Seaslug-equipped Leander

Dilandu

Dilandu

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As far as I know, in mid-1950s the planned role of Seaslug SAM was changed (not the first time), and shifted from the carrier protection to surface ship groups and convoys defense. It was assumed that carrier groups would be sufficiently protected by carrier own fighters, and SAM's are more needed for convoy escorts and small tactical units, that could not have carriers for protection. Essentially, the only Seaslug-carrying ships ever build were County-class destroyers/cruisers, which weren't exactly numerous enough for convoy protection role.

My question is - would it be possible to create a Seaslug-equipped air defense escort on the basic of Leander-class (Type 12I) hull and machinery?

1764144518527.jpeg
Such radical reconsturction, of course, would include removal of nearly all original Leander capabilities: 4.5-inch turret, Limbo mortar, helicopter hangar. Still, for dedicated air defense escort - designed to provide SAM protection for merchant convoys and amphibious assault groups - it won't be a critical loss.

So the idea is:

* Position the Seaslug launcher around the place of former Limbo mortar well;
* Use the corresponding space on 2nd deck to fit a missile magazine for at least 12 assembled missiles (side by side, two layer configuration) and crated storage for some diassembled
* Move the crew facilities (sick bay, mess, dining halls) into superstructure in place of former helicopter hangar
* Install Type 901 radar & corresponding equipment over it
* Add a Type 278 height-finder to work with available Type 992Q to provide targeting data for Type 901
* In place of former 4.5-inch turret, install a forward radar house with Seaslug fire control room inside

1764146690639.png
Something like that, presumably?
 
Would be interesting if some 4 missiles were the Anti-ship option....
 
Considering how hard it was to fit the smaller Mark 13 Tartar I suspect this is not possible.
 
SeaslugMk2 said:
It was. There were very few fired against surface targets, but the hit on the target ship HMS Venus was spectacular!
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I bet it was - the Seaslug hitting surface target was basically a good analogue of battleship's shell fired almost point-blank!

P.S. By the way, wondered for quite a while - if General Belgrano avoided British torpedoes and started to close with RN groups, would Antrim and Glamorgan be able to handle Argentinean cruiser in within-the-horizon battle? Seaslugs vs 6-inch guns, would be an interesting challenge.
 
I vaguely recall reference to Seaslug being used in a land bombardment role during the Falklands Campaign.
A quick search turned up a Wiki (I know, sorry) reference:
Quote:
‘The first combat use in a surface-to-surface role occurred on 26 May, when Glamorgan fired a Seaslug Mk 2 at the radar site near Port Stanley Airport, claiming the destruction of a radar installation and several helicopters.Glamorganconducted further bombardments using Seaslug missiles against the runway on 28 and 30 May.A total of six Seaslug Mk 2 missiles were launched during the campaign: four operational firings and two jettisoned for safety after Glamorgan was struck by a land-launched Exocet missile on 12 June.Also during 1982, the Mk 2 variant was used as a target drone in Sea Dart missile trials, although reliability issues affected both systems’.
 
Dilandu said:
I bet it was - the Seaslug hitting surface target was basically a good analogue of battleship's shell fired almost point-blank!

P.S. By the way, wondered for quite a while - if General Belgrano avoided British torpedoes and started to close with RN groups, would Antrim and Glamorgan be able to handle Argentinean cruiser in within-the-horizon battle? Seaslugs vs 6-inch guns, would be an interesting challenge.
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Antrim and Glamorgan were both Exocet ships, so they would have fired their SSMs first.
 
pathology_doc said:
Antrim and Glamorgan were both Exocet ships, so they would have fired their SSMs first.
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Yep, as well as two Argentinean destroyers following the Belgrano. Problem was, the MM38 on both sides have only about 40 km range - not exactly grean standoff range - and it's not clear, would they be able to knock Belgrano out from safe distance. She was armored, after all, and while apparently lacked ECM's, her 5-inch guns were provided with chaffs.
 
Re-checking reports regarding, as it is so colloquially termed, the Falklands ‘conflict’…
I can find no record of any of the Royal Navy ships firing Exocet missiles….
 
Pirate Pete said:
I can find no record of any of the Royal Navy ships firing Exocet missiles….
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Well, they mostly did not have any suitable targets nearby. After the Belgrano sinking, the rest of Argentinean Navy (still pretty combat-capable, with one carrier, two modern air defense destroyer, and a bunch of older destroyers and corvettes fitted with anti-ship missiles) retreated to harbors.
 
Dilandu said:
I bet it was - the Seaslug hitting surface target was basically a good analogue of battleship's shell fired almost point-blank!

