plywood

[scottscotland]

why can i not use exterior ply to build a boat as its as waterproof as marine as i sat two bits of ply in a bucket for 6 months one of each and both were ok .the boat im thinking of building is coated in fibre glass anyway so why can i not use exterior ply ???????????help anyone know why not ...................................................................................................

[gonzo]

Go ahead, it works. However, it won't bend in as fair a curve. Also, because of the voids, it is more likely to rot. I have built many skiffs that lasted over five years. They were stored outside in the weather too.

[scottscotland]

was thinking of building a 26 foot thunderbird or 32foot thunderbird was wanting more than 5 years from it uuuuuuummmm.

[gonzo]

For a boat that size the cost of plywood is a small percentage of the total. A better quality is a good investment.

[botebum]

Voids in exterior grade plywood will speed rot and worse- delamination. The investment you will make(time and money) in a boat of the size you intend to build will be wasted after 3-5 years. Initially, during the build process, you will have difficulty achieving a fair curve with ex grade ply also. I have used ex grade for small, "throwaway" boats. I can afford to keep them afloat for 5 years by annually sanding and recoating with epoxy and paint, inside and out. I wouldn't want to do the same with a boat of 26' or 32'.

[CT249]

Originally Posted by scottscotland

was thinking of building a 26 foot thunderbird or 32foot thunderbird was wanting more than 5 years from it uuuuuuummmm.

A 32' Thunderbird? Does such a beast exist?

If you are planning on scaling up a Thunderbox to 32', why not go straight to a 32 footer designed as such. Two I can think of are the Gulf 32 by John Spencer (Kiwi designer, famous for the Cherub dinghy and Transpac-winning maxi Ragtime) and the Nelson 32, by Peter? Nelson in NZ.

Both are very much in the big T-Bird style, BUT they are designed to that length and they are proportionately faster, especially the Nelson. The T-bird is a great boat, but in a chop and light airs their very full bows can stop them dead at times. Spencers are probably easier to build; I'm not sure about the Nelson. I've sailed T-birds, have a 28' Spencer which is sort of like a T-bird with less weight (good), better bow (good), more space (good) and narrower stern (bad) and would seriously consider the Nelson.

[scottscotland]

CANT FIND ANY INFO ON THE Nelson 32 ON THE NET Any help on it would be great thank for the help so far i have ordered plans for the thunderbird 26 but am still looking for plans for a 32 foot sloop thanks scott in scotland

[captword]

You can use exterior ply wood with the same aspects as mentioned above. but you can get it to last longer but at a cost. you have to put as much glass n cloth on the inside of the hull as the outside. preferably b4 youbed the frames,stringers engine beds,etc. at that cost though its cheaper to go witha better ply.
Howard