Alternative Sea Slug launcher

[zen]

Such alternatives do exist in model form held. Photos of which are available at Barrow's archive.

So one ponders what if one of these twin arm launchers had been adopted instead....?

Certainly in real history the RN preferred the scaffolding arrangement which wrapped around the missile containing it securely.

But what if they had accepted one of these alternatives?

It would seem these alternatives are simpler externally and this may make them easier to maintain and lighter.
What they also offer is easier adaptations for alternative missiles.

And with options to adapt for tandem booster and missile, a change in weaponry is more affordable.

 

[Nick Sumner]

Any hints? I searched the Vickers Barrow photo archive with the keywords 'Sea Slug' and 'Sea slug launcher' but no joy.

 

[zen]

Discussion about Sea Slug.

https://www.secretprojects.co.uk/threads/sea-slug.31264/

Link to Barrow's archive and one of the launcher options.

The Dock Museum | Collections

collections.dockmuseum.org.uk

 

[zen]

If....if the decision is to use this sort of launcher, then it has implications not just for the range of missiles but the very missile it's originally intended for.
If Sea Slug rises this, it's fine don't need to carry it's weight.....so it could potentially be moved around inside the ship without cages as well and thus the missile handling gear would be different and potentially cheaper and lighter and more compact.
As well the fins could change shape or size through developments.

 

[uk 75]

Someone has asked this before, but I ask it here:
Why are the launchers and related radars on the RN's UK built SAM systems (Seaslug, Seadart and Seawolf) more space and weight intensive than US systemd? ( You could add ib the VLS on T45)

 

[zen]

Someone has asked this before, but I ask it here:
Why are the launchers and related radars on the RN's UK built SAM systems (Seaslug, Seadart and Seawolf) more space and weight intensive than US systemd? ( You could add ib the VLS on T45)

Is this really the thread to ask that?
Shouldn't you ask it in the missile section?

 

[Dilandu]

Why are the launchers and related radars on the RN's UK built SAM systems (Seaslug, Seadart and Seawolf) more space and weight intensive than US systemd? ( You could add ib the VLS on T45)

Er, in comparison to which American radars? "Talos" launchers and radars were extremely heavy.

 

[uk 75]

To take both points:
If you are looking at alternative Seaslug launcher options, the issue of space and weight intensiveness ought to be a factor.
As for Talos, this is a thread about Seaslug. So the Terrier launcher and radars are the analogue. Actually, both take up a fair amount of space and weight.
Given that you only have a single ended DLG requirement (guns forward) the launcher and hangar on a County wouldnt have been helped much by making it more like Terrier. The radar is a different matter, but that is dealt with elsewhere. The launcher, though bulky, seems to have been more than adequate for its launch rate and could have coped with a bulkier weapon (NIGS backfit)

 

[zen]

NIGS as it became wasn't fitting in the Sea Slug launcher. If it had stayed as a MkIII Sea Slug that might have been different.

What an Alternative Launcher opens up is greater flexibility and less constraints on the missile. Which could extend to the ship's missile handling system.

 

[uk 75]

Farragut-class destroyer (1958) - Wikipedia

en.m.wikipedia.org

What was possible with a single ended Terrier system. Ten ships were built before a single County was operational. They stayed in service for the whole of the Cold War. The RN could really have used a ship like this
If Seaslug could have been upgraded like Terrier to Standard ER performance perhaps the Countys might have lasted longer. On the other hand manpower constraints might have still made it better to replace them with T42s

 

[zen]

However it is progressively cheaper to build per ship after the lead of class. The more Countys built, the cheaper they get.

So there is an incentive to start incrementally improving them and among those options those that reduce personnel numbers would rank highly.

A move to COGAG for instance would potentially cut numbers by 25 or more.

A move to fully transistorised systems reduces the failure rate and replacement rate of components drastically. Cutting maintenance.

So shifts from Type 901, to Type 909 radars for instance. As could a move from CDS to ADAWS.
Automation of main guns.
that C-band ASWE radar replacing the Type 965....

 

[Dilandu]

If Seaslug could have been upgraded like Terrier to Standard ER performance perhaps the Countys might have lasted longer. On the other hand manpower constraints might have still made it better to replace them with T42s

Well, the main problem (besides the lack of money) was the beam-riding guidance system. If it could be replaced with some kind of homing seeker - the interferometer one, for example, like of Sea Dart - it could improve the performance of missile (especially against low-flying target).

