Actual Test: Spelljammer 5e Fleet Combat (Fantasy Space Combat Rules Part 7)

tl;dr: not really a fantasy space fleet combat ruleset - but it sort of works at table.

I have run the 'fleet combat' set up for Spelljammer 5e by the book twice now (and it ran in the background for a third session) and it sort of serves its purpose as a dramatic device but I really hesitate to call it a rule-set. Following from writing on the Spelljammer 5e lack of rules before there is actually, toward the end of the adventure in the set Light of Xaryxis, some minimal mass combat rules: once you are in mass ship combat, each side loses a ship each round and the players get to focus on boarding actions.

Recalling what we saw previously - you practically cannot batter a 5e Spelljammer out of action through weapons fire alone without it being a deeply tedious dice-rolling exercise so the players getting stuck-in as boarders is the sensible thing to do - they will rip up an enemy crew a lot more quickly than their ship will hammer an enemy ship out of action. This 'chalk one ship off per round' is really just a timing mechanic to drive urgency in the boarding actions - but then making sure that the players have material targets that make enough of a difference within reachable distance is purely down to GM sleight of hand - exactly how far things are and how fast things are needs to get handwaved hard or players spend a lot of time too far off to be doing anything once they have crushed a first target but the battle is not yet resolved - or have foes come to them. If you actually look at the relative ship speeds, a foe trying to avoid boarding drives relative closing speeds per round down to 10-30' per round - starting even at the closest range of 250' that makes a long, long time trying to get to grips with folk.

Recapping the three instances where I've used the mass fleet combat:
First was the finale of the Spelljammer Academy extended campaign - and the players used their fleet to tie up the enemy fleet while they did an end run around to board the enemy base
Second was a variation on Chapter Nine of Light of Xaryxis where the players decided to slug it out with Xeleths fleet when he came to grab Xedalli because they had managed to round up some allies by then. That was an extended series of boarding actions to the backdrop of the fleets tearing each other apart.
Third was Chapter Ten of Light of Xaryxis where the players used their fleet as a blocking force against the citadel fleet and did a run directly for the citadel - fighting solar dragons on the way in.

It is enough mechanic for players to judge 'how is this fight likely to go' - which is purely 'have we at least a matching number of hulls to tie the enemy up while we do our thing'. Not very elegant but enough for the purposes of getting a session moving.

I guess it is *a* way to do multiple ship combats and my player groups have enjoyed the fleet actions because it keeps the focus on the heroes which I guess is the point for 5e. I write it up grudgingly because while I dislike it conceptually, my players have enjoyed the effect at the table. This feels wierd to me, but maybe it might be useful to you. It all feels a bit quantum ogre for me - the enemy will stumble upon you just at the appropriate moment - but really it just makes all the ship combat as wallpaper. The ships are just the shapes to have combats across; as long as you know that is the style of campaign you get with Spelljammer 5e, all is well.

If you want actual mechanic sets with a bit of heft to them, we have previously gone through two magazine-published sets of rules for fighting magical flying ships - the 3e adaptation Shadow of the Spider Moon and the 5e Aces High aerial combat rules from Arcadia #3 published by MCDM as well as the original AD&D Spelljammer and the to-be-published OD&D compatible Calidar. Most recently we also tried the gridless, Theater of the Mind house ruleset for the Spelljamming focused 'Tales from the Glass Guarded World' podcast.