Torpedo Boats, Gunboats, and the Like

We talk so much about the big ships, what about the small ones? The American PT boats, the German S-boats (E-boats to the Allies), the British MTBs and MGBs...all these, and their brethren in other navies, offer a wide scope for discussion. So let's compare them and examine their good points, bad points, and their battles.

 

The diesel-powered S-boats are in a category all by themselves. No other MTB approaches their capability.
The RN's Dog Boats are always a crowd-pleaser. The 6-pdr was a good weapon.
I must admit I'm not impressed by the MAS-boats. Apart from Pedestal, they did not have much of an impact.
Soviet boats were numerous rather than especially good. There was hardly a job they didn't undertake. I have a photo of one with its torpedo troughs filled with landing troops.
Japan's MTB are a sad tale. As small as Italian boats, they had the additional problems of engine procurement. That's why you find Japanese 24-knot MTBs.
I should get myself a signature that says, "I don't wanna be a butterbar!"

 

Tiornu,

Do you have any techincal specs for the MTBs, S-Boats and MAS boats?

 

Yeah, I have loads of stuff. Hopefully either later tonight or tomorrow, I'll post some illustrative stats.

 

Thanks!

 

British Light Craft

Brown suggests Britain was very limited in its engine choices for its light craft - what do you have on that?

The 6-pdr - that was a varient of the army's 6-pdr AT gun???

Were larger torpedo sizes considered for MTB's

 

Re: British Light Craft

The 6-pdr most commonly used in British MTB was the Mk IIA, which was a development of the anti-tank weapon but with the MV reduced from 2845f/s to 2150f/s. The rate of fire was good for such a large weapon, theoretically 40rpm. To me, this looks like the start of a good AA weapon, though I have no idea if it ever went that direction.
The British were not as committed to heavy torpedo weaponry as the Americans, so 18in models were common, and you'd usually find only two torpedoes regardless of their size. The Americans decided very early in their program that they wanted full-sized torpedoes; after one early batch, all subsequent PTs had 21 in torpedoes or modified 22.4in aerial torpedoes.
The weakest weaponry was mounted in the Italian boats. They usually had just one machine gun or small cannon, and their torpedoes were small even by 18in standards; one model had a 110kg warhead, which is just embarrassing. Compare it to the 600-lb charge on an American PT torpedo.
One could argue that torpedoes were not that important for motor torpedo boats, given the rarity with which they encountered torpedo-worthy targets.

 

The S 100 class is representative of the boats most common in German service. At 100 tons, they were much larger than foreign boats, but the key difference is in their engine--a diesel of unique power. Several other nations tried to copy this German success, and no one came close.
The other most important feature of German boats was their round-bilge hull form, very different from the PT hull that most people associate with MTBs. Put this size, diesel propulsion, and hull form together, and you have a boat with excellent speed and range and seakeeping. S-boats typically got over 40 knots, which is not unprecedented, but they managed this without the hazard of a gasoline-powered engine. Just grabbing some typical figures, the S-boats ranged to 700 miles at 35 knots, versus 480 miles at 28 knots in American PT-boats. Seakeeping does not lend itself to statistics, but the benefits are no less real; even in seas that would not be challenging to jumpy PT boats, an S-boat could maintain a lower silhouette at speed, making it stealthier and more stable as a gun platform while also allowing wider arcs of fire for its guns.
The Italians had great success with their little MAS boats in WWI; in fact, one skipper (Luigi Rizzo) became the only MTB skipper to sink not one, but two battleships. Unfortunately for them, the Italians then basically stood pat with their current ideas and went into WWII depending on designs like MAS 526. At just 25 tons, the boats were nimble but cursed with marginal seakeeping. I've mentioned their skimpy weaponry already. Wartime exposure to German designs prompted a wholesale shift in priorities. Large designs like MS 11 (62 tons) gained almost instant laurels despite a drop to 32 knots which would have earned cries of heresy prewar.
Britain had some notable successes with their CMBs during the Intervention, but the RN was less than infatuated with these little craft. Consequently, domestic industry failed to develop suitable engines, and the best ones available on the eve of war were Italian Isotta-Fraschinis. Fortunately, American Packards soon became available. Vosper was probably the most prolific MTB maker; they made boats in the 35-ton neighborhood with speeds of 40+ knots (assuming the availability of good engines)--very average, all around. The most famous type, though, would be the Dog Boats, or Fairmile D. These were as large as S-boats, but with four gas engines providing only 64% as much HP as the three-engine German diesel plant, speed was only 29 knots. A quick minelaying sortie of the sort routinely performed by S-boats would not have been possible for Allied boats.
American boats owed much to British prototypes, and the sizes and speeds were similar. The main difference was the refusal to remove the torpedoes, and there were no large designs. The two most important types were from Elco and Higgins. Both displaced about 35 tons. Elcos had better seaworthiness and speed (42 knots), and they had the most success. Higgins boats were stronger and more maneuverable.
The Americans were famous for loading their boats with all manner of weaponry. The Germans and British certainly "souped up" their firepower, but the Americans were manic about it. JFK's PT 109 had an anti-tank gun on board at the time of her loss.
The American Packard engine was the best gas engine in any wartime MTBs. They were reliable and efficient.
The French had only a handful of immature designs in service by May 1940. The Dutch had a more numerous force, but circumstances did not allow them much opportunity to accomplish anything. Their designs were related to British types.
Japan tried too late to get into the MTB game. They ended up building maybe 200 or so, but it really was hopeless. One attempt to copy the size of German types failed when it turned out their dimensions were the worst possible ones for Pacific swells. Mostly the Japanese followed the Italian model with boats as small as 15 tons. An attempt to mass-produce a 20-ton type turned into a tragi-comedy of engine procurement; the T23 variant managed a top speed of 17 knots (not a typo).
The other major MTB fleet belonged to the Soviets. Victimization by British CMBs caused the leadership see the MTB as a mighty weapon. The prewar G5 program (15 tons, 45+ knots) provided numerous vessels, but no more impressive than their size would indicate. In fact, they wore out rapidly and demanded more upkeep than was practical amid the Barbarossa retreat, but their endless presence proved an annoyance to the Germans. The wartime D3 type represented an improvement, being more like British/American types in size and speed, especially when Packards became available.

