where the dingy mount bracket was traping water. It eventualy found it’s way into the core. Using a router on a convex surface was not much of a problem but on a concave surface I dont know about that. Numbknots
My project is almost finished. Inside skin is built to original thickness, I have a few places to finish, one or two days of work, clean up everything and start piecing galley together. I leave a room for drop -in refrigerator, in place of destroyed ice box.
New tanks in order, I had to cut out water tank, it was dropped in before deck went in, I couldn’t remove it without cutting it in pieces.
Also building long locker - I need a room for storage of dry-out legs which are one of my next projects. A bicycle will go there too.
No photos, I left my camera at home, hopefully I wont forget it next time.
Area is concave, as Numbknots noticed, I don’t think that router would work. It was a large area to open, I used hummer, chisel, pray bar and disc grinder with cutting disc.
Laminating fiberglass was a tough job. I’m covered in epoxy:) Working in tight spots with glue and fabric, getting in and out with each batch, It was pretty good workout, my body hurts.
CrazyRU
Sounds like your making progress!
Our survey didn’t go very well, big parts of the starboard side read saturated, not delaminated.
The yard where she is kept quoted $30,000 to make the hull right.
I think I can remove the gel coat ,glass, core, leaving the interior glass to hold the shape of the hull, the interior( perhaps the only redeeming quality of the boat)
Cold mold the hull for 20,000 have a new better boat provided if I can buy it for substantially less than our offer.
This boat has the solid wood butternut interior not the teak ply veneer interior.
Maybe crazy but I can’t find a another boat that does what this one does for me.
OOps maybe we are thinking of the same boat. Which model are you thinking of buying and surveyed?
Thanks