P.S. By the way, wondered for quite a while - if General Belgrano avoided British torpedoes and started to close with RN groups, would Antrim and Glamorgan be able to handle Argentinean cruiser in within-the-horizon battle? Seaslugs vs 6-inch guns, would be an interesting challenge.
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I don’t think that a Seaslug would do much damage to an armoured cruiser. The best that could be hoped for would be to render the radar/optical systems useless. Given a maximum range of 35k yards, they’d be used after firing off the Exocets; but I’d like to see a DLG firing off all its Seaslugs* at a target. A 25% hit rate in CASWTD** mode might give them 8 hits each.

*Both HMS London and HMS Glamorgan did that before paying off for the final time.

**It’s pronounced ‘custard’, just in case you wanted to know.

SRJ
 
SeaslugMk2 said:
I don’t think that a Seaslug would do much damage to an armoured cruiser.
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Well, Seaslug at 30+ km would impact at about 1,5-2 Mach, if I recall correctly. I.e. about the same velocity as battleship's shell fired at close range. And Seaslug Mk.II, even with completely burned-out sustainer would still be very heavy missile, more than 700 kg of mass.

Impact of such supersonic mass against cruiser armored deck (51 mm uniform) or belt (51-127 mm, depending of exact location) would likely shatter the armor plate; while complete penetration of the belt might not be achieved, there would clearly be a lot of fragments shot inside. Direct hit into turret would likely knock it out of commission, even if face armor (165 mm) would not be penetrated.
 
At what range a Sea Slug could hit a surface target? Nothing beyond the visual horizon?
 
As shown in the drawing, it would not work. Seaslug needed two magazines. One stored the Seaslug without fins. Then came a room where fins were mounted and maintenance was carried out, followed by a third room where assembled, ready-to-use Seaslug were stored right behind the launcher. Overall, it was a complex system that took up a lot of space.
 
Martes said:
At what range a Sea Slug could hit a surface target? Nothing beyond the visual horizon?
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Yep, strictly within the horizon missile. For surface shots, the Type 901 radar was slaved to Type 903 gun control radar; the Type 903 tracked the target, and Type 901 moved its beam accordingly in azimuth, with elevation calculated by range data. The missile was fired up by high elevation, then Type 901 depressed the beam at calculated rate, so the missile would descend toward the target. When the mimimal beam elevation was achieved (about 0.5 degrees), the radar sent "glide" command to missile - after recieving this command, the missile followed the beam in azimuth only, maintaining its previous descend angle.

xena said:
As shown in the drawing, it would not work. Seaslug needed two magazines. One stored the Seaslug without fins. Then came a room where fins were mounted and maintenance was carried out, followed by a third room where assembled, ready-to-use Seaslug were stored right behind the launcher. Overall, it was a complex system that took up a lot of space.
Click to expand...
Erm... No. The diassembled storage was not required. It was implemented on HMS London first and second batch of County-class as an attempt to increase magazine capacity. But it was not required for missile system to function; three first County-class have no disassembled storage.
 
Dilandu said:
As far as I know, in mid-1950s the planned role of Seaslug SAM was changed (not the first time), and shifted from the carrier protection to surface ship groups and convoys defense. It was assumed that carrier groups would be sufficiently protected by carrier own fighters, and SAM's are more needed for convoy escorts and small tactical units, that could not have carriers for protection. Essentially, the only Seaslug-carrying ships ever build were County-class destroyers/cruisers, which weren't exactly numerous enough for convoy protection role.

My question is - would it be possible to create a Seaslug-equipped air defense escort on the basic of Leander-class (Type 12I) hull and machinery?

View attachment 793161
Such radical reconsturction, of course, would include removal of nearly all original Leander capabilities: 4.5-inch turret, Limbo mortar, helicopter hangar. Still, for dedicated air defense escort - designed to provide SAM protection for merchant convoys and amphibious assault groups - it won't be a critical loss.

So the idea is:

* Position the Seaslug launcher around the place of former Limbo mortar well;
* Use the corresponding space on 2nd deck to fit a missile magazine for at least 12 assembled missiles (side by side, two layer configuration) and crated storage for some diassembled
* Move the crew facilities (sick bay, mess, dining halls) into superstructure in place of former helicopter hangar
* Install Type 901 radar & corresponding equipment over it
* Add a Type 278 height-finder to work with available Type 992Q to provide targeting data for Type 901
* In place of former 4.5-inch turret, install a forward radar house with Seaslug fire control room inside

View attachment 793166
Something like that, presumably?
Click to expand...
It's the surface equivalent of a submarine.

Only one weapons system.

I don't think that's a design the Admiralty would approve of.

The base hull is just too small.
 
Dilandu said:
Hm, an argument! Maybe put the Seaslug on bow, then?
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There's next to no volume in the Type 12 bow; Seaslug would extend so far aft that it would start competing with unimportant things like 'engines' and 'the bridge'.
 
I like the premise of a Seaslug armed Leander, but wouldn't just be better to build more County class Destroyers or the proposed Escort Cruiser for convoy Area Air Defence. Plus they are both able to operate Wessex helicopters.
 
