Type 42 Batch 1 Hull Cut

[JFC Fuller]

I am trying to get to the truth behind the story about the Type 42 ending up with a hull shorter than the designers wanted. The sources that I have available are contradictory. Norman Friedman states that there is no indication that the Type 42 was shortened from the a preferred 434ft (the length of the Batch 3 ships, which were also 2 ft wider) in the design phase. However, R.J Daniel, in his book, is explicit that not only was the design shortened but that he argued against the decision and took great delight in correcting it with the Batch 3 ships though he does not mention what the length of the original proposal was. I have seen a number of books over the years that state that the Batch 1 ships were 30ft (which would have made them 422ft) shorter than the designers wanted. Does anybody know the truth behind this?

 

[M. A. Rozon]

I have Marriot's book on British DD's as well as D. K. Brown's "Rebuilding the Royal Navy" so I will check those. A definitive answer and source for reference would be something I'd like to see as well!

B)

 

[RP1]

Bear in mind that "shorter than the designers wanted" is not the same as "were shortened from the preferred length". i.e. there may not have been an explicit "shortening" phase, rather, the external pressures pushed it that way, whilst the designers wanted something else. This is not unusual.


RP1

 

[PMN1]

the external pressures pushed it that way,

RP1

How about someone getting it wrong on the drawings and not being able to correct it?????

 

[JFC Fuller]

RJ Daniel (The End of an Era: The Memoirs of a Naval Constructor), who worked at the DNC at the time (was head of the Forward Projects Group at its formation) is explicit that the fore-body of the ship was reduced in length after the Type 42 project was transferred from the Project Group Constructive to the Destroyer Design Group.

Daniel states that the Forward Projects Group, then lead by Chief Constructor Tony Austin, believed that the vessel could not be built on less than 4,100 tons. He also attributes much of the other cost saving elements to the Destroyer Design Group such as the removal of one of the anchors and reducing the number of boats. Apparently, the shortening of the hull, which Daniel himself claims to have argued against, saved the equivalent of less than 1% of the total cost of the ship.

It seems that prior to being sent to the Destroyer Design Group the Type 42 design had two anchors, more boats, some other fittings and a longer fore-body with a displacement of 4,100 tons. What is not clear is how much was cut out of the hull, the 30ft figure that has been used in several places must have come from somewhere?

 

[blackstar]

Apparently, the shortening of the hull, which Daniel himself claims to have argued against, saved the equivalent of less than 1% of the total cost of the ship.

Steel is cheap compared to the stuff that goes into a ship. However, when cutting that length, what were they eliminating as well? Was it just just berthing compartments and interior space or were they also eliminating a weapons system like a gun?

 

[pathology_doc]

Certainly the primary weapons didn't change - (Mk8 4.5", Sea Dart), though the extra hull volume might have given them space-and-weight reserve for the light AA they so desperately needed (e.g. Phalanx).


I remember there being some surmise when the Batch 3's came out that it might be to make room for more Sea Darts or even VL Seawolf, but I'm not sure they ever got more than the basic 22-missile Sea Dart fit.

 

[M. A. Rozon]

From Friedman and some others (USNI references on World Naval Weapons Systems), all Type 42's carried the 22-round Sea Dart fit. Only the single Type 82 and the Invincibles carried the larger 38-round system.

As I understand it (anecdotal from my time in the Canadian Navy, way back when...), the reduction in size of the Type 42 hull had "unforseen" consequences in terms of the amount and positioning of damage control assets which negatively impacted Sheffiled's ability to survive the Exocet hit it took in the Falklands.

With regards to the Batch 3's and lightweight Sea Wolf, IIRC HMS Edinburgh had it's Phalanx suite reduced to one mount forward as a prepatory step for the refit that was to see the ship fitted with Sea Wolf, but things never went further than that. I can't remember exactly where I read that but that is the memory I have.

Can anyone provide a reference or more solid source I can check for these last two points?

Thanks.

 

[pathology_doc]

With regards to the Batch 3's and lightweight Sea Wolf, IIRC HMS Edinburgh had its Phalanx suite reduced to one mount forward as a preparatory step for the refit that was to see the ship fitted with Sea Wolf, but things never went further than that. I can't remember exactly where I read that but that is the memory I have.

I'm pretty sure I read that one in Jane's All the World's Warships, but I can't remember the year.

 

[JFC Fuller]

This thread: http://www.secretprojects.co.uk/forum/index.php/topic,218.0.html

Mentions that Seawolf was planned and that it was actually ordered in 1988. My understanding of the Edinburgh story is that she briefly had a single Phalanx mounted in a "B position" between the Sea Dart launcher and the main gun and behind the second breakwater. The ships two breakwaters were also enlarged and a bulwark built around the bow in order to try and keep water away from the mount. Apparently it was not successful. I can understand the Seawolf launchers being mounted where the Phalanx's are usually mounted on either beam, I have never been able to envisage where the sea Wolf directors would go though.

