Torpedo Boats

I hadn't thought about the lack of elevation for AA duties.
The increased mining strikes me as odd, as the S boats were not designed for mine laying and whilst you could obviously replace torpedo's with mines to make a decent job of it you would need more aft deck space.
RN Minelayers reduced the guns to carry more mines and kept the front gun, which was often the main weapon. Its interesting how differently each navy approached the same task.

Thanks again

parsifal said:

QUOTE=Glider;550336]You could well be right as some carried up to 4 x 21in Torpedo's. They varied considerably the normal selections being one of the following.

4 x 21in Torpedo's e.g. German S Boats, some PT Boats
4 x 18in TT e.g. RN MTB's no 380-395 some others as well
2 x 21 torpedo's loads of types
2 x 18in torpdoes loads of types.

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Hi Glider


All S-Boote types were fitted with with two torpedo tubes plus 2 torpedo reloads. the projected 700 series were designed to fire all four fish simultaneously, but weree never built.

S Boats never carried 4 x 21 in torp tubes . They carried a maximum of two. However, from 1942 they were using a modified G-7e T-2 type toprpedo , which carried a 660 lb warhead, and had a nominal range of 5000m @ 30kts. The torpedo was relatively slow, but was electric (no wake). It was similar to the later war electrtric torps used by the Boats

Thanks for this. You will note that for the first line I did say torpedo's not torpedo tubes. As you rightly say the original idea was for the S Boat to reload but in the cut and thrust of night battle it almost never happened and the reloads were often left behind. I didn't know about the modified torpedo and thanks for that.

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There was massive differences in the British MTB/MGB armament. One of the best was the MTB 601 series, which represented the main types from 1942 to 1944. As an MTB they were fitted initially with 2 x 18, later this was modified to 2 x 21in or 4 x 18in. However the increase in torpedo broadside made these relatively slow boats even slower. Gun armament of the MTB was typically 2 x 6pounders, 2 to 3 x 20mm and 4 x 0.5in or 0.303in.

I think we need to be clear about the two basic types of RN MTB/MGB for those who are fairly new to this topic. They fell into two classes
a) The smaller faster MTB that weighed in at between 40-50 tons often called the Vosper. These had a top speed of about 40 knots give or take depending on the version and at wars end often carried a 6pd, 2 x 21in torpedo's and a twin 20mm plus the beloved twin vickers in the bridge wings.
b) The much bigger Fairmille D class often called the Dog Boats or Type 601 which you mentioned. These were about 100 tons with a max speed of about 28 kts again give or take depending on type. As you mentioned these Battleships of the coastal forces carried 2 x 6pd, 2-4 20mm and MG's of various sizes and at the end of the war 4 x 18in TT.

On the Fairmile D there were all sorts of versions of weapons depending as much as what was available and preferences as to standard.

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Italian MAS boats were much smaller and mor lightly armed, but were very fast. They had an excellent engine to work with in the Isotto Fraschini which yielded 2300hp. With two of these, their 30t MAS 551 could exceed 43 knots. These engines were also very reliable.

Whilst I do not believe that the MTB boat was more hevaily armed lb for lb than a destroyer, I think as a comparaison of lb for lb firepower between this general class of vessel, the prize would have to go to the MAS Boats. They only had a displacement of 28 tons, yet carried a significant proportion of the the firepower of their larger northern cousins. An S-Boat weighed 117 tons. A type 601 weighed 97 tons

My vote would go to the 45 ton Vosper, its a nice balance of speed, guns, torpedo's and not forgetting they had radar something missing from German S Boats.

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I remembered this photo. She was HMS Gay Archer (yes, you did read that right) built post war around 1950 as an MTB and is being renovated but in most respects is very similar to a war time RN MTB.

Her weapons are not original when built she carried a 4.5in and a twin 20mm but is sometimes used for film work. You can see how tight deck space was even in this configuration.

Glider, do you have this book?



The 6pdr 7cwt Mk II gun on a Mk VII mount did not appear on the Fairmiles til 1944.

Nope but I must cry for Mercy, the Christmas list will get me divorced!!

Seriously No I don't but have other books namely one Warships of WW2 which covers everything in the RN from the largest BB to the smallest requisitioned drifter and yacht. One of its best aspects is the photos which cover literally everything and give details of the weapons on each ship.
For the Coastal Forces they break the MTB's into the individual sub types and give the details for each in most cases as built and as they developed during the war.

Hi Glider

An interesting, and often overlooked nationality in this field are the Russians. The Russianss specialised in ultra-small MTBs, of which the most successful were their D3 and Komsolec Types.

The D3 were considered large, by Soviet standards, at 35 tons. normal armament was 2 x 21 in torps, and either 4 x 0.5 in or 2-3 x 20mm shvak cannon. They had a very wide selection of machinery types, which also produced huge performace differences, ranging from 32 knots through to 53 knots (yes 53 knots)

The Komsolec design was ready in 1940, but really they were not produced until 1944. They were ultra small, at 15 tons, but they packed a considerable punch. 2 x 21 in torps, with either 4 x 0.5in MG or 2 x 20mm cannon. They were made of reinforced Aluminium, and possessed the fantastic max speed of 57 knots.

The Soviets were also highly successful subtype in this general class were the armoured river gunboats, and in this field the Soviets reigned supreme. They produced two basic types, the Type 1124BKA type and the much larger MBK type.

The MBK type was 150 tons, armed with 2 x 85mm guns, 1 x 37mm and 4 x 0.5 in HMGs, with a top speed of 28knots. They were armoured, turret faces to 2 inches, CT 1.5 to two inches, light plate to hull sides .

Over 300 were built during the war, and they allowe3d the Soviets to completely dominate the major rivers of the Eastern Front. This was a significant advantage in the major river crossings the Red Army wa obliged to undertake during the war.

yes the S-Boote 700 series was indeed operational in 1945. S-Boot mine ops were chiefly in the Kanal-Denmark straits and on the coastal waters of England, also in the Baltic as the 8th S-Flottille and others based there moved continually almost every other week.

Did some of the Soviet boats use tank turrets to mount their 85mm?

PJay said:

Did some of the Soviet boats use tank turrets to mount their 85mm?

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The river gunboats Type 1125BKA and the smaller MBK types were produced from 1935. The earlier types were fitted with a 3in (76mm) gun as used in the T-28 and T-35 tanks. Later the types converted to the Type 3in/41.2 guns and turrets as fitted to the T-34/76, and later with 85 mm and associated tank turrets. At the end of the production run, they were being fitted with 100mm guns in turets.

But basically they were using tank guns and turrets as you say

Made them look quite modern I thought.