Re: floor and transom removal progress and ?
Just a personal opinion here, but it is based on not only my experience, but that of many commercial designers and builders. Plywood is not stonger than natural growth wood. I know this flys in the face of many, but just check out the studies done by the National Forestry Association. I will check my notes and post some references in the next few days.
It is true that plywood is "stiffer" in some directions than natural growth wood, but the ultimate yeild strength is not higher unless the bonding adhesive has been increased above normal usage. Although high strength ply can easily be obtained, it is not commonly sold at big box outlets.
Plywood is used whenever the cost of natural growth wood can be undercut. You can bet that if ply was the best choice for things such as stringers, chines and keels then the manufacturers and designers would have used it.
Why use natural growth wood in such applications? Flexability and resiliance is greater with it. The very fact that plywood is "stiffer" reduces the chance of the parts survival when impact loaded. Natural growth wood is also more resistant to vibration loads. One other aspect is that natural growth wood is more rot resistant than plywood. The many voids in most plywood retain water more than natural growth wood and this provides a needed ingredient for rot.
Plywood can be ordered pressure treated to reduce the dryrot aspect, but so can NGW. Another advantage of NGW is that you can obtain species that are naturally resistant to rot, such as Southern Yellow Pine, Cypress, Teak etc.
One other aspect that I find intresting is that most on this web want to completely encapsulate stringers, tramsoms etc., when they find the original rotted. There is a reason that very few manufacturers encapsulate wooden parts. If there is the slightest crack in the fiberglass encapsulation then water can and usually will, get into the wood. When it does there is very little chance of the wood drying out before dryrot can get a good start. When wooden parts have only one or two faces glassed over then the other faces allow the wood to dry out and stop the growth of the dryrot.
I used to use a good deal of copper naphthenate products to prevent dryrot in my wooden boats and on the wood parts of my plastic boats. I have been fortunate enough to become friends with several commercial fishermen and all of them have convinced me of the value of plain old ordinary salt. I finally put salt boxes on my craft. I fill them with rock salt when I can get it in the summer and watersoftener salt in the winter when I can't. I have had no dryrot in any of the salted wood. It has been a very good inexpensive solution. I am presently modifying a fiberglass daysailer to have saltboxes to prevent the decay shown in this thread.
Please don't think that I am against plywood. I have used it for transoms, flooring, seats and other uses that require a lot of coverage. It definately has it uses and is superior to NGW in some applications, but I don't believe that stringers is a good use for it.
Remember, it's just my opinion.
