compulsion

That's what I'm looking at and thinking about being in a ship chase. You cast this 4th level spell, that they have no way to counter, creating a trench right in front of them. They crash into it and then you create a whirlpool, as the water fills in the trench the whirlpool sinks the already crashing ship. Wait till near the end of the spell then change the current to bring up what's left of the ship and finish off or capture anyone that managed to survive. One 4th level spell in the right place and you can finish off how many dozens or hundreds of people.

I've got some questions for the Flood effect from this spell.

The material component from the spell is just "A drop of water and a pinch of dust", so alongside the part of the Flood effect quotes " You cause the water level of all standing water in the area to rise by as much as 20 feet."  It means you can actually Flood the area of effect of the spell with only just one drop of water? Since technically the drop of water on the floor is "Standing water".

Also I have another questions about the component and how it can work with Flood, if you use as the component  Holy Water instead of regular water (In the case that you can cast Flood with only one drop) or you choose to apply the effect on a source of Holy Water (A fountain or even a Vial with it), all the Water produced with the Flood effect is Holy Water?

The ship sinking cube won't work. The spell dictates what happens when you use the flood effect in a large body of water. It instead makes a 20-foot tall wave.

Ah, but you're not using the Flood effect but Part Water instead. A ship is usually not standing still on anchor but moving forward in a battle. It's huge momentum will carry it forward into the trench that opens up in front of it. A 130 ft long galley should have enough time to turn completely vertical as it falls over the edge, impacting the still water on the bottom with it's bow and all of it's weight behind it, if it doesn't break earlier, at he moment of tipping, from the stress of not having half of it's length supported by water.

you know, I see no indicator of how deep the trench is, nor how wide... it merely states trench ("300ft range/area")... it is incredibly vague especially concerning the part water effect.

The trench is generally going to be up to 100 feet deep. If you read the Part Water effect, it states:

You cause water in the area to move apart and create a trench.

The spell's affected area is defined on the first line of the spell description:

Until the spell ends, you control any freestanding water inside an area you choose that is a cube up to 100 feet on a side.

So you can make a trench up to 100 feet deep, assuming you're not doing any of the cube rotation tricks.

Y'all need to chill lol. This spell is already on the brink of becoming a thesis paper. No one has fun interpreting and waiting for spells to resolve; it's a chore.

If you dare to cast an abomination of a spell like control water—please, for the sake of all your friends, keep it simple...

Flood. You flood the senses of your DM and fellow players with a 551–word spell. Your turn won't finish for another 10 minutes, and until the spell ends, every turn takes an extra 1d4 minutes.

I'm unclear on how the flood ability works. Could a small puddle in a dungeon be instantly transformed into a 20'x100'x100' area?

Given the wording of the spell says the cube can be "up to" 100 ft on each side, and that Flood raises the water level by "as much as" (i.e., up to) 20 ft, that generally means smaller sources of water only create smaller spell effects. RAI I don't envisage a single small puddle suddenly being able to flood a 20x100x100ft cube dungeon chamber.

The way I imagine it, the surface level of that puddle would shoot (Flood) 20ft into the air much like a geyser, before spilling over onto the surrounding floor, following the flooding rules regarding spilling onto dry land in the spell description.

This isn't Create Water either, so that one burst of water is all you're getting, you're not getting a continual geyser for the next 10 minutes flooding the entire room.

Then once the spell concentration ends, the water magically disappears, because it's magic.

Quote from Arketon >>

Ah, but you're not using the Flood effect but Part Water instead. A ship is usually not standing still on anchor but moving forward in a battle. It's huge momentum will carry it forward into the trench that opens up in front of it. A 130 ft long galley should have enough time to turn completely vertical as it falls over the edge, impacting the still water on the bottom with it's bow and all of it's weight behind it, if it doesn't break earlier, at he moment of tipping, from the stress of not having half of it's length supported by water.

 

 

Beyond 20

 

 

 

 

 

IRL that's how it would work, but D&D is looser on momentum, presumably to account for the fact that it's much easier to position an effect right where you want it relative to IRL. I'd personally rule that if someone is manning the vessel they get to make an INT or STR roll, depending on the nature of their vessel,  with vehicle prof if they have it to try and steer around the trench, with DC scaling up on larger vessels as they wouldn't handle as well. Or at least, that would be my rule if I wanted to keep up the tension or this was going to be a heavily ship-to-ship adventure. As a one-time move that doesn't wreck the plot, I'd allow as is for Rule of Cool.

Bro this spell is overpowered and godly. Definitely should be bumped up a level or two. I mean, for a 4th level spell slot you can just straight up become Moses for 10 minutes, so long as you maintain your concentration. I swear bro, the Bible was just a really lit and really long DnD game, where the DM and his two buddies created an awesome world, occasionally joined in with the players, and engaged in godly shenanigans.

I dont know why english speakers have a hard time understanding the limits of this spell, but in spanish, french and german the wording of the spell says that it affects water that is not in movement. Freestanding water mean several things in english?

The spell seems designed to be used on swamps, puddles, flooded areas on a dungeon, underground waters but not rivers, lakes, seas, oceans and other moving bodies of water.

It talks specifically about its effect on seagoing vessels. One of the uses of the spell is to redirect flow of a body of water. It seems like it is designed for use on large bodies of water. 

I see where you are coming from.  Freestanding in this context is 'unconstrained'.  The spell effects, explicitly, talk about large bodies of water with huge vehicles and, separately, flowing water.  So a moat, cistern, barrel, bucket and other types of containers would not fit the concept of freestanding but a lake, pond, puddle, swamp, stream, creak, river, sea, or ocean would.  The examples of swamps and puddles match 'standing water', though a lake may be also be standing if it does not have strong current.  Is a flooded area in a dungeon constrained in the same way as a cistern? How about a canal? [insert shrug here]

Yes, but a huge vehicle are just row boats, canoes or even rafts, while seafaring ships are listed as gargantuan (Ghosts of Saltmarsh). The problem with "freestanding" is that for english speakers it means several things while in the spanish, french and german translations it just says water that is not in movement. So as far i understand a large body of water that is not in movemente is what i listed before, from puddles to swamp waters.

Quote from jorgemargenat >>

Yes, but a huge vehicle are just row boats, canoes or even rafts, while seafaring ships are listed as gargantuan (Ghosts of Saltmarsh). The problem with "freestanding" is that for english speakers it means several things while in the spanish, french and german translations it just says water that is not in movement. So as far i understand a large body of water that is not in movemente is what i listed before, from puddles to swamp waters.

 The only problem with that is one of the effects you can activate, Redirect Flow, requires water that is in movement, so I think it's just translated poorly. If it could only target water that's not in movement, then Redirect flow could never be used.

Very powerful if there just so happens to be water nearby, which is somewhat rare. Useless otherwise.

can the caster who made the whirlpool freely swim in it?

Quote from ZOOCHTHEMAN >>

can the caster who made the whirlpool freely swim in it?

 no, casters aren't immune to the effects of their own spells