Long Lance torps.

[Riain]

Heavy torpedoes are fantastic ship killing weapons but, other than the IJN, ships had to get well within gun range to get an accurate shot. WI the Japanese Long Lance torpedo, with its ability to run to 20+km at 50 knots, was the rule rather than the exception? How would these types of torps go coupled with the radar and mechanical fire-control computers that the Brits, Germans and US had? Would they change the nature of surface battles in WW2? Would the USN abandon torps for cruisers if they had the power of the Long Lance at their disposal? Would torps remain a central naval weapon well into the missile age?

[Redbeard]

IMHO the greatest impact of the Long Lance (LL) was its larger warhead and the circumstances in which it was used first.

At the extra range of the LL the hitchance would be very low no matter if the speed was 30, 40 or 50 knots.

But it was used with great effect in the early battles in SEA which often took place at night, in confined waters and adding to already great confusion.

Both the USN and the Kriegsmarine had serious reliability problems with their torpedoes early in the war, and here any more reliable torpedo would be very handy indeed.

But back to the LL I think its status as a "wonder weapon" to a degree came from the need to explain the USN defeats early in the war, any reliable torpedo would have had a similar effect under those circumstances. That doesn't take away that the LL was a very good and reliable weapon. It was developed as a part of the IJN doctrine of grinding down the USN as it crossed the Pacific to meet the IJN in a final decisive battle. The LL should be used in night attacks by light forces (destroyers and cruisers) and never materialised in that context, but the training in night fighting came to good use in SEA early in the war.

The USN however soon learned the balance between utilising radar and not being too reliant on it, and from then on the IJN rarely got a chance to get close enough to perform its massive torpedo attack tactics with notable effect.

Regards

Steffen Redbeard

[Mike Stearns]

Originally Posted by Redbeard

It was developed as a part of the IJN doctrine of grinding down the USN as it crossed the Pacific to meet the IJN in a final decisive battle.

If that's the case, it probably could have done very unplesant things to American supply convoys. Thanfully the Japanese didn't think like that.

[CalBear]

The Long Lance, had everyone had them, would have changed the war mainly in the Battle of the Atlantic, where the U-Boats would have been somewhat more effective.

In the Pacific the American war effort in the first two years would have greatly benefited, especially given the horrible performance of the American weapons during the early war years. There would have been a number of additional Japanese warships that went to the bottom from torpedoes rather than later to bombs.

It needs, however, to be remembered that the Long Lance was, in the end, just a torpedo. It didn't win the war for the Japanese, it wouldn't have won it for anyone else. The U.S. might have done better in early surface engagements had they known how well torpedoes would work (as they would if they had toprs of the same quality). Torpedoes of the era, including the LL, were less than perfect weapons, they didn't have any active target seeking abilities and were dependent on rather primitive presets for targeting. MANY LLs missed simply because the aimpoint was off by a fraction of a degree, a problem that became worse as range to the target increased. In many ways, the later, but more revolutionary, early versions of wake following weapons were the real breakthrough (followed by the later wire guided and active somar guided weapons still in use today).

[zoomar]

In the first few decades of the 20th century, the US Navy toyed with the design concept of "torpedo battleships" as an alternative to the standard BB. Heavily armored ships displacing up to 30,000 tons, armed with large torpedo batteries rather than heavy guns. These designs were done when torps were short-ranged and unreliable, and were nover pursued. I wonder if the USN (and other navies) had access to Long Lance quality torpedos in 1920, such designs would have been built. Could this have radically changed the nature of future surface combatants?

[Mike Stearns]

Interesting idea. You'd probably see a greatly accelerated pace for sonar and torpedoe development. Such a ship could potentially be an excellent sub killer.

[zoomar]

They were, however, envisaged as ships of the line, gun-armed only against light ships (and aircraft), with the torpedo battery used instead of heavy guns to sink other capital ships. If you ever get a chance, Chek out Norman Freidman's US Battleships: A Design History It's got a great discussion and some design drafts.

I suppose if the concept did take hold and survive into the post WW2 period, such a ship would make a good ASW ship armed with modern homing torps...but in a way that is what a modern cruiser can be anyway.

[Mike Stearns]

Originally Posted by zoomar

They were, however, envisaged as ships of the line, gun-armed only against light ships (and aircraft), with the torpedo battery used instead of heavy guns to sink other capital ships.

