It is currently 25 Jun 2017, 23:27



Welcome
Welcome to Campaigning Through Time, a ‘historum’ for the discussion of military history and the archiving of current events and commemoration. As founders, our goals were to create a community that would last, that would pride itself on purposeful discussion and relaxed moderation, and would ultimately nurture and encourage interest in military history. Working with the University of Kent's Military History Society and their network of students and alumni, we hope to extend military history to all who wish to learn more. All are welcome!

If you are new to our site, have a look at our rules and FAQ, browse our upcoming events, get help with coursework, check out our magazine, peruse our archive, or simply have some fun!

Registration is fast, simple, and absolutely free, so join the discussion today!





 Page 1 of 1 [ 4 posts ] 
Author Message
 Post subject: The US Navy's Unusual Deterrent
Unread postPosted: 13 Dec 2015, 21:57 
Lieutenant-Colonel
Lieutenant-Colonel
User avatar

Joined: 30 Jan 2012, 19:49
Posts: 1874
Location: United Kingdom
Has thanked: 65 time
Have thanks: 119 time
The US Navy's seaplane deterrent
Policy, merits, and failings: The unusual nuclear strike option considered by the USN

by John Ash

Image
USN Martin P6M-1 SeaMaster in flight, circa 1955. (USN)


It's the 1950s and the Cold War is beginning to reach new and increasingly tense heights. The pressing doctrinal (and common sense) need for an effective nuclear deterrence became ever more important whilst simultaneously more difficult to achieve. The United States was no longer the sole Nuclear power and had not been for some time. Anti-aircraft missiles and airborne interceptors were becoming more and more potent, being increasingly effective at higher altitudes, longer ranges, and at higher speeds. The distances involved were vast, and if a strike was ordered the traditional method of launching nuclear strikes by way of strategic bombers was no guarantee of success.

The submarine launched missile system, today's primary means of delivery, had yet to be developed. The second system of land based missile silos were vulnerable and expensive, plus immobile. Air delivery, as mentioned, was even more vulnerable - especially as the viability of air defence systems all but removed the high altitude option. However, at least the aircraft were typically new, specifically designed for the role, and could move around, be in the air on standby, easily supported by other assets, had the ability to defend themselves. It was generally a more flexible system, and certainly more viable than other methods such as nuclear artillery shells.

With the historically smaller size of carriers of the period, and limits that placed on the size, range and payload of carrier aircraft, the US Navy had a problem. It had to develop a flexible and viable means of delivering a nuclear device at a time where the first nuclear submarine, USS Nautilus, was still under construction, a concept yet to be proven, and was incapable of delivering a nuclear weapon. To solve this problem, the US Navy would look to the past.

For much of first decades of flight, it was the endurance, range and flexibility of the seaplane that impressed. However, the seaplane was surely no longer capable of impressing. In the military realm, the type had become obsolete for almost all but rescue and patrol by the 1940s. They were slow, ungainly, and impractical, vulnerable, and certainly not suitable for carrying nuclear weapons which at the time could weigh nearly as much as a Sunderland or Catalina - fairly large aircraft.

Therefore when the legendary (and sadly now defunct) Glenn L Martin company developed a seaplane you might be surprised at the result.

Viable and Modern:

Image
Martin P6M-2 "SeaMaster" flying boat on ramp following taxi out of water, 1959 (San Diego Air & Space Museum Archives)


The US Navy had changed drastically in under 15 years. Like all navies, it had entered the Second World War pursuing a doctrine based on the power and status of the traditional battleship. Events such as the Taranto Raid, Pearl Harbour, and Midway convincingly proved the viability of the carrier as a capital ship, as the lynchpin and primary means of attack for a fleet, and showed how the carrier had surpassed the big-gun battleship. This realisation came at a time of rapid expansion and modernisation, with two very different sea wars against two very different foes, and at a time where not only was the USN allied with Britain and her powerful Royal Navy, but were operating with them on a day to day basis, sharing technology and tactics wit each other - and it was a two way thing, the USN had a lot to learn as well as a lot to give.

