I presume you fill the cooler with ice and then let the little fan blow across it. If so, I kinda doubt even block ice will last very long. For about twice that amount you can buy a
cheap 5,000 btu window ac that will freeze you out of the
boat on full
power. That's what I had on my first 32
Morgan. It sat in the
companionway hatch and was a pain to get around but oh my, the pleasant sleeping it provided. If you go that
route there are a number of articles on making
hatch adapters or even gutting the rascal for permanent
installation. The major downside is that you need ac
power.
On the other hand, I really only used it at the
dock anyway. At
anchor a breeze booster or two was comfortable enough. Also, a quick way to lower your
interior temp by around 10 degrees is to simply rig an awning. The 5,000 btu worked great at night but during the day, in direct sunlight, it made the
interior bearable but not comfortable until I rigged an awning.
Anyway, good luck with your
purchase.
Rich