Hi
I will back up the doubts --- my experience is that it is a huge
trouble, the exact thing you shuld not do, an aproach no one with just
a bit experience would show , one layer of glasfiber and only covering
the bottom is not good you simply are asking for trouble and it don't
make it better looking for CHEAP means.
If you use polyester to save an old wooden hull you shuld not make it
into a patchwork you shuld cover it all, you must make the glasfiber
stronger than the old hull ,that's the only way, if you doubt try look
around and find a boat where one layer just covering the bottom have
worked , beside the attitude to make it CHEAP will only produce a CHEAP
boat something you never will be pleased with, a cheap repair will
bring nothing but vorry and I am sorry to say, I never seen covering
just the bottom, ever had brought anything but vaste of money and time.