Sea Slug

[Tzoli]

Thank you!
So the final GW96 missile cruiser design with one twin launcher but two Type 901 could track two targets and guide theoretically 4 missiles yes?

 

[SeaslugMk2]

Thank you!
So the final GW96 missile cruiser design with one twin launcher but two Type 901 could track two targets and guide theoretically 4 missiles yes?

Yes, but you'd have the issue that missiles could work with either Type 901 but not both; you could change components in the guidance receiver to allow it to work with the 'other' 901 but that takes time, and it is one missile at a time.

SRJ.

 

[Hood]

Some time ago Chris Gibson sent me a photo of a Treasury minute from 1958 that contains a codename for the Type 901 radar system, referring to the radar system as 'Project Jelly'.
From reading the minute, it seems to refer to Type 901 specifically.

I have never come across this codename before in any published sources. Was this a temporary codename assigned by the Admiralty? It certainly doesn't fit the MoS rainbow system.

 

[zen]

Hmmm...
Project Jelly
I like that!!

 

[zen]

Amazing that one can read a chapter peruse the margin note and still miss things. Only to catch up later.
Seaslug MkI was originally refered to as a test vehicle for the guidance system in 1945.
During this early phase the intended system was to launch vertically.
In '47 the pressing need drove to have prototype ready for service by '57.

A later note if the missile magazine and handling system was thst devised for the abortive Cruisers.
The Destroyer design group wanted the vertical arrangement albeit horizontal storage. But no resources for a separate magazine snd handling system....

 

[pathology_doc]

The system could cope with two missiles in the beam (by designating them 'left' and 'right') so that they could be given individual 'arm' and 'detonate' commands; the Mk2 also had the dive/glide command. Extra missiles in the beam would react to commands to earlier missiles so no, only two at a time. The salvo separation was six seconds, and the computer only required a couple of seconds between salvoes -a reset time between 'end of engagement' and another salvo.

When I played the Cold War simulator game Harpoon way back in the day, I was once faced with a South American County as my enemy. I fired four Exocets at it and it sent out what seemed like an endless stream of Sea Slugs that shot them all down. I was highly annoyed, because I figured there was no way a real County should be able to do that and it looks like I was right.

 

[deejay]

I can't find any post that asks the question about UK joining with France to develop Masurca. I would also like to know how Sea Slug would compare to Masurca, and how a County would compare to a Suffren? Given the the strength of the Fleet Air Arm during 1962-66 I wonder if the Counties were built too early and 8 UK-Suffrens would have been better built at 2 per year from 1967 to 1970?

 

[Dilandu]

I would also like to know how Sea Slug would compare to Masurca,

Well, Masurca was clearly more advanced. It was essentially a French analogue to RIM-2 Terrier, and it have both beam-riding and semi-active homing modes. It have more range than Seaslug, better guidance (at least in the homing version), and faster loading from horizontal drums. Still required finning, though.

 

[pathology_doc]

Well, Masurca was clearly more advanced. It was essentially a French analogue to RIM-2 Terrier, and it have both beam-riding and semi-active homing modes.

I recall reading somewhere that the SARH version was introduced after the Americans gave some input and technical assistance, after which it pretty much becomes Monsieur Terrier.

Seaslug fans will point to their missile having a more exacting definition of what constitutes a kill, but I'm not sure it was ever fired in anger against an aircraft - and if so, in numbers large enough to draw reasonable conclusions (I know at least one was fired as a land-attack missile).

 

[Kiltonge]

The 'radial bands' are the spoiler rings; they are there to provide drag when the boost motors are released so by the time they have rotated they are behind the missile.

Bosster bands seen clearly on the Sea Slug in the Museum of Naval Firepower, Gosport.

 

[pathology_doc]

Bosster bands seen clearly on the Sea Slug in the Museum of Naval Firepower, Gosport.

"Ribbed for her booster-dumping pleasure."

 

[Scott Kenny]

Pardon me, binged the whole thread.

That seems like a false equivalence - Seadart seems more Talos than Standard.

Compare the sizes. Seadart (~1200lb) is essentially a ramjet powered SM2-MR (~1500lb), maybe with a bit more range but not as much as SM2-ER.

Also should be noted that Terrier was essentially the accidental byproduct of "Bumblebee" program) It could pretty easy never been born, and gun-launched Zeus/Arrow guided shell would took its place)

That really would have been interesting in terms of how modern ships would look...

