Here's a link to a free downloadable book (pdf) by Rod Stephens that covers all aspects of sailboats and it is well written too. Yacht Design - Rod Stephens Book
In case you are not aware of who Rod Stephens was he was the man in the field for S&S - the designer half being his brother Olin. Rod was the one that made sure in trials that Swan got it right - there were things they had to correct too.
Cockpit design and drains is from page 80 - 86.
The entire book is a great read. Full of all kinds of ideas.