Interesting. I'm envisioning this idea with a totally differtent role in mind. I could imagined these being use as sub killers. I could also imagine them laying into a convoy. I could see where they'd be very effective for that sort of work. There'd be no muzzel flash or sounds associated with gun fire. They'd have a low radar profile because they'd utilize sonar to track possible targets. You might not even know that they are there until ships start sinking.

[zoomar]

Sounds like you are talking about a ship which is virtually a submarine, but which is only 80-90% submerged rather than fully submersible. Only a small armored deck surface with an armored conning tower above the water, with all offensive sensors -as well as the torpedo mounts - all well below the water line. This is an interesting concept, but apparently unlike the US "torpedo BB", which was essentially a surface combatant, just armed with torps instead of guns.

Also, you are thinking WW2. The US torp BB was essentially a WW1 concept. No radar or sonar. The closest thing I can think of in real life is the IJN Kitikama CL modification with 40(?) torpedo mounts.

[Mike Stearns]

Originally Posted by zoomar

Sounds like you are talking about a ship which is virtually a submarine, but which is only 80-90% submerged rather than fully submersible. Only a small armored deck surface with an armored conning tower above the water, with all offensive sensors -as well as the torpedo mounts - all well below the water line. This is an interesting concept, but apparently unlike the US "torpedo BB", which was essentially a surface combatant, just armed with torps instead of guns.

Also, you are thinking WW2. The US torp BB was essentially a WW1 concept. No radar or sonar. The closest thing I can think of in real life is the IJN Kitikama CL modification with 40(?) torpedo mounts.

Yeah, I was sort of envisioning something that vaguely resembels a Civil War Iron Clad, but way more advanced. As for weapons, I was sort of thinking that it would have torpedo tubes built into the hull below the water line in addition to torps in launchers on gun mounts, in a system somewhat similar to the way cruise missiles are launched and powered by compressed air. That's what I had envisioned. Evidently you were thinking of something a little more conventional, but either way its an interesting idea. I would have liked to see whether it could actually work or not.

[Atreus]

Originally Posted by zoomar

In the first few decades of the 20th century, the US Navy toyed with the design concept of "torpedo battleships" as an alternative to the standard BB. Heavily armored ships displacing up to 30,000 tons, armed with large torpedo batteries rather than heavy guns. These designs were done when torps were short-ranged and unreliable, and were nover pursued. I wonder if the USN (and other navies) had access to Long Lance quality torpedos in 1920, such designs would have been built. Could this have radically changed the nature of future surface combatants?

Do you have a link? I'm interested.

[Riain]

I think the long lance's reputation is deserved, it allowed the IJN to do things that no other navy could contemplate. Part of the LLs repuatation stemmed from the confusion that torpedo attacks could even occur at LL ranges. The USN developed doctrine which reduced the LL threat; long barrage fire from 6" cruisers. But this doctrine wouldn't work if the USN didn't have radar or dozens of 6" cruises, 6" cruisers are a very expensive way to combat destroyers. Transfer the LL's ship-killing capability, enhanced with modern fire control and perhaps radar, to the RN cruiser which shadowed the Bismark, or the 3 cruisers at River Platte, or any number of surface actions in Europe.

[CalBear]

Originally Posted by zoomar

In the first few decades of the 20th century, the US Navy toyed with the design concept of "torpedo battleships" as an alternative to the standard BB. Heavily armored ships displacing up to 30,000 tons, armed with large torpedo batteries rather than heavy guns. These designs were done when torps were short-ranged and unreliable, and were nover pursued. I wonder if the USN (and other navies) had access to Long Lance quality torpedos in 1920, such designs would have been built. Could this have radically changed the nature of future surface combatants?

Not really. Big guns were effective at 20K+ yards even before WW I, by WW II they were effective at 35K+ (IOW Over the visible Horizon, needing spotting aircraft) or very close to the max range of the LL & much greater than the range of other torpedoes. The big gun could be fired, drop of shot observed, either by gunnery officers or, at extreme range, by trained spotters, and adjusted onto a target. Torpedoes, as noted earlier were far less accurate, much more difficult to predict, and getting two to hit the same place, while not impossible, was akin to drawing to consecutive inside straight flushes. A well handled ship, at high speed, can also dodge non-guided torpedoes (as Yorktown did at Coral Sea, despite being a bloody CARRIER), but dodging shells, while possible, is much like an extended game of Russian Roulette. Each shell had the striking power to sink anything smaller than a capital ship (same as a LL torpedo), and no matter how specific the design, a capital ship would always be able to carry many more shells than torpedoes.