At the risk of repeating myself, the comparison between Seaslug1 and Terrier is pretty much even, perhaps with Seaslug being a shade better.
The question I want to resolve is the comparison in the 70s between Seaslug 2, Masurca and Standard ER. At first sight, the advantage lies clearly with Standard ER, but ?
Similarly Seadart is competing not with Tartar but Standard MR on Perrys, Kidds etc

Masurca seems to be equivalent to Standard MR, so the -ERs are still winning in terms of range.

Both Standard and Masurca beat Seaslug 2 in terms of not having a minimum range due to being pure rockets instead of ramjets that need to be accelerated to working speed.

I was told in 1972 as an RAF CCF cadet at school when we went on Kent that Seaslug Mk1 performed better than Terrier or Tartar.
This was as we leaving Portsmouth and I had asked our escorting crewmember why a visiting Adams class destroyer had a neat looking launcher and the RN had all "this scaffolding" pointing to the Seaslug launcher.
As a little "crab" I was risking it. But we actually got to see the assmbly magazine. The RN looked after us very well.

When my sub did midshipman operations, we showed them all the cool stuff. I think they even got to see the engineroom, which is usually off limits to visitors. (Not that it's very exciting or interesting back there)

Sea Dart really was an evolution of Sea Slug albeit to a different specification because it was developed by the same engineering team at AWA (later HSD) Whitley/RAE/RARDE/RSRE/ASWE. They took all they had learned and yielded a far more compact/capable system. The loss to the industry was not following on from Sea Dart because once the team was disbanded, the deep learning, continuity, and basic development network ceases to exist.

Very much agreed here, the UKRN really needed to keep pushing Sea Dart. It could have made a nice SM2ER/SM6 equivalent, while Aster fills the SM2MR role.

A success was defined as the fuze triggering (or command detonation signal received) at the right time for the warhead to inflict sufficient damage to cause the target to break up within 15 seconds -the F(15) definition. The US had a series of softer effects; ie forced to abort the attack, down to suffering damage on landing but these were regarded as irrelevant by UK missile development teams.
Expected targets would have been trans-sonic bombers of the fifties and sixties for Mk1, and attack aircraft and missiles of the sixties and seventies for Mk2.
These were the practice shoots by the ships once 'in service' and are not part of the development of the missile.
I hope to have some more data soon.

Combined response below:

The NATO standard was originally KH -Target will disintegrate immediately, K -Target will fall out of control within 15 seconds, A -Target will fall out of control within 5 minutes, B -Target will return to base, C -Target's attack will not be completed, and E -Target will be structurally damaged while landing. The USN/missile manufacturers would class all of these as a success (see ADM 1/28039 -TNA) while UK manufacturers would only consider KH and K as successes. UK/US arguments on this resulted in a new NATO standard; K(t) where t is the time taken in seconds for the target to disintegrate. Seaslug, Bloodhound, Firestreak etc., all had to meet K(15).

In terms of "preventing someone from putting a hole in your ship", everything above and including "target's attack will not be completed" is an effective shot.

If you're shooting at the missiles and not their launchers you probably need to go with the KH or K standards, though. K0 and K15 today.

 

[Yellow Palace]

Compare the sizes. Seadart (~1200lb) is essentially a ramjet powered SM2-MR (~1500lb), maybe with a bit more range but not as much as SM2-ER.

AIUI, Sea Dart basically managed to get SM-2MR performance out of SM-1MR technology level by using a ramjet, with the tradeoff of having an appreciable minimum range.

If you're shooting at the missiles and not their launchers you probably need to go with the KH or K standards, though. K0 and K15 today.

The Royal Navy never quite seemed to go for the idea of shooting the launching platform. Probably a self-licking ice cream cone of 'we don't have the ability, therefore we'll develop systems that don't need the ability, therefore we don't have the ability, therefore....'

 

[zen]

Interception of the attacking missile was judged a better assurance of defence and had been from late 40's. Experiences in WWII and postwar analysis. Whether it was German Anti-ship Missiles or Japanese Kamikazi attacks, the conclusion was the same.

Nothing beats stopping the weapon, launch aircraft can launch prior to their destruction even.

This led the RN down the path of Popsy, Mopsy, Orange Nell, the early NMBR.11 to SIGS and ultimately Sea Wolf to Sea Ceptor.

But funds and hopes for Mopsy were dashed when the USN went for Tartar using G-band guidance.
Orange Nell never proceeded and NMBR.11 became SIGS......but to be fair Sea Dart retained a decent Anti-missile-missile capability. Which it actually proved during the Gulf War.

