Help please?

[Litvyak]

So, I've got an Airfix 1/600 HMS Ajax kit that I want to build as a Royal BC Navy ship, but as the final version of it, and I'm hoping someone who knows about ships might be able to help me with some info...

As far as name goes, I'm leaning towards probably HMBCS New Westminster, but that's not important... What I've got in mind is that the ship underwent a number of refits over the years, the last one in the early 1960s... I've had a few ideas, but one that I for sure would like to include is a missile system - either Sea Cat or Sea Slug. And - if it's reasonable - removing the aft guns and that little structure behind where the aircraft catapult is, and replacing it with a hangar and helicopter deck. Of course, there would be new radars and such installed, too (going by what I've been able to find, something like a Type 992Q, a Type 960, a Type 278 and a Type 903?). The goal is for it to be a (ideally) helicopter-equipped command cruiser.

So: assuming the above... a number of questions:

1. Where would the Sea Cat (or Sea Slug) be mounted? Two quad launchers either side of and just aft of the funnel (around where the catapult was)? Or perhaps atop the hangar structure?

2. On the model, at least, there are four twin mounts around the funnel - I assume these are the 4" AA guns. Would it make sense to replace these with four twin Bofors 40 mm... or would those have been removed when the Sea Cats were installed?

3. The two fore turrets. Would both of those have been kept? If not, which would be the most likely to have been removed - the upper one or the lower one?

That's what I've got questions-wise for now... any help is much appreciated!

[AGRA]

1. Where would the Sea Cat (or Sea Slug) be mounted? Two quad launchers either side of and just aft of the funnel (around where the catapult was)? Or perhaps atop the hangar structure?

Sea Cat was designed to replace 40mm Bofors mounts so can go just about anywhere. But it also needs to include a director. Sea Slug needs a very big missile magazine and assembly room which has to be laid out horizontal to the launcher. You could probably put your hangar and flight deck on top of the missile magazine.

2. On the model, at least, there are four twin mounts around the funnel - I assume these are the 4" AA guns. Would it make sense to replace these with four twin Bofors 40 mm... or would those have been removed when the Sea Cats were installed?

They are 4” guns and would mostly be redundant with Sea Cats. This is actually a good place to put your Sea Cats as there is plenty of space for their magazines and directors.

3. The two fore turrets. Would both of those have been kept? If not, which would be the most likely to have been removed - the upper one or the lower one?

It depends on what the ship is for. In the early 1960s there were no Exocets so big guns like this were also anti ship weapons. So they would probably keep them if it’s a multi role ship. If it is an anti aircraft ship then replacing them with some 4.5” guns or more missiles would make sense. There were anti aircraft 6” guns but you’d never fit them on an Ajax type ship.

Heres a quick draw to scale. Leander class weren't so big...

[Litvyak]

Ooh, thanks for that profile!

I've started hunting around for parts I'll need... White Ensign seems to be a good place to start with a couple of their etching frets with radars and whatnot, and they list Sea Cat launchers (but out of stock).

What director went with the Sea Cat? (And more importantly, what did it look like, and is there one in 1/600?)

And, is there a Wessex in 1/600?

Stupid Airfix and their 1/600...

[AGRA]

The Sea Slug, Sea Cat and Wessex in the picture all came from a County class destroyer. If you could find a 1/600 model of this you would have a donor.

A quick net search indicates Airfix made one:

http://steeleelstudios.blogspot.com.au/2012/05/model-of-hms-antrim-1982-falklands.html

You could even be more exotic and replace the 4" guns with a port and starboard 4.5" and put the Sea Cats either side of the hangar (aft) like on the County or forward beside the bridge.

[Cliffy B]

The Sea Cat director as well their postwar gun director (Mk VI 4.5" and 6" autos) were adaptations of the USN's Mk-56 GFCS.  The Brits made some slight cosmetic mods as well as used a different radar.  MRS3 was the designation for the gun director and the second gen Sea Cat launchers (first ones were purely optical and based on the Bofors FCS).  The Type 21's carried the Italian Alenia Orion RTN-10x Fire control system, completely different than the MRS3.  Also, Sea Cat was designed to replace the WWII vintage twin Bofors 40mm on a one per one basis so keep that in mind when you place them.

