Can you mount a force of warlocks and shamans? (Or just warlocks?) They traverse water, and warlocks can attack (but a significant shaman support would probably aid them greatly).
I could sell my buildings and get a dragon or build warlocks. But I don't have warlocks researched either and the new dragon rule is preventing me from using my dragon. Even though I could get enough recruits to use it.
It also seems dumb that transports are not researched by default since I started with a transport on the campaign map...
I just went ahead and save/loaded and auto-resolved it until I got a win. Since it should have been mine anyway.