We really need to talk about the M-class. https://twitter.com/TheDreadShips/status/1126565091074293760

I mean, the British had already set a pretty low bar with the steam-powered, coal-firing K-class: https://twitter.com/Canocola/status/1090350394482589697

So when you discover they cancelled the last four so that they could order something worse...

For context, this thing here - looking for all the world like a clown car falling apart in the circus - is a K-class sub preparing to either dive, explode, or otherwise embarrass itself.

Someone looked at that and thought "naah - it's not nearly silly enough".

I'm not saying the Royal Navy were definitely possessed with the mentality of a 14-year old boy (insert copious discharge of seamen gag here) - but they decided that what they really needed was to add a 12-inch gun taken from a battleship.

And because the post-dreadnought era was going through its difficult teenage phase the second most important design consideration was a kick ass paint job.

History fails to record if lime green MONSTER claw marks were badly applied to the sail, but I have my suspicions...

One bright point was that - stung by the tendency of the K-class to inflict more casualties on the Royal Navy than any possible opponent - the coal fired boilers were quietly deleted. The M-class was to be an all diesel-electric sinking machine.

The basic doctrine of the M-class was that it would pop up, sink something, and fuck off.

I'm not saying this is a bad plan. The execution though...

The "popping up" thing determined the design considerations. The range was expected to be short so a rangefinder wasn't necessary. Instead they put an iron sight on the end of the gun like a cheap fairground air rifle.

Any captain hitting the ring off the bottle got a prize.

I'm not kidding - the crew were expected to use the periscope to view iron sights on the end of the gun and then pull the trigger. I've used more advanced Nerf guns.

btw, I've only just noticed that M1 is inevitably shown trying to fire its gun down its own ventilation shaft...

M1 was the only one to enter service as planned. It was immediately obvious the idea was stupid, although nobody thought to tell the French. The other hulls were hastily redesigned to test other ideas.

M2 was redesigned as a submersible aircraft carrier.

Somewhat predictably it was lost when some idiot tried opening the hangar door underwater.

M3 was repurposed as a minelayer.

A sort of supermarket checkout belt threw the mines off the back.

Good job it wasn't inspired by Aldi or it'd still be circling Portsmouth today waiting for a cashier to show up.

M4 was never completed, presumably as the Navy ran out of whatever they'd been smoking and couldn't find an even more ludicrous weapon system for it.

The main contribution of the M-class to the Royal Navy was their experimental camouflage: essentially they were so desperate to hide them that they tried various schemes until they found one that worked.

M3 survived long enough to be cut up. M2 sank itself as discussed above. M1 had a brief moment of self-awareness and dashed itself to death against a Swedish freighter.

It's a bit harsh to call them failures - the admiralty was clearly just kicking ideas around to see what worked - but they were far from a success. Perhaps the traditional British view of submarines as cheating worked against them.

On the other hand it's hard to defend a class that suffered 66% casualties without actually fighting a war.

Whatever the reason they were an evolutionary dead end.

There aren't many images - probably because they made photographers cry if they entered the shot. Just occasionally though they look quite, er, cool. Perhaps I'm going soft...