The Centaur carrier fleet - a better fate...

[A Tentative Fleet Plan]

I learned about the island thing here in February, and will repeat like a good schoolkid.

British carriers have big (or 2) islands because they didn't have a gallery deck between the flight deck and hangar roof. The British believed that a ship needed a 120' beam to have a gallery deck, otherwise the ship wouldn't be stable. So the big island makes perfect sense, its a simple design constraint/compromise.

Both the 1952 Fleet Carrier and CVA-01 had a gallery deck.

 

[EwenS]

But what does everyone mean by a "gallery deck", and what do you believe existed there?

And in part this brings us back to the differences in carrier construction between USN & RN.

In the Illustrious class and successive armoured carrier designs, the beams supporting the flight deck were sufficiently deep that there was space between them at the "upper gallery deck" level which was used in part at least for various purposes.

In the 'closed' hangar overhead area between those beams of the Illustrious class that included, in various places, store rooms, a parachute packing room and a compartment forward for the accelerator / catapult gear. Forward of the hangar and lift well were crew accommodation and recreation spaces, while aft of the after lift were more stores, squadron offices etc. Between the hangar walls and the ship's side the space at this level was put to other uses.

There was also a "lower gallery deck" at about half hangar height, with compartments fore and aft the hangar & along its sides.

When Victorious was reconstructed, the "Upper Gallery Deck No.2" was used almost entirely along its length for crew accommodation.

Looking at the deck plan of CV-11 Intrepid of the Essex class as completed, only part of the "Gallery Deck" was used. Virtually all of the space at that level aft of the after lift was unused and open to the hangar as was most of the area between the island and the forward lift. These were the areas which I assume would have been used to suspend the spare aircraft intended to be carried in the original design. The latter practice was discontinued in US carriers in late 1942, as it was found to be a fire hazard. Very little of the remaining space was taken up with crew acomodation (a bit forward of the forward lift and another for senior officers abreast the island). Most was squadron offices, stores, ready rooms and other compartments necessary for the air group.

 

[A Tentative Fleet Plan]

By "Gallery Deck" I mean a deck between the flight deck and hangar roof, running the full length of the ship.

 

[Rule of cool]

But what does everyone mean by a "gallery deck", and what do you believe existed there?

Obviously this was where the carrier displayed Art, people practiced pistol shooting and played pinball and other games. In addition to this cool stuff it's the interface between the flight deck and the iceberg of stuff that keeps it moving: aircrew ready and briefing rooms, the huge amount of admin before a plane is signed off as servicable, aircraft spotting etc etc etc. A full length gallery deck keeps all this under armour, without it at least some has to be moved into the island.

BTW the 120' beam thing is a stability requirement for both a full gallery deck AND deck edge lifts. Get rid of deck edge lifts and you can have a full sized gallery deck, or whatever other design comprises that best suit the requirements.

 

[BlackBat242]

Both the 1952 Fleet Carrier and CVA-01 had a gallery deck.

In addition to the comments between these two posts, it was also an issue of (in general):
two hangar decks = no full-length full-width gallery deck
one hangar deck = yes full-length full-width gallery deck

 

[GK Dundas]

When one examines the operating concepts of British Defence industries. One doesn't know whether to laugh or cry.
Almost every ship or aircraft seems to been a "one off " in particular their Carrier fleet
I'll bet finding spare parts even with a laid up sister ship must have been interesting.

 

[Rule of cool]

In addition to the comments between these two posts, it was also an issue of (in general):
two hangar decks = no full-length full-width gallery deck
one hangar deck = yes full-length full-width gallery deck

Apparently its all about freeboard and weight up high in the ship and its effects on stability. It appears that these ship designers aren't totally stupid.

 

[zen]

When one examines the operating concepts of British Defence industries. One doesn't know whether to laugh or cry.
Almost every ship or aircraft seems to been a "one off " in particular their Carrier fleet
I'll bet finding spare parts even with a laid up sister ship must have been interesting.

No a great deal is standardised parts.
From catapult sections to seats to pipes. It all pretty much standard really.
For aircraft there was...is a need to fit in aerodynamic form and spread weight rationally. So things had to have alterations to fit.

 

[Temeraire]

British carriers have big (or 2) islands because they didn't have a gallery deck between the flight deck and hangar roof. The British believed that a ship needed a 120' beam to have a gallery deck, otherwise the ship wouldn't be stable. So the big island makes perfect sense, its a simple design constraint/compromise.

That is some complete and utter Bollocks. HMS Victorious had a gallery deck from her Rebuild (Hermes might of, I can’t remember and honestly i can’t be bothered to check this late at night) Eagle was supposed to get one however she only got a half-assed refit (i don’t think it even qualifies as a rebuild) and Ark Royals was even worse than that.

The reason for two islands, (or one long one) is because it allows the funnel uptakes (and thus the machinery spaces) to be spaced out which Improves Survivability. Conventional American super carriers didn’t do this, which reinforces my notion (as a proud Brit) that the Americans are dumb, and Nuclear carriers don’t need funnel uptakes, meaning their islands can be much smaller

 

[Temeraire]

When one examines the operating concepts of British Defence industries. One doesn't know whether to laugh or cry.
Almost every ship or aircraft seems to been a "one off " in particular their Carrier fleet
I'll bet finding spare parts even with a laid up sister ship must have been interesting.

Not our fault the yanks piled mountains of debt on us that meant we couldn’t afford jack shit.

 

[Temeraire]

BTW the 120' beam thing is a stability requirement for both a full gallery deck AND deck edge lifts. Get rid of deck edge lifts and you can have a full sized gallery deck, or whatever other design comprises that best suit the requirements.

