RAN Essex class

[Thorvic]

As part of the Ship Group Build on the What-If Modeling forum i am attempting to build a 1/700 Essex Class that was proposed as a replacement for HMAS Melbourne based on the thread Abraham Gruber posted on here.

Build wise i am using the Trumpeter Essex class kit that depicts the WW2 original format of the ship and using a scaled drawing of the USS Oriskany as a basis for the modernisation.

The modelling of the ship has raised a few questions, as this envisaged a 1965 refit of an existing unmodified Essex rather one of the currently modified ships of the time, so this limits it to one of the designated Aircraft Transports or one of the LPH ships (the war damaged ones being excluded - Franklin & Bunker Hill). So given the later date what revisions would the US do to the Oriskany design to improve performance.

The 1964 date still has the F-4B Phantom as the aircraft of choice as at this time the USN hadn't disclosed that the F-4B wasn't suitable for smaller fleet carrier operations, so would they use the British inspired F-4K with the spey engines and extended leg, or would the F-4HL variant be built which coupled the K mods with a revised wing to give higher lift and a safer margin for smaller carrier operations ?

The other question regards weapons and sensor fit as at this time most of the RAN weaponry mirrored the RN, light AA being based on 40mm Bofors and SAM using the Sea Cat system. I suspect Seacat would have replaced the 5" guns and bofors with the Dutch search radar as fitted to the Melbourne as found in the 1965 edition of Janes that Melbourne would be modernised with Seacat (it wasn't much like Ark Royal wasn't ) but in 1964 the weapon was still in vogue.

I did find this interesting snippet on Wiki "An unmodernised Essex was offered to the Royal Australian Navy in 1960 as a replacement for HMAS Melbourne but the offer was declined due to the expense of modifications required to make it operationally compatible with the RAN's primarily British-designed fleet.[18]" which references Frame, Tom (1992). Pacific Partners: a history of Australian-American naval relations. p. 101..
So i suspect i am on the right track

Geoff

 

[Abraham Gubler]

The modelling of the ship has raised a few questions, as this envisaged a 1965 refit of an existing unmodified Essex rather one of the currently modified ships of the time, so this limits it to one of the designated Aircraft Transports or one of the LPH ships (the war damaged ones being excluded - Franklin & Bunker Hill). So given the later date what revisions would the US do to the Oriskany design to improve performance.

The most likely Essex class for conversion to HMAS Australia would be the USS Philippine Sea. It was in the condition required for a full SCB-125A conversion (as applied to the USS Oriskany) that the RAN and USN had specified. The details of the conversion are covered in the Navy report that was linked to in this thread.

http://www.secretprojects.co.uk/forum/index.php/topic,8449.0

The link has gone dead so I will endeavour to re attach it to this post. Because of the size of the document (it is picture intensive) I have cut it up into six sequential parts and will attach two per post to this thread. Parkinson's Law in action.

 

[Abraham Gubler]

The 1964 date still has the F-4B Phantom as the aircraft of choice as at this time the USN hadn't disclosed that the F-4B wasn't suitable for smaller fleet carrier operations, so would they use the British inspired F-4K with the spey engines and extended leg, or would the F-4HL variant be built which coupled the K mods with a revised wing to give higher lift and a safer margin for smaller carrier operations ?

That’s not quite accurate. The F-4B was qualified for flight operations from Essex class carriers. That the USN never allocated F-4s to Essex wings was for two reasons: Firstly the Essex carriers did not have wings that routinely flew interceptors like the F-4, they had ASW wings with Trackers and Skyhawks and attack wings with Crusaders, Skyhawks and Skyraiders. Secondly it would be very demanding to fly F-4s from these carriers. But the RAN was game.

 

[Abraham Gubler]

The other question regards weapons and sensor fit as at this time most of the RAN weaponry mirrored the RN, light AA being based on 40mm Bofors and SAM using the Sea Cat system. I suspect Seacat would have replaced the 5" guns and bofors with the Dutch search radar as fitted to the Melbourne as found in the 1965 edition of Janes that Melbourne would be modernised with Seacat (it wasn't much like Ark Royal wasn't ) but in 1964 the weapon was still in vogue.

The new carrier was to be equipped with standard USN weapons and sensors. The RAN had ordered its first two American built Charles F. Adams DDG in 1962 (and a third in ’63) and was actually keen to convert to US standard weapons. There would be no need to replace radars because it was being refitted with new. Melbourne needed her radars replaced in the late ‘60s because it was still using ones built in the early ‘50s. Sea Cat is a possibility for late fitting to replace the 5” guns. The RAN ordered a second batch of Sea Cat in 1969 so its possible that this order could have been expanded for the new carrier.