Yellow Palace said:
There's next to no volume in the Type 12 bow; Seaslug would extend so far aft that it would start competing with unimportant things like 'engines' and 'the bridge'.
Click to expand...
I wasn't talking about incorporating County-style magazine.


Caryina2642 said:
I like the premise of a Seaslug armed Leander, but wouldn't just be better to build more County class Destroyers or the proposed Escort Cruiser for convoy Area Air Defence. Plus they are both able to operate Wessex helicopters.
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Well, yes, but they also far more expensive...
 
Dilandu said:
Well, yes, but they also far more expensive...
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True, but how much more expensive would this redesign make the Leander to build? If it makes it nearly as expensive as the County Class, it would make more sense to build the County Class
 
Dilandu said:
Hm, an argument! Maybe put the Seaslug on bow, then?
Click to expand...
No, with an AA system it doesn't hugely matter where the missiles are. Aft mounted missile launchers are quite viable. See also the Boston-class CGs.

I was meaning that it was a surface ship with only one weapons system instead of at least 2 like the various US frigates.
 
This would allow be easier if Seaslug had been that bit smaller.
 
Dilandu said:
I wasn't talking about incorporating County-style magazine.
Click to expand...
I know: the bow form is so fine that the 4.5-inch gun position is as far forward as the launcher could go, which means that the magazine (such as it is) has to go in the forward superstructure, wiping out the officers' accommodation and the operations room.

Incidentally, on the missiles-aft version you'd be amazed at how much resistance the Royal Navy would have to putting junior ratings on the same deck as officers. They might start thinking they were social equals!
zen said:
This would allow be easier if Seaslug had been that bit smaller.
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And even harder if Seaslug was an inline-boost weapon.
 
Yellow Palace said:
I know: the bow form is so fine that the 4.5-inch gun position is as far forward as the launcher could go, which means that the magazine (such as it is) has to go in the forward superstructure, wiping out the officers' accommodation and the operations room.
Click to expand...
Erm, no. Launcher could be moved more forward, at least in theory. It's recoiless, so it doesn't need to be as heavily supported as gun mount.

So at least in theory we could move launcher further forward, placing elevator/check room over the former gun mount, and magazine below it.
 
Scott Kenny said:
No, with an AA system it doesn't hugely matter where the missiles are. Aft mounted missile launchers are quite viable. See also the Boston-class CGs.

I was meaning that it was a surface ship with only one weapons system instead of at least 2 like the various US frigates.
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I know, I was trying to save helicopter capability, so it could have 2 weapon system.

Alternatively, we could try to save the gun mount, but IRRC, on all Leander refits it was sacrificed first.
 
Caryina2642 said:
True, but how much more expensive would this redesign make the Leander to build? If it makes it nearly as expensive as the County Class, it would make more sense to build the County Class
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Or follow the example of Girdle ness, and build Seaslug-capable escort ships on merchant hulls...
 
There were escort ship designs in the GW series. Some with a low as 12 rounds of Seaslug.

It was the effort to add other capabilities beyond 40mm Bofors that was a problem.
 
I've been doodling options for smaller seaslug on a modified Leander in shipbucket.
Having perused online deck plans I think the rear options be best, since the system would either site in place of the helicopter pad and hanger for a tube system (similar to a County) or replace the Limbo mortars and their ammunition storage in a vertical storage system (smaller seaslug being 15ft long this is viable and only 2 decks in height).

The problem with replacing the forward twin 4.5" is below the turret ring is accommodation spaces which would need relocation elsewhere.
 
zen said:
I've been doodling options for smaller seaslug on a modified Leander in shipbucket.
Having perused online deck plans I think the rear options be best, since the system would either site in place of the helicopter pad and hanger for a tube system (similar to a County) or replace the Limbo mortars and their ammunition storage in a vertical storage system (smaller seaslug being 15ft long this is viable and only 2 decks in height).
Click to expand...
Hmmmm. But would smaller Seaslug worth the efforts? Wouldn't its range be too limited?
 
Dilandu said:
Hmmmm. But would smaller Seaslug worth the efforts? Wouldn't its range be too limited?
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More this was the hoped for outcome. For mkI 15nm range I don't think there's likely any real difference.
Maybe a delay on mkII 30nm range?
 
zen said:
The problem with replacing the forward twin 4.5" is below the turret ring is accommodation spaces which would need relocation elsewhere.
Click to expand...
Theoretically, we could probably use something like pop-up launcher, raising from former mortar well on hydraulic lift. After all, it's not very likely that the frigate would need to use both helicopter pad AND missile system at once. Then we could use space beneath the helicopter hangar for missile storage.

Another idea - to cut the stern just behind the helipad end, thus creating enough space for launcher to work (probably with raising bulwarks to protect it in heavy seas).
1765191848575.png
 

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