Single weapon that had the greatest effect.

Panzerfaust was great at least in the Finnish 1944 summer battles. End of attack. Of course there´s more to it but the power on tanks and morale was massive on both sides, as well as the Stukas helping 24/7.

 

And air warfare too. A BoB with no radios(and no radar).

 

The soldiers and civilians of the USSR.
In terms of weapons, I like the suggestion of the M1 Garand but my vote goes to those things (HF/DF, Hedgehog, airborne radar, etc) that defeated the U-boats.

 

Surprised this was only mentioned in passing in one post, but right next to the atom bomb, the proximity fuse was probably the single most devastating invention/weapon of WWII. It was so important to the US that the Navy refused to allow it to be used over land. It used to take 2400 rounds to shoot down a plane, but with the proximity fuse, efficiency increased by an amazing 6 fold. The reason the US Navy was able to destroy 92% of Japanese planes during battles in the Pacific and were able to mitigate Kamikaze types of attacks was because of the proximity fuse. Over land, the results were equally devastating to the German soldiers during the Battle of the Bulge, so much so that they were considering mutiny during Allied artillery shelling that was using proximity fuses (because it was so lethally effective):

https://www.youtube.com/watch?v=Kq_Uy5hGazc


The US would have had a hell of a lot harder time island hopping in the Pacific if they weren't as effective at shooting down Japanese planes as they were with the proximity fuse. The US fleet would have been in much tougher dog fights and would have been destroyed with much greater ease. You can't land any marines without a fleet. All of it was allowed by the proximity fuse. It also helped take down hundreds and hundreds of German V-1 rockets over the English Channel as well as V-2 over Belgium. It's amazing the secret never got out during the war, because you could have jammed the proximity fuse with a 50-W transmitter in planes.

 

Submarines weren't war winners. They were spoilers. They primarily sank merchant ships conducting a modern version of raiding / Guerre de Course. For Germany they were about the only choice to conduct some sort of effective naval campaign against the Allies. For the US, Japan, and Britain they were a means of supplementing their naval forces by scouting and attacking enemy shipping.
On their own, nobody's submarines were going to win a naval war.

 

I had to chuckle reading this...one thing ive picked up reading countless WW2 combat stories is the radio never bloody worked! Seemingly always a problem...

Id have to say the bomber...which one?
The B-17/24, various Russian and Lancasters took the war to the Germans and Japanese, destroyed their capability to wage war...and with the B-29...ended the war.

 

I agree with lwd.

They kept Britain in the war, got America to the war and even gave the Soviet Union a margin to wage a offensive war.

 

PIAT, the MK 11 with the extra strong spring.

 

There's nothing particularly noteworthy about liberty ships. They were just cargo vessels designed (poorly) for quick manufacture. They might have saved torpedoes for the Germans since the compartments rarely held up when they got hit and a second shot wasn't usually required. They did perfect welded hull construction, but the general design of the vessels didn't change much through the war as it should have. Simply reinforcing the watertight compartments might have saved a lot of men, vessels and cargo.

 

They were cheap, dirty and far from sexy, but could the US prosecute the war without them? They were made the way they were because that was all that was needed. Victory in the 'Tonnage 'war' was assured by our ability to build merchant ships faster than they could be sunk. A effective, standard design ship gave us the ability to produce as many as we needed, while not compromising our ability to produce the other weapons of war we also needed.

 

The Liberty design did leave a bit to be desired, but the main problem was the low-grade steel used in their construction...The steel did not lend itself well to welding and it was very susceptible to fracture. This, coupled with the rush to complete the ships, led to many defective welds that would fracture under high stress(of normal operation or torpedo hit) and/or low temperature.

 

I suspect that if we'd built a small class of anti-sub vessels we'd have had far fewer losses in the Atlantic. The Flower Class Corvettes were over 200 feet long and had a crew of 90, and they were the smallest ASW vessels running out there except for a few odds and ends from the Coast Guard and refitted civilian vessels.

Imagine a smaller vessel a bit larger than a PT boat - 100 feet or so - but with a deeper steel V hull for weather and a crew of 20 or so, just large enough to carry 8 or 10 depth charges and something like a single 37mm gun. You could have put a solid ring around those convoys at half the cost of destroyers and corvettes which could only put a thin picket line around the convoys at best. Smaller vessel could re-arm and refuel from a mother ship in the convoy and you'd easily triple the number of escorts. Any submarine contact could have been saturated with a half dozen or more vessels in minutes.

That just seems like a better way to go than simply building cargo vessels faster than they could sink them.

 

I do not contend there weren't better possible options, but that isn't the topic of the thread. We might have produced 20 knot plus transport's also but we did not.

As to your suggestion, it was my understanding the best way to get kill's was to have escorts who could execute prolonged periods of hunt and strike to keep the sub away from the convoy, Your suggestion would not do that as effectively as either britain's corvette's or our DE's.

 

The big problem with Liberty ships and welding was the design was originally intended to be riveted. The drawings were redrawn for welding with a minimum of changes. This meant that things like cargo hatches that were square with sharp corners weren't redesigned initially, to give one example. This would result in cracking at the corners on a welded vessel. Once the hatches got rounded corners the welding held. The same goes for the hull. The deletion of stringers and backing that the riveted ship had (unnecessary on a welded vessel) weren't replaced with redesigned framing so the hulls tended initially to be weak and crack. Changing the framing and material thicknesses fixed that problem along with better welding techniques.