I did find this interesting snippet on Wiki "An unmodernised Essex was offered to the Royal Australian Navy in 1960 as a replacement for HMAS Melbourne but the offer was declined due to the expense of modifications required to make it operationally compatible with the RAN's primarily British-designed fleet.[18]" which references Frame, Tom (1992). Pacific Partners: a history of Australian-American naval relations. p. 101..

This would probably apply to the flight deck for air wing compatibility not ship to ship integration. It wouldn’t be fun trying to fly Sea Venoms and Gannets of an axial deck carrier, even a medium sized one like the Essex. Have a good look at the RAN’s report it is pretty comprehensive about what they wanted.

 

[Thorvic]

The 1964 date still has the F-4B Phantom as the aircraft of choice as at this time the USN hadn't disclosed that the F-4B wasn't suitable for smaller fleet carrier operations, so would they use the British inspired F-4K with the spey engines and extended leg, or would the F-4HL variant be built which coupled the K mods with a revised wing to give higher lift and a safer margin for smaller carrier operations ?

That’s not quite accurate. The F-4B was qualified for flight operations from Essex class carriers. That the USN never allocated F-4s to Essex wings was for two reasons: Firstly the Essex carriers did not have wings that routinely flew interceptors like the F-4, they had ASW wings with Trackers and Skyhawks and attack wings with Crusaders, Skyhawks and Skyraiders. Secondly it would be very demanding to fly F-4s from these carriers. But the RAN was game.

Your thinking of the CVS ASW Essex's but some like Oriskany & Hancock were CVA attack carriers with the Crusaders, Corsairs, Intruders, and previously Skyhawks.

 

[Abraham Gubler]

The 1964 date still has the F-4B Phantom as the aircraft of choice as at this time the USN hadn't disclosed that the F-4B wasn't suitable for smaller fleet carrier operations, so would they use the British inspired F-4K with the spey engines and extended leg, or would the F-4HL variant be built which coupled the K mods with a revised wing to give higher lift and a safer margin for smaller carrier operations ?

That’s not quite accurate. The F-4B was qualified for flight operations from Essex class carriers. That the USN never allocated F-4s to Essex wings was for two reasons: Firstly the Essex carriers did not have wings that routinely flew interceptors like the F-4, they had ASW wings with Trackers and Skyhawks and attack wings with Crusaders, Skyhawks and Skyraiders. Secondly it would be very demanding to fly F-4s from these carriers. But the RAN was game.

Your thinking of the CVS ASW Essex's but some like Oriskany & Hancock were CVA attack carriers with the Crusaders, Corsairs, Intruders, and previously Skyhawks.

Same thing.

 

[Abraham Gubler]

Oriskany and Tico both deployed to VietNam with A-7s. No Intruders flew from Essex class wings that I know of.

http://www.history.navy.mil/avh-1910/APP26.PDF

The nosewheel gear was backwards compatible with older cats. But the older cats didn't have the power to launch many of the newer planes. The RAN Essex was to have the latest catapults.

 

[zen]

F4 operating from a modernised Essex is not impossible, but it does require a number of changes. As was it was not an ideal solution to unhitch the fourth wire and land very light.

Principaly due to the pull out distance. Something that could be covered in how the recovery zone is constructed. Easily coverable during the modernisation process. Though perhaps making it a little more specific and 'one-off' for the RAN. That said it be of interest to the USN.

Would be highly interesting to ponder the knock on effect of this. If the timing is right, it opens a possibly cheaper option than CVA-01 to the RN.

 

[Abraham Gubler]

While the RAN was benchmarking on an Oriskany type upgraded Essex they were looking at further improvements. This included 250’ catapults in place of the 211’ and SPS-48 3D radar in place of SPS-30 height finding radar. It stands to reason that the landing on deck could be modified to provide additional run out length.

The Australian Essex (HMAS Australia) would have a very different air wing to USN Oriskany class. It would include 16 Phantom strike fighters, 12 Tracker ASW aircraft, 4 Tracer AEW aircraft, 16 Wessex ASW helicopters and 2 Whirlwind SAR helicopters. In effect this is far more like an ASW air wing than an attack air wing and would benefit from the long endurance of the Tracker and Tracer aircraft and large number of helicopters. This would place less demand on the elevators for movements compared to an attack carrier air wing. A typical cycle would only need to include 10 aircraft launches and recoveries compared to around 30 for an attack wing. The need to strike down aircraft to keep the deck moving would be much, much less. So it is feasible that they could even do away with the port elevator to extend the deck, if they had to.

