Water Tactics?

[Gargoyle]

Okay, you've taken half the map and eliminated all but 2-3 of the other pretenders. You have a large Land army, high income of gold and gems (but low water gem income). You have no water troops or commanders. One of your opponents (Ulm) has invested greatly in troops that are waterborne and has several water provinces in his control and has annoyingly assaulted you from them, forcing you to set up a fantasy version of Normandy coastal defenses.

If you do not naturely have water mages or areas that can generate waterborne troops and commanders, how would you counter waterborne activity by your opponent?

Is there a solid way to self-start a waterborne strategy late in the game under these conditions?

[Alneyan]

I would recommend going on the offensive here: Ulm isn't a water nation, so they must rely on troops to protect their provinces, and won't be building forts beneath the waves. That aside, water provinces are much better for defence, since they offer protection against artillery spells (Murdering Winter/Flames from Afar), and getting in the water to begin with is tough; underwater nations also have a much easier time attacking you.

Most undead can go under water, so they are a worthwhile solution if you happen to have death gems lying around; other paths should have amphibian summons for the same purpose, but they will be fewer of them, I believe. If you want to bring in mundane troops, an air item can allow you to bring X troops with you underwater, and similar items exist in the Water path; you should really start building some Water magic if you are serious about invading the seas with hosts of troops. Raising Water to 2 can be done easily with Construction 6 and a Water-1 mage, and you should have recruited a mage with a Water-1 random by now.

Another solution is to build hit squads, that is commanders with little to no support, but a lot of firepower: you would then rely on Water magic to bring your commanders underwater, or Rings of Water Breathing (or any similar item). This is a cheaper solution than bringing all your troops with you, but commanders are vulnerable, of course. A last way of dealing with the underwater provinces is to bring the heavy guns: Sea of Ice will make it much harder to leave (or enter) the seas, and it might be just what you need. Of course, this is a Water enchantment, so it will be pretty tough to cast for you.

[Gargoyle]

I do have quite a few undead scattered over the map and I can summon quite a few of the better undead. I see you say many undead can go underwater. I'll have to look at thier stats, I really never realized this. The main thing is leadership and mages. I'll have to pull together whatever random water mages I have. I'm Machaka and I am so use to my hoplites backed by Javelin and bow with Spider hunters on the flanks and mages in support. I now have to build an entirely different type army that I cannot reinforce very well and it has to be able to beat a well established waterborne foe.

[archaeolept]

both water and air mages can forge items for leading troops under water. any water mage can go under water, and take along a number of human sized units equal to the mage's path in water. As well, most undead are poor amphibians. And, of course, since he's Ulm, you can just wipe him out on land and then dominion push him into non-existance.

once you have a sea province you can also buy a ton of tritons (most likely).

[NTJedi]

Gargoyle...
Death Magic is one of the best sources for marching into the sea. Undead units such as Longdead Horsemen, Dispossed Spirits, and Ghosts work good.
Also a spell I don't use except in multiplayer games called GHOST RIDERS will kick major butt in the water. Cast 3 or 4 in a single water province and watch everything die.

[Oversway]

Many golems can go into the water. I'll point out a lot of golems and undead are poor amphibians, which means they suffer some penalties. They can still be very effective.

I thought for water magic, it was the number of units (of any size) you could take under water?

You may be able to conquor a coast province where you can recruit ambibious units. If nothing else, once you conquor a sea province, you can recruit units there.