"Falling" in water, aka sinking. What is the speed?

Rules Questions

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So what is the speed of a person (in armour, or not) sinking?

Is the speed similar to a fall? (As insisted by a party member.)

Or if there are rules for sinking speed, where can I find them?

Pathfinder Rulebook Subscriber

I don't know of any rules for sinking. For most cases, the swim rules in the Core rulebook suffice. You make a swim check, and if you fail it by 5 or more, you're underwater. If you're underwater and you can't hold your breath anymore, you start making CON checks. If you fail a CON check, you're drowning.

When this came up at our table, we used the character's encumbrance (light, medium, heavy load or light, medium heavy armor) to determine how quickly they sank. I think we did light load/light armor sank 1d6 x 5 feet per round, medium armor or encumbrance was 2d6 x 5 feet per round and heavy was either 3d6 or 4d6, I can't remember. Obviously, those "sinking rates" were on a failed swim checks.

Its going to vary with factors such as weight and shape, plus the human factors of a creature attempting to swim or having buoyant air in its lungs, but I think 10 feet per round as a rule of thumb is fine.

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An average human being will float, if not weighed down.

@Vod Canockers

PRD Swim wrote:
If you fail by 5 or more, you go underwater.

"Underwater" is a state that is not defined by RAW. This is the problem of the thread starter.

You need a houserule in my opinion and the idea from MechE is something in the right way but a sinking speed of 1d6 x 5 feet per round compared with a swiming speed of basespeed/4 is to difficult.
I would use
- 1d6 feet per round for light load
- 2d6 feet .. medium load
- 3d6 feet .. heavy load
Armor already gives a penaly to the swiming checks and is part of your load. So no special penalties due to your armor.

If you want to sink/dive use the houserule but multiply the result with 2 (2d6*2 feet for medium load) but only in one direction .. down :)

Eridan wrote:
You need a houserule in my opinion and the idea from MechE is something in the right way but a sinking speed of 1d6 x 5 feet per round compared with a swiming speed of basespeed/4 is to difficult.

You're probably right, it may have been a bit harsh. Using load and excluding armor type might be a good way to go. If I recall right, we only instituded a dice roll if a swim check was failed by 5 or more. Also, instead of using 1d6 x 5 feet, you could always use 1d3 x 5 for a light load, 1d4 x 5 for a medium load and 1d6 x 5 for those under a heavy load. Then again, a dice roll may not be necessary, but we're playing a tabletop game and I like rolling dice so I try to go that direction whenver possible.

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In the adventure Crypt of the Everflame (by Jason Bulmahn), there is a room filled with water with some pits.

The hazard says, "Creatures that step into the pit must make a DC 10 Swim check or immediately begin to sink into the dark water. Characters carrying a medium or light load sink 10 feet per failed check, while characters carrying a heavy load sink 20 feet per failed check."

You will float unless you have items denser than water on you or breathe out completely (or have lungs full of water). Leather, paper and other animal/vegetable products are all about the same density as water so will not cause you to sink. Even if you have lungs full of water or have a tree/animal source item that has no air trapped in it at all - it will only sink very slowly (5ft/round - I experimented on this once).

In effect that means carrying mineral based items like gems, rocks and weapons/rods items are the things that will make you sink at any speed.

It should be harsh. You will sink quite quickly in heavy armor.

Running it through an online calculator it appears that if your total weight is:

20% metal then you sink roughly 60ft in the first round.

40% metal = 120ft in the first round

etc

yea... 60/40 seems a bit harsh... maybe with die roll, if you succeed at the check, you go up by difference - armour check penalty.

So if DC was 15, you roll a 22 with a -2 penalty:

22-15 = 7 -2 = 5ft up. Still underwater possibly, potentially drowning, but going in a more favorable direction.

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This topic seems like a prime topic for FAQ/Errata attention.
Please hit the FAQ on the top post, people.

Given the falling speed seems based on real-world data (reflected by 'casting while falling' limitation), real-world sinking data seems liable to use, thus ZomB's figures seem realistic. Sinking speed even more than falling speed needs FAQ/Errata because there isn't even an indirect reference (like 'casting while falling') in the rules.

There are also some related topics that need to get their FAQ button hit:

GM Jeff wrote:

In the adventure Crypt of the Everflame (by Jason Bulmahn), there is a room filled with water with some pits.

The hazard says, "Creatures that step into the pit must make a DC 10 Swim check or immediately begin to sink into the dark water. Characters carrying a medium or light load sink 10 feet per failed check, while characters carrying a heavy load sink 20 feet per failed check."

This is a great catch! The rate isn't over the top, I like it :)

BTW, to the FAQ/Errata topic should also be added how sinking is related, if at all, to Failing a Swim check.
As of now, failing a Swim check does not make you sink, you just 'go underwater',
which does not require actually moving any squares[cubes], and certainly once you are already are underwater
there is no implied movement from continuing to fail a Swim check...

I would rule that sinking distance happens 'just before your next turn', as I rule for falling distance, based on how '1 round duration' events resolve in the Init system.