Submarine Cruisers/ Monitors

[RAFF-35]

So I was thinking about how cool it would be for a submarine to have turrets fitted to it. Then I did some digging and found out that it was actually quite trendy in the inter-war period due to the Washington Naval Treaty not being too strict on the use of submarines.
I know that there was the M-Class that entered service at the end of WW1 so it never really achieved much. Then there was the super cool sounding HMS X-1. It was kept secret as it was designed to hunt merchant ships which was a bit frowned upon.
The main issue with the X-1 was its unreliability, it was eventually scrapped in 1936.
My question is, would the X-1 have been useful or effective in WW2 at all? Whether it was refitted with more reliable systems, whether there were more that had been built or whether the weapons were changed??

(Photos pinched from Google)

[jcf]

The Surcouf is possibly, in many ways, the one that was the most completely thought out.
Surcouf

[jcf]

The USN did some studies, these are from 1920, from the 1911-1925 Spring Styles Book:

[jcf]

As to the question of usefullness, not really. They were large, slow to submerge,
would require a very specific set of circumstances to be effective and realistically
wouldn't have much in the way of targets in WWII. The Nazis didn't have much
going in terms of global maritime commerce, Japan's shipping was pretty much
relegated to the Northern/Western/Southwestern Pacific, the China Sea and some
in the Eastern Indian Ocean. The long range US Fleet boats pretty much had it
covered. They were designed to primarily carry out long, independent missions in
the Pacific and thus were big, fast, reliable and reasonably comfortable.

[Charlie_c67]

So I was thinking about how cool it would be for a submarine to have turrets fitted to it. Then I did some digging and found out that it was actually quite trendy in the inter-war period due to the Washington Naval Treaty not being too strict on the use of submarines.
I know that there was the M-Class that entered service at the end of WW1 so it never really achieved much. Then there was the super cool sounding HMS X-1. It was kept secret as it was designed to hunt merchant ships which was a bit frowned upon.
The main issue with the X-1 was its unreliability, it was eventually scrapped in 1936.
My question is, would the X-1 have been useful or effective in WW2 at all? Whether it was refitted with more reliable systems, whether there were more that had been built or whether the weapons were changed??

(Photos pinched from Google)

This being Whifworld, go for it! Do the model, come up with a backstory that you like and enjoy doing it 

[Andrew Gorman]

Here's an interesting article from 1915 about the submarine battleship!
https://www.reddit.com/r/WarshipPorn/comments/k5vfoi/3274x4299_the_submarine_battleship_richmond/#lightbox

[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.

Drachinifel did a good deep-dive (pun intended) video about the X1:

[kerick]

The submarine battleship seemed to be right up there with the land battleship. A popular idea but really not very doable. I can't imagine how big a sub would have to be to pack similar firepower. I'd worry about it being too top heavy from all the gun barrels and turrets.

Of course to sink a merchant ship you wouldn't need more than five inch guns and only a couple of those I would imagine. Turrets would seem unnecessary. It's beginning to sound like some of the subs that had deck guns of several inch size. Didn't some subs sink a few merchant ships with deck guns early in the war?

[NARSES2]

Of course to sink a merchant ship you wouldn't need more than five inch guns and only a couple of those I would imagine. Turrets would seem unnecessary. It's beginning to sound like some of the subs that had deck guns of several inch size. Didn't some subs sink a few merchant ships with deck guns early in the war?

Here's a neat little piece about U-Boat deck gun usage during WWII

https://uboat.net/technical/guns.htm

[Weaver]

The submarine battleship seemed to be right up there with the land battleship. A popular idea but really not very doable. I can't imagine how big a sub would have to be to pack similar firepower. I'd worry about it being too top heavy from all the gun barrels and turrets.

Of course to sink a merchant ship you wouldn't need more than five inch guns and only a couple of those I would imagine. Turrets would seem unnecessary. It's beginning to sound like some of the subs that had deck guns of several inch size. Didn't some subs sink a few merchant ships with deck guns early in the war?

One advantage of the fully powered gun turrets on X1 was that they speeded up the critical time between surfacing and opening fire. The submarine's rangefinder was on a periscope and connected to a fire control computer, so it could work up a firing solution while still submerged. When the submarine surfaced, the guns could then be slewed onto target in both azimuth and elevation at the touch of a button, before any gun crew had reached the mountings.

[RAFF-35]

The submarine battleship seemed to be right up there with the land battleship. A popular idea but really not very doable. I can't imagine how big a sub would have to be to pack similar firepower. I'd worry about it being too top heavy from all the gun barrels and turrets.

Of course to sink a merchant ship you wouldn't need more than five inch guns and only a couple of those I would imagine. Turrets would seem unnecessary. It's beginning to sound like some of the subs that had deck guns of several inch size. Didn't some subs sink a few merchant ships with deck guns early in the war?

One advantage of the fully powered gun turrets on X1 was that they speeded up the critical time between surfacing and opening fire. The submarine's rangefinder was on a periscope and connected to a fire control computer, so it could work up a firing solution while still submerged. When the submarine surfaced, the guns could then be slewed onto target in both azimuth and elevation at the touch of a button, before any gun crew had reached the mountings.

What an incredibly fantastic design! Especially considering when it was launched too!

[RAFF-35]

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?

[RAFF-35]

This being Whifworld, go for it! Do the model, come up with a backstory that you like and enjoy doing it 

Thanks Charlie! My issue is that I like to have a backstory set up before I can start building my model 😅 With this concept,  I haven't even decided on what nation or theatre it would be used in yet. Could even be German, Soviet or Japanese

[RAFF-35]

The Surcouf is possibly, in many ways, the one that was the most completely thought out.
Surcouf

I love the Surcouf! How do you think it would've fared had it successfully made it through the Panama Canal? Would it have been effective against Japanese merchant shipping?

[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.