Whoops, sorry. Got mixed up on who was posting what. I'll fix it.
No complaints. Just silent judgement.

Whoops, sorry. Got mixed up on who was posting what. I'll fix it.
I was going to go all scientific on you but instead I will ask you to consider metal shipsIs the water permanent? I.e. it's actually gated in from the Plane of Water or similar, doesn't vanish into nothingness after a few rounds? If so, I'd take the 8th level Elemental Gate spell that I remember from AD&D, reduce it a level because it's a one-time burst... consider raising it again because Waterball acts so quickly, but decide against it... I'd call it 7th level overall.
BTW, you wouldn't sink a ship unless it was heavily-loaded with cargo already, like coal or metal. After all, wood floats.
BTW, you wouldn't sink a ship unless it was heavily-loaded with cargo already, like coal or metal. After all, wood floats.
I was going to go all scientific on you but instead I will ask you to consider metal ships
It's not like ships being heavily loaded enough to sink is an unusual phenomenon. There are plenty of wooden shipwrecks on the bottom of the ocean. Wood gets waterlogged, after all; a ship that's been at sea a while probably doesn't need much cargo to send it to the bottom if it gets swamped.
And even if the ship didn't go to the bottom, a ship full of water is useless for anything but clinging to and waiting to be rescued.
There are really two issues with this spell: First, the water is permanent. Second, the water weighs 1,000 tons. Putting a 1-round duration on it addresses the first issue but not the second. You can still use it to squash buildings.I'd have the water last only one round, and put it at 2nd or 3rd depending on how strong the push is.
There are really two issues with this spell: First, the water is permanent. Second, the water weighs 1,000 tons. Putting a 1-round duration on it addresses the first issue but not the second. You can still use it to squash buildings.