Why no heavier RAF machine gun calibres? (1 Viewer)
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SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Wasn't the problem getting the larger calibers to work which the .303s did?
Of course, and both the gun and the munitions are heavier which adds to the problem. When the Whirlwind was ordered no single engine was powerful enough to lift 4 cannons in its wings and cannons didnt fire effectively or reliably in aircraft wings at the time. Stanford Tuck wanted cannon in 1940, but so did the RAF. If there was a cannon as reliable and long firing as a 0.303MG then it would have been fitted. As it was they didnt get cannons to work reliably until after the BoB and it has been discussed ever since.
The Hispano had a higher rate of fire than the .50 browning as well as having more effective ammunition, two 20mm's being the equivalent to six .50's so don't know where your coming from here, I bet if P47's-P51's pilots had four Hispano's fitted and loaded with SAPI HEI API belts they would never give the .50 and M8 rounds another thought.
Alan Stevens
Airman 1st Class
- 129
- May 24, 2023
I would not argue against bringing as may barrels into the fight as possible.
I just wondered if there was a selector switch on that forward upper turret.
Reluctant Poster
Tech Sergeant
- 1,682
- Dec 6, 2006
The war was won when the British Purchasing Commission gave $100,000,000 to Todd Shipbuilding to construct 60 Ocean Class freighters and to construct the entirely new yards where they were to be built. The Ocean Class freighter was designed by J L Thompson and Sons to be cheap to build and cheap to run. One of the myths is that the design they brought with them was based on an 1879 tramp steamer. This is complete nonsense. It was an up-to-date design with extensive water tank testing to develop a hull form with low resistance yet with as few curves as possible to make it easy to build and cheap to run.
At the same time as the Oceans were being built the Americans began producing their modified version of this design, the Liberty ship. The main change was the substitution of oil-fired water tube boilers for coal fired scotch boilers. Contrary to popular opinion when the Americans continued producing the design they did not redesign it for welding. The design was always intended to be riveted and or welded and in fact some British shipyards made extensive use of welding and only one American shipyard use full welding.
Without the 2,700 + Liberty ships and 100s of the same design produced in Canada and Britain bringing everything needed to fight a war across the oceans nothing else matters.
Honorable mention goes to Sun Ship Building's T-2 tanker design.
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I think your going to have to expand on this, I think we are all very interested in learning more.
Thumpalumpacus
Major
There's that whole Battle of the Atlantic thing, you might have heard of it.
Here's a short overview in case someone missed it:
View: https://youtube.com/watch?v=dCqa9_ZOnT0&pp=ygUcbWl0c2kgYmF0dGxlIG9mIHRoZSBhdGxhbnRpYw%3D%3D
Referring to the money granted for the design and manufacturing of the ocean class of freighters
John Henshaw in his book " Liberty's Provenance. The Evolution of the Liberty Ship from its Sunderland Origins" published in 2019 delves into the whole subject in detail and demolishing the various myths and claims that grew up from early on in the story of the Liberty Ship.
Currently available heavily discounted here.
The family tree can be traced back to Thompson's SS Embassage (completed Sept 1935), to SS Dorrington Court (completed May 1939), to the Empire Wind / Wave series (completed Oct 1940 to Oct 1941), to the Empire Liberty series (completed Nov 1941 to Oct 1944).
Thompson led a Mission to the USA in Sept 1940 to see about constructing new merchant ships there. (Confusingly there was another Mission at the same time concerned with acquiring existing ships from the US merchant fleet.). But he arrived in the middle of the US elections so initially it proved difficult getting officialdom engaged. In the space of 3 weeks he toured 35 shipyards in the US and Canada, plus engineering works and potential green field sites. Negotiations proved difficult. Many yards were already very busy with home orders. Many in the USA thought Britain a lost cause and didn't want to become involved.
Then Henry Kaiser appeared on the scene. The first meeting was on 23 Oct 1940. More meetings followed and a report went to the US Treasury Dept on 13 Nov. The deal was worth about £24m ($100m in 1940 terms) with 10% relating to the two new shipyards and the remainder for 60 ships. On 1 Dec he received the necesary US approvals and sailed for Britain on the 6th with all the necessary contracts, only to be sunk by a U-boat en route. Fortunately he and his soggy paperwork were rescued, and despite protests from the British Treasury that the cost was higher than expected, the contract was signed on 20 Dec 1940.