Regardless, as pressing and stressful the two wars at sea were, there was not a better time for the USN to progress and develop. By 1943, the USN was larger than the combined fleets of all the other combatants in the war, even when including Britain, Italy and Japan, who had huge fleets of their own. By 1945, the US had 70% of the world's total number, and total tonnage, of naval vessels. By VJ Day, the US Navy was officially operating 6,768 ships.

The US operated a large number of aircraft carriers, which as already mentioned, had rightly been identified as the ship of the future. However, soon after the war's end, unlike any other navy (even others facing the potential of a war with the USSR) the USN had to push continued development and transformation into a highly technological navy. In the dawn of a nuclear age, without the worry of budgetary issues that plagued other nations, the USN had to focus on developing new weapons systems, ships, and aircraft. The Navy was in a strong position post-1945, but the situation demanded viable options to enable the USN to remain ahead - of the other services as much as any foe.

The fact that the USAF was the primary service is no surprise. They had the aircraft with the range, and the friends with the bases, to ensure that the USAF was positioned ready. It is true that the USN had it's fleet of carriers, but in this new age of jet aircraft with nuclear payloads, they were almost strategically unimportant (in a strike against the USSR). Carriers at the time were not well suited to jet operations and they had not been designed to cater for them. The ships were much smaller than today's supercarriers and had limited range, to effectively operate jet aircraft a range of expensive modifications would need to be developed. The prop-driven aircraft they originally carried could not carry a heavy payload over the distance needed to deliver a strike into the USSR, in reality, few aircraft could. But the large jet engined strategic bombers that could were very much in the domain of the USAF and could operate from the USN carriers in service at the time.

Image
Martin XP6M-1 "SeaMaster" (No 138822) jet-powered flying boat in flight. 1958 (U.S. Navy National Museum of Naval Aviation)


To stay viable and modern, a number of options were considered and pursued, of these, a seaplane carried deterrence would, perhaps surprisingly, be the most viable. Of course, this was a seaplane unlike any other.

The result, Martin P6M SeaMaster. A flying boat strategic bomber specifically designed for the USN to fulfil their requirement, and it was a hairs width away from entering service although the type had its problems and politically such an aircraft was undesirable.

The aircraft was officially designated by the Pentagon a 'Patrol Flying Boat' because of political difficulties (presumably with Strategic Air Command) and according to Stan Piet and Al Raithel in their 2001 book Martin P6M SeaMaster, it was produced under the guise of being a high speed mine-layer. Twelve were produced and tested. They were ready to enter service and their USN crews were undergoing operational conversion and training, another six months and the SeaMaster would have been flying operationally, but the program was cancelled on 21 August 1959.

Troubled Beginnings:

As mentioned, in the immediacy of the postwar climate, the USAF's Strategic Air Command became the linchpin of US nuclear security and the sole means of delivering nuclear weapons. The Navy felt threatened in its strategic role by the Air Force, and it's commanders knew that both the US Navy's prestige and budgets were at stake and facing huge cuts, a number of important cutbacks had already been made.

Image
Martin P6M SeaMaster (US Navy)


The development of the supercarrier had its funding cut and therefore slowed. The Navy felt this loss considerably, as the supercarrier would have enabled the navy to operate their own strategic bomber force. Their only alternative would the SeaMaster, a "Seaplane Striking Force", but the design requirements, issued in April 1951, were difficult and ambitious. The aircraft would have to be useful for both nuclear and conventional warfare and would have to fulfil roles such as strategic bomber, reconnaissance, patrol and mine-laying.

Being seaplanes, these aircraft could land on water and the intention was that groups of these planes, supported by seaplane tenders and/or special submarines, would operate close to the enemy shore. They could relocate easily to any stretch of ocean, as could their supply base. This mobility would make the force harder to neutralise. The seaplane had to carry a payload of 30,000lbs (14,000kg) of munitions from an aquatic operating base up to a range of 1,500 miles. Although the design did not call for a supersonic aircraft, it still needed to be quick and would almost break the sound barrier at low altitudes.

