But I am curious how hard it is to get block ice where you are. Your only charging problem is refrigeration I suspect. When cruisers run refrigeration, they're moving under power often enough that it's not as much an issue as a sitting boat like most of that coastal cruise close to home. As you mention, refrigeration may determine how you'll sail(or won't) as engine charging time is needed almost always.

We have it easy here with ice and use a couple blocks for a long weekend. If ice weren't so easy, I'd probably get more serious about building an efficient box. But there is no efficient box that can be refrigerated without major charging issues.