This pertains to the first ship encounter: Jolly Rogers and his Ghost Ship. It's what should have happened, if we'd had time and I'd considered the rules, better, ahead of time.

You're running. you wait until the last minute to turn around. That would be when distance is 850'...1 round of normal tactical travel outside of Mangonel range (800'). Closer to two rounds to two rounds with them chasing you.

Speeds, both with tail winds:
Sailing ship: 60'
Keelboat: 35'
Gap is closing at 25'/round, so you're actually 2 rounds out of range

You turn 90 degrees, your wind turns with you, maintaining speed. They continue to follow, closing gap to 825'.

You turn 90 degrees, your wind follows you. Distance is now 755', and closing at 95'/round.

You are in mangonel range now, with 3 rounds before you're in Ballista range. That's 3 mangonel shots followed by 5 rounds of mangonel and ballista vs your ballista.

Then they turn 90 degrees, firing only mangonel. They are now even with you.

Then they turn 90 again, firing both weapons. They are moving 15' and falling behind you  at a rate of 20'/round

That's 24 rounds of ballista fire and 40 rounds of Mangonel fire. Assuming enough ammo, of course. Less if one of you sinks, they run out of ammo, or those ghost chains do something (and they are chains, it's pretty obvious what they do...)

So...real sea combats are going to end in a ship sinking.

What's really bad is how much worse it would be without Marvek and his wind power
This message was last edited by the GM at 04:19, Sat 16 Jan 2021.

Ok, something else I missed, and something that will make ammo usage a little more tolerable:

Ballistas take an action to load, an action to aim, and an action to fire. 1 shot every 3 actions or 3 rounds

Mangonels take 2 actions to load, 2 actions to aim, and an action to fire, for 5 actions, or 5 rounds.

Most ships get 2 or more actions, but movement is considered an Action for ships, and each may only take one movement. However, staying dead in the water or having more than 2 actions (or both) could well speed up fire rate.

Potential targets on a ship:

Most ships have different locations that can be targeted.

Hull: Has a threshold (minimum damage per hit before damage counts against hits). Taking it to zero hits sinks the ship

Sails: Damage reduces speed, to 0' eventually

Oars: As Sails.

Helm: If destroyed, ship can not turn.

Weapons: Each one is a separate target. Destroyed weapons can not be used.

Mind you, hit points can vary quite a bit, but it allows for targeted results

Also note that not all ships have both oars and sails.
This message was last edited by the GM at 04:04, Sat 30 Jan 2021.

Because the thought occurred and I wanted to know the mechanic, I started researching fire from fire spells. Some ignite things, some don't. Worn or carried things are generally immune, and ships are treated as creatures (complete with stats) with  few component (like weapons and sails) that are close enough to worn items.

Then I studied the Fire Hazard event in Ghosts of Saltmarsh, which gave me damage for fires, but it was damage that took 5 minutes of burning to manifest.

So... Spells may well set hull or ship component on fire, but it won't help in combat. All such WILL be tracked though, to help determine the DC for the Fire Hazard.

A ship on fire and unattended will take nearly an hour to burn to the waterline (maybe longer for a reinforced hull). It's not something that matters in combat unless it's a very LONG combat. A Chase, possibly, but not combat.

I've been asked abut fire damage a few times. This is what I have:

It takes 5 minutes to try to extinguish a fire, ad failure does 6d6 fire damage to the ship's hull and 1d3 other components.

That's about all I can find official, and it's from the Fire Event. And, of course, there may be some spells that will extinguish it faster.

Now, the Event also has a variable DC for extinguishing fires, which I'm going to assume means a higher DC is a larger fire. witout digging through the three books that provide the bulk of spells, I'm going to figure that the lower level ones, in general, have smaller areas. A small area effect will simply lower DC. Once DC reaches 0, of course, the fire is out.

Conversely, multiple fire attacks on shipboard that actually set things on fire will increase the DC.

As spell are used and I have to make a determination, I will list that spell and it's results below.

This means that a burning ship isn't a factor in ship combat...unless it was burning before the combat started, or the combat lasts more than 50 rounds after the fire starts.

However, after combat when you're healing, searching, etc, time becomes an issue and a ship can burn around you.