New member: Coosa deck

[cej2525]

Will you be removing the midship bench with the seat on it and then also what about the box behind the seat and the half bench the helm seat is on?
Yes I will. It will pretty much be stripped down to a bare hull and patched before I start.

Also is that a capacity plate mounted on the stern? If so I believe it has to be visible so the boat can be inspected.
Good catch on the plate. I haven't even thought about that yet. I have been watching so many fiberglass tutorials my brain hurts!

The deck in the front would it just be an extension of the small deck that is already there? And also what is the game plan for the aft deck? Even with the sides? Dropped down a few inches to help keep things in the boat? I am sorry for all the questions but I really like following all the builds and like what other builders are thinking.
I invite questions as it usually brings up aspects of the build I haven't even thought about yet. This will primarily be used for fly fishing so I want to keep it streamlined and snag free. I have 2 avenues of thought. One is to put a flat deck overlapping the edges. To clarify the best I can, it would be making the top of the skiff flat from bow to stern. The second would be recessed by about an inch. This stops things from rolling off but makes for a tighter fit and more accurate installation and finish. But It looks like either way that nose will be redone to fit the rest of the hull lines.

Where seats are concerned I doubt there will be any. Probably do a grab bar for a small chart plotter I already have but that's about it. No trolling motor mount either. I am not going to be super sensitive on the weight but I am going to keep the heavy stuff away. I have a 2017 Alweld 1756 I fish out of that does 90% of what I want to do. This fits the other 10%. My Alweld drafts 10in with me alone. It's not impossible to pole but not practical for a day. Plus the hull slap is loud and the aluminum amplifies everything. That being said I know my trolling motor scares most of the fish that are spooked by me. I've watched over half a flats worth of fish scatter after I drifted in and had to adjust my position or run aground. I have attached a picture that shows what I already fish out of that may help understand what this build is about for me. I also found some pictures of the underside of the hull. Looks like it should pole pretty straight.

[cape_fisherman]

You can use it, of course, but it won't save you any weight. Now I don't have any numbers for you to compare, but a boat that small won't realize any real weight savings...certainly not any worth the extra cost.

[cej2525]

Thanks for the reply. Don't take this sarcastic but most folks report that its roughly 30% lighter than marine grade plywood of the same thickness. I am also under the assumption it soaks up less epoxy and needs less cloth. Most of my research says that when both products are dressed out as needed that the coosa is still lighter plus it will not rot. I have no sources for marine plywood in my area and can pick up coosa locally. I know it doesn't hold screws well but I can deal with that. Folks on here keep saying coosa weighs the same as plywood of the same thickness. Are their claims bogus?

[Fuzz]

According to the Coosa sites weight chart bluewater 26 is 35 pounds for 1/2 inch 4x8 sheet. Plywood would run around 50 pounds for the same size. If you can not get good plywood and the cost of Coosa does not bother you it looks like a good option. I say this not having ever used it myself so take this for what it is worth.
I have used Nidacore and like it very much. I think it would be real good for your decks. And it will be lighter than Coosa or plywood. 1" or 1.5" with 1708 on each side would be very stiff.

[cej2525]

The Nidacore has come up talking to quite a few people. I'll call around and see if I can find a vendor close by. If I understand correctly Nidacore will still need reinforcement built out of a different material. It was my understanding that Nidacore isn't adequate for building the substructure that reinforces the deck.

[Fuzz]

I believe you are correct. Coosa, plywood or something else would be much better for stringers or deck supports. Nidacore is great for decks where you do not have to worry about the panel edges.

[TomW1]

According to the Coosa sites weight chart bluewater 26 is 35 pounds for 1/2 inch 4x8 sheet. Plywood would run around 50 pounds for the same size. If you can not get good plywood and the cost of Coosa does not bother you it looks like a good option. I say this not having ever used it myself so take this for what it is worth.
I have used Nidacore and like it very much. I think it would be real good for your decks. And it will be lighter than Coosa or plywood. 1" or 1.5" with 1708 on each side would be very stiff.

Yep Coosa is lighter but not by much. And you need 4 layers of epoxy/fiberglass, Okuma is 40 lbs for 1/2 inch sheet and only needs one layer of fiberglass/epoxy.

[fallguy1000]

According to the Coosa sites weight chart bluewater 26 is 35 pounds for 1/2 inch 4x8 sheet. Plywood would run around 50 pounds for the same size. If you can not get good plywood and the cost of Coosa does not bother you it looks like a good option. I say this not having ever used it myself so take this for what it is worth.
I have used Nidacore and like it very much. I think it would be real good for your decks. And it will be lighter than Coosa or plywood. 1" or 1.5" with 1708 on each side would be very stiff.

Yep Coosa is lighter but not by much. And you need 4 layers of epoxy/fiberglass, Okuma is 40 lbs for 1/2 inch sheet and only needs one layer of fiberglass/epoxy.

I don't know that you need 4 layers of glass...depends on many variables.

[cej2525]

I've researched builds where folks have use 0-4 layers of cloth. It already has 2 layers of woven roving reinforcing it in an I-beam construction. As of now I am planing on 1 layer top and bottom. When calling around looking for sources I had one shop tell me they make all small decks out of the 1/2". I'm not trying to build a tank. Just a deck that won't rot and hold about 300lbs max.

[fallguy1000]

My decks are made with 12mm 5 lb corecell M or pvc. They are laminated in some places with two layers of 12 oz biax or about 24 ounces total per side.

A coosa deck will be much stronger with laminates on it.

I am building my hatch covers with 20mm coosa sort of compatible corelite board. They will get a layer of 1708 on each side. I am pretty sure you would like a 1708, 12mm coosa, 1708 deck. I would also think you would be able to use an electric planer and rebate the coosa to 3mm for the overlaps where needed as the glass is probably not wide enough for the entire span. Of course, I have no idea if you have any opportunity to avoid overlapping the glass.

A rebate is basically like a sheet rock tape seam..if you want a picture of a rebate, I can take one for you to avoid confusion, but like I said, not sure if you need them or not..