I know I’m not the most qualified person to talk about balance, but I’ve been playing with Koreans, and Turtle ships just seem so dang useless.
I’ve hear people say that they should be used to tank damage - but fire ships do this much better. Fireships get you more hp/cost*, and are faster which is very important for tank ships, because the ships that are tanking damage need to be replaced quickly enough to shield the ships behind.
Turtle ships deal splash damage - but caravels and demolition ships do so much more effectively. Koreans lack demolition ships; sucks to be them.
I feel like Turtle ships ought to be good on 4 lakes, but 2 fire ships beat 1 turtle ship. A cost-effective trade for the fire ships.
There’s 2 caveats where TS are almost useful:
Elite turtle ships trade efficiently against fire ships when there is a 2v1 numbers advantage to the fireships. The elite TS upgrade just buys the TS a lot more hp than Fast Fire buys the fire ship. However; the elite TS upgrade is also extremely expensive (compared with other ship upgrades) and will happen too late to matter on hybrid maps like 4 lakes.
I had an opponent mass Turtle Ships, and he did manage to kill my whole navy because TS are so population efficient. I then had to take unfavourable fights to delay him whilst trying desperately to build up my navy again. However he had to give up map control for a long time to manage this, as a result of which I had a significant resource advantage. In the end I whittled down his fleet and he didn’t have enough resources to maintain it.
*fire ships cost 75/45 and have 120 (140) hp, turtle ships cost 180/180 and have 200 (300) hp. Turtle ships have extra armour, which effectively doubles their hp against some threats, but if you factor in gold being more valuable it still doesn’t look good for the TS