I am a halfling with both the mariner fighting style (swim speed equal to walking speed) and the rogues cunning action and my Con mod is +3.
How far can I swim underwater before needing to surface?
I have a swim speed of 25. do I double this or tripple it with Cunning Action
This seems well off...but,
Swim 75 feet in six seconds (1 Round)
4 mins (40 Rounds of holding breath) suffocation rules.
=3000 feet (600 Squares) before having to surface
or is it more like 400 Squares without using CA which is still insane.
Are my calculations well off? They must be somewhere. Please help me clarify this.
Many thanks
It's actually 3300 ft/660 squares as you get 4min+4 rounds of breath with 16 Con.
In real life, the world record is either 658 ft or 800 ft, depending on the source, so even without Mariner your average Fighter would be superhuman on Earth... but isn't that the point of D&D 
?
rgoodbb wrote:
In addition to this, the maximum depth that you can dive is around 100 ft. without equipment, after that, pressure starts becoming a problem.
200 ft. is around the maximum depth you can dive in an old fashioned divingsuit, or diving bell.
1000 ft. is about the maximum depth you can dive in a heavy atmospheric diving suit or bathysphere.
1,090 ft. is the world’s deepest scuba dive ever attempted (with modern equipment).
The average whale can dive to a depth of 7,382 ft.
I suggest that the swim speed is the surface speed. Swimming underwater is slower than swimming on the surface.
Barb 3 not Totem / Ranger 2 SpellLess pick Mariner
and your party Wizard has Animate Dead.
"Kill Me" and the Wiz raises you as a Skeleton.
(minor handwave on how you'd be a skeleton)
(minor handwave on Wiz alignment issues)
Don't have to breathe. Immune to Exhaustion.
Swim til you die. Oh wait you're dead already.
Swim til they make a youtube video out of it.
(minor handwave on aqua-dynamics issues)
Clutchbone wrote:
Great replies thanks,
OK. I want to be able to slip off the far side of my ship, swim underneath it and towards another ship, Plant some pre-made alchemist's fire and swim back.
Assuming swimming underwater is slower and I am exertimg more effort than just standing there and suffocating, and taking in the depth of going under my ship, How far could I get? What would be reasonable with my stats?
Ps. this could be during combat or a stealthy night mission out of combat
Thanks again.
Well a DM would also take currents and weather into account. So regardless of the distance, you are already facing a couple of swim checks just to overcome the waves.
An average ship, such as the Caravel, is 60ft. by 20ft., with a heigh of 10 ft., and a draft of also 10 ft.
So I think you need to swim 10 ft. down and 20 ft. to the side, just to swim underneath it. However, if you dive from a height of at least 10 ft, you should be able to clear the first 10 ft. underwater simply by the dive alone. So that leaves 20 ft. to still swim underneath the ship.
So it's 20 ft + the distance between both ships, that you need to swim, if you dive off the ship.
Or 10 ft. down and 20 ft. + the distance between both ships, if you don't dive, but lower yourself into the water.
rgoodbb wrote:
Iserith.
I hadn't even though of it in that sense. That would definately be a much more exciting way of doing it for me.
Hungry Shark!....you.....
rgoodbb wrote:
It may still come into play.... Ex. one way to get past the 'vigilant crew' obstacle is to just swim there underwater.... so now you need some way of determining if that is possible.
Coredump00 wrote:
While context is a perfect reason to make this just one skill check, I wouldn't say that negates the need for measuring distance entirely. It kind of depends how far apart the ships are. We wouldn't ignore movement distance on land, so why ignore it underwater?
iserith wrote:
Imaculata wrote:
But that's exactly what I mean. If the ships are close together, then you might as well ignore the distance and make it one check. But if the ships are far apart, then I would definitely take distance into account. If the player can't swim to the ship in one round, then the chance for discovery increases, plus he'll need to hold his breath.
And btw, thats something I think the OP left out. He asked how far he can swim before having to surface, but that doesn't only rely on swim speed. It also relies on how long you can hold your breath.
I did actually say 4 mins but was corrected by Clutchbone to 4 mins and 4 rounds with my 16 Con.
I think having an approximation is good to see if the task is dooable in the first place, but once I know it may be possible, running various checks seems a nice way for a player to get into their task/s
Imaculata wrote:
Iserith is skipping over a necessary point of preparation: if the ships are too far away, you cannot possibly succeed - no uncertainty involved. So the distance covered, the time needed to travel it, and your hold-breath duration are important. But that ought to be something the player does and shows his initial conclusion to the DM for review. The DM then gets to decide if there is anything he wants to put in that the PC doesn't know - like sharks, or a current, or the underwater swim speed is off so the math needs re-done (also check for just a silly math oopsie).
By the Rule of Cool, I'd allow the attempt and make it harder to plant the 'mine' than to get over there. I'd also - because I think the drama is greater - encourage him to surface for the last round or so of swimming. Did he blow his "Stealth"? -sound of rolling dice-
I missed the part regarding holding his breath, my apologies.
But still, if this were a combat situation, and multiple players were doing things, then I would definitely measure distance. Because that's how I as a DM know how many rounds are needed for the player to reach that ship. Plenty of other things could be happening at the same time.
BRJN wrote:
I see. Maybe my approach to these sorts of things is more mechanically and by the numbers, rather than narratively.