Last session in my DF game, we had an underwater fight.
I knew there were underwater combat rules somewhere, but I couldn't remember where. So I just winged it.
What I ruled was:
- Swimming move is per Basic Set p. B354.
- To hit is -4 for attacking into or out of water, 1/10th range (which didn't come up), lightning wouldn't penetrate water.
- No swinging attacks, but I was ready to rule if people sawed.
- Half damage for broad-area thrusting attacks (slams, shield bashes).
- Thrusting attacks unaffected if you're Aquatic, Amphibious, or have Swim on (which ultimately the only fighting PCs did).
- No Retreat.
After the session, as I drove home, I remembered where the rules are - in a digest form in the excellent GURPS Martial Arts: Yrth Fighting Styles.
I went home and looked them up.
They felt both too complicated and too generous for my DF game. Lots of penalties, even for thrusting attacks (a standard spear or trident would be -8 to hit, for example), and pretty weak penalties for swinging attacks. Oh sure, -1 per die per yard of reach isn't nice, but it's basically no penalty in DF. Vryce would go from Skill-27 and 4d+12 cutting to Skill-19 and 4d+4 cutting. Average damage 18 underwater? Eh . . . I could double the penalty so it's basically -1d per 1d, but that's nerfing the weak and leaving the strong pretty well off. Even without a Swim spell he'd be able to fight in the water not much worse than in the air . . . No word on shield bashes underwater, either.
Also, you can Retreat, too, if you have the right skills or right traits (including the Swim spell.) That I still can't get my head around. Maybe you can veer off course while swimming at speed, but go from stationary to one yard back for a +1 or +3 to defenses? I just can't see it, even for pretty nimble fish. Water has more resistance than air, and even if you can potentially move in three dimensions up-and-back it's not going to be as fast. Dodge and move forward for a slip? That I could maybe see. I could see reduced Retreat bonuses, maybe, but even so . . . it's a pretty generous concession.
Obviously, I'm looking at a summary subset of the rules from Pyramid and Roger Burton Wests's Fathom Five article.
But even so, I feel like the guesstimates I made on the day were a little more DF-like for my tastes. Underwater creatures are pretty well off. Surface dwellers need magic to get around well. Fighting underwater is limited to thrusts but given the right spells and traits you can triumph.
Short version? Fighting in water should be limited, favor the fish, and be a real change of pace from "I swing and cut it in half."
Here is what I'm thinking . . .
DF Felltower Underwater Combat (Simple)
- Swimming move is per Basic Set p. B354.
- Weapon skills are capped by Swimming skill, unless you have the Swim spell on or are Aquatic or Amphibious.
- No Reach 1+ weapon swinging attacks underwater. Sawing, close combat weapon swings, etc. use thrust-based damage. Based on maximum reach.
- Thrusting and unarmed attacks are unpenalized.
- Attacks into and out of the water are at -4, 1/10 range, -1 per die of damage, some attacks can't penetrate.
- Shield bashes do half damage and are -2 x DB to hit.
- No Parry except unarmed or purely close combat weapons, no Block (but you get DB), Dodge is normal for your move, no Retreat (except with Ethereal Body or Walk Through Water).
Plus the usual rulings as needed. I've already made a fair amount of concessions to "if it looks like a Bond-vs-Frogmen fight, it's not penalized" so I'm not inclined to make more. I'd deal out of a lot of "No, even though you're a Weapon Master with the Swim spell on." You wouldn't need to make a lot of Swimming rolls, or anything else besides "fight more or less normally."
Those rules would explain fishmen with spears and shields (great on land, great offense in the water, no real loss when you can't Block) and saw-edged swords and knives, and encourage special underwater crossbows (spearguns!) and grappling and knife fighting. At the same time, it makes powerful spells powerful, and encourages PCs to do water-specific moves (stab instead of cut, grapple, pick touch spells over Lightning, etc.)
I'm leaning very heavily to the latter. It's both pretty fair, it is simple, and it didn't cause any complaints or weirdness last session, either. A simple set of rules that worked smoothly is probably the way to go. No need for specialized skills, either. Save Aquabatics for the Aquabats!
And yes, Swim is very powerful. It should be, it's cost 6/3 and has a lot of prereqs. Its wording did engender some "doesn't suffer penalties means I fight in water like it's air" arguments until I said, no, "impossible to do" isn't a penalty. And it's not a D&D-like Free Action item that says, basically, throw out the rules and pretend you're fighting on land. Those are lame, really, because they take an interesting environment and say "nevermind, it's normal."