Stringer Repair 1985 2001 Ski Nautique

Bagging a whole stringer would be quite a chore for someone who doesn't have a lot of experience with the process. I think you would have an easier time with resin infusion, but its still something that you should work the kinks out of the process before you attempt a whole stringer.

If you have to start over, run a round over bit down the top of the stringers to make it easier. Since everything will act as one structure when its done, some biax on the floor and up each side of the stringer covered with some woven cloth to tie it all together would be easier. I doubt you need the strength of the biax going across the top of the stringer with the floor sitting above that.

I have looked at quite a few race boats where they used very little material to keep the weight down, but the boats still take way more abuse then our boats will see. I think we seriously over do it with materials to make up for the fact that we don't know exactly how much we need and if its being done correctly. I'm sure it will be fine, I've never seen someone post about blowing their new stringers out. There is an interesting thread on Wakeword where this will likely happen, but he glued new wood to rotten stringers and then covered it with bed liner.

I didn't say don't wrap them, I said you don't need to have a complete piece of biax across the top. Use biax like tape on the floor and the sides and tie the layers together with cloth that covers everything. Not as strong as one piece would be. The only difference would be a little less strength in the direction the stringer is least likely to break, there's still fiberglass over the top.

Infusion can burn up a lot of money real quick and leave a huge mess thats hard to clean up, but if it worked it sure would be easy and it would leave you with a stronger end result. My thinking is that you would have to be familiar with the process from doing smaller parts first so you could work out the specifics of doing something as long as a stringer. I would guess a stringer would require some sort of manifold on each side to pull resin from the floor level to either the top or across to the other side from more than one spot. The benefit would be that you could use less resin and possibly less cloth and end up with as strong a laminate as possible.

If they can do whole boats with it then a stringer should be no problem, we just don't have the advantage of using a highly paid consultant or engineer to work out all the bugs for us in advance. It's definitely on the list of things I would like to learn to do, just don't have a reason to move it to the top right now.

If you use the same cloth & resin in a composite lay up ,fiberglass,Kevlar(nomex),carbon whatever
The strongest part is determined by cure type, autoclave is far and away best. Second best is atmospheric pressure (vacuum bagging/ resin infusion , then wet lay-up.
With an autoclave you still use vacuum pressure at first and bleed off the vacuum as the external pressure is applied. External pressure can be as much as 100 PSI.
Bagged parts are very good quality with minimal porosity
The hang up is the time it takes to lay up the part with the bleeder schedule and bagging it.
Room temp resins will kick if you have a medium or large part.
So pre pregs are used (resin infused fiber) frozen rolls that are thawed the night before and cured in an oven. Usually temps are 250/350*f
When using a wet lay-up weigh out small amounts of resin never more than 400 gms. On a large lay-up
weigh out several cups then mix them as needed to avoid an exothermic reaction.    

TX Foilhead wrote: I'm suggesting the same thing you drew last May with some additional layers of cloth over the top. If it is all laid down at the same time then is cures as if it is a single piece and should be strong enough to do the job. All you're trying to do is glue a board to the floor and keep it from getting wet and rotting, we're not building the space shuttle here.

I thought I was clear, but somehow I am failing to make my point... From the transom of the boat to the front of the engine compartment, the mains are fully exposed- even when the boat is finished. The floor does NOT attach to them. They are exposed in the engine compartment, and a removable panel sits on top of them just aft of that. The gas tank sits on them all the way in back. Nothing "glues" on top of them, floor or otherwise. This is why they need to be wrapped over the top in these areas- to make them fully sealed, added impact resistance, etc.

Not sure if youre thinking of the secondary stringers and how they tie to the floor, or if youre just way out in left field. Take a look at the pic I posted above, it should be pretty clear?

Agreed, this is not rocket science.

Trying to get the bilge to drain perfectly will be an exercise in futility. Filling low spots as deep as 1" with low strength filler is impractical and ill advised. Poly based fillers like bondo won't stick well to epoxy either. I'd leave it be.