 

[Pioneer]

Interesting!!
Thanks gents

P.S. Some great knowledge shared Abraham Gubler - thanks


Regards
Pioneer

 

[Thorvic]

F4 operating from a modernised Essex is not impossible, but it does require a number of changes. As was it was not an ideal solution to unhitch the fourth wire and land very light.

Principaly due to the pull out distance. Something that could be covered in how the recovery zone is constructed. Easily coverable during the modernisation process. Though perhaps making it a little more specific and 'one-off' for the RAN. That said it be of interest to the USN.

Would be highly interesting to ponder the knock on effect of this. If the timing is right, it opens a possibly cheaper option than CVA-01 to the RN.

Zen have you had a look at the F-4HL thats in Phantom:Spirit of the Skies ?, as McDD revised the Phantom design to a higher lift format mixing the F-4K features such as RR engines with a slightly stretched fuselage along with new wings and tail planes. It says they were hoping to replace the UK's F-4K's and for the USN to take some so i suspect it was aimed at making the Phantom more compaitable with the smaller carrier such as the Essex's and the RN carriers.

The F-4FVS also follows a similar path by replacing the wing with a VG version.

Going to be fun trying to create those in 1/700 as the Trumpeter 1/700 are moulded in clear plastic which does make them a little more difficult to work with all for the sake of creating a clear canopy (The plastic is more brittle, its difficult to see the details during building and th surface clouds up in contact with the standard model solvent glues !!)

G

 

[Sheriff]

RAN F-4K's operating from an RAN Essex class carrier (HMAS Australia) in Strike Fighters 2: Vietnam

 

[uk 75]

The RN reportedly examined the Essex class carriers offered them as an alternative to CVA 01 and found too many problems in the state of the ships and their incompatibility with RN practices. However, given how poor the material condition of Ark Royal was in this period one has to wonder if this was not driven by politics.

Until the 70s when the USN introduced the S3 and moved them on to the Nimitz/Forrestal ships the Essex class were key units of the US Navy and needed for a range of duties notably in Vietnam. However in an alternate 1960s with no Vietnam and a continuing emphasis on the US Soviet naval match Essexes might have been disposed of quicker to countries like Australia, Brazil and possibly the UK.

If HMAS Australia had been transferred in the 60s-70s the Phantom/Buccaneer combination might have been a valid alternative to the Crusader/Skyhawk/ US ASW/AEW/COD that doubtless would have been part of the package offered by the US. As mentioned in other Threads if the UK had gone down the path of a Hermes sized new build with Buccaneers alone or with the BAC 583 this too would have been a good alternative for Australia.

If Australia had been continuing in a more intensive Vietnam, Buccaneers in the strike role could have filled the gap left by F-111 delays both on and off carriers (The RAF got theirs in 69 so it would fit). Buccaneer was definitely a better strike aircraft than the F4.

 

[Abraham Gubler]

RAN F-4K's operating from an RAN Essex class carrier (HMAS Australia) in Strike Fighters 2: Vietnam

The F-4K proved itself incompatible with Essex class carriers during cross decking between the RN and USN. The RN Phantoms had no problem getting on-board but when it came time to leave they caused quite the uproar. The increased exhaust plume of the Spey on reheat combined with the wooden deck caused the later to combust while waiting for the catapult shoot. Once the fires had been put out the Phantoms had to take off on military power with the pilot selecting reheat during the run down the catapult line which lead to a very, very dicey take off. They decided never to cross deck to Essex class again!

 

[kaiserbill]

Didn't some of the later Essex post-war conversions do away with the wooden flight deck?

 

[Abraham Gubler]

Didn't some of the later Essex post-war conversions do away with the wooden flight deck?

Only on the landing on area. Which was replaced with an aluminium deck. The rest remained wood. Which was fine until someone tried to launch a high nose, Spey powered Phantom from it.

 

[Thorvic]

Only partially with aluminium beams replacing the the timber, the problem with the Essex was they couldn't stand up to getting a steel flight deck, which is what they needed to make them capable of operating the new generation of USN carrier aircraft.

Ironically the big heavy combat aircraft of the late 50's (Phantom, Buccaneer) had shown they were a bit to big and heavy, thats why the UK were looking at the 583 and then AFVG at least matched the performance of the current aircraft but using the best of new technology to achieve this in samller more compact airframe more suited to operations on smaller carrier fleet carrier rather than super carriers.

