Well, there's this bug, nothing you can do about it.
You need to get Water for the main hero.
There's also randomness here; you might not develop the main hero the way you want, and then you have to start over (as an example, Expert Slow -> Expert Earth, I got it after Water, Fire, and Air).
Anyway, I've already given my rating.
Logistics, Pathfinder, Wisdom, Earth, Air, Defense, Archery, Tactics.
And no Water or Fire!))
Water was with one of the lesser heroes, obtained by completing all the upgrade quests, so there were no problems with summoning a boat at the beginning, and later, when we control the shipyard, it will no longer be necessary to create boats; we can just summon them!))