WWII destroyer sized torpedo boats?

[Avimimus]

Hello,

For years I've periodically daydreamed about the ultimate convoy raider. I initially imagined moderately sized boats with a single battle-ship sized cannon for range. I then explored other insanities like mounting a dozen fixed azimuth recoilless rifles on the deck of a ship (to fire a single short range barrage saturating an area). As I got older I settled on the idea of a large torpedo boat.

Here is the logic:

- Sufficient power could potentially allow a ship to run from escorting destroyers (this could be a critical issue in the design).

- It would be possible to carry over a dozen torpedo tubes per ship, mounted obliquely. The ship could be maneuverable enough to aim them (with good timing used for release).

- A small silhouette could allow the attacker to close distance and a larger quantity of torpedo tubs could allow a group of such ships to potentially saturate larger (cruiser sized) escorts.

- As a surface ship, it should be easier to coordinate in groups. In this way a formation could release dozens of torpedoes - compensating for the longer range release through shear quantity (especially using pattern running torpedoes). The number of torpedoes would limit the effectiveness of defensive maneuvers and flares could be used to signal allied submarines once the barrage had stopped running. The disrupted convoy would make it easier for submarines to pick off the survivors and the submarines would further distract any escorts.

- A moderately sized boat could have a small enough size and sufficiently good turn performance (to avoid dive bombers), and be fast enough to be immune to effective torpedo attack. Deck armour could provide some resistance to aerial rockets and anti-aircraft weapons could also be carried. This would make the design more survivable in the presence of enemy aircraft than a located submarine or a larger ship.

Questions to follow up on:
- What is wrong with this scheme tactically?
- Would it have been possible to build such a ship?
- What would the ideal design be like (eg. number of tubes, silhouette, displacement and tonnage)?

 

[Jemiba]

That brings the Japanese torpedo cruiser conversions Kitakami and Ooi to my mind,
former conventional light cruisers, but from 1941 carrying 10 quadruple mountings
for Long Lance torpedoes. Just to stay with Japanese ships, because the 60.9 cm
Long Lance torpedo seems very weel suited for such a ship, a similar conversion
of, say, the Kagero destroyer class could do the trick ?
Made just a quick and dirty sketch, based on a drawing I found on the Hasegawa site
http://www.hasegawausa.com/product-pages/hsgs4072.html

 

[cluttonfred]

Forty ready torpedoes? Yikes!

 

[Jemiba]

.. and, as the deck rails show, there were reloads, too !
Those ships weren't intended as commerce raiders, but as some kind of
"silver bullet" against the US battle fleet in the decisive battle, the Japanese
admirals were dreaming of (and probably several American admirals, too).
At least a drawing of the Oi can be found here:
http://www.navypedia.org/ships/japan/jap_cr_kuma.htm

 

[Avimimus]

Fascinating - one thing that amazes me about this forum, is that any idea I've come up with - no matter how odd - appears to have been tried. I'd love to hear about any other proposals.

I was thinking that the 750-1500 ton displacement might be ideal. It would certainly be less vulnerable to air attacks, and harder to see, but they might still be able to reach into the North Atlantic. Attacks at night in bad weather could be particularly deadly. The biggest problem I see for the designs is being able to outrun light escorts and survive cannon fire.

Thanks,

 

[gollevainen]

Weren't the KM Type35/37 class torbedo boats in sense rather similar in concept of the platform-vise than what you are wanting? To have maxium ammount of TTs in the hull, made as fast as possible with high-pressure boilers and to have low-siluette to be optimised Torbedo attack vessels?

I think the concept/ship you are after will most likely end up in same fate than the those mentioned KM boats, when the mass-torbedo attacks aren't possible (due lack of targets or other reasons), then the ships wouldn't have any other use in more GP tasks that smaller surface ships usually ended up in wartime due lack of good gun armamanent and minelaying capacity. Taken that high performance requires high-performance propulsion that would be the most expensive part in such ships, I doupt the cost-effectiveness would that great.

This is naturally "post WWII" hindsigth opinion but worth of consider atleast, don't you think.

 

[royabulgaf]

For commerce raiding, here is an idea- Around the Spanish-American war, the US Navy experimented with what were called dynamite guns. The gun was powered by compressed air, and was solidly mounted to the ship. The range was adjusted by varying the air pressure. With multiple tubes firing singly, you could fire largish shells at a rapid rate of fire all day. A perfect convoy raider in a small package.

 

[OM]

...Ah, the very concept of one LCDR Quintin McHale having command of a vessel like this.

"Hey Skip! Look portside!"

"Oh NOOOO! Chuck! You blew up the whole island with that salvo!"

[Cut to: Cpt. Binghampton sitting in a life raft, UOD smudged and blast-torn]

"Why? Why, why, why *me*?"

 

[Abraham Gubler]

Fascinating - one thing that amazes me about this forum, is that any idea I've come up with - no matter how odd - appears to have been tried. I'd love to hear about any other proposals.

A few years ago for a fiction book I was working on I developed a similar idea. I have a few configuration designs that I will post later when I’m at the right computer. While not conceived as a commerce raider my very large (~600 tonne) motor torpedo boat’s role was coastal defence of island bastions. I used British 1930s technology and it was quite a neat looking ship if I say so myself. Designed to defend bases like Singapore, Ambon and Rabual from a Japanese attack.

Attacks at night in bad weather could be particularly deadly. The biggest problem I see for the designs is being able to outrun light escorts and survive cannon fire.

The problem with running as a defence is it’s a mission kill. If the destroyers keep chasing off your commerce raider then it’s not going to raid any commerce. All of the commerce raiders were designed to penetrate the escort shield. Either by guns and armour (German pocket battleships, cruisers) or by stealth (submarines). When the Allies started sailing old R Class battleships with each convoy the German response was to sortie the Bismarck battleship. Even a low super-structure motor torpedo boat is not going to be stealthy enough to sneak past the escorts.

Perhaps an idea is to combine your concept of a high speed, low profile motor torpedo boat with the submarine. That is a high surface speed, barrage torpedo submarine. By having its hull underwater (with the casing awash and only the tower above water) it will present a very low profile and filling the casing with single shot torpedo tubes will provide the needed fire power. To achieve high power you could gear together eight diesels on three shafts. With eight Daimler Benz V20s (German WWII technology) that is 30,000 hp. In a long and thin ~2,000 tonne submarine that should get you over 30 knots. Such a ship wouldn’t be so good underwater but it would only dive to escape being gunned by the destroyer escorts.

With the high speed and low profile it should be able to get inside the convoy box and wreak havoc. A one ship wolf pack.

Here is a configuration drawing of my River class torpedo motor sloop (TMS). Such a ship would have been built from the mid to late 1930s in Australia for the RAN to equip deployable island defence flotillas. These flotillas would guard island bases (Singapore, Tarakan, Ambon, Rabual, Tulagai, etc) that were to be used as bastions for airpower to disrupt any southward advance of the Japanese (an actual strategy proposed by the RAAF leadership at the time). The hullform is based on the circa 1900 Bainbridge class torpedo boat destroyer but would be of all welded, longitudal construction. The machinery is four Admiralty pattern supercharged diesels as found in the Thames class submarine. Armament is 12 21’ torpedo tubes, two 4” guns and multiple automatic cannons (20mm and 40mm). Maximum displacement would be around 600 tonnes, length 76m (250’), beam 7m (23’) and draft 2m (6’6”). Maximum speed with 16,000 hp would be over 40 knots. Despite the fineness the hull would have plenty of room thanks to the comparatively narrow engines.