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What do I call this?



Seat support? Tank tray? Seat tray? Suggestions? Anyway, its the next part of the project. Slight problem, though. There are six pieces of wood encased in it seen here:





All six have had screws put in them and the two that I checked have dark wood that squirts water when pushed. Great! Now I will need to grind them all out and replace. My kneeboards will need to be slightly smaller than I thought which will hopefully leave enough scrap coosa to do the job. Another hassle is that due to the way the kneeboards need to be bonded to the side of the seat support thingy, I will need to repair and bed the seat support before I install the kneeboards which means that I will need to flip the boat over to install the tray and then turn back upside down to install them. If I do it kneeboards first, I cannot be sure of a good bedding as the tray is slid into place. And after my experience with the transom, there's no way in hell I can do the tray upside down. Anyway, got the tray trimmed down to allow for the now thicker transom and here it is wedged in place.



Once trimmed, got it to match up exactly with the lines left when I removed it. That's it for now. Back to your regularly scheduled programming.

OK. I need some advice. I just found out what the core is and mine is wet balsa! How screwed am I? Did some exploratory 1/8" holes and the core has water in it at the back but seems dry two feet forward of the transom. My questions are, how far forward should I replace the core or would I just be better off taking it all the way to the front? Do I go back with balsa or would coosa(blue water 26-the strongest they make) be a better choice? I want to do what's best for the boat. I'm not scared of the shitload of work required to do so but I also don't want to waste time and materials. Thanks, Steve.

I'd go with balsa....it's the strongest, cheapest and easiest to work with.

Cut out as much as you want....but note how easy the stuff comes out. Obviously the wet rotten stuff needs to go but if the dry core is real hard to remove than you may want to leave it.

Thanks for getting back to me, Dok. You think the balsa would be stronger? That's too bad, I'm starting to like working witb the coosa. Doesn't split, splinter, or burn when cut.

Finally got a chance to start on the core. Started at the transom where I knew it was wet and started working back.


three feet out and I kept running into pockets of very soft dark balsa. Not wet to the touch but very easy to scrape out. Also something else. The heavy woven roving that covered the balsa was not fully wetted with resin. That's not good, right?


Anyway, the core is basically out.


Still leaning towards coosa 26 for the core. Looked into balsa and its compressive values are, as I understand it, heavily dependent on being and staying dry. It's very humid here every day, I'm a novice, and fiberglass does not always keep the moisture out. Coosa doesn't have the same compressive values of balsa(820 vs 1837) but it can't absorb water and a hammer blow leaves barely a dent. Fitting it is going to be a PITA. I don't know. Balsa would be much easier. One other thing, if anybody is listening. does anybody know what kind of foam was used to bed the floor support/ center stringer? It's very dense, light, and looks like it might be pourable. It showed no signs of degradation after all these years and I would like to use it under the coosa in the front where there is more of a V to fill. Many thanks for any feedback. Steve.

To get around the Balsa getting wet and then rotting some boat builders now will vacuum bag the Balsa wood. I have not restored a boat so I don't know the techniques involved but I imagine it would be doable for a DIYer. Search around if you are interested.

Is that all the Balsa that's in there?? If it's that little I'd put Balsa back in...it'll be quick and easier to work with. Put a layer of mat with vinylester to bond to the old hull, then corebond putty which you bed the Balsa into (make sure you wet the balsa out with Poly!!)...put some good weight on it...then cover it. If you're worried about humidity maybe a dehumidifier in the boat for a few hours while you do the work??

My worry about using a board as core is getting it bedded down correctly with no voids under it. I don't think you'd ever run into issues of compressing the core in a small boat like this (you'll break your back first I would assume) but delamination would be a real concern if you don't get the core stuck down right.

Keep up the thread...we are watching your progress!

Damn! you were right, Dok. There's more:





There's two more cores on either side of the center section and the upper starboard side was pure black mush. Oh well, no turning back now. Had my die grinder out to fix a corrosion hole in the block of my pontoon's "tower of power" and decided to try it on grinding out the rest of the cores. Works great. Larger millings are not as itchy and air instead of electricity means using the hose to wash off the work is not nearly as dangerous.

Dok, I get what you're saying about the importance of not having any voids. What if I poured 16 pound foam down the center to fill the shallow v, sanded it to get a flat surface, wet it out with epoxy, lay 1/2" board on top, layer of 6oz glass, another layer of 1/2" board, and another layer of 6oz. The foam would only be about 1/8" thick in the center at the transom but about 3/4"-1" thick up by the way front. I looked into nida bond but it 3M states that its really only supposed to bridge up to 1/4" and I need more than that up front where the v is deep. I like the foam because its light and the 1/4" of it that supported the old floor support stringer was solid as a rock when I removed it. I can't pour the foam in after I glass the first layer of board because I can't guarantee that it will completely fill the void. Especially close to the transom where the void is so thin. I'll have a better idea once the cores are completely gone. Got about half the starboard side done tonight. tomorrow's another day.

Here's the specs from Coosa:


The nautical 24 .50" looks like the best choice as it has the best compressive values. Flatwise tensile is lower but that's because the nautical doesn't have the embedded woven roving. Compressive value is more important. Since the core's stiffness is a function of the resistance to compression of the core material and the tensile strength of the core skin, I'm going to add a layer of 10oz. cloth between the 16lb foam and coosa. This would give me the foam to completely fill any voids below the board, layer of cloth, 1/2" of board, layer of cloth, 1/2" of board, and another layer of cloth. All using epoxy for maximum secondary bonding. Whadya think?

If you're worried about moisture absorption don't use foam...and compression values of foam are obviously not great either. I honestly think it will be much easier, cheaper AND stronger just to stick with balsa...or a similar core material...