 

For further reading on MTB designs, I can recommend FLEETS OF WORLD WAR II for a general overview.
Perhaps the best specialized source is FAST FIGHTING BOATS 1870-1945 by Harald Fock. It's no longer in print, and if you are fortunate enough to find a used copy somewhere, it will likely cost you $100US. Thank God for libraries.
Whitley wrote a fine book called GERMAN COASTAL FORCES OF WORLD WAR TWO which makes the Fock book seem positively common by comparison. I can't even guess how much it would cost you; it's not a gigantic book, so maybe the seller won't charge more than a hundred bucks. It offers the bonus of info on midget subs and minesweepers. Fortunately, you have another worthy option, a book currently in print called S-BOOTE: GERMAN E-BOATS IN ACTION 1939-1945 by Jean-Philippe Dallies-Labourdette. It's a visually impressive presentation on a wide range of S-boat topics.
For American boats, the source naturally is Friedman: US SMALL COMBATANTS. Victor Chun's AMERICAN PT BOATS IN WORLD WAR II is also excellent, and you can try U.S. PT BOATS OF WORLD WAR TWO by Frank D Johnson as well. And if you're looking for operational histories and anecdotal material, there are many, many titles.
The British are equally prolific with their MTB histories, and LC Reynolds alone has published four in the past decade or so. You can find lots of stats, if not juicier material, in ROYAL NAVAL COASTAL FORCES, 1939-1945 by AJD North.
ALLIED COASTAL FORCES by Lambert and Ross is not comprehensive, but the MTBs that are in it get very detailed coverage.

 

6-pdr AA

Well a 6-pdr fitted in the nose of a Mosquitto is supposed to have demolished a Ju-88 that wandered in front of the Mosquitto with a single shot.

How about this - 57mm (not sure who made it) vs 40mm Bofors?

 

Re: British Light Craft

In Nelson to vanguard, Brown mentions that 'the 4.5" 8 cwt gun was just too late for the war' - was the army's 17pdr A/T gun ever considered though I would image all that could be made would be wanted by the Army.

 

Re: British Light Craft

I really like that 4.5in gun, though I wonder if it could succeed against fast targets. The muzzle velocity was 1500f/s--urkh!

 

Would there be any point in having a 17pdr on an MGB?
It was designed to punch small holes in very thick armour.
MGBs needed rapid-firing guns to try and demolish a target before it demolished them!

 

Bear in mind that a motor boat barreling along at 30kts+ is not going to be the most stable gun platform. A 17 pounder would reduce any MTB to splinters but in practice you probably wouldn't be able to hit anything smaller than a battleship at any sane range.

 

But would it?
It is superb at knocking small holes in stuff, but unless you want a series of holes through the enemy boat (in preferance to, say, a much more rapid series of explosions on/in the enemy boat) why not stick with the rapid-fire 6pdr?
The 17pdr was not exactly known for its good HE load.

 

i've read about a greek sailing ship that had a small gun on it and on its way escaping to britain they were stooped bt a large number of italian warships so the captain asked the second ship in the row for the password and it was given so he passed it on to the first ship and passed through the line of battleships

 

17pdr

If a 4.5" was considered for light craft then would a 17pdr cause too many problems - with a HE round of course.

 

American PT boat skippers were especially fond of automatic cannons as added armament. They salvaged 37mm cannon from wrecked P-39 fighters in the Solomons; the Bofors 40mm and Oerlikon 20mm were also common and popular.

The PTs also used their depth charges as anti-surface ship weapons from time to time: The boat, when pursued by Japanese destroyers, would sometimes drop one or two charges set on shallow in front of the enemy ship. The explosions usually caused the bigger ship to break off the pursuit, since one of the charges going off under her would likely break her back. An unlikely event, I know, but you only have to get lucky once.

 

The P-39 37mm cannon was mounted in old 3pdr mountings.
The "timed mine" use of depth charges was not exclusively American. In fact, I suspect everybody tried it occasionally.

 

If I had a tin can chasing me, I know I'd bloody well try it!!!