Seaslug wasn't this. It was developed to use against attacking aircraft. But this hit the problem that as stand off Anti-ship missile launch ranges increased the next development step for Seaslug would require a move to SARH and increasing use of autopilot and Command Guidance as on Blue Envoy to Bloodhound.
This spiralled away into NIGS, the British version of USN's Typhon. With predictable results.

 

[Dilandu]

Nothing beats stopping the weapon, launch aircraft can launch prior to their destruction even.

Well, shooting down aircraft is technically much simpler. And if it could carry several missiles, then you would destroy all together, instead of going after each individual bird.

Problem is, improving flight range of air-launched missiles (so they could maintain standoff range) is simpler than improving range of surface-to-air missiles. Especially shipboard ones, that must fit into magazines & therefore are strictly limited in size.

 

[Dilandu]

Seaslug wasn't this. It was developed to use against attacking aircraft. But this hit the problem that as stand off Anti-ship missile launch ranges increased the next development step for Seaslug would require a move to SARH and increasing use of autopilot and Command Guidance as on Blue Envoy to Bloodhound.

I wonder, could basic Seaslug be redesigned to use Talos semi-active homing system? The early concept of homing Terrier missile suggested that Talos-like interferometer seeker could be used (Terrier and Talos shared a lot of guidance tech anyway). But what about Seaslug?

 

[zen]

I wonder, could basic Seaslug be redesigned to use Talos semi-active homing system? The early concept of homing Terrier missile suggested that Talos-like interferometer seeker could be used (Terrier and Talos shared a lot of guidance tech anyway). But what about Seaslug?

This is essentially my contention, that the polyrod interferometer guidance system, just as used on Talos, began life in the UK as something that could be applied to Seaslug.
With the avionics bay on Seaslug at the rear, which helped with Beam Riding Guidance, it's relatively easy to run coaxial cable along the sides of the missile to that bay from receiving aerials around the nose. There being not much room in the nose for a conventional SARH dish.

This would ultimately be applied on Sea Dart. Polyrod interferometer guidance, that is.

But of course, for longer ranges a sort of Command Guidance and autopilot is needed. Which is why Seaslug MkIII spiralled away into NIGS.
This bogged down in complex radars and computer systems, lots of theory and precious little outcome.
Because existing Type 901 guidance system was Beam Rider only a new navalised set was needed.

All this new stuff lured people away from incremental change and improvement to revolutionary change......and failure.

 

[Dilandu]

But of course, for longer ranges a sort of Command Guidance and autopilot is needed.

Well, yes, but for Terrier-comparable ranges the semi-active homing as sole method of guidance would suffice, at least for 1950s.

 

[xena]

I thought Sea Wolf was responsible for intercepting guided missiles, so Sea Slug and Sea Dart were free against airplanes.

 

[Scott Kenny]

Interception of the attacking missile was judged a better assurance of defence and had been from late 40's. Experiences in WWII and postwar analysis. Whether it was German Anti-ship Missiles or Japanese Kamikazi attacks, the conclusion was the same.

Nothing beats stopping the weapon, launch aircraft can launch prior to their destruction even.

Which is odd, based on how quickly the USN went to "shoot the archer, not the arrows" with Missileer/F-111B/Tomcat

 

[Scott Kenny]

The Royal Navy never quite seemed to go for the idea of shooting the launching platform. Probably a self-licking ice cream cone of 'we don't have the ability, therefore we'll develop systems that don't need the ability, therefore we don't have the ability, therefore....'

As opposed to the US saying "We really want X capability"... Is it as frustrating to the Brits in the house as it is to me how much stuff yall never developed because you didn't have the capability and nobody apparently wished that you did?!?

 

[Dilandu]

Which is odd, based on how quickly the USN went to "shoot the archer, not the arrows" with Missileer/F-111B/Tomcat

Royal Navy was much more limited in both money and engineering capabilities. The medium-range air defense was an absoulte priority, since without it fleet would be absolutely defenseless.

 

[zen]

Which is odd, based on how quickly the USN went to "shoot the archer, not the arrows" with Missileer/F-111B/Tomcat

That's later in the late 50's to early 60’s.
Seaslug is late 40's to early 50's
Orange Nell is mid 50's.
It's Blue Envoy and NIGS that offer effective interception of stand-off attackers.....much like Typhon.

And let's not forget the substantial failure of Mauler and Sea Mauler.

 

[Dilandu]

And let's not forget the substantial failure of Mauler and Sea Mauler.

By the way - were there any ideas about making a naval HAWK?