Looking for Suggestions: Underwater Exploration

[WizarDru]

So in tomorrow's adventure, there's a very real chance that the players will be exploring the ocean floor, with the aid of magic. In search of a place called the "Deep Library", they will need to explore ruins long submerged on a sunken island chain. Therein they may learn the fate of a heretofore unknown race, part of an embarrassing secret that the oldest mortal race has kept hidden from all but a few of their own kind.

What I'm looking for suggestions for is this: I'd like to make explore the ocean and undersea ruins interesting. I'm thinking skill challenge, but I'd like something a little more sophisticated than 'give me six successes at swimming'. However, I'm trying to figure out some creative uses for the base skills.

I'm also trying to envision options. On the one hand, they may be walking/swimming. On the other, they may be navigating by submersible (a dwarven-built submarine named 'the Iron Bolt'. How would a skill challenge work from here?

Also, has anyone run any underwater combats? Any suggestions? My memory is kind of shaky, but iirc, the DMG has scant rules on battling underwater, other than a few minor rules additions.

 

[Dannyalcatraz]

First of all, check out the Aquatic database link in my sig- Aeolius and others have a bunch of stuff in there.

Second, think of UW adventures as being like aerial ones- the natives think in 3 dimensions at all times, whereas most landlubbers think in 2. Thus, NPCs & critters should attack from unexpected angles.

For the most part, thrusting melee weapons will be the most effective. The other types matter in certain situations, but are generally too slow to be useful underwater.