 

[Abraham Gubler]

Only partially with aluminium beams replacing the the timber, the problem with the Essex was they couldn't stand up to getting a steel flight deck, which is what they needed to make them capable of operating the new generation of USN carrier aircraft.

The last laugh of the armoured flight deck?

 

[Cobrapilot]

According to Norman Polmar in Aircraft carriers (Pg 203), The F-4 Phantom flew carrier trials on the USS Intrepid CVA-11 (Essex Class). They were proven capable of safely operating the Phantom. In the same reference (pg 205) he later describes the trials of the A-6 intruder, he states that ALL Attack carriers were intended to operate the A-6 Intruder as a replacement for the A-1 Skyraider. Production schedules and Vietnam losses did not permit introduction of the A-6 onto the Essex class.
I have another reference that shows photos of both types conducting carrier qualifications onboard Essex class carriers (believe USS Lexington) and another that details the reduced loads that would be required to operate the A-6 off the Essex class. I also have pics of USN F-4's and A-6's on deck of the HMS Ark Royal next to her aircraft. If I find those I will post them later.

 

[Cobrapilot]

F-4's, A-6's and A-7's on HMS Ark Royal

According to Norman Polmar in Aircraft carriers (Pg 203), The F-4 Phantom flew carrier trials on the USS Intrepid CVA-11 (Essex Class). They were proven capable of safely operating the Phantom. In the same reference (pg 205) he later describes the trials of the A-6 intruder, he states that ALL Attack carriers were intended to operate the A-6 Intruder as a replacement for the A-1 Skyraider. Production schedules and Vietnam losses did not permit introduction of the A-6 onto the Essex class.
I have another reference that shows photos of both types conducting carrier qualifications onboard Essex class carriers (believe USS Lexington) and another that details the reduced loads that would be required to operate the A-6 off the Essex class. I also have pics of USN F-4's and A-6's on deck of the HMS Ark Royal next to her aircraft. If I find those I will post them later.

Also in the 1981 DOD Appropriations hearings, Sen. Goldwater asked whether F-18 Hornets could be operated off the Essex class carriers if they were reactivated. The answer was no, without some modifications. His next question was what modifications and how much would they cost? The answer on page 2183 was a list of items (different Jet blast deflectors and inertial nav equipment, etc, totaling about 13 million dollars.

 

[Archibald]

Wow, A-6 Intruders and Buccaneers side by side. Pretty cool. I think you posted the same photo twice.

A loooooong discussion about keeping Essex carriers operational in the 80's.

Keep the Essex class as a strike carrier

I suspect the C2 speed issue is less of a red herring that it is made out to be, mainly because of what it would take to put such a slow aircraft out to the tanking point; turning the carrier and its entire Task Force into the wind maybe 30 minutes before the strike to launch a single aircraft...

www.alternatehistory.com

Oriskany, Hancock would be the most likely candidates. Also note that the two crippled of WWII, Franklin and Bunker Hill, were patched up, repaired, put in reserve until the 70's. Proposals were made for a thorough rebuild which would have made them even better than a SBC-125A. First, USS United States -style with a flush island (not good) and later with a far more interesting heavy rebuild. As long as they didn't end like USS Midway in the 80's, that went a... bridge too far (lame pun assumed).

Keep the Essex class as a strike carrier

Don't forget, the 27A mod carrier like short hull Hornet handled the heavy A-3 Whale Yeah, but those aircraft weren't launched at anything even approaching their MTOW. And they had a very low stall speed. The Phantom needed more oopmh from the cats to get airborne

www.alternatehistory.com

What is really interesting is that the thorough rebuild of Franklin and Bunker Hill could eliminate three major reasons that prevented the RN, RAN or other navies to get Essex as second hand carriers. The wooden deck, for a start. The very long service lives since 1945: these two sat in reserve, so it doesn't apply. And, most importantly, the huge manpower requirements: 3000 sailors... a complete rebuild could get more automation.

Hmm, shame the RN couldn't jump into that bandwagon after the CVA-01 disaster. They were proposed second-hand SBC-125A Essex but that was (rightly) rejected, too old, too large manpower requirements.

 

[ZacYates]

I was idly thinking about modelling a replacement for the Melbourne and was looking at a Midway-class, then I found the comment Geoff cited about the Essex-class. Some fascinating discussion here, gents!

