While we are on the topic of locks. Buy a large pack of locks that all have the same key (marine grade if you can find them). There are so many things to lock up on the boat it is nice to have one key that fits them all. Make sure you regularly corrosion block them because they do seize up if to much salt water gets in them.
One last thing on locks (and would be good for those of you that live on land too) are these key rings which don't rust and are easy to open and close but very secure. Whenever a marina gives us a key fob or bathroom key we need to carry with us it's super easy to slip it on and off my key ring.