By allowing the potent fleet of bombers to resupply at sea from tenders or submarines, the range and endurance was reasonably limitless. One ship, the USS Albemarle, was modified to support the SeaMaster at sea. The aircraft could operate individually or in small units, as a force of its own, or in support of a battle fleet - complete with carriers. The flexibility of the seaplane deterrence would mean that the USN could engage in a war against the Soviet Union, that required strategic aviation, almost anywhere and in addition to a massive confrontation in Europe or away from Japan where USAF assets could be massed quickly. In a world where supercarriers were not yet dominant, as fast as the range of USAF strategic aviation was, it required land bases, the SeaMaster removed that necessity and restriction on strategic air power as they could operate and rapidly deploy anywhere without the big investment in infrastructure needed to support the other arms - all that would be required is a prearranged rendezvous with fleet elements.

Two companies, Convair and Martin, submitted proposals. Both designs were viable and capable, but the Martin design, inspired by the streamlined natural design of the Dolphin (look at the SeaMaster upside down and note it's shape) was seen as more promising. A pair of prototypes were ordered, which were followed by six pre-production aircraft. It was planned to operate up to 24 aircraft in service.

Image
Martin XP6M-1 SeaMaster from below, 1955 (U.S. Navy Naval Aviation News November 1955)


The Martin P6M-1 SeaMaster first flew on the 14 July 1955 and testing immediately revealed problems with the positioning of the engines. The first prototype disintegrated mid air at 5,000 feet on 7 December 1955 following a tail malfunction, killing all on board. Almost a year later, on 9 November 1956, the second prototype was also destroyed after an alternation in the horizontal stabilizer control system was made without evaluation. However, this time, the crew ejected and survived.

The two catastrophic failures and loss of life did not bring about the end of the project, testing resumed after the completion of the first pre-production model in January 1958. Five more aircraft were built in that year, and the fleet got its own dedicated testing facility in Hertford, North Carolina. The tests advanced to evaluate the SeaMaster's combat equipment suite and rated the performance when bombing, mine laying and conducting reconnaissance flights. Overall, the testing proved the design to be successful, but it was not without its flaws. The engines were not as reliable as demanded by the design requirements, and the design, like all jet powered seaplanes, was plagued by spray ingestion problems. Trim was also an issue, so the decision was made to cut back development and the type was deemed to not have any future potential.

Cancellation:

Image
Martin P6M-2 "SeaMaster" flying boat taking off, 1959 (San Diego Air & Space Museum Archives)


Despite the disheartening results achieved in testing, both the Navy and Martin felt that there was a future for the aircraft. In early 1959 they rolled out a new variant with improved, more powerful, Pratt & Whitney J75 engines known as the P6M-2. The aircraft now boasted improvements such as an aerial refuelling probe which was paired with a buddy refuelling drogue kit developed to fit in the bomb bay. Improved avionics were another feature, as was a redesigned canopy offering better visibility. Three of these new aircraft had been completed and their crews were midway through their training and conversion when the project was abruptly cancelled in August 1959.

Despite cancellation, the P6M-2 SeaMaster was an incredibly impressive aircraft. Spray ingestion problems were solved by the high engine mountings, while performance on the water was improved by modifying the wing-tip tanks to double as floats. The innovative rotating bomb bay was another design success, and was pneumatically sealed to keep out seawater. The P6M-2's speed at low level could be equalled by very few aircraft at the time, and it was incredibly tough - the outer skin being over an inch thick in places.

Those presiding over the program were amazed at the docile and pleasant handling characteristics of the aircraft, but were simultaneously shocked by some of the problems that occurred as the plane approached the listed top speed. Severe buffeting and wing drop were key problems as the sound barrier was neared, and this was all that stood between the P6M-2 and fleet service. The cause of the problem was identified and fixed, with modifications made to the large engine nacelles required for the new engines, but the fixes came too late to allow the SeaMaster to avoid major the defence budget cuts that defined the Eisenhower administration.