 

[alejandrogrossi]

RAN F-4K's operating from an RAN Essex class carrier (HMAS Australia) in Strike Fighters 2: Vietnam

The F-4K proved itself incompatible with Essex class carriers during cross decking between the RN and USN. The RN Phantoms had no problem getting on-board but when it came time to leave they caused quite the uproar. The increased exhaust plume of the Spey on reheat combined with the wooden deck caused the later to combust while waiting for the catapult shoot. Once the fires had been put out the Phantoms had to take off on military power with the pilot selecting reheat during the run down the catapult line which lead to a very, very dicey take off. They decided never to cross deck to Essex class again!

Abraham
Does exits any photo of that cross-deck?

 

[GTX]

I'm curious: Would the F-4 (FVS) proposal have helped in any way regarding having F-4s operating off the Essex class?

 

[alejandrogrossi]

The 1964 date still has the F-4B Phantom as the aircraft of choice as at this time the USN hadn't disclosed that the F-4B wasn't suitable for smaller fleet carrier operations, so would they use the British inspired F-4K with the spey engines and extended leg, or would the F-4HL variant be built which coupled the K mods with a revised wing to give higher lift and a safer margin for smaller carrier operations ?

That’s not quite accurate. The F-4B was qualified for flight operations from Essex class carriers. That the USN never allocated F-4s to Essex wings was for two reasons: Firstly the Essex carriers did not have wings that routinely flew interceptors like the F-4, they had ASW wings with Trackers and Skyhawks and attack wings with Crusaders, Skyhawks and Skyraiders. Secondly it would be very demanding to fly F-4s from these carriers. But the RAN was game.

Abraham
The Pt3 page 209 talks about "..stengthening of the hull by the addition of blisters, re construction of the flight deck and island..."
One question
That upgrades is apart of that upgrade that have - in this case the USS oriskany ? or the idea was that the chosen one will stay like this?

.

 

[BlackBat242]

The existing modernizations of the Essex class carriers already incorporated hull "bulges" ("blisters").

Original hull beam at waterline: 93'
SCB-27A modernization (hydraulic catapult version)*: 101' over bulges
SCB-27C modernization (steam catapult version)*: 103' over bulges
CVA-34 Oriskany: 106' over bulges


* 7 of the 8 -27A ships (exception was CV-39 Lake Champlain) and all 6 -27C ships also received SCB-125, which was the angle-deck modification.
CV-34 received -27A features during completion in 1950, but then received a unique "all-in-one" modernization (incorporating -27C & -125 as well as a few other changes) designated SCB-125A in 1957-59 (completing work 2 years after all other ships of the class).

8 Essex class ships received no modernization work, and CV-33 Antietam received only the improvised "test" angle deck, but nothing else.

 

[Light Blue Job]

According to Norman Polmar in Aircraft carriers (Pg 203), The F-4 Phantom flew carrier trials on the USS Intrepid CVA-11 (Essex Class). They were proven capable of safely operating the Phantom. In the same reference (pg 205) he later describes the trials of the A-6 intruder, he states that ALL Attack carriers were intended to operate the A-6 Intruder as a replacement for the A-1 Skyraider. Production schedules and Vietnam losses did not permit introduction of the A-6 onto the Essex class.
I have another reference that shows photos of both types conducting carrier qualifications onboard Essex class carriers (believe USS Lexington) and another that details the reduced loads that would be required to operate the A-6 off the Essex class. I also have pics of USN F-4's and A-6's on deck of the HMS Ark Royal next to her aircraft. If I find those I will post them later.

What is the reference for reduced loads on the A-6?

 

[H_K]

What is the reference for reduced loads on the A-6?

I believe the reduced loads were only for the Essex carriers with H8 hydraulic catapults, which limited the A-6A’s launch weight to 40,000lbs with 25kts WOD. See paper below:

https://apps.dtic.mil/sti/pdfs/ADA382399.pdf

The Essex carriers with C11-1 steam catapults could launch an A-6A at 54,000lbs in tropical conditions with 18kts WOD, per the A-6A SAC:

A2F / A-6 Intruder

The catapult end speed at this weight was approx 116kts at a launch setting of 480psi.

 

[CV12Hornet]

I'm curious: Would the F-4 (FVS) proposal have helped in any way regarding having F-4s operating off the Essex class?

Most likely. The biggest issue behind the stores consumption was the high landing speed. VG wings are in large part a solution to reducing takeoff and landing speeds.