 

[M. A. Rozon]

On Shipbucket I believe one of the regular contributors did up a possible version of the Batch 3's with Sea Wolf. I'll see if there is a direct link available to it.

B)

 

[M. A. Rozon]

It wasn't up on Shipbucket but I had downloaded the graphic from a board (maybe this one?) at one time or another and so here it is:

 

[uk 75]

The manufacturers model that was always shown in Janes and elsewhere before the Sheffield was built always seemed to be of the longer version. I always wondered why this was.

I think it was also planned to fit the single armed SEADAWS launcher to a Type 42 variant or to a Vosper Mk 10 version for export. I don't know at what stage this launcher was given up. Its capabilities would have been very limited I imagine.

 

[M. A. Rozon]

I'd love to see the builder's model as well.

B)

 

[uk 75]

Would need to scan a picture from a late 60s Janes Fighting Ships, which is a big prob as I do not have a scanner at home. The model may be an MOD RN model rather than a manufacturers model.

 

[JFC Fuller]

@M. A. Rozon that is as good of a suggestion as I could imagine, the only issue i can see is that the platform behind the funnel is actually fairly narrow and would put the 805SW director behind the launcher and possibly give it a narrow field of view. Perhaps on the platforms on the side of the fore and aft superstructures might be a better location?

I have been giving a lot of thought to the Type 42 light-weight Sea Wolf configuration and I am starting to think that there are two likely configurations:

1) Lightweight Sea Wolf Launcher mounted between the Sea Dart launcher and the 4.5inch gun where HMS Edinburgh briefly had her Phalanx with the directors mounted amidships; one on each beam

2) Lightweight Sea Wolf Launchers mounted in the normal Phalanx locations on either beam with the director on the very rear of the hangar

 

[Hood]

I attach an interesting picture of an offical model of the Type 42 reproduced in Brassey's Annual 1970. It has all the features and layout of the Type 42 we know but seems to have a bridge, forward superstructure and funnel modelled on that of Leander. An interesting feature that I haven't noticed in other sources or plans, including in Friedman's 'Frigates and Destroyers'.

 

[Hood]

I've looked at the photo again in the annual and the four large vertical rectangles are radio anntenna bases, the single smaller fore-aft axis box is, I think, on the T42 as built and was part of an ESM system. I remember seeing a picture of similar boxes on HMS Endurance somewhere else.

 

[Volkodav]

I recall an article with photographs of the forward Phalanx arrangement but not the publication it was in. If I recall correctly the article stated the light weight seawolf was to have been fitted port and starboard in the old Phalanx position and that the aft 909 was to have been removed to provide space and weight for the seawolf director.

 

[MihoshiK]

Well, there's one whole and rather small and bad picture of that Phalanx installation online...

 

[JFC Fuller]

Looking for something else I found a google books snippet from the Transactions of the Royal Institute of Naval Architects: Volume 131 from 1989 that states the following about the redesign of the Type 42 Batch III, emphasis mine:

When it came to a repeat class it was decided to wrap a new hull around the 'existing' internal arrangements by adding 42 ft to the length, 2 ft to the beam and 2 ft to the depth.

In addition, the forward lines, which had been distorted in the original to fit in a four-lane Seadart magazine (which, in the end was not fitted) and snubbed, could be faired out to their logical conclusion.

As built the Type 42 had the same 7-6-7 three lane magazine layout as the Invincible class. Based on the 10-9-9-10 layout in HMS Bristol it seems logical to think that a four lane layout for the Type 42 would have been 7-6-6-7 for a magazine capacity of 26. I don't know why this didn't happen but it is possible that it was decided to use the already designed magazine for the Invincibles as a cost saving measure and accept the loss of magazine capacity versus the ship's potential.

If anybody has the full article from the RINA journal I would love to see it.

 

[Hood]

That is indeed interesting information. It seems logical that when the ship was trimmed that the magazine was too. Given that every class with Ikara ship had a different magazine layout and that every Seadart class so far had a different arrangement, there must have been a push for some kind of standardisation. It would have saved design time too and makes more sense of the decision to trim off a bit of length, which as pointed out in posts above, saved very little money in real terms.

I hadn't really realised that the Batch III hull was effectively a new hull.

 

[Ron5]

Richard Scott tweeted this a couple of days ago ...



The Phalanx can just be seen peeping from behind the main gun.

 

[Hood]

Another view of the 1966 Type 42 model that I posted in #17.
This image is from Warships of the British and Commonwealth Navies, by H T Lenton, 1966.

A surprising amount of Leander heritage in the design given the Type 17 studies done before it.

 

[uk 75]

It would have been more honest to call the ship a frigate like the US Perry class.
The T22 could then have used the same hull and been in service sooner.

 

[Yellow Palace]

It would have been more honest to call the ship a frigate like the US Perry class.

The words 'destroyer' and 'frigate' don't have immutable meanings carved on tablets of stone by the Almighty. For good or ill, the Royal Navy determined in this timeframe that 'destroyer' meant air defence, and 'frigate' meant anti-submarine.