Despite earlier cuts, the supercarrier project had progressed and the success of the USS Forrestal proved the concept. The USN was previously able to pursue a number of options, and the attempt to develop a seaplane carried deterrence was serious and not folly. However, the programme was incredibly expensive and was competing too much for funding while becoming increasingly over budget and behind schedule. Therefore, although viable, the P6M-2 lost out to three alternative and expensive projects designed to give the USN a renewed strategic relevance - the first supercarrier USS Forrestal (commissioned 1955), the USNs first dedicated nuclear missile submarine, the USS George Washington, (commissioned December 1959), and the 1961 introduction of the Polaris ballistic missile system.

Conclusions:

Image
The six Martin XP6M-1 SeaMasters in the late 1950s (U.S. Navy Naval Aviation News June 1974)


The P6M-2 SeaMaster was an impressive, capable, and viable aircraft that sadly just came a little too late. It was envisioned as a way to give the USNa strategic nuclear force, but was soon was eclipsed by the Polaris submarine-launched ballistic missile and the supercarrier. However innovative the seaplane programme was, the combination of the strategic capability of new supercarrier, and the nuclear armed submarine meant that the phenomenal technology of the P6M was obsolete and in August 1959 Martin was told to halt operations. Time had moved on, seaplanes only held the support of an absolute minority in Naval Aviation, and the manned bomber was now considered an expensive and unreliable way to deliver nuclear weapons. The SeaMaster was later marketed as a civilian aircraft, known as the SeaMistress, and even as a flying tanker to resupply lone ships at sea. However, both approaches failed and Martin abandoned the aircraft business entirely.

Had the SeaMaster entered service on time, and it had its advantages - the entire ocean being their landing strip, perhaps it would have served alongside successor options, but there was no need to continue to pursue the programme when the USNs foray into this unusual Cold War experiment was doomed by the USS Forrestal. Entering service in 1955, the Forrestal was the first (super)carrier specifically designed to operate jet aircraft. She had an angled flight deck to make landings safer and possible for larger aircraft, and, most importantly she had steam catapults to allow heavier aircraft to take off with heavier payloads - such as thermonuclear devices. Her air wing could counter almost all threats, and the supercarrier terrified the Soviets, who had no means to match or counter the ships (they would later develop the equally innovative Ekranoplan, but it would be 1975 until the first dedicated Soviet carrier entered service.)

While the carriers enjoyed flexibility and the freedom, like to a lesser extent the SeaMaster, to operate anywhere in the world, conversely, the Polaris boats enjoyed secrecy and stealth, like to a lesser extent the SeaMaster, at the expensive of flexibility, but the unrivalled threat (which continued when the boats were not at sea) they posed allowed for the most effective strike option. The SeaMaster somewhat bridged the gap between the carrier and the sub, but the P6M program had cost $400 million and the USN never could justify the expense of this amazing technical feat when other alternatives would, frankly, produce a pair of more viable deterrence options.



_________________
Historian, Journalist, Feature Writer, and Editor.
Society Chairman/Advisor 2013-, Society President 2012-2013, Society Vice President 2010-2012, Archive/Forum Administrator 2011-

Image
Offline
 Profile  
 
 Post subject: Re: The US Navy's Unusual Deterrent
Unread postPosted: 13 Dec 2015, 21:59 
Lieutenant-Colonel
Lieutenant-Colonel
User avatar

Joined: 30 Jan 2012, 19:49
Posts: 1874
Location: United Kingdom
Has thanked: 65 time
Have thanks: 119 time
Below is a list of the SeaMaster's specifications.

Variants:

XP6M-1
Prototypes: 2 built, Nos 138821, 138822. Both crashed.
YP6M-1
pre-production: 6 built, Nos 143822-143827. All examples scrapped when cancelled.
P6M-2
production: 8 built, Nos 145876-145899.
145877-145879 were completed and flew, 145876 and 145880-145883 also completed. 145884-145899 were cancelled.

