Kinda hard to give advice on that. Our issue with kids was a place where they could go to that they would be safe and comfortable. That means an Air conditioner and generator, which rules out many boats. Getting rid of a boat is not a pain... it is a REAL PAIN! On the other hand, I would hate to dump 8o k into something before you know for sure if you will really like it. In my opinion, with the children you have, if you do not have an air conditioner & generator, your sailing period in Texas will be quite limited.
Just a side note: Why 80k? Why not a note at 100k. The reason being is that you get better terms and generally a better interest rate. An 80k boat may cost you more/month than a 100k boat. If you are paying cash, you might consider taking a loan anyway since you will have more liquidity and will be able to write off more on your interest for seond home.
It's not my money... just some thoughts.