Plywood got wet for a long time. Once, some years ago, it was swollen and broke its shell. Then it rotted, but no one paid any attention on it. And thank God, I didn't notice it too, when I took the boat from the previous owner: otherwise, I don't even imagine, how was I could to sail from Goteborg to Vyborg, knowing about it all.
Today I destroyed old beam. Tomorrow I will manufacture a new beam of steel, and then I shall to install it.