The ship plans Thompson took with him to the USA were those of the Empire Liberty according to the company history written in 1946. The US Naval architects Gibbs & Cox became involved in assisting the amendment of those plans to suit Kaiser's methods, including widespread use of welding, and assembly by a new largely unskilled workforce, which required many more drawings of greater accuracy than would have been normal for a British yard with a skilled workforce. And so was born the Ocean class.
The Richmond yard on the west coast was quickly constructed and was able to lay down its first Ocean on 14 April 1941. It was launched as Ocean Vanguard on 16 Aug 1941 and completed Nov 1941.
The Portland, Maine site proved a bit more difficult to construct, but managed to lay its first ship down on 24 May 1941.
At the beginning of Dec 1940, someone from Thompson's Mission went to Canada and signed contracts for the construction of the first Ocean type vessels there. These became the -
Fort ships - coal fired with 3 Scotch boilers (198 built)
Park ships - as above for the Canadian govt owned Park Steamship Co Ltd (114 built)
Victory ships - (not to be confused with the later US Victory ships) - two water tube oil fired boilers identical to the Liberty ships.
Canadian ships - 3 Scotch boilers but capable of burning coal or oil.
Meanwhile back in the US the US Maritime Commission (USMC) was trying to decide which US designed ships could / should be built. Three days before Thompson left for Britain there was a request from the White House to Gibbs & Cox for details of the Oceans, as the newly re-elected President wanted another increase in merchant shipbuilding. Thompson agreed to the release. On 26 Dec 1940 the head of the USMC, seeing the writing on the wall, wrote to the President proposing a new construction programme including 200 of a new emergency type. Eventually in Jan 1941 it was decided to base it on the Ocean but modified to meet US requirements. Gibbs & Cox were once again involved. The first Liberty Ship was laid down on 30 April 1941, just 6 weeks after contracts were signed, and about 3 months after the decision to base it on the Ocean design.
So what changes were made to get from an Ocean to a Liberty? Well firstly most of the framing forming the bones of the two types were identical. Thereafter:-
1. Oil firing in place of coal, with oil tanks in the double bottom and the coal bunkers eliminated in no3 hold.
2. Water tube boilers in place of Scotch type.
3. Combining accommodation amidships into one block.
4. Reduction in number of different plate thicknesses required in construction from 75 to 27.
5. Minimization or removal of deck camber where possible, again to simplify construction
6. A number of other more minor modifications to replace chain railings or canvas Dodgers with steel bulwarks, different davits for lifeboats.
So in summary a US Liberty was an amended Ocean design which in turn was an amended Empire Liberty designed by Thompsons in early / mid 1940. Gibbs & Cox were involved in both amendments, but their claim to have designed the Liberty Ship is without foundation, as the author John Henshaw demonstrates. Given the timescales it would have been impossible for them to design an entirely new ship from a blank sheet of paper.
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Brilliantly informative post as always Ewen, thanks mate.
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Thanks for the hint, ordered (along with another heavily discounted book that looked interesting).
Speaking of which as we've already drifted far from the original topic, why did the Liberty ship and other freighters of the era, have the machinery and bridge midships? If one looks at contemporary cargo ships, they tend to have the machinery and superstructure as far aft as possible. This brings several advantages, like shorter and cheaper propshaft that doesn't eat valuable cargo space, and a single big unobstructed deck space for cargo handling, and using the widest part of the ship for cargo rather than the machine room.
My suspicion is that the steam plants were so heavy that without cargo the ship would have to be heavily ballasted lest the bow point skywards?
Tankers of that era did often have aft mounted machinery, but OTOH tankers were easy to ballast with seawater (particularly as back then nobody cared if some tonnes of oil were pumped out along with the ballast water..). See e.g. a T2:
If you are interested in pursuing the subject further I'd recommend
In terms of ship design, you need to look at ship development over time from the days of sail, through paddle steamers to screw powered ships. Those WW2 standard ships were the backbone of the world's merchant fleets into the 1960s and even 1970s. By then there was a move from steam to large marine diesels (although diesel had started to become popular in the mid-1930s). But even at that point while the machinery had moved aft, it had not moved all the way aft.
This is the layout of the Austin & Pickersgill designed SD14 cargo ship designed in the 1970s. It was a very successful design, with over 200 built around the world.
Then figure in the move to containerisation from the 1970s and the huge growth in size of these vessels. Much more steel out front to balance machinery aft. These "boxboats" have now grown so large, and have the containers piled so high that the bridge structure is now placed forward of amidships, just to let the crew see the bow of the ship.