As for your conversion, the RN originally wanted to remove all of the older single purpose 6" turrets from their cruisers and replace them with the automatics found on the Tiger-class.  In lieu of those the Mk VI 4.5/45 would be the best replacement as it was very good DP gun for the time.

These links should help you:

http://www.navweaps.com/Weapons/WMBR_Sea_Cat.htm
http://www.navweaps.com/Weapons/WNBR_45-45_mk5.htm
http://www.navweaps.com/Weapons/WNBR_6-50_mk23.htm
http://www.navweaps.com/Weapons/WNBR_6-50_mkN5.htm
http://www.navweaps.com/Weapons/WNBR_Main.htm

As far as Exocets go, depending on the time frame you want to eventually depict you can opt for US Harpoons instead as a space saving measure.  Those Exocet launchers took up way too much deck space and WTF is up with not stacking them?  Surely they could have mounted them on top of each other to better utilize the space at hand?  Another option is using the British Sea Eagle in box launchers.  There were plans to fit them to fast patrol craft but they were dropped for one reason or another.

Look at the Countys, they're a great source for 1960's RN inspiration.

Keep at it man and keep asking questions.  I know more about the USN then I do the RN but I'll help as much as I can.

[AGRA]

As far as Exocets go, depending on the time frame you want to eventually depict you can opt for US Harpoons instead as a space saving measure.  Those Exocet launchers took up way too much deck space and WTF is up with not stacking them?  Surely they could have mounted them on top of each other to better utilize the space at hand?  Another option is using the British Sea Eagle in box launchers.  There were plans to fit them to fast patrol craft but they were dropped for one reason or another.

The Exocet “coffin” launcher could not be stacked because they were extremely heavy. They had to be fully armoured boxes to protect the ship from the Exocet. Because unlike the Harpoon Exocet was powered by a rocket motor that if it blew up from a splinter hit would cause severe damage to the ship. Harpoon was more sensibly powered by a mini Turboket which just burnt from a small tank of Kerosene so was of minimal danger to the ship so could be stored in light weight glass fibre canisters. Either way neither missile is available until the mid to late 1970s.

[AGRA]

Here is an improved vertical of a Leander class light cruiser upgraded with County class destroyer equipment. I’ve revised the magazine arrangement after looking it up and finding out it is only one deck high. However on the County it ran almost all the way to the bridge and there is only half this length available on the Leander. The solution is to make the magazine full width because it is quite narrow on the County. This will enable a full 40 odd missiles to be carried and all their check out and assembly rooms.

Above the magazine from aft to forward you have the flight deck then the Sea Slug guidance radar. Forward of the Sea Slug radar I’ve added a new main mast for communications and forward of that the Wessex hangar. This is the same sort of hangar as on the County and the helicopter gets into it from the side. On either side of the hangar are the Sea Cat launchers and their directors mounted on a pedestal.

Changes forward are the deletion of the 4” guns and a new foremast with the air search radars. The problem here is because of the full width missile magazine there is no space for ship’s boats aft. So they will have to go where the 4” guns used to be. Not drawn in is above the bridge a new radar guidance system for the 6” guns.

Replacing the 6” guns with a dual purpose anti aircraft and anti surface gun would mean a huge rebuild and reduction from four guns to two. With Sea Slug and Sea Cat anti aircraft 6” is really not needed and keeping these guns as is provides significant anti ship and shore bombardment capability.

For realising this as a model the Airfix Country class should provide all of the detail bits and masts and the like.

[Weaver]

As far as Exocets go, depending on the time frame you want to eventually depict you can opt for US Harpoons instead as a space saving measure.  Those Exocet launchers took up way too much deck space and WTF is up with not stacking them?  Surely they could have mounted them on top of each other to better utilize the space at hand?  Another option is using the British Sea Eagle in box launchers.  There were plans to fit them to fast patrol craft but they were dropped for one reason or another.

The Exocet “coffin” launcher could not be stacked because they were extremely heavy. They had to be fully armoured boxes to protect the ship from the Exocet. Because unlike the Harpoon Exocet was powered by a rocket motor that if it blew up from a splinter hit would cause severe damage to the ship. Harpoon was more sensibly powered by a mini Turboket which just burnt from a small tank of Kerosene so was of minimal danger to the ship so could be stored in light weight glass fibre canisters. Either way neither missile is available until the mid to late 1970s.

