Submarine Cruisers/ Monitors

[Weaver]

The theoretical advantage of big-gun subs was that they could carry many more gun rounds than torpedoes and sink a lone merchantman with just a handful of them, so they could undertake extended commerce raiding patrols without running out of stored kills. In practice, the adoption of convoy tactics would have greatly reduced the opportunity for leisurely "surface and shoot" kills.

The X1 was surprisingly good in many ways. It's gun system worked very well, it was quick to dive and, after some modifications, handled nicely. The main problem, as already stated, was it's grossly unreliable power plant. The main reason that more weren't built was that the naval treaties set a total limit on submarine tonnage, so the RN (and every other signatory) had to choose between a smaller number of big boats or a larger number of small ones. Submarines of the day were slow and had very limited sensor range, so clearly the area coverage afforded by a larger number of boats was advantageous.

Another advantage to guns over torpedoes was that, at the time, guns were more accurate,  plus the shells were considerably cheaper than torpedoes.

What do you reckon its service history could've been like had the X-1 made it to WW2?

Drachinifel addressed that very question at the end of the video I posted earlier. He reckons that, refitted with reliable engines, it could have cut a bloody swath through Japanese shipping, especially troop transports for invasions, in the early part of the Pacific war or done similar dammage in the Mediterranean once the Axis powers were in North Africa and needing to keep their troops supplied. As the war went on, it would have become less effective as convoying and better escorts came in. It would probably have acheived less in the Atlantic and North Sea, simply because there was less unescorted German shipping to find and attack there.

Of course, this only considered X1 in isolation. The effect of investing a large chunk of the available treaty tonnage in one hull would have cost the RN at least three conventional submarines, with all the opportunity costs that implies.

[Weaver]

During WW1 & WW2 submarines did surface to engage lone merchant ships with their deck gun(s).  It led to the Q Ships.

IMO widespread use of gun armed subs would have led to more openly armed merchant ships.  A number of 5 inch guns manned by naval crews for example.
When the enemy is using torpedos then there is no point in arming every merchant ship because they have nothing to shoot at if the enemy is underwater.  However, if the enemy are surfacing to engage with guns then it is worth putting defensive armament on the merchant ships.  And if the lookouts are sharp and the gun crews ready then they are going to engage the attacking sub before it is itself ready to fire.

Hence why speed-into-action for the sub's guns was so significant.

[zenrat]

During WW1 & WW2 submarines did surface to engage lone merchant ships with their deck gun(s).  It led to the Q Ships.

IMO widespread use of gun armed subs would have led to more openly armed merchant ships.  A number of 5 inch guns manned by naval crews for example.
When the enemy is using torpedos then there is no point in arming every merchant ship because they have nothing to shoot at if the enemy is underwater.  However, if the enemy are surfacing to engage with guns then it is worth putting defensive armament on the merchant ships.  And if the lookouts are sharp and the gun crews ready then they are going to engage the attacking sub before it is itself ready to fire.

Hence why speed-into-action for the sub's guns was so significant.

But they are never going to be quicker than a well drilled gun crew and an alert lookout.

[Weaver]

During WW1 & WW2 submarines did surface to engage lone merchant ships with their deck gun(s).  It led to the Q Ships.

IMO widespread use of gun armed subs would have led to more openly armed merchant ships.  A number of 5 inch guns manned by naval crews for example.
When the enemy is using torpedos then there is no point in arming every merchant ship because they have nothing to shoot at if the enemy is underwater.  However, if the enemy are surfacing to engage with guns then it is worth putting defensive armament on the merchant ships.  And if the lookouts are sharp and the gun crews ready then they are going to engage the attacking sub before it is itself ready to fire.

Hence why speed-into-action for the sub's guns was so significant.

But they are never going to be quicker than a well drilled gun crew and an alert lookout.

Agreed, and that advantage to the ship would become greater as the war went on and the neccessity for good drill and sharp lookouts was drummed home by losses.

Having said that though, it's not that much of an advantage. X1 could open fire in under 90 seconds from the order to surface being given, and most of that was the time needed to get the boat above the surface, so the reaction time of the target ship crew wouldn't start until some way into that minute-and-a-half. In trials, she managed to get off eight salvoes, with five hits, within two minutes of the order to surface being given. Even if the merchant ship crew managed to generate enough return fire to drive X1 off within the first three minutes (which would be very good going), they'd still be left dealing with half-a-dozen 5.2" shell hits, which would have a pretty good chance of sinking her eventually, even if it took a while.

[RAFF-35]

During WW1 & WW2 submarines did surface to engage lone merchant ships with their deck gun(s).  It led to the Q Ships.

IMO widespread use of gun armed subs would have led to more openly armed merchant ships.  A number of 5 inch guns manned by naval crews for example.
When the enemy is using torpedos then there is no point in arming every merchant ship because they have nothing to shoot at if the enemy is underwater.  However, if the enemy are surfacing to engage with guns then it is worth putting defensive armament on the merchant ships.  And if the lookouts are sharp and the gun crews ready then they are going to engage the attacking sub before it is itself ready to fire.