Was that really a thing?
As far as I’m aware the only thing that prevented Victorious from getting a Deck edge lift was her low freeboard

 

[zen]

To get freeboard at hanger deck level over 24ft AND a full Gallery deck as per HMS Victorious's rebuild. The freeboard needed for deck edge lifts.
DNC stated the ship needed ideally 120ft waterline beam.

Victorious's Gallery deck was a little cramped and so new ships would have to have a greater height to fit all the piping, lagging and air ducting (for aircon)

The 1952 carrier started out at 115ft but got to 116ft prior to cancellation. The favoured design had a full Gallery deck and deck edge lifts. But how stable compared to the ideal is an interesting question and it may have forced compromises.

Later CVA-01 studies seem to imply some would either choose between deck edge lifts or full Gallery deck. Likely to examine trade off in capabilities.

The bigger island designs were to house the full two deck AIO arrangement. Victorious avoided this by citing the lower deck AIO in the Gallery deck beneath the island.

Twin island design was to increase capacity to operate with damage and provide greater separation of radar and radio aerials, of which there wouldbemany and avoiding them conflicting with each other isn't a trivial matter.
It also eased trunking of exhaust from the engines.

CVA-01 seems to start out with twin islands, but they then add a walkway between them to carry cables and things spiraled until there was just a tunnel through the island remaining.

 

[BlackBat242]

That is some complete and utter Bollocks. HMS Victorious had a gallery deck from her Rebuild (Hermes might of, I can’t remember and honestly i can’t be bothered to check this late at night) Eagle was supposed to get one however she only got a half-assed refit (i don’t think it even qualifies as a rebuild) and Ark Royals was even worse than that.

The reason for two islands, (or one long one) is because it allows the funnel uptakes (and thus the machinery spaces) to be spaced out which Improves Survivability. Conventional American super carriers didn’t do this, which reinforces my notion (as a proud Brit) that the Americans are dumb, and Nuclear carriers don’t need funnel uptakes, meaning their islands can be much smaller

So they planned to cut Eagle from 2 hangar decks to 1?

 

[Rule of cool]

IIUC the 120' is the stability baseline for a single hangar, full length/width gallery deck AND deck edge lifts. I reiterate that this is a baseline, and everything is negotiable: want less stability with those 3 things you can have less beam. If you want a gallery deck and stability on less beam cut back on deck edge lifts or gallery deck size, if you want 2 hangar decks then other things must go, the combinations are endless.

 

[Temeraire]

So they planned to cut Eagle from 2 hangar decks to 1?

No they didn’t, it was late at night where I am so I couldn’t really remember correctly

 

[GK Dundas]

I think the biggest problem with the Gannet is the compact size of the airframe. That limits the amount of electronics that can be packed in when compared to a Grumman S-2 Tracker or Lockheed S-3 Viking.

Where do you put all the extra sonobuoys (Gannet carried less than a dozen IIRC), plus MAD gear, diesel sniffers etc.? And do you then need a third operator to man them? And unlike a helicopter it can’t stop and hover to dip a powerful active sonar into the water to prosecute underwater targets.

So the RN took the view in the mid-1950s to move to the helicopter for ASW equipped with that active dipping sonar as the best tool for the job. Only later in the 1980s do they add do they add sonobuoy and MAD gear to the Sea King.

I should have known the answer to this , one of the reasons the CP 121 trackers were retired in the 80's was you really couldn't cram any ASW systems aboard them. That would have provided enough of an advantage to be worth the costs of a refit.
A couple of years later and the boom in computer development it would been a genuine gamechanger.

 

[BlackBat242]

The S-2 carried plenty of sonobuoys...
The engine nacelles carried JEZEBEL sonobuoys in the rear (16 in early marks, 32 in the S-2E/G). Early Trackers also carried 60 explosive charges, dispensed ventrally from the rear of the fuselage and used to create sound pulses for semi-active sonar (JULIE) with the AN/AQA-3 and later AQA-4 detection sets, whereas the introduction of active sonobuoys (pingers) and AN/AQA-7 with the S-2G conversion saw these removed. Smoke dispensers were mounted on the port ventral surface of the nacelles in groups of three each.

It also carried other ASW systems... The Tracker had an internal torpedo bay capable of carrying two lightweight aerial torpedoes or one nuclear depth charge. There were six underwing hard points for rocket pods and conventional depth charges or up to four additional torpedoes. A ventrally-mounted retractable radome for AN/APS-38 radar and a Magnetic Anomaly Detector (MAD) AN/ASQ-8 mounted on an extendable rear mounted boom were also fitted. Early model Trackers had an Electronic Support Measures (ESM) pod mounted dorsally just aft of the front seat overhead hatches and were also fitted with a smoke particle detector or "sniffer" for detecting exhaust particles from diesel-electric submarines running on snorkel. Later S-2s had the sniffer removed and had the ESM antennae moved to four rounded extensions on the wingtips. A 70-million-candlepower searchlight was mounted on the starboard wing.

 

[GK Dundas]

Most of those dedicated ASW systems had been removed from the CP 121's .The government of the day was more interested in surface contacts then sub surface ones. Fisheries patrols ( Fish Pat) and Sovereignty Patrols. (Sov Pat )were the order of the day
At the same Soviet submarines were getting disturbingly quiet. A slightly larger aircraft then the Tracker dedicated to coastal ASW work might have been nice .
DeHavilland offered up both the Dash 7 and 8 as I recall.

 

[Rule of cool]

Early Trackers also carried 60 explosive charges, dispensed ventrally from the rear of the fuselage and used to create sound pulses for semi-active sonar (JULIE)

I read a novel when I was at school about a RAN Tracker sinking an Indonesian sub by accident with one of these explosive charges.