[Steko]

You can only get 3 per boat at max size. Level 20 landing craft have 24 seats, tanks take 8 slots.

3 tanks does take a long time but every other unit trains in a fraction of the time tanks do. Tanks take longer because you will often take no casualties with them.

[Greenisus]

Ah you're right. I'm not that far (and honestly I'm starting to get bored with it).