Hence why speed-into-action for the sub's guns was so significant.

But they are never going to be quicker than a well drilled gun crew and an alert lookout.

Agreed, and that advantage to the ship would become greater as the war went on and the neccessity for good drill and sharp lookouts was drummed home by losses.

Having said that though, it's not that much of an advantage. X1 could open fire in under 90 seconds from the order to surface being given, and most of that was the time needed to get the boat above the surface, so the reaction time of the target ship crew wouldn't start until some way into that minute-and-a-half. In trials, she managed to get off eight salvoes, with five hits, within two minutes of the order to surface being given. Even if the merchant ship crew managed to generate enough return fire to drive X1 off within the first three minutes (which would be very good going), they'd still be left dealing with half-a-dozen 5.2" shell hits, which would have a pretty good chance of sinking her eventually, even if it took a while.

You make a very strong case for the X-1!
I'm now thinking of some sort of blend of X-1 and the Surcouf? Maybe if the Navy adopted the Surcouf after it came to England for repairs in 1940? They fitted it with some of the tech lifted from the X-1?

Or maybe staying closer to the X-1 idea as it seemed so promising in concept.

[Weaver]

You make a very strong case for the X-1!
I'm now thinking of some sort of blend of X-1 and the Surcouf? Maybe if the Navy adopted the Surcouf after it came to England for repairs in 1940? They fitted it with some of the tech lifted from the X-1?

Or maybe staying closer to the X-1 idea as it seemed so promising in concept.

Yeah, maybe, although the problems of adopting a foreign design into a navy without full technical information and spares backup shouldn't be underestimated. The biggest problem with Surcouf, as I understand it, wasn't anything technical though, it was the low expertise and questionable loyalties of her crew. To whiff your way around this, you could say that the sub fled to the UK with it's designer and ALL it's technical documentation on-board, and/or that British managed to find a more competent and trustworthy crew for her. Another issue would be the floatplane, since no spares existed for it in the UK, and it would need them sooner than the sub itself would.

As for X1, the biggest reasons for not buying more was a) the cap on total submarine tonnage in the 1930 London Naval Treaty and b) the cost of operating her. The easiest solution to that would be to just change the treaty. Maybe the RN lays down a couple more X1-type boats in 1928/29, and that allows them plus X1 to be "grandfathered" into the treaty by name, not counting towards the tonnage limit? If X1 is specifically allowed by name, that also gives a huge incentive to upgrade her to the Nth degree, which would actually reduce her running costs, which had been driven up by her unreliability as much as anything else.

[jcf]

The X-1 gun system operated well under pre-determined test scenarios how well it actually would have worked in combat service is an unknown. Drachinifel is overly sanguine about how well it would have done in reality, and "cut a bloody swath" is absurd as it relies on the X-1 having "more reliable engines".

As to the floatplane on Surcouf, they wouldn't bother about spares because they'd simply not use it. The notion of using a small aircraft to search for targets was ultimately a silly notion, the requirement to fit in a small hangar meant that the design was compromised for the role of scout. The performance was reduced across the board, most critically in regards to range and endurance. All in all it ended up as a pointless experiment.

[Weaver]

Submarine diesels made massive strides between when X1 was commissioned and WWII. Her original pushing-the-limits engines had 3000hp. By the time she was taken out of service, 5000hp engines of the same dimensions were available. I don't think it's unreasonable to suggest that she could have performed as intended with an engine swap. As to the effectiveness of her guns in action, well we don't ultimately know because they didn't see action, but then you can say that about any weapon system that never saw actual combat.

[Captain Canada]

I really like the look of those.

[seadude]

Any time I think of submarines with big guns, I remember watching a movie a friend let me borrow called "Lorelei: The Witch of the Pacific Ocean".
https://en.wikipedia.org/wiki/Lorelei:_The_Witch_of_the_Pacific_Ocean
Pics of the sub are below.

[seadude]

More pics of the Lorelei sub below:

[Weaver]

More pics of the Lorelei sub below:

That's pretty much Surcouf, but with the aircraft replaced by a mini-sub. Not a half-bad idea actually.

[PR19_Kit]

That's pretty much Surcouf, but with the aircraft replaced by a mini-sub. Not a half-bad idea actually.

Just what I was thinking too. Does it say anywhere what the model was built from?

[NARSES2]

That's a good looking submarine and an interesting film.

Must admit that "display" area is  intersting as well. Not only the sub model, but the uniforms and the number of models and various other bits and bobs on the shelving behind.

[jcf]

That's pretty much Surcouf, but with the aircraft replaced by a mini-sub. Not a half-bad idea actually.

Just what I was thinking too. Does it say anywhere what the model was built from?

The big one is a filming miniature. I-507 is supposedly the sistership of Surcouf.
Pit-Road did a 1/350th resin kit/built up and Takara a 1/700th built up. The latter isn't too hard to find, the first has become a high dollar collectible. Not surprising as the film was released twenty years ago.