Also the MM38 launcher was replenished by craning the whole box in from above, so if you stacked them, how would you replace the bottom one, given that the top one's support structure would be in the way. The low launch angle is needed because the MM38 motor doesn't have a separate boost phase, so it needs to accelerate up a "ramp" for launch.

Later MM40 Exocets are delivered in disposable fibreglass tubes just like Harpoon. MM40 has a separate tandem booster, so it can launch at a high angle (although I think it's still lower than Harpoon's 45 deg?) However many MM40 installations are refits on MM38 mountings, so they use the old, low angle container bases with two tubes on each, with a short, non-ribbed box around them. It would seem possible in principle to fit four MM40s in place of each MM38, but they never do - I don't know why.....

[Volkodav]

How's this build going?  I am quite interested to the how it turned out.

[Litvyak]

Hasn't even started yet as I still haven't found the necessary things like that HMS Antrim kit...

[Volkodav]

Hasn't even started yet as I still haven't found the necessary things like that HMS Antrim kit...

Ok, I have one but have already made a start on it, it hasn't progressed in 20 od years.  What bits do you need, I may be able to help if the bits you want aren't ones I've butchered already?

Also I thought this my be of interest

 http://www.okieboat.com/Talos%20launching%20system.html

[Weaver]

Since you havn't started yet, you might like to have a look at this Shipbucket page that has a schematic of how the real horizontal Sealslug magazine and a proposed vertical one worked:

http://www.shipbucket.com/images.php?dir=Parts Sheets/Royal Navy Weapons Parts.png

The vertical magazine woulf be particulary suitable for a converted big gun warship, since the magazine could fit in place of X turret and the launcher in place of Y turret.

The Sea Cat director mentinoed by Cliffy B, derived from the MRS3, was actually the third Sea Cat director, known as GWS-22. Here are all the variants (all used the same missile and launcher):

GWS-20 : Based on the STD (Simple Tachymetric Director) and entirely visual in operation. The operator tracked the target via binoculars and steered the missile via radio commands and a small joystick.

GWS-21 :  Based on the CRBF (Close Range Blind Fire) director used for 40mm bofors guns. It looked like an open-topped drum with a hemispherical canvas weather cover. In operation, it held two men, one of whom kept the director facing toward the target, and the other who steered the missile. Some versions had a Type 262 radar which could track the target and missile, but steering commands still had to be generated manually.

GWS-22 : Based on the MRS-3  gun director, this was still a manned director, but had radar, TV and visual tracking modes, and most importantly, SACLOS command guidance, i.e. the operator only had to track the target whilst the system automatically tracked the missile and generated command signals for it.

GWS-24: Based on the Selenia Orion RTN-10X radar tracker. This unmanned director consisted of a radar tracker with a TV tracker looking through a hole in the dish. Same MO and options as GWS-22, but contralloed from the Ops Room, not on the mount. This wa the most advanced Seacat director in RN service.

Seacat was very flexible and could work with a wide variety of other fire control systems too. In particular, the Dutch developed a range of systems to control them, based on M-44 fire control radars and the ubiquitous SIGNAAL WM-series "egg" track-while-scan radars.



The Airfix 1/600th County is pretty easy to come by over here, usually boxed as HMS Derbyshire, so if you're stuck, give me a shout and I'll get you one. It was also included in a Falklands boxed set with a Leander and an Amazon: obviously you pay more money for that, but it's an excellent bits mine for RN projects.

[Volkodav]

I like the concept of Commonwealth cruiser missile conversions, US and Europe did enough to prove it viable.  The three Minataurs would have been a good start and could probably have had a US Mk7 GMLS in a similar setup to the Clevelands fitted under MAP.  Terrier was designed as a destroyer systems that didn't quite fit on the Gearings as planned but would have easily fit the Leanders or even the Didos.  Would love it if I could get some affordable UK cruiser hulls to play with, I have more Dragon / Skywave MK10 launchers than I know what to do with. 

Maybe I need a 3D printer and cad data for the hull forms.