I've tried several bilge finishes and like gelcoat best.   With a vinylester conversion coat over the epoxy, gel can be brushed on. It'll lay down pretty well and look good with 1-2 coats. It'll also be very durable. Bilgekote will NOT stick directly to epoxy, it needs a special conversion/primer (ask me how I found that out). It's decent stuff as far as paint goes but gel is no more work, more durable and similarly priced.

Isn't an '87 hull built with polyester? So the Bondo should stick to original hull laminate?

TRBenj wrote: I thought I was clear, but somehow I am failing to make my point... From the transom of the boat to the front of the engine compartment, the mains are fully exposed- even when the boat is finished. The floor does NOT attach to them. They are exposed in the engine compartment, and a removable panel sits on top of them just aft of that. The gas tank sits on them all the way in back. Nothing "glues" on top of them, floor or otherwise. This is why they need to be wrapped over the top in these areas- to make them fully sealed, added impact resistance, etc. Agreed, this is not rocket science.

+1

Forgot to mention the bilgecoat...

I wanted to use gel as I also think it's the best skin for the bilge, but I didn't for lack of time and equipment. I used white BC without the flakes(if I remember right) and it's held up very well; much better than I expected. It's very durable and easy to clean.

Does the boat have the same attitude now as it will have in the water? Will it float like it is sitting?

I think I've been convinced to do the gelcoat in the bilge.

One of the biggest reasons is that I'm planning on doing a gelcoat floor (gelcoat over fiberglass over plywood instead of carpet over fiberglass over foam).

I need to begin pricing a gelcoat gun...... or an auto body spray gun. Does anyone have any suggestions?

Alright ~~~~ it's starting to look like a boat again (I tried to attach a picture to see the current state of affairs, but the picture was too big..... and I can't figure out how to reduce it).


Progress being made daily. I figure I'm about 5 days from spraying gelcoat on the bilge...... (so maybe this Friday).

I need to know how much gelcoat to order to do the entire bilge area and the floor (I'm going to do a gelcoat floor like gundriver did).

Is 5 gallons too much, too little, etc.?

Also, I need specific recommendations on gelcoat application tools.

People have said, "just brush on a couple of coats and sand it." That said, since this is going to also be on topsides is brushing the preferred method. I do not have an air compressor or paint gun ~ but am willing to purchase both if it is deemed necessary.

Finally, what exactly do you put down before you put down the gelcoat ~~~ I know you need a primer of some sort to go between the epoxy and the gelcoat, but is there a specifically recommended brand?

Best,
iplan

A gelcoat floor is going to be slippery unless you add some anti-skid to it... but that can be done. Honestly, I'd be tempted to brush it on- especially if the plan was to put snap in carpet over it eventually. If you thin it slightly, the brush marks should lay down ok... I certainly wouldnt worry about spraying the bilge. 1 gallon would be more than you need for the bilge... it might take a little more than that for the bilge + floor. 2 would do it all, I would think.

Clean the epoxy resin with soap and water to get rid of the amine blush, then wipe it down with acetone. Giving it a quick sand isnt a bad idea. Vinylester resin can be used for the conversion coat between epoxy and poly (gel).

TRBenj wrote: A gelcoat floor is going to be slippery unless you add some anti-skid to it... but that can be done. Honestly, I'd be tempted to brush it on

I'd consider rolling it on the floor. Get some of the high end roller covers designed for epoxy and cut them down in width to 4" to fit a 4" frame. Jamestown and US Composites have the covers. DO NOT use the foam covers from the hardware store. Ask me how I know!! Not original but do what you must!!

Gel coating bilge sounds sweet. Sounds like a lot of work for something no one will see. I put some of the dye in my epoxy and painted it on. Looks fine .

lakedog55 wrote: Gel coating bilge sounds sweet. Sounds like a lot of work for something no one will see. I put some of the dye in my epoxy and painted it on. Looks fine.

My thought was that since I was doing the floor and walls with gelcoat (that could be seen), that it would be nice to practice on something that could not be seen.... and someone pointed out that the cost of bilgecoat paint and gelcoat were about the same.....