General Information:

Crew: 4
Length: 134 ft 4 in (40.94 m)
Wingspan: 102 ft 7 in (31.26 m)
Useful load: 86,841 lb (39,390 kg)
Max. takeoff: 190,000 lb Calm water/160,000 lb Rough water (86,183 kg/72,575 kg). Could operate in 9 ft (2.7m) swells.
Powerplant: 4 × Pratt & Whitney J75-P-2 turbojets

Performance

Maximum speed at Sea Level: 686 mph/1,104 kph
Cruise speed: 535 mph/861 kph
Range: 2,083m/3,200 km
Combat radius with 30,000 lb payload: 863m/1389 km
Ceiling: 50,000 ft/15,240 m

Armament

Guns: 2 × 20 mm cannon in rear remote operated turret
Bomb: 2 x MK91 Nuclear bomb (3,500 lb/ea, 1,588 kg/ea)
Bomb: 1 x MK28 Nuclear bomb (1,800 lb/ea, 817 kg/ea)
Mines: 28 x MK36 (1,001 lb/ea, 454 kg/ea)
Mines: 15 x MK25 (2,030 lb/ea, 921 kg/ea)
Mines: 36 x MK50 (504 lb/ea, 228 kg/ea)
Mines: 15 x MK52 (1,348 lb/ea, 611 kg/ea)
Mines: 8 x MK39 (2,025 lb/ea, 919 kg/ea)
Mines: 15 x MK19 (540 lb/ea, 245 kg/ea)
Mines: 5 x MK10 (1,960 lb/ea, 889 kg/ea)
Reconnaissance: High Altitude Reconnaissance Camera 4,050 lb/Tot
Reconnaissance: 27 x M120 Photoflash (154 lb/ea, 70 kg/ea)



_________________
Historian, Journalist, Feature Writer, and Editor.
Society Chairman/Advisor 2013-, Society President 2012-2013, Society Vice President 2010-2012, Archive/Forum Administrator 2011-

Image
Offline
 Profile  
 
 Post subject: Re: The US Navy's Unusual Deterrent
Unread postPosted: 14 Dec 2015, 19:02 
Private

Joined: 22 Jun 2014, 21:34
Posts: 7
Has thanked: 0 time
Have thanks: 3 time
Yet another fantastically written article, John, about an aircraft with which I am not entirely familiar. I feel I could add some interesting additional points.
Firstly, concerning the USN budget at the time. There was a feeling that the next war (beacause Korea was the forgotten war and Vietnam had yet to happen) would be a nuclear one, and as you correctly assert the only way for the USA to deliver a nuclear weapon in the wake of the second world war was by entrusting it to the strategic air command (SAC). The weapons at the time were big and heavy and some required arming in flight. The USAAF became the USAF in September of 1947, gaining its own funding and government departments and under the auspices of some powerful leadership did very well for the youngest service. The funding available and the strength of soviet defense networks persuaded the budgeters that SAC needed a new bomber every few years and multiple research projects to get them to fly higher, faster and further, and for there to be enough of them to counter the number the soviets had. As well as SAC another branch of the USAF was air defense command (ADC), who too got a new type of fighter every five years and new missile systems both ground and air launched and they were seen to be the only defense against high flying soviet bombers coming to destroy Ma, Pa and apple pie. To direct these fighters a new chain of radar stations were built in canada and alaska, the distant early warning (DEW) line and for more local direction the SAGE stations were built (google them, the fighters were flown on autopilot from the ground with the pilots just along for the ride!)
All this adds up to lots of money, which the USN, previously the apple of the eye of congress, was missing out on. Hence the Seamaster, but there were other projects that were less ambitious (Sort of). For example, carrying of land based bombers on essex and midway class carriers, the maritime patrol aircraft the pv2 neptune was experimentally flown off of aircraft carriers, and this was kept as a contingency measure for many years.Image
The USN also submitted a proposal for a larger carrier, the USS United States, that would be able to take larger and heavier aircraft that it was also designing. However this was turned down as being too expensive, probably because SAC stole all the money to build cushy 24 hour alert facilities with swimming pools and pool tables. The USN was understandably pissed and started something called the revolt of the admirals, where the publicly told Harry Truman where to stick it. Then the north Koreans invaded south Korea and the USN got its carrier, the USS Forrestal.
The USN did build one carrier aircraft that fit the bill for carrying nuclear weapons of the day, the AJ Savage, which was already approved and in the design/test phase when the USN changed the shape of the bomb bay to fit nuclear weapons.
Image
Nuclear weapons also got smaller and lighter during this period, meaning they could be used by tactical fighters such as those flown off the navy's current class of carriers. What a money saver? Well, the most up to date tactical fighter the USN had was the F2H banshee which had... limited ground clearance.
Image
That isn't very good for nuclear weapons, so the USN fitted metal sleeves around the landing gear of its nuclear armed banshees to max out the suspension and raise them a few inches, the sleeves would fall away on take off allowing the landing gear to be retracted.
So did the USN have a point? Again, as you say, John, SAC and its bases remained vulnerable to a first strike, and there was no chance that ADC would stop all of the russian bombers. There is a good paper on that herehttps://www.rand.org/content/dam/rand/pubs/special_memoranda/2007/SM15.pdf however it also gave rise to russian subs trailing carrier groups, ready to strike.
It also gave the US a first strike capability the Russians did not have, because the russians did not have an aircraft carrier in the 50s and 60s.
So it may have been a good idea, but SAC was a more visible deterrent, and would give more time for negotiation, and until the Gary Powers shoot down in 1960 it was assumed that a high flying bomber would be much safer than a low flying tactical aircraft and more likely to get the job done.

