To think there is not much difference

[noavailablename]

Between being crammed together on a submarine and having a gathering on the dock?

You mean crammed on a sub with recycled air

Well, in terms of today's news that their commander has been arrested ( or whatever the navy do) for allowing his crew to have a barbecue on the dock. IMo it is no different from a household being in their garden.

But happy to corrected if IABU.

Can you clarify a bit? Were the crew all working together on the submarine at the same time? Or did he bring together lots of people who wouldn't otherwise have come into contact. If he literally just took a bunch of people who were in close quarters in a sub then arranged for them to sit on a dock with a BBQ instead I don't see the danger.

I only know as much as the very brief news item. It was suggested that it was the crew of the sub that had a barbecue on the dock.
Maybe there will be more information in later news reports.

I assumed it was the actual crew wh had been living together in a sealed metal tube, and who would therefore count as ine household.

Presumably in trouble because it looks bad? Or because one or more of the shipmates had been in contact with other people since docking and should not have returned to the otherwise isolated crew?

The captain of a nuclear-powered submarine is under investigation after being filmed having a “rave-themed barbecue” in a Plymouth dockyard
The crew had reportedly been on a mission for several weeks but instead of returning home they were told to remain in quarantine.

there must be more to it?

yanbu

YANBU.

A submarine would be my idea of hell in the best circumstances (even the thought of it makes me a bit panicky!) and allowing the crew outside to let off some steam seems like an extraordinarily good idea and a human thing to do.

I once read an account from an American navy officer where he described how they arranged their dining seats early on in the mission so that right and left handers were sat to allow maximum room to eat. Their bunks are arranged like catacombs. There’s no social distancing on a submarine!

He's been sent home on leave, not arrested. He won't be in serious trouble it's just a pr thing.
My comment about the recycled air was to point out that it's more dangerous to live on the sub than have a bbq.
The crew will be quarantined to prevent them from catching covid19 not because they have it. The British navy has dealt with "plague " in the fleet before and have strict well tested methods for keeping it out, so to speak.

I heard this news story this morning and couldn't honestly see what all the fuss was about - assuming that all the people at the BBQ were the crew who had been together already anyway and there were no invited guests.

Sounds like another case of "Oh dear you can't be seen to be having a good time even if you aren't breaking any rules. It's against the spirit of the lock down don't you know?