need some guidance. stringers & transom

brywheat said:
Tartuffe

For composite board dose it have to be infused vacuum bagged? Or whatever the proper terminology is? Doing research and it looks like awesome stuff. Did you start your rebuild onthe exterior of the hull? How did you flip it? Still have your support? Sorry for so many questions but I really appreciate the help!
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You can use composites the same way you would use traditional wood. I started with the inside first, rebuilt the stringers and transom and then flipped the hull over. I put an I-bolt through the transom drain hole with big washers on the inside and out, tied a rope to the u-bolt where your trailer winch attaches, raised it up like a hammock and rolled her over with a friends help. Boat is pretty light without the cap on it/fuel tank, or floor. You can slide some stout sawhorses underneath and lower it back down.
 
The pic of the straightedge against the gunnel showing the wave in the hull, that will come out with the construction of the cap. Take it easy with the sanding. Sanding sucks and damn its enticing to go with a grit to actually make some progress like an 80 or even 60. In reality you should probably use a chemical stripper and a 200 grit. The more of that gelcoat you save the better. Gelcoat is a waterproof coating that protects the fiberglass from water intrusion. Its kind of like an insurance policy.

Most of your fairing will be with high-build primers and a longboard. Takes many coats but the lighter the color of the finished product, the more forgiving it is. These boats are not incredibly fair to begin with. I wouldn't be too worried with that. Few sanded coats of high build primers with some longboarding and it is what it is. We can talk about that after you get the structural fixed.
 
That photo you refer to as resin starved, don't think that is what is going on there. Not really sure what is going on there from the photo. I would't blow that up until you get some more pics to see what exactly it is we are looking at.

Just curious if that area seems weak? Can you separate the layers with little force. My boat has an interior liner so I'm not familiar with that style of construction.
 
Tartuffe,

The pic shows where the inner skin meets the outter hull at the gunwale, next to the transom. It appears the 1975 hull had three piece construction. Outter hull, inner skin which matches the outter hull shape and included the original floor, and the gunwale cap. It looks like weave that isnt filled or smooth with resin and only looks like its an issue in that one spot. With force Im sure some layers would separate about an inch or two down and weak in that area. Here is the same pic edited. Ill try and get a better one for you.



Thanks again!
 
Im sure separating the inner and outter skin wont be too bad, I was going to leave it in place but i want to do it right, coming out this week.
 
Tartuffe?

Love your build, awesome work. Im sure ill say it a million times and such a great reference. Question, why did you fill the strakes with thickened epoxy and glass over? Just wondering what that does? easier for stringer replacment?
 
I don't think I would worry with pulling that inner skin out. What you see is woven roving. Basically just a very heavy-duty fiberglass.

If I wanted to bond those 2 layers together I would sand the top 4 inches of the inner layer with a heavy grit sand paper or even a grinder. You want to sand it so that the inner layer is paper thin where it meets the roving and full depth 4" away, so sanded at an angle. Use a putty knife and smear some thickened resin over the roving to squish it into the holes. Next I would roll a thin coat of resin over the sanded portion and then overlap the smeared resin and sanded/coated portion of the inner layer with a layer of 17 oz mat. I would then finish wetting out the piece of 17 oz cloth and then roll the whole thing with a metal roller. Once cured out sand the whole thing smooth.

Also youtube has alot of good videos to see different ways to approach things. Gotta watch a few as there are several that deliver some sub-standard advice.
 
brywheat said:
Tartuffe?

Love your build, awesome work. Im sure ill say it a million times and such a great reference. Question, why did you fill the strakes with thickened epoxy and glass over? Just wondering what that does? easier for stringer replacment?
Click to expand...

The boat originally had big pieces of roving that went across the strakes with a big air pocket so that it formed a triangle. I ground all of that out as some places did not have a very good bond. I didn't know if this was originally just sloppy craftsmanship or had some type of structural property with the triangle. In hindsight I'm pretty sure it was just sloppy work so I wouldn't worry with doing that. I used alot of material to do that and probably added 10-20 unnecessary pounds for added strength that really isn't needed. Would be like putting bulletproof glass on your center console.
 
tartuffe said:
The boat originally had big pieces of roving that went across the strakes with a big air pocket so that it formed a triangle. I ground all of that out as some places did not have a very good bond. I didn't know if this was originally just sloppy craftsmanship or had some type of structural property with the triangle. In hindsight I'm pretty sure it was just sloppy work so I wouldn't worry with doing that. I used alot of material to do that and probably added 10-20 unnecessary pounds for added strength that really isn't needed. Would be like putting bulletproof glass on your center console.
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Ive seen the same on mine, It appears that the roving is used fro the factory stringers, with tons of air pockets too, suprised at the things Ive seen in this hull that is sloppy craftsmanship, Not sure if its from factory or the PO.

