Thank you for converting this. I think it's a great starting point for naval combat.
My main issue is the lack of description of how to incorporate the magical possibilities. Attacking a ship with a spell is clear. But I think a good addition would be to add what for example an engineer could repair if he has access to the mending cantrip. My inclination is to give an engineer advantage on repair checks, because it is so much easier to repair broken lines etc. Could you use the ability of the Shape Water cantrip to freeze the water in a small hole to temporarily stop the water from entering?
Making repairs is even easier if the Fabricate spell is available. I think I would lower DC's for repairing, not just giving advantage.
What influence has the Control Water spell on naval combat, or control winds and control weather. I would like to see
this mentioned in the relevant sections. I think the last two spells would give you the weather gage at least. There are a lot more spells capable of influencing the wind or the weather, so a section on how to use these spells in naval combat would be very useful.
And just out of curiosity, how would a literal skeleton crew function on a ship?
You're welcome!
Seas of Zeitgeist was a supplement for helping to resolve the naval combat in the Zeitgeist adventure path. Even then, it is not very exhaustive. Admiral o' the High Seas was the more exhaustive naval book that expanded on the basics in SoZ. SoZ even says on one or two occasions that you are on your own when it comes to magic, since there are so many ways it could be used.
With that in mind, I think the point was to give a framework that would allow DMs to answer these questions as they come up.
Mending. I don't think
mending should help during naval combat. The casting time is 1 minute and only affects breaks up to 1 foot in any dimension. Disabled components are generally much larger than that. Spending 1 minute (the minimum length of a naval round) to cast a spell would preclude the engineer from working on the rest of the problem. Now if another character acted as an aide to the engineer for the turn, eschewing an officer or attacker role, maybe they mended a critical piece, granting the engineer advantage on the check.
Shape Water. It might temporarily plug a hole in the hull long enough to make repairs easier, but the water pressure would be intense and probably pop the ice patch out quickly. I could see it granting advantage on repairing 1 hull integrity.
Control Winds. This probably only affects sailing ships within the same zone. The area is fairly small, and a ship would be able to sail out of it fairly quickly, but those seconds could be disruptive and knock it off course a bit. It could impose disadvantage on the ship's Command checks during the Location and Bearing phases (or possibly Terrain if the ship is navigating a hazard).
Fabricate. It takes too long to cast to be effective in naval combat. Outside of combat, it would be very effective in repairing the ship.
Control Weather. I could see this being used to set the wind direction leading into naval combat, but changing the wind takes 10-40 minutes to take effect, making it very difficult/nearly impossible to take the wind gauge mid battle.
Another consideration would be that concentration spells will probably need saving throws whenever the ship is hit by an attack or is affected by an extreme situation. The DC might be 10 or 10 + the number of strikes dealt by the attack.
