Commencement Bay Class Conversion Seaplane Tender (mid-1950s)

[Triton]

A mid-1950s proposal was to convert escort carriers of the Commencement Bay class into sea plane tenders for the Martin P6M SeaMaster jet sea plane bomber. According to Friedman, this conversion program died when the P6M was canceled to offset the cost of the Polaris missile program.

Images from US Aircraft Carriers: An Illustrated Design History by Norman Friedman (1983).

http://books.google.com/books?id=-UT7MDTeKj8C&pg=PA346&lpg=PA346&dq=Commencement+Bay+seaplane+tender&source=bl&ots=HTbk_LCwMa&sig=uSEV06NeWzHPCHtiaNvjDDTfoxs&hl=en&ei=wkNmSom4D43usQO55IjbDg&sa=X&oi=book_result&ct=result&resnum=3

http://en.wikipedia.org/wiki/Commencement_Bay_class_escort_carrier
http://en.wikipedia.org/wiki/P6M

 

[minoslas]

What specification, displacement, speed and capability on seaplane replenished, helicopter carrier, hangar capability, weapon systems, sensors and magazines tell that ship project? I can´t see google reference book.

 

[TomS]

I have a copy of Friedman's book at hand. The basic characteristics of the CVE 105 conversion isn't given, but would probably not have differed too much from the unmodified ship (possibly a bit longer with the seaplane ramp at the stern?)


As shown in the drawing, armament would have been 4 twin 3-inch/50 mounts, with SPS-10 surface-search radar and SPS-12 air-search radar as sensors. The ship would have carried six HSS (aka SH-34) helicopters. Magazine space was about 900 tons for conventional weapons an 80 tons for "special" nuclear weapons. Fuel capacity is given as 1.1 million gallons of JP-5 (something around 3,400 tons), plus 45,000 gallons of avgas (around 120 tons).

 

[Tzoli]

Looks like it could service one Martin P6M SeaMaster and refuel two other.
Nice proposal and probably the last seaplane tender project?

 

[TomS]

Looks like it could service one Martin P6M SeaMaster and refuel two other.
Nice proposal and probably the last seaplane tender project?

Just had a look in Martin P6M Seamaster by Stan Piet and Al Raithel. It has a drawing of another ship -- an AV (seaplane tender) rather than an adapted escort carrier (CVE) -- two AVs were earmarked for conversion to support the P6M Seaplane Striking Force.

The drawing has more detail on those booms, which would likely have been used in the CVE conversion as well. The booms were for both refueling and rearming. Remember than the Seamaster's bomb bay was accessible from above so the plane could reload on the water. In the photo, you can see a large cylindrical payload -- probably something like a Mk 39 special weapon -- being moved out suspended from the boom.

 

[Tzoli]

According to Friedman it would be one of the Commencement Bay class Escort Carriers. The "Air Group" would include 3x P6M Seamasters and 6x SH-34 Seabats

 

[TomS]

According to Friedman it would be one of the Commencement Bay class Escort Carriers. The "Air Group" would include 3x P6M Seamasters and 6x SH-34 Seabats

That was another proposal. In reality, however, Albermarle (AV-5) and Currituck (AV-7) were actually chosen. AV-5 actually began the conversion process but was stopped part way along and later reconverted back to serve as an (Army) helicopter repair ship. AV-7 was decomissioned in anticipation of the conversion but was reactivated as a general purpose seaplane tender in Vietnam.

 

[TomS]

The P6M book actually lays out a couple of proposed force structures with various combinations of aircraft, floating docks, LSDs, tenders, and escorts. (Edit: and submarine tankers for forward operations) Another CVE-105 proposal was a conversion of operate F2Y SeaDart fighters for protection of the forward operating bases.

In practice, this would have been a huge logistical effort to support a relatively small number of bombers. The addition of A3Ds to the CVA airwings was a much more cost-effective solution.

