[Jim Clark]

This may help, I posted it elsewhere. Sorry for the cross post.

Here is how I found leaks on several sail boats I have restored. The leaks were water coming in from deck fitting and leaking ports. BTW the leaks coming from below the wateline are easy to find as your level of motavation tends to go up real quick for those.

Seal all your openings as best you can. Make a cover to fit a hatch opening, in this case a window or such and attach a yard blower. Turn it on and soap down the boat/trailer. Bubbles will tell you where the leak is. You may have to vent some of the air, a vacume cleaner discharge may even work. Hope this helps.