The PO rasied the floor by screwing 2" x 10" to the inside of the factory stringers. Gave me a good guild for the rebuild. I think Im might still need to remove the inner liner or cut the rest of the old cuddy flooring out. PO just cut the floor to the cuddy.

Tartuffe,

What resin/ glass combo/ Brand name did you use. Is West systems worth it?
 
I used US Composites for my resin and Boat Builder Central for my cloth and fillers. Make sure you get a mat roller as well.

http://www.ebay.com/itm/Fiberglass-...514?pt=LH_DefaultDomain_0&hash=item19eb2c938a

Something similar to this.

I had bought a bunch of different sizes but ended up using one that was about 1/4" diameter by 2" length, it just worked really well. Also, plenty of acetone, disposable rags, and neoprene gloves, stir sticks and cups. You will never imagine how much of these supplies you will go through. Also buy the good titanium scissors. Other scissors dull very quickly when cutting cloth.

I used epoxy resin but read up on vinylester, you may find it fits your budget better. Lots of people use it. I just didn't want my neighbors and wife having to smell it. Buy the large kits to save more money, I used to buy 7 gal kits. When mixing, start with a small batch. Large batches (over a quart) will kick off very quick, as in bucket smoking in 15 min rendering it useless because it will be like jelly.
 
I used divynicell for my deck. Its a great product but while it is lighter than wood you will use far more fiberglass and resin in such a crucial structural application so the weight savings will be offset and it will be more difficult to use compared to the wood in the stringers. The transom wouldn't be a suitable application either since the foams are crushable.
 
I thought I would ask if it would be a suitable replacement for the wood transom. I've had one boat builder here in Jacksonville tell me that is all he uses in his, around 3~4 inches thick depending on the application. Yet he builds small skiffs. Boggy Creek Boats. (Sorry for taking over the thread, but I had to ask)
 
Starzofchaos said:
I thought I would ask if it would be a suitable replacement for the wood transom. I've had one boat builder here in Jacksonville tell me that is all he uses in his, around 3~4 inches thick depending on the application. Yet he builds small skiffs. Boggy Creek Boats. (Sorry for taking over the thread, but I had to ask)
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No problem Starzofchaos, had the same questions about it myself!
 
You can absolutely use divynicell in the stringers, especially if you could get it in the full sheets. The cheapest place I found to purchase it cuts the 4'x8' sheets into 2'x4' sections to reduce shipping costs. You will just have to find a layup schedule that will compensate for the loss of strength the wood adds to the stiffness equation. Only problem in short is that it is a little more complicated to use and the expense is higher for marginal weight gains. Probably the largest advantage is being able to say its wood free. If a boat is built with wood taking into consideration how water would get to the wood (screw holes, permeation through the resin where water stands) and eliminating those paths of infiltration, a wood boat will last as long as a composite built boat.

There are also composite materials that can be used in the transom such as coosa bluewater 26. A great site with a lot of technical knowledge is boatdesign.net lots of builders on there versus some of us 1-off project guys.

Earlier I recommended researching vinylester resin. One thing to consider is that epoxy tends to be a better material to encapsulate wood to prevent water infiltration and rot. When you buy your fiberglass, make sure the resin you will use is compatible with that particular fabric. Polyester resin allows the most water intrusion over time and even it lasts multiple decades. I used epoxy and I like epoxy, to me it is more forgiving and CYA to make up for our rookie mistakes. It does cost more but others have had great success (like every successful large scale boat builder) using polyester and vinylester resins.
 
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Thanks for the advice
Think I'm going to research about composite and lay up schedules for the transom and stringers. And obviously save up more if I decide to go that route. Decision really seems to be how much glass do I want to lay
 
So Im really considering Coosa board now. I like the idea of zero water penetration & after a nice talk with the a saleperson at coosa Ive learned a few things

You can actually use less glass, full encapsulation isnt needed for stringers. The bottom of the deck wont need to be glassed unless connected over a free floating seam, Ill just add a bulkhead at the seam location.

The guy couldnt give me a straight forward answer about how much flex the coosa bluewater 26 board has. He did say its similar to ply, 1/4' has the same flex as a 1/4" piece of ply? Any input from those who have used it? With the curvature of the transom, I believe going with 1/4" piece first, then 1/2" cuts I'll be able to get the curve I need.

Anybody familar with coosa 26?

Thanks for your help!!
 
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