For that matter, at the time they were designed, the US Navy designated that kind of ship as an 'ocean escort', because a frigate was intermediate between a cruiser and destroyer.

Personally, yes, I'd consider them frigates. But it doesn't really matter.

The T22 could then have used the same hull and been in service sooner.

Not really. The Type 42 hull would have been equally unsuitable for the Type 22 whether it was called a frigate, destroyer, large rocket ship, or aircraft carrier.

 

[Hood]

I've found two better shots of the Type 42 model, though Jane's dates it to 1969.
Also included is the 1970 official model. A lot of similarities in the overall design.
To me the forecastle on the 1970 model looks visibly shorter (the 4.5in is closer to the bows) but I've not attempted any scaling or estimates to confirm that.

 

[Hood]

I am currently doing a Shipbucket drawing of the 1969 model shown above.
From this I can confirm that the hull length is 392ft, same as that of the original Batch 1 & 2 ships.
Interestingly the forward superstructure block is about 14-15ft shorter with a corresponding displacement further aft of the Sea Dart and 4.5in Mk8, which is why the forecastle looks less cluttered.

The shorter superstructure seems to be due to main gas turbine downtakes being parallel to, and aft, of the uptakes, rather than the Olympus intakes being in a blockhouse forward of the funnel, and less internal space provided within the superstructure block (2 decks rather than 3).

This model seems to correspond to Friedman's descriptions of the 1967 cut-price designs (392ft, space for 280 crew) but with two 909s and lacking UAA-1 and Bexley (though its possible Bexley is on the model). There are no obvious torpedo tubes (perhaps tucked away near the ship's boats on the model?). I am convinced that it is an official model from 1969.
But it does raise an interesting possible change as shown on the 1970 model that has not been documented in histories so far; when the forward superstructure block was enlarged into the final design and the Olympus intakes refined, the the Sea Dart and 4.5in gun were shunted forwards 15ft towards the bows which is why the final design was so cramped forward.
It seems that the simple expedient of adding 15ft to the length was not suggested, or if it was, not countenanced given the design had already grown from 385ft in early 1966.

All in all its looking like story of the Type 42 being trimmed from 434ft is a myth. The Type 17 and its AAW variant and none of the early T42s during 1966 were ever that long and in fact grew from 385ft to 392ft. Had the final design kept the more compact superstructure layout with the armament 15ft further aft, I wonder if there would still have been a push to lengthen to 434ft in the Batch 3s?

 

[uk 75]

I always felt that the 1969 model was closer to a Leander frigate in appearance. Hood's explanation makes sense to me.

 

[uk 75]

I have managed to get hold of the 1968/69 and 1969/70 editions of Jane's Fighting Ships.
The 68/69 has a brief mention of the Type 42 and an early sketch in the Addenda Section.
The 69/70 has much fuller information in the form of a model and a newer artist's impression.
The two sketches appear to have shorter forward sections than the model and are less Leander like.

 

[uk 75]

The Type 82 in its single funnel version offers a glimpse of what a pure Air Defence T42 with Seadart aft might have looked like. This variant, however, would have cost the RN 14 platforms for operating Lynx helicopters.
The Dutch Navy was also building new air defence ships based on the Leander frigate. They rejected Seadart in favour of a single Tartar launcher which like the T82 Seadart could be mounted aft but allowed a helicopter hangar and flightdeck.

 

[Hood]

The Type 82 in its single funnel version

Actually there are two funnels, on the model you can see the circular exhausts immediately aft of the mainmast, the blockhouse itself being a crude funnel.

 

[uk 75]

Sorry I cheated a bit to compare with the T42

 

[Mr Clark]

I suppose the Type 42 ( batch one and two) where always going to be compromised by their displacement, beam and length.

Clearly the Batch 3 are how they should have looked from start. I always thought they were a rather attractive design with the extra length.

At least they were cheap enough to buy in quantity, unlike their horrifically expensive and an order of magnitude larger replacements, the T45.

 

[Pirate Pete]

Found this illustration of the Type 42 from an article in a Dutch publication - Schip en werf, from 1970 - The article itself was about Main Propulsion Gas Turbines in the Royal Navy.

 

[uk 75]

I suppose the Type 42 ( batch one and two) where always going to be compromised by their displacement, beam and length.

Clearly the Batch 3 are how they should have looked from start. I always thought they were a rather attractive design with the extra length.

At least they were cheap enough to buy in quantity, unlike their horrifically expensive and an order of magnitude larger replacements, the T45.

The RN has always had to balance quantity with quality. It is perhaps unfair to compare the T45 with the T42 as their roles while originally similar have become very different.
The T42 was intended to help provide an area anti aircraft screen with other NATO warships around a convoy or task group within a wider air defence zone either provided by the RAF or a US aircraft carrier.
The Type 45 has evolved into a platform able to detect and shoot down missiles as well as aircraft within a much wider area. Two or three such ships could cover much of the UK depending on the direction of threat.
Both systems have serious flaws in service but when they work perform well.