The USN was also skeptical about flying supersonic aircraft off its straight deck carriers, higher approaches and no chance of going around made the idea dangerous. So again they turned to tried and tested seaplanes in the form of the convair sea dart

And the RAF tried it as well with the SRA1 (https://en.wikipedia.org/wiki/Saunders-Roe_SR.A/1)
So the flying boat bomber was not that whacky an idea after all.


Offline
 Profile  
 
 Post subject: Re: The US Navy's Unusual Deterrent
Unread postPosted: 14 Dec 2015, 20:06 
Lieutenant-Colonel
Lieutenant-Colonel
User avatar

Joined: 30 Jan 2012, 19:49
Posts: 1874
Location: United Kingdom
Has thanked: 65 time
Have thanks: 119 time
Thank you for your kind and informative response.

I was going to cover the Sea Dart and SRA1 in this article but it got wordy pretty fast and I couldn't comfortably place them within the context of this article.

It is true that the Soviet's had nothing that was comparable to the super carrier or the SeaMaster for a very long time - although it is easy to imagine the Ekranoplan, although not related to SeaMaster and a dedicated counter to the supper carrier, as a viable sea skimming first strike weapon, or at least a good way to shoot down Seamasters at low altitude.

When I mentioned the Forrestal and its smaller nuclear capable aircraft, I did in fact have the Skywarrior in mind. However, you are quite right. These did not come about for a while, so your comments on the Banshee and the Neptune are incredibly enlightening.

Ultimately, I think the low level, rotary bomb bay, navalised nuclear bomber that the SeaMaster was a head of this time. As you say, the focus was on high-altitude strikes, so the early move of low level is interesting and at the time controversial - hence covering it up as a skimming patrol minelayer.

Regardless, the next closest thing to the SeaMaster was the British Blackburn Buccaneer... I wonder if the SeaMaster inspired certain features of that design...



_________________
Historian, Journalist, Feature Writer, and Editor.
Society Chairman/Advisor 2013-, Society President 2012-2013, Society Vice President 2010-2012, Archive/Forum Administrator 2011-

Image
Offline
 Profile  
 
Display posts from previous:  Sort by  
 Page 1 of 1 [ 4 posts ] 


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

cron

suspicion-preferred