 

[zen]

If Seaslug could have been upgraded like Terrier to Standard ER performance perhaps the Countys might have lasted longer. On the other hand manpower constraints might have still made it better to replace them with T42s

Well, the main problem (besides the lack of money) was the beam-riding guidance system. If it could be replaced with some kind of homing seeker - the interferometer one, for example, like of Sea Dart - it could improve the performance of missile (especially against low-flying target).

So mkI beam rider got out to 15nm.
MkII beam riding got out to 30nm
This using the Type 901 guidance set.

A switch to SARH polyrod using a Type 909 gets upto 50nm, but the potential is upto 80nm that we know of.

 

[Dilandu]

A switch to SARH polyrod using a Type 909 gets upto 50nm, but the potential is upto 80nm that we know of.

The problem is the widening the beam. If the beam is too narrow, it would be very hard for the missile to stay in it on initial flight pass. If it too wide, the hit probability decreased fast. As far as I knew, for Talos hits without SARH were considered possible only with nuclear warhead.

 

[pathology_doc]

Farragut-class destroyer (1958) - Wikipedia

en.m.wikipedia.org

What was possible with a single ended Terrier system. Ten ships were built before a single County was operational. They stayed in service for the whole of the Cold War. The RN could really have used a ship like this
If Seaslug could have been upgraded like Terrier to Standard ER performance perhaps the Countys might have lasted longer. On the other hand manpower constraints might have still made it better to replace them with T42s

Britain was on the bones of its a***e financially and did not have the capacity to build that many ships that quickly. In addition, Sea Slug was all it had; there was no single-stage alternative, no Tartar equivalent. Improvements to Terrier were ultimately driven by Tartar, which was SARH from the start and quickly surpassed the original Terrier BW-0 that went into Boston and Canberra (and almost into Wichita).

You can point to the Farragut/Coontz class all you like, but note that the Farraguts don't have helicopter facilities. Why not? Because they are designed to operate in the context of a carrier air group that supplies the rotary-wing ASW, not to be a jack of all trades that might have to do convoy escort duty without the benefit of a supporting CV. The only British area-defence guided missile ship I can think of that didn't have a helicopter was Bristol, and that's because she was explicitly designed as a close escort for CVA-01 (we won't count the Invincibles, which had a Sea Dart system as-built and also an air group; they were a different beast, and even they lost their missiles later in favour of better air facilities).

 

[Dilandu]

You can point to the Farragut/Coontz class all you like, but note that the Farraguts don't have helicopter facilities. Why not? Because they are designed to operate in the context of a carrier air group that supplies the rotary-wing ASW, not to be a jack of all trades that might have to do convoy escort duty without the benefit of a supporting CV.

Must point out, that the other closest analogue - Project 61 large anti-submarine vessels (Kashin-class), also did not have hangar, only a helicopter pad.

 

[zen]

A switch to SARH polyrod using a Type 909 gets upto 50nm, but the potential is upto 80nm that we know of.

The problem is the widening the beam. If the beam is too narrow, it would be very hard for the missile to stay in it on initial flight pass. If it too wide, the hit probability decreased fast. As far as I knew, for Talos hits without SARH were considered possible only with nuclear warhead.

I too thought that, but we have live fire exercise results to look at and Sea Slug comes out rather well and at times impressively so.
Impact (not proximity) with a supersonic high altitude target out at 28nm.
This is almost certainly a result of the complex Type 901 set.
While the beam widens yes, it actually narrows again in intensity out near it's maximum distance, in cross section like an elongated lozenge or orange pip.

 

[Dilandu]

I too thought that, but we have live fire exercise results to look at and Sea Slug comes out rather well and at times impressively so.
Impact (not proximity) with a supersonic high altitude target out at 28nm.

Yes, it was quite impressive missile for her time. But my main concern is that trying to lengthen her range without switching to some other guidance system would not be practical - there would be far too many new problems to dealt with.

 

[uk 75]

The UK as I commented somewhere else actually does very well compared to other navies and taking into account its resource and budgetary limits.
The Countys were elegant ships and could fill various roles as mentioned above. Seaslug as we have learnt from its namesake was pretty good at what it was designed to do.
I agree the RN wouldnt have traded them for Farraguts. But as we are looking at alternate Seaslug fits they are the closest we have.

 

[zen]

I too thought that, but we have live fire exercise results to look at and Sea Slug comes out rather well and at times impressively so.
Impact (not proximity) with a supersonic high altitude target out at 28nm.

Yes, it was quite impressive missile for her time. But my main concern is that trying to lengthen her range without switching to some other guidance system would not be practical - there would be far too many new problems to dealt with.