 

[Cobrapilot]

RAN F-4K's operating from an RAN Essex class carrier (HMAS Australia) in Strike Fighters 2: Vietnam

The F-4K proved itself incompatible with Essex class carriers during cross decking between the RN and USN. The RN Phantoms had no problem getting on-board but when it came time to leave they caused quite the uproar. The increased exhaust plume of the Spey on reheat combined with the wooden deck caused the later to combust while waiting for the catapult shoot. Once the fires had been put out the Phantoms had to take off on military power with the pilot selecting reheat during the run down the catapult line which lead to a very, very dicey take off. They decided never to cross deck to Essex class again!

Abraham
Does exits any photo of that cross-deck?

The RN Phantoms had a longer nose gear than US Phantoms. This in turn angled their afterburner exhausts down toward the deck in comparison to US Phantoms. This angle is what caused the deck burning issue.

 

[F.L.]

@Thorvic the image link you attached to your first message is dead.
Would you repost the picture ?

 

[Archibald]

The existing modernizations of the Essex class carriers already incorporated hull "bulges" ("blisters").

Original hull beam at waterline: 93'
SCB-27A modernization (hydraulic catapult version)*: 101' over bulges
SCB-27C modernization (steam catapult version)*: 103' over bulges
CVA-34 Oriskany: 106' over bulges


* 7 of the 8 -27A ships (exception was CV-39 Lake Champlain) and all 6 -27C ships also received SCB-125, which was the angle-deck modification.
CV-34 received -27A features during completion in 1950, but then received a unique "all-in-one" modernization (incorporating -27C & -125 as well as a few other changes) designated SCB-125A in 1957-59 (completing work 2 years after all other ships of the class).

8 Essex class ships received no modernization work, and CV-33 Antietam received only the improvised "test" angle deck, but nothing else.

24 Essex built, all of them with H-4 hydraulic catapults
-2 crippled, fully repaired, never returned service (my beloved CV-13 Franklin and CV-17 Bunker Hill, I have great plan for them in my TL)
-1 orphan: Antietam: pioneered angled deck but went no further, poor thing.
-3 AVT, no SCB mods, ever (AVT-10, AVT-11, AVT-12)
-3 LPH (LPH-4, LPH-5, LPH-8: lost amid the Iwo Jiwa LPHs)

Of the 15 left,
Lake Champlain became an orphan, too (got its SCB-27A but not its SCB-125A, so no angled deck)
7 got an improved H-4 called H-8, still hydraulic (SCB-27A) then SCB-125 = angled deck
7 got C-11 catapults (SCB-27C) then SCB-125 = angled deck

And Oriskany screwed all the others and always raced ahead of the pack !

The AVTs went away first, around 1960
The LPHs followed
Then Antietam
Then the two crippled
And finally, the H-8 and the C-11 after them.
By 1977 it was mostly over except for Lexington, which soldiered on as a training carrier until 1991 .

 

[Scott Kenny]

As part of the Ship Group Build on the What-If Modeling forum i am attempting to build a 1/700 Essex Class that was proposed as a replacement for HMAS Melbourne based on the thread Abraham Gruber posted on here.

Build wise i am using the Trumpeter Essex class kit that depicts the WW2 original format of the ship and using a scaled drawing of the USS Oriskany as a basis for the modernisation.

The modelling of the ship has raised a few questions, as this envisaged a 1965 refit of an existing unmodified Essex rather one of the currently modified ships of the time, so this limits it to one of the designated Aircraft Transports or one of the LPH ships (the war damaged ones being excluded - Franklin & Bunker Hill). So given the later date what revisions would the US do to the Oriskany design to improve performance.

The 1964 date still has the F-4B Phantom as the aircraft of choice as at this time the USN hadn't disclosed that the F-4B wasn't suitable for smaller fleet carrier operations, so would they use the British inspired F-4K with the spey engines and extended leg, or would the F-4HL variant be built which coupled the K mods with a revised wing to give higher lift and a safer margin for smaller carrier operations ?

I'd expect Spey Phantoms, F-4Ks as-is.

I find it unlikely that the HL would be built.

Color me surprised about the wooden decks having to stay. That would complicate things. Maybe a patch of steel where the exhaust hits the deck?

The other question regards weapons and sensor fit as at this time most of the RAN weaponry mirrored the RN, light AA being based on 40mm Bofors and SAM using the Sea Cat system. I suspect Seacat would have replaced the 5" guns and bofors with the Dutch search radar as fitted to the Melbourne as found in the 1965 edition of Janes that Melbourne would be modernised with Seacat (it wasn't much like Ark Royal wasn't ) but in 1964 the weapon was still in vogue.

Sounds likely.