Please help me with Buoyancy rules

[Oryan77]

Here is the situation:

The PC's will be travelling in the Elemental Plane of Water. There is no water pressure there & there is no "up" or "down". Up & down is whatever direction the swimmer thinks it is.

I'm not sure if this is how it's done, but I'm making move checks be 1/2 speed when they're not in combat & don't have a swim speed. When in combat, they'll make a swim check DC 15 to continue moving 1/2 speed. If they fail, they move 1/4 speed.

The thing is, it seems like swimmers in armor should be penalized due to buoyancy. I'd like to get the heavily armored PC's thinking about buying lighter armor (possibly underwater armor materials) for their journey in the plane.

If they don't wear lighter armor, what kind of rule would I use to represent their struggle with buoyancy? Use the fatigue rules or make up some other kind of penalty?

 

[Andor]

What bouyancy? Bouyancy is a direct consequence of gravity. No gravity, no bouyancy. OTOH they are encumbered, and have extra mass, so apply the same penalty to their swimming speed that they would normally have to their walking speed and I'd call it good.

 

[Oryan77]

No gravity, no bouyancy.

There's still gravity. Gravity works in whatever direction you think it is. So if you think you are swimming "up" and you stop swimming, you will sink "down".

 

[Andor]

There's still gravity. Gravity works in whatever direction you think it is. So if you think you are swimming "up" and you stop swimming, you will sink "down".

Really? Sweet. I'd strap lead weights to my feet and think down was whichever way I want to swim. ^^

Failing that, I'd still go with a proportionate movement penalty and armour penalty.

 

[ValhallaGH]

I thought the Armor Check Penalty to swim checks was for just this sort of thing. Is double ACP to swim checks not enough of a penalty? The -5 from masterwork full plate quickly cancels out a 30 Str (-5 * 2 = -10), and if they also have a shield then they're looking at a -12 to -28 depending upon how large a shield it is.
If you need more penalties, go the 3.0 route and impose a -1 for every 5 pounds of gear. If you want to be really mean, stack the -1 per 5 pounds with the double ACP. Suddenly masterwork full plate would be imposing a -20 on all swim checks (-10 for weight, -10 for double ACP), and that doesn't even count the greatsword he's hauling around (another -2).

You're already being very generous with your swimming, so it is likely that you want the players to move quickly and safely through the water with a minimum of fuss and bother. How this jibes with your desire to take their best protections away (and make the inevitable combats even more dangerous than they already were going to be) I don't know, but to each their own.

Good luck!

 

[Primitive Screwhead]

In a game where I expected lots of water borne movement, I chose to go the route of emulating the Jump skill mechanic.

Swimming in water became a skill check where the result is how many feet you move.
The DC's for moving water changes to penalties to the checks...meaning its possible to move backwards in a fast moving stream.

Get a result below 0 and you risk going under.

Swim speeds grant the normal +8 to the skill, then the same scaling as the Jump rules have.
Additionally you can Take 10 and retain your Dex mod to AC.

The rules worked well with Profession (Sailor) and sailing/rowing a boat {Rowing checks based on STR, sailing checks based on WIS...the type of boat modified the check}

Did the same for Climb checks....and was working on something for flight that matched.