[PSUBS-MAILIST] Alternative hull material

I considered building a sub out of GRP (glass-polyesther). This is easier to handle than kevlar-epoxy and a lot cheaper. I changed my mind because both materials have unknown specs. The strenght depends on a lot of factors such as the know-how of the builder, the quality of the resin, the way different types of cloth are used and so on. It can be done of course, the LR5 is a good example. But for an amateur like me i thouhgt it would be far more simple and cheaper to use steel. When you use steel you can simply have a look in the books and find out how to make the details such as though-hulls, viewports and so on.

Another problem is formed by the unknown decline of the material as a result of water pentrated in the laminate. This means that you can do an unmanned pressure test but you will never know in what condition it is after a view years. If you use A516 you can be sure that after a hundred years it's still the same A516 steel.