As for the Flower class... This class was rejected for US service almost entirely on the basis of a number of deficiencies in its design. The crew quarters and arrangement of things like the galley, head, etc., were inadequate for the size of the crew and reasonable accommodation at sea. The speed was deemed inadequate, something even the RN recognized. A surfaced U-Boat could outrun a Flower. The armament was considered too light with its one gun main battery and AA firepower likewise insufficient.

The USN took on strength just 12 Flower class and those were listed as "gunboats" (PG) rather than frigates. The US also build a large number of frigates classified in US service as PG also like the Tacoma class primarily for Lend Lease. These were considered minimal ASW vessels with 3 3"/50 guns, some light AA weapons, usually triple expansion engines, and capable of 15 or so knots.

The USN's preferred ASW vessel was the DE. These came in several classes with 3" or 5" main armament, mounting triple 21" torpedo tubes, and capable of 18 to 22 knots. Of course, from the US perspective this made sense as the US could turn out such a ship in about the same time (12 months) that the British could turn out a Flower corvette. The RN's Hunt class DD were about equivalent to the US DE's and took 18 to 24 months to complete in Britain.

For ASW work whatever you built had to have sufficient size to mount a sonar, surface and air search radar 3 or 4 K guns per side of the ship with 6 to 8 depth charges per gun available, two stern racks with 30 to 60 depth charges available, and by mid war take a hedgehog in place of either a 3" gun or twin 40mm AA gun.

The vessel Kodiak describes is pretty much a 110 foot Subchaser except of steel instead of wood. These had one or two 3"/23 (ex- naval landing party) guns initially replaced by 40mm AA guns and some 20mm and .50 machineguns. They carried 12 to 18 depth charges, lacked radar until later in the war and usually had a minimal SC or SD sonar installation. They could make 19 knots on calm water.
As ASW vessels they were largely for show and used primarily in coastal areas. There was no way one would make an Atlantic crossing with a convoy. They didn't have the seakeeping, lacked the range for such a transit without refueling (a major mess to do with convoys), and lacked the crew accommodations to be at sea for weeks at a time.
Some did transit the Atlantic for duty in Europe, and others the Pacific, but these were one time trips accompanied by a tanker and other larger military auxiliary ships to assist them if necessary.

 

You do realize that the German U-Boats were carrying either an 88mm gun(Type VII) or 105mm gun(Type IX) don't you?

Not to mention that such small vessels would have little or no sound gear, no radar until, at least late-42 but more likely early-43. Probably no room for any radio direction finding. And, would likely be very roughly handled in the North Atlantic storms.

 

No U-boat would come up and risk a hit - once hit they're dead meat. And there's no reason a small craft couldn't carry sound gear. As for weather, there's 110 foot cutters in the North Atlantic, North Pacific, Bering Sea right now. Heck, there's fishing boats less than half that size out there year-round. Any weather rough enough to interfere would preclude a torpedo attack anyway.

 

I pretty much explained the limitations of the 110 foot SC sub chaser. There is no galley aboard. The crew quarters are limited. It has a sonar but it's the most basic set available and by 1943 it isn't even the "cutting edge" set anymore. Normally, it's the pre-war SC set. It has no radar until late 1943 when an SO type surface search set, much like a PT boat got, was installed. They carried enough depth charges to lay one full pattern (14 total laying a 8 charge pattern) and have a few left over for their 2 K guns. Later they carried 2 or 3 Mousetrap launchers but these proved all but useless due to the motion of the boat.
Typically, these boats were used in coastal settings. In the Atlantic a typical use might be to escort convoys between two ports over a day or so at sea. These were the so-called "Bucket Brigades." The convoy might leave say, Boston Harbor for Chesapeake Bay with several escorts including some SC type boats. These would be at sea maybe a day, day and half and then pull into harbor. They'd be in harbor a day or so refueling and letting the crew shower and eat hot food then they'd make the return trip.

The US did allow the "Hooligan Navy" to operate with mostly irrelevant results during 1942. This "fleet" consisted of private yachts, fishing vessels, and such "patrolling" off the US coast. The boats and ships were all but unarmed and often didn't even have proper radio equipment.

 

The Uboats were much more cramped. The crew had to "hot rack" meaning one rack between two men, who alternated watches. If small cutters and even smaller fishing boats can work in those waters so could other vessels designed for the purpose. I just don't think it occurred to the navy to provide a new class of small ASW vessels for the Atlantic runs. They were looking to the big battles in the Pacific.

All of this is getting off topic, but I just wanted to point out that I think it was a missed opportunity. We could have saturated those convoys with smaller vessels, but they got the odds and ends and it cost us a lot of cargo ships and merchant seaman.

 

AFAIK, the "small ships" and trawlers did not work out well in ASW for the British early in the war. So, I find it hard to believe that they would do any better under us Americans.

Also, it is rather amusing that these "small ships"(83-footers & 110 footers) crossed the Atlantic & Pacific...

Snugly secured aboard Liberty ships as deck cargo.