 

[Archibald]

And Vigilantes. And Regulus I & II. But the real deal of course was the Polaris inside the nuclear submarine.
41 submarines with 16 tubes each, 656 tubes with 656 Polaris later with three warheads each, total 1968 nukes hiding into the ocean depths and then flying balistically at Mach 15, so no possible interception. All this with stacked steel tubes filled with fertilizer, so ,not that expensive per unit.
That was a huge leap forward. And it hasn't been bettered since then (I use to think the Air Force Cold War Scary Generals had kitten over this, even with plenty of Minutemans - by 1950 they thought they had beaten the Navy into a pulp at nuclear delivery systems - only for the Polaris to turn the tables 10 years later).

 

[TomS]

That was another proposal. In reality, however, Albermarle (AV-5) and Currituck (AV-7) were actually chosen.

Rereading Friedman's caption about this design, it seems the CVE-105 conversion was to follow after the two AV conversions. The AVs would have had only one rearming boom each, while the CVE (maybe AVE in this application?) would have two. The CVE conversion would also have much more JP-5 (1.1 million gallons versus 307,000 for AV-7), more conventional ammunition (900 tons versus 400) and slightly more special weapons (80 tons versus 70). The AVs would carry more avgas, which is weird, because I can't see what they would use it for. Maybe supporting older seaplanes?

 

[Firefinder]

That was another proposal. In reality, however, Albermarle (AV-5) and Currituck (AV-7) were actually chosen.

Rereading Friedman's caption about this design, it seems the CVE-105 conversion was to follow after the two AV conversions. The AVs would have had only one rearming boom each, while the CVE (maybe AVE in this application?) would have two. The CVE conversion would also have much more JP-5 (1.1 million gallons versus 307,000 for AV-7), more conventional ammunition (900 tons versus 400) and slightly more special weapons (80 tons versus 70). The AVs would carry more avgas, which is weird, because I can't see what they would use it for. Maybe supporting older seaplanes?

The P5m Marlins did serve till 67...

Plus the Grummam Albatross till the 70s...

Also likely for the same reason why the navy has not unified the Fuel type they use since all the ships are either Nukes, or Turbines with some deisels that dont care bout fuel type.

Cost too much to clean out the tanks...

 

[Archibald]

https://www.secretprojects.co.uk/threads/sea-control-ship-scs-and-vstol-support-ship-vss.7635/page-3#post-647299

 

[A Tentative Fleet Plan]

Other candidates for conversion into
P6M Tenders were the Curtiss-class Seaplane Tender USS Albemarle and Ashland-class Landing Ship Dock USS Ashland.

USS Albemarle (AV 5) P6M conversion

An artist's rendering dated 28 January 1955 of the SCB 134 conversion of Albemarle that was funded in the Fiscal Year 1956 conversion program. The tender is shown supporting two of the large aircraft, one being hauled out on a stern ramp and one moored to a servicing boom to starboard. The conversion began on 15 August 1956.

Photo No. None
Source: U.S. Naval History and Heritage Command (UA 437)

USS Ashland (LSD 1) P6M conversion

An artist's rendering of the SCB 186 conversion of an LSD to a tender for the P6M jet seaplane. This option began to gain favor in mid-1957 when doubts on the effectiveness of the lifting device in the AV 5 conversion made docking type tenders like the LSD appeared more promising. The LSD is shown supporting two of the aircraft, one in her docking well and one moored to a servicing boom to starboard.

Photo No. None
Source: U.S. Naval History and Heritage Command (UA 437)

USS Ashland (LSD 1) P6M conversion

A design sketch of the SCB 186 conversion design dated 16 September 1957, when the LSD conversion was called AVD 15. The sketch shows the cradles and cradle tracks that were needed to bring the aircraft into the docking well, a system with less engineering risk than the recovery ramp in the AV 5 conversion. It also shows support for the initial mission of the aircraft, long-range minelaying.

Photo No. None
Source: U.S. Naval History and Heritage Command

Source: https://www.shipscribe.com/usnaux2/AV/AV21-p.html

Further information on the design here: https://www.shipscribe.com/usnaux2/AV/AV21.html