Coosa board decking

[plowin]

Not to derail but related…I’ve used coosa and nida…coosa dust is definitely nasty…has anyone used divinycell for a deck and how did you like it ?

My deck is Divinycell. I have had no issues with it and would not hesitate to use it again. With that said understand its limitations and weak points. It is not particularly “puncture” resistant. If a something were dropped from a significant height and it were pointed or jagged it could puncture the skin of glass. It also will not hold a screw very well as the glass is only about 1/8” thick. You must de-core and fill with epoxy or some other filler in order for it to hold with any amount of tension. Water intrusion is not and issue as it is closed cell so that is a plus and its also comfortable under foot. If I had a choice and cost were not an issue I would use coosa but have been very happy with the divinycell. Its plenty strong, imagine a 900lb Bluefin bouncing along the deck, no issues yet.

 

[Diesel Jerry]

I did 1/2 coosa with 1708 and system 3 epoxy. I hav 24ish inches between supports (longitudinals). When I put down the coosa at first I was slightly worried because I could get slight flexing when I jumped up and down on it I weigh between 240 and 260 lbs depending on the season). After laying down the 1708 it made it much more rigid. No flexing anywhere, but I still consider this light duty which is fine for the boating I intend to be doing. If I was doing a bigger boat, or something more commercial I would either do 3/4 coosa or two 1/2 layers of coosa.

 

[AndrewMarani]

I'm in the middle of a stringer rebuild and am getting ready to order Coosa for the stringers and deck. Largest span between deck supports is 19", most are 16 or less. I like the idea of using the 1/2" board because I will have some left over from my stringer layup. If I use 1/2" I will only need to buy two additional sheets for the deck instead of three and Coosa is expensive. Light duty use on the boat.

Diesel Jerry, what weight 1/2" Coosa did you use and did you glass both sides or just one side?

 

[leaky]

I'm in the middle of a stringer rebuild and am getting ready to order Coosa for the stringers and deck. Largest span between deck supports is 19", most are 16 or less. I like the idea of using the 1/2" board because I will have some left over from my stringer layup. If I use 1/2" I will only need to buy two additional sheets for the deck instead of three and Coosa is expensive. Light duty use on the boat.

Diesel Jerry, what weight 1/2" Coosa did you use and did you glass both sides or just one side?

This doesn't sound bad or anything. 19 inches isn't much of a span.

Keep in mind, the glass on the bottom probably does more, or at least as much as, the glass on the top as far as making it rigid. And the type of glass that makes stuff rigid the best is that which is a weave of some sort - even 6 ounce cloth beats a thicker layup of csm as far as being stiff and strong.

Coosa is not very tough until you cover it with something. I don't know what sorta boat, but my guess is it would wear over time if left bare and set down atop a frame and it'd make things loosen up.

Where a thin deck is going to flex the most is if you cutout a hatch, anywhere that lacks continuity with the supports underneath.

 

[Diesel Jerry]

I'm in the middle of a stringer rebuild and am getting ready to order Coosa for the stringers and deck. Largest span between deck supports is 19", most are 16 or less. I like the idea of using the 1/2" board because I will have some left over from my stringer layup. If I use 1/2" I will only need to buy two additional sheets for the deck instead of three and Coosa is expensive. Light duty use on the boat.

Diesel Jerry, what weight 1/2" Coosa did you use and did you glass both sides or just one side?

Blue water 26 and just glassed the top.

 

[Bill]

I'm in the middle of a stringer rebuild and am getting ready to order Coosa for the stringers and deck. Largest span between deck supports is 19", most are 16 or less. I like the idea of using the 1/2" board because I will have some left over from my stringer layup. If I use 1/2" I will only need to buy two additional sheets for the deck instead of three and Coosa is expensive. Light duty use on the boat.

Diesel Jerry, what weight 1/2" Coosa did you use and did you glass both sides or just one side?

1/2” should work for those spans . If you are worried about glassing the underside just glass one side of a sheet and put it on the boat and see if it’s stiff enough when you walk on it. I personally like to glass it both sides but I think most of the builders in Maine just glass 1 side ..

 

[AndrewMarani]

Thanks for all the replies, very helpful. Just placed the order for the Coosa. I'm working on a 1986 ski nautique I bought with some cousins in 1990. Inside gets carpeting, still trying to decide which side to put fiberglass fabric on. I will put a woven mat one side and then seal the other with epoxy.

We try to ski every week during the summer and after 30 years it's time to give the boat a major rebuild. Kids are all in their 20s, no grandkids to teach to ski yet but i'm planning ahead...