The whole idea reminds me of when the U.S. decided to arm some of it's sail frigates with nothing but carronades on the theory that the guns were far more destructive than regular cannon. Of course they also had half the range of regular cannon, resulting in Britsh frigates, with 1/3 the broadside weight, pounding the carronade armed ship into splinters. Great on paper, weak in RL.

BTW: This thread got me to look into the LL a bit more deeply. The weapon was apparently more than a bit twitchy, mainly due to the oxygen fuel source. They had a nasty habit of detonating if damaged during battle (one source, admittedly a Wiki, indicates that later in the war Japanese DD commanders would sometimes dump the fish overboard in case of air attack). Apparently the IJN lost at least one cruiser to this sort of malfunction.

[PMN1]

The range that Long Lance gives is potentially very good, as long as the opposition isn't watching you on radar, knows you are likely to have them and has the experience to take advantage of that knowledge.

[Riain]

HMS Warspite against an Italian BB and the S & G against HMS Glorious got the longest range big gun hits ever, both about 26.5km against big targets. While this may translate down to an 8" cruiser it gets fuzzy at 6" cruiser and destroyer level, which is the premise of the IJN's development of the LL. Also keep in mind that the RN, USN and KM had radar and F-C computers which would make their long-range shots more accurate than the IJNs. These navies would get hits in situations where the IJN couldn't, further increasing the lethality of these fast, long-range torps.

[MrP]

Originally Posted by zoomar

In the first few decades of the 20th century, the US Navy toyed with the design concept of "torpedo battleships" as an alternative to the standard BB. Heavily armored ships displacing up to 30,000 tons, armed with large torpedo batteries rather than heavy guns. These designs were done when torps were short-ranged and unreliable, and were nover pursued. I wonder if the USN (and other navies) had access to Long Lance quality torpedos in 1920, such designs would have been built. Could this have radically changed the nature of future surface combatants?

The first time I hear of a similar design was the Imperial Russian version of this. Let me just grab my book.

1913 design
p.264-6, McLaughlin, Russian & Soviet Battleships
Displacement: 23,000 tons normal
Armament: 84 * 450mm under-water torpedo tubes
Speed: 28 knots

More details, if you like.

[Riain]

I think torps were too feeble until the 30s to base major surface combattants on them. A number of propulsion improvements, led by the RN and IJN made them far more effective in this decade; pure oxygen, oxy enriched air-burner cycle, HTP. But even the 2nd best torp of WW2, the RN Mk IX with OEA-BC propulsion could do 11km @ 41kts (LL-90% more range and 20% more speed) was well within gun range. That was the beauty of the LL, the range AND speed to be fired with a good chance of success from the edge of gun range. I do wonder what would be the result of further developing the 25" torp on the Nelson & Rodney (15Km @ 35kts) and deploying it on cruisers and destroyers, a bit more range and a lot more speed would make it a serious threat to the LLs dominance.

[Markus]

IIRC the biggest advantage of the LL was the fact that the USN made incorrect assumptions about them. They thought the Japanese fishes were similar to theirs, so when they were hit by LLs they concluded the torpedoes could not have been launched by the enemy’s surfaces ships, because the distance was too long. There had to be some subs operating in front of the surface ships that fired the torpedoes.

Once they captured a LL intact, they knew better and changed their tactics. And if all nation´s torpedoes are as good as LLs, the USN will not make this false estimation in the first place.

[Riain]

The USN dropped development of a HTP torp in 1941 which did 16km@50kts, it's a shame they didn't credit the IJN with that sort of performance. If the USN looked like having access to this kind of torp in the mid 30s would they have kept torps on their cruisers? Would BBs have been considered so important if all a light cruiser or destroyer had to do was get within about 15-20km to get a killing shot? That is a world of difference to the 5-7km that everyone other than the IJN had to close to, giving secondary guns on heavy ships plenty of time to engage their attackers.

[zoomar]

Originally Posted by Atreus

Do you have a link? I'm interested.

No link. It's an actual book published by the Naval Institute Press. Remember them?