I'm saying that a change to SARH is the obvious way forward and removes the need for the 901. SARH using polyrod interferometer guidance is potentially intigratable into a Sea Slug missile. Easier than a dish based system due to the internal layout of the missile.
Coupled with the 909 it can certainly extend range. Coupled with Command Guidance or inertial guidance or TVM or even beam riding it can reach out much further. Double or more the range compared to Sea Slug mkII.

But the restrictions on the missile's aerodynamics are ultimately due to the launcher configuration. To fully exploit improvements in guidance rocket motor technology, refine the aerodynamics (nose and fins) then the fins cannot be used to support the missile in storage, handling and the launcher.

Remove that constraint(s) and a mkIII with SARH and much greater range is achievable.
Move to SARH and the bottleneck of low rate production of expensive 901 sets can be removed.

This implies that a change of launcher and internal handling gear on the ship, should result in such a mkIII, avoiding the black hole of NIGS and if anything sucking funds away from SIGS becoming a medium range missile.
If anything the launcher so scaled is applicable for Orange Nell as well.

 

[Dilandu]

I'm saying that a change to SARH is the obvious way forward and removes the need for the 901. SARH using polyrod interferometer guidance is potentially intigratable into a Sea Slug missile. Easier than a dish based system due to the internal layout of the missile.

Yeah, it would be next thing to impossible to put a radar dish inside Sea Slug.



Essentially the only way to do it was probably to elongate the power supply section behind engine and put antennas on wings.

 

[zen]

Actually put 4 interferometer aerials around the nose but run their cables along the sides back to guidance system compartment.

 

[Dilandu]

Actually put 4 interferometer aerials around the nose but run their cables along the sides back to guidance system compartment.

Wouldn't they affect the fuse work?

 

[zen]

Actually put 4 interferometer aerials around the nose but run their cables along the sides back to guidance system compartment.

Wouldn't they affect the fuse work?

No I think they'd end up around the warhead for greater diameter/distance.

 

[pathology_doc]

I'm saying that a change to SARH is the obvious way forward and removes the need for the 901. SARH using polyrod interferometer guidance is potentially intigratable into a Sea Slug missile. Easier than a dish based system due to the internal layout of the missile.

Yeah, it would be next thing to impossible to put a radar dish inside Sea Slug.

View attachment 632373

Essentially the only way to do it was probably to elongate the power supply section behind engine and put antennas on wings.

This picture shows off the aerodynamic profile of the "bare" missile very well. Look at the resemblance to Red Top, mostly evident in the shape of the wings.

Note also the way the motor is positioned amidships, with the nozzle exhausting through some of the control systems, power supplies and tail actuators. This was done to keep the motor as close to the centre of gravity as possible, as serious CG shifts can alter the control response in a way that the early GM control systems found very difficult to handle.

 

[Nick Sumner]

Discussion about Sea Slug.

https://www.secretprojects.co.uk/threads/sea-slug.31264/

Link to Barrow's archive and one of the launcher options.

The Dock Museum | Collections

collections.dockmuseum.org.uk

Many thanks!

 

[JFC Fuller]

The only British area-defence guided missile ship I can think of that didn't have a helicopter was Bristol, and that's because she was explicitly designed as a close escort for CVA-01

This is not the case. Bristol did not have a helicopter because she was evolved from RN First Rate ASW frigate (FSA) designs/concepts of the late 1950s, these carried a Wasp for ASW torpedo delivery (MATCH). In Bristol, this role was to be performed by Ikara, so that system replaced the helicopter. It took the RN quite a while to consistently put medium/large helicopters on frigates and destroyers, the County class being something of an outlier. I admire the Canadians in this respect, the Beartrap was ingenious and allowed them to distribute CH-124s (Sea Kings) throughout their frigate and destroyer fleet.

As this is an Alternative History thread, it is fun to imagine the RN adopting the Beartrap almost in parallel with the Canadians via the Fairey Aviation link. They would then have dropped the over-specified NAST.358 very quickly and focussed on NAST.365 which would have produced a joint force medium helicopter, via the Westland WG.4/7 studies, that could ultimately fulfil the RN ASW and Commando roles and the RAF medium lift role in place of the Sea King and Puma. The British helicopter industry would get large volume orders, the British Armed Forces would get a common airframe, engines, transmission and systems and the RN would deploy medium helicopters across its fleet.

 

[pathology_doc]

Bristol did not have a helicopter because she was evolved from RN First Rate ASW frigate (FSA) designs/concepts of the late 1950s, these carried a Wasp for ASW torpedo delivery (MATCH). In Bristol, this role was to be performed by Ikara

I stand corrected.

 

[zen]

During the examination of Green Flax (I think '56), the major attractions were quick assembly and SARH guidance.