Which foam for stringers

[JohnC]

I think in our situation the limber holes were what allowed water to leave the flooded bilge area and fill other spaces under the deck. It's rare to lose bilge pumps so getting water into the bilge area is almost always a good thing. Water alarm is a must! It doesn't do much for an unattended boat at dock but it is definitely a must and would have tipped us off of a problem when it was more manageable.
Foam provides flotation in all situations but there us a down side to it, as with most things.