How does setting ships on fire affect combat?

Question

Appendix A of the Ghosts of Saltmarsh adventure, "Of Ships and the Sea", describes a number of common hazards during sea travel, one of which is fire (p. 201). Fire is presented as a hazard that requires a group check to get out of the situation. Each check requires 5 minutes of work.

I know my players will try and set ships on fire in combat using magic, or by any other means. How would this work in combat?

By the hazard rules, it seems like it would just put all officers (PCs) out of combat for the duration.

Answer 1

In D&D, a tactical combat encounter is typically under a minute, whereas the time scale for a burning ship is 5 minutes. If the crew is busy for a few rounds with actual combat, there's still time after that to combat the fire.

It would be reasonable for a DM to decide that this delay increases the difficulty of the fire while it burns uncontrolled. Personally, I'd go with something like +1 DC per round, which can be prevented if 2 or more officers use an action against the fire that round.

Regarding effects on the combat itself, natural fire is usually treated as Improvised Damage. DMG page 249 recommends 1d10 damage for touching a fire, 2d10 for moving through one, and perhaps more for remaining engulfed.

p.s. Note that the Group Check rules in GoS represent actions made by mundane humanoids (e.g. removing burning objects, throwing buckets of water). Magical capabilities (e.g. Decanter of Endless Water, Sleet Storm) are likely to be more effective.