Internals

Can you cast the "flood ship" spell while on a ship? Because if you want to sink an enemy ship, you need to land on its island, and when it's their turn, they'll defeat you... But I like the idea of trapping a hero.

I'm not sure, I think it was possible...
It's difficult to implement right now, but in my opinion, it's the only way to win quickly...
The map is XL, but the distances are actually small. I haven't played the map itself yet, but I had some ideas...
First, we need to deal with the blue player, as they have direct access to the shipyard and are closer to us, while the green player will take a long time to emerge.
There are many small islands, and the distances between some of them are small, which the AI will use to land. Since there are no portals, it will spend a turn landing/disembarking.
There's a risk that the blue player will reach us by the 2nd week with strong stacks. We won't have any mana, magic, troops, or skills yet... So, we'll either have to find a way to outsmart them in battles or run away from them...
In any case, this will prolong the game, so we need to catch and trap them...

Another option is to recruit 100 swordsmen, but this again requires manipulating the generation so that the shipyard is guarded by suitable monsters...
Another problem is that we can't build a shipyard, so we'll have to do everything with one hero at the beginning