List of largest container ships - Wikipedia
But still the have hold space aft of the engine room and any aft superstructure. Some even have their machinery more or less amidships.
EMMA MAERSK - Container Ship | Vessel Tracking
Emma Maersk is the first vessel from the Maersk E-class containers. At the time of her launching she was the biggest container ship that was ever built.
www.vesseltracking.net
One generalisation I've come across is that ships designed to move bulk cargoes (Oil, grain, coal, various metallic ores) were more suited to an engines aft layout. But even that was not universal.
WW1 saw oil tankers based on standard merchant ship machinery amidships designs. 62 Liberty ships were built as tankers with their midship machinery. At the same time 24 Liberties were built as Collier with their machinery moved aft.
There are plenty of examples of standard types of merchantmen with machinery aft. In the US and Britain these tended to be at the smaller end of the shipping scale but Britain built a series of full sized engines aft heavy lift ships. Japan had a standard type of 6,600grt with machinery aft and built over 100 of them in WW2. Oddly a number of these were rebuilt post war and had the machinery moved amidships.
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Reluctant Poster
Tech Sergeant
- 1,682
- Dec 6, 2006
An excellent book. Those interested in the evolution of the Steam and motor ships shouldalso look at
Tramp Ships
With 300 stunning photographs, this pictorial history of tramp trade ships illustrates the evolution of these charming, itinerant merchant vessels. The tramp ship was the taxi of the seas. With no regular schedules, it voyaged anywhere and everywhere, picking up and dropping off cargoes, mainly...
books.google.com
Also I posted this article on Liberty ships a while ago. It tells much the same story.
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Reluctant Poster
Tech Sergeant
- 1,682
- Dec 6, 2006
It is impossible to over estimate the impact of the Liberty on the war. The size of the program and its contribution to winning the war is staggering.
To put things into perspective, according to the June 1939 Lloyds Register of Shipping (see attached), the British Empire had by far the largest merchant possessing 8,977 ships with a total tonnage of 21,001,935 gross tons. In comparison the 2,710 Liberties totaled 19,446,960 gross tons! In other words the carrying capacity of the Liberties almost equaled the capacity of by far the world's largest merchant fleet.
Note that the average tonnage per ship was much lower for the prewar fleets. Liberty ships were big ships by the standards of the day at 7500 gross tons while the vast majority of the existing fleet was less than 6000 tons.
The second largest fleet belonged to the United States with 2345 ships totaling 8,909,892 gross tons. This fleet was very old, comprised mostly of emergency ships built for WWI. Only 6% of the fleet was less than 5 years old as compared to 21.1% for Britain and 27.5% for Japan. The US emergency program was based on very sophisticated ships with high pressure geared steam turbine propulsion. While this offered many advantages the brutal truth was that they were severely limited in the number of ships of these types that they could build.
There was much resistance to the Liberty program among the Americans in charge of merchant shipbuilding. Luckily FDR forced the issue and the Americans grudging accepted the Liberty program. If they hadn't the war would have lasted a lot longer. The Liberties were more than half of the merchant ships constructed in the US at 52% with the Victories and the T-2 tankers a distant 2nd at 10% each. Even then the T-2s were not a homogenous class with significant differences between the various shipyards designs. More importantly than just total numbers they were available much earlier with Liberties making up 68% of US merchant ships constructed in the pivotal year of 1943. The ship building program was under water (pun intended) until October 1943 when the Allied tonnage available finally matched prewar levels. Without the Liberties and the Canadian versions this simply doesn't happen for months if not years
.
To put things into perspective, according to the June 1939 Lloyds Register of Shipping (see attached), the British Empire had by far the largest merchant possessing 8,977 ships with a total tonnage of 21,001,935 gross tons. In comparison the 2,710 Liberties totaled 19,446,960 gross tons! In other words the carrying capacity of the Liberties almost equaled the capacity of by far the world's largest merchant fleet.
Note that the average tonnage per ship was much lower for the prewar fleets. Liberty ships were big ships by the standards of the day at 7500 gross tons while the vast majority of the existing fleet was less than 6000 tons.
The second largest fleet belonged to the United States with 2345 ships totaling 8,909,892 gross tons. This fleet was very old, comprised mostly of emergency ships built for WWI. Only 6% of the fleet was less than 5 years old as compared to 21.1% for Britain and 27.5% for Japan. The US emergency program was based on very sophisticated ships with high pressure geared steam turbine propulsion. While this offered many advantages the brutal truth was that they were severely limited in the number of ships of these types that they could build.
