Alan,
Thanks for the description, surely the solution you adopted could be fine in my case too.
My problem however is that I see where the water enters the cabin from but I don't know where it enters the hull from.
Right. That's what makes it tricky.
Take a look at this photo. I've marked where the water entered vs. where it showed up inside the boat. The way it presented itself on my own boat was that water would just well up in the very aft end of the skeg and then run downhill into the bilge. So Neil and I naturally assumed that the water was entering from the aft end of the skeg, more or less directly below where the water was entering the boat. So that's what we set out to repair initially.
In tearing into the skeg, we did see a number of voids in it and figured we had identified the issue. You can see from the photo the initial glass work that we did on the skeg to repair the leak--or so we thought. Well, after splashing the boat with this nice newly reinforced and glassed-over skeg, water was still entering the boat and showing up in exactly the same place! What the heck!
It was only on the second haul out that we were able to discover the true source of the water ingress. And then we put Neil's genius idea for rectifying it into play.
I've alerted Neil to this thread and he is now watching it. I'm sure he'd be willing to weigh in here with more specific advice if it's needed. Neil used to work for some of the 70's boat builders in southern California (e.g., Jensen, Islander) and so knows his way around this stuff. Here's a few things he pointed out to me via email last night, and I'll pass them on as they might be useful:
"I haven't studied your boat [i.e., my Ericson 26-2] that closely but I believe the hull came out of a one piece mold rather than two halves joined together and if true, that was the problem with the poor glass work in the area of the skeg. It is exceedingly difficult to laminate inside a deep, narrow profile. The molders never stood a chance."
"I just looked at this guy's pictures. He may be a good candidate for our vacuum infusion technique but the boat will have to be hauled out and from what I can see, the prop shaft will likely need to be removed .... Like us, he should create a reservoir to hold water on the inside of the boat where it appears to enter and then look for where it comes out on the outside to learn the path of the leakage. Only then can a vacuum plan be developed to be certain to address the problem area.
On second thought, acetone would be a better - although riskier - detection medium because 1) it's density is less than water, like around 75% and 2) it will help dry out the leakage path in preparation for the resin."