But it doesn't take any account of any upgrades you've fitted.Did you press F11/Reinit at any point?
That button now also resets your ship to ensure it matches with any ships_init.c updates you make.
I found that one because the new installer doesn't include my changes to privateer ranks, so when I got promoted I got one of the lower titles instead. I replaced "nations_init.c" with my own version, reloaded the pre-promotion game, got the promotion again, still got the lower title; reloaded the pre-promotion game again, got the promotion, got the correct low rank, and Golden Hind was back to its default stats, though all the upgrades were still there. One workround would be to sell the upgrades, which would probably degrade the ship, then press F11 and buy them back, but this has two drawbacks. For one thing, upgrades cost time and money. For another, that won't work on the corsair refit. However, I found another workround.
You can berth the ship. Even if it's your only ship, you can berth it. Berthed ships are immune to the F11 reset. Then relaunch the ship and continue the game.