There was much resistance to the Liberty program among the Americans in charge of merchant shipbuilding. Luckily FDR forced the issue and the Americans grudging accepted the Liberty program. If they hadn't the war would have lasted a lot longer. The Liberties were more than half of the merchant ships constructed in the US at 52% with the Victories and the T-2 tankers a distant 2nd at 10% each. Even then the T-2s were not a homogenous class with significant differences between the various shipyards designs. More importantly than just total numbers they were available much earlier with Liberties making up 68% of US merchant ships constructed in the pivotal year of 1943. The ship building program was under water (pun intended) until October 1943 when the Allied tonnage available finally matched prewar levels. Without the Liberties and the Canadian versions this simply doesn't happen for months if not years
.
MiTasol
1st Lieutenant
That is by far the best laugh I have had in weeks.
There are many documents claiming that the P-38 and P-47 were the fighters that won the war. ALL written by Americans and all totally biased in their content. Same for all the other The XX that won the war books and articles written by Americans - ALWAYS it was an American XX. There is even one out there on how the SCR-522 radio won the war. Absolutely ZERO mention of it being a BRITISH radio though.
For a truly unbiased view of the most important allied fighter in WW2, the one that did the most to change the course of the war, that is the one that could claim to have won the war read the official British history of the ww2 air war (The Strategic Air Offensive Against Germany 1939-1945), written by a Brit (Anthony Frankland) who was a ww2 RAF veteran and who went on to resurrect the Imperial War Museum.
His opinion, spelt out in detail, is the fighter that "won the war" was the P-51.
MiTasol
1st Lieutenant
Sorry - double post
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MiTasol
1st Lieutenant
That was a lot of the problem and was made very difficult in many cases by what can best be called military politics.
There is a good book from 50 odd years back called Guns of the Royal Air Force (I think - or maybe Guns of the RAF). I cannot remember the authors name or find my copy right now but he was involved in the processes so wrote from personal experience.
Bare in mind that much information was still classified when that book was written so better information has come out since but the book goes into some detail on the reasons it took so long for the Browning 303 to pass British acceptance tests. These tests were the same for Vickers and all other belt fed machine guns.
Because the RAF guns were controlled, not by the RAF but by the Army, the committee who set the specs were all Major Bloodnok clones holding the rank of General (for those who do not know that reference look up The Goon Show) so instead of requiring two second bursts they required something ridiculous like 1500 round bursts followed 20 seconds later by another such burst without any cook offs in the mean time. And the propellent was limited to Cordite because that is what the Bloodnok's had used in ww1. You can imagine the barrel wear and warping that took place. Naturally this all was done on the firing range where there was none of the cooling air flow that would exist in flight.
There is one paragraph in the book where it is said that one of those Generals was on record as saying something like there is a place for cavalry in modern warfare, so long as it is thoroughbreds, ridden by gentlemen. These people were not re-fighting the last war (ww1) but still back pre Crimean war mentally.
There were a mass of other problems due to those Army people, such as all ammunition had to be lubricated (and naturally the lubricant would freeze at attitude).
The Hispano also had a string of problems caused by manufacturers politics. It was a Spanish/Swiss design with a British company representing Hispano's interests and vetoing changes and generally being bloody minded plus the Bloodnoks stopped all usage at one stage near the beginning of the BoB and demanded high speed cameras and films be developed to prove that it was not a "blowback" gun because they decreed that the RAF were prohibited from using blowback guns. Like with the 303 Browning the British substantially redesigned the gun and took it from little more than a prototype to a fully operational weapon.
That said I totally agree with the 1930's British decision not to "Britishize" the then highly unreliable Browning 50cal. I think the end result would have been better than Browning themselves produced in late 43 or early 44 but it would not have been operational when critically needed in that 27 months of the war before Pearl Harbor that the Americans conveniently forget existed.
At best the Browning 50 cal became fully operational about four years after the real war started in 1939.
Notes
I had avoided reading this thread until today when I had 3 hours to kill between medical appointments. From one look at the heading I knew it would rapidly turn in to a discussion of why the Brits were idiots for not fully embracing and manufacturing the late 43/early 44 Browning M2 and its amunition in 1937/8.
If you can track down a copy of Guns of the Royal Air Force it is well worth the read as it covers all the problems like how to machine stack bullets in containers and mass assemble in MG belts (solved by the cigarette machine packing companies), designing and producing amuntion feed chutes and feed motors and all the rest of the problems no one thinks of.
MiTasol
1st Lieutenant
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