So, I was going along with my plan of waiting for the next free ship that I'd heard we receive near the end of Cool Ranch. Then I suddenly realized the following: don't be silly.
The ship in Pirate 101 is treated like another piece of gear, in a lot of ways: you can't level it up (Nautical Level only effects what you can use/equip, no the power of the ship itself), you equip it and, therefore, every so often you replace it by talking with a vendor.
The problem that I'd been having was that I'd run out of gold quickly trying to keep all of my companions at least 2 lvls below my pirate. This can be a very expensive venture. The strategy I'm trying now is to not buy training tomes unless I really feel I have to (companions feel too weak, etc.) and instead save up so that I can buy the next tier or ship when it becomes available. In Cool Ranch, you can buy a lvl 18 ship for about 7k gold and at level 22 ship for around 10k gold. I'm sure there's at least one more, but that's as far as I've gotten as of this writing (lvl 27 Pirate, lvl 21 Nautical). Doing things this way has made the game significantly more enjoyable. I actually stand a chance in ship-to-ship battles and, as I have said before, I much prefer sinking ships to boarding them. I like the distinction between ship and land based combat.
So there you have it: don't forget to update your ride!