Torpedo Arcs of fire

[tone]

Having watched the demo battle a few times, I observe a lot of torpedoes leaving the firing ship at angle considerably off the perpendicular. I have not looked at the ships in detail in any source, but it is my belief that almost all the battleship and AC torpedoes were in submerged tubes, and that few if any of these were in any way articulated.

Moreover, the ability to set gyro angles so the torpedoes could take up a heading different than roughly that of their tube when they were fired required not only gyroscopes (which these early torpedoes lacked entirely) but also the ability to SET gyro angles (a feature not intrinsic to possession of a torpedo with a gyro).

Looking at the ship data files, I see that the submerged tubes have two arcs mentioned, arc0 and arc1. For several of these, at least, arc0 is defined as being 90 degrees and arc1 as "none". I'm curious how they are applied? Is arc0 perhaps the angle in which the AI will start to examine potential targets, but arc1 is the one on which the weapon fires?

If (to cite the first ship in the datafile for instance), the Peresvyet were to be permitted to fire her bow tube anywhere from red 45 to green 45 (as IO infer from arc0=ARC_BOW_90), this would, I think, be far more flexibility than these weapons actually enjoyed.

If it's wrong, of course, one game-play problem would be that instances of torpedo firing would plummet. But as others have suggested (and I can sympathise), it may be that DG torpedoes are producing too little damage when they impact, even considering their moderate warhead sizes.

Just asking!

edit: checking up on what I said (source: the RN's Annual Report of the Torpedo School, 1901), these torpedoes might well have had gyros... but they would not have had gyro angle firing. I'll backpedal and describe the initial use of gyros in torpedoes.

Gyros were initially used solely to ensure that the torpedo ran straight, and that any stern-ward kink in travel caused by the torpedo's nose entering the water before the rest of it could be quickly corrected. Prior to their introduction, torpedoes relied on careful adjustment of their rudders to provide as straight a course as possible.

Sometime around WW-I, various marks of torpedoes were acquiring gyro-angle settings. These were far from magical, however. Most such weapons had to have their angle set when removed from the tube, a requirement which made blithe adjustments unthinkable, as it might take 5-10 minutes to get the torpedo ready to fire from there (depending on the mounting). Moreover, these angles were not infinitely settable: a typical constraint was that the adjustments were possible only in fixed quanta (15 or 10 degree steps being typical), and with only a maximum number of steps possible (often less than 45 degrees).

A lack of true flexibility in this regard meant that firing a torpedo at a moving target required you to be ahead of her... particularly if your tube were not articulated and had to fire out on the beam. Some internal tubes were smartly mounted to face ahead of the perpendicular to limit the impact of this requirement, but not many. When navies started to take deliveries of torpedoes capable of having a gyro angle set, the inability to rapidly alter this setting would have caused its use to be limited in most cases to simply setting it to jink toward the bow, as this would usually offer the most opportunities for firing later as conditions changed. The sighting apparatus would likewise just be twisted by the same angle toward the bow.

tone

[saddletank]

Most tubes were angled within the hull, and not fixed to fire out at 90deg

[tone]

Most tubes were angled within the hull, and not fixed to fire out at 90deg

I know some were, but I wonder what proportion were. It is a nice extra element for research on a case-by-case basis. I see it done seldom in later ships (WW-I era), but on occasion.

The issues of having to fire along a lengthened hypoteneuse was an especially important factor, particularly in the cold torpedo era of the RJW, to want to obtain a position ahead of the enemy battle line, or to fire against the ships at its end rather than those opposite.

tone

[saddletank]

I think Janes ship plans show the hull TT angles. I have seen many ACs and PCs fire 2 torps from the beam. I wasn't aware that many ships of this era had more than say 6 tubes: bow, stern and 2 each side, one angled forward and one back. Altogether the 6 tubes faced out in 6 different directions. That means that only 1 torp could be launched at a time yet I frequently see two launched. Perhaps the game is specifying 2 tubes per beam but not the mount angle?

[SunScream]

In the sim torpedo tubes on the cruiser and above sized ships have 90 degree firing arcs like guns, hence the fore and aft tubes often fire together.

It sort of preempts the Germans ball-and-socket trainable submerged tubes, which were just being introduced at the time of the RJW.

[vertical]

Certainly learning a lot about early 20th century naval warfare from you guys. :)

vertical

[tone]

In the sim torpedo tubes on the cruiser and above sized ships have 90 degree firing arcs like guns, hence the fore and aft tubes often fire together.

It sort of preempts the Germans ball-and-socket trainable submerged tubes, which were just being introduced at the time of the RJW.

Was this a true capability of the torpedo tubes, or an accomodation in their simulation? I'm pretty sure almost all tubes were fixed and fired out directly ahead/astern/abeam, with a modest handful of exceptions.

tone

[SunScream]

As far as I am aware all submerged tubes of this era would have a fixed mount, excluding new German construction mentioned above.
Side tubes would be angled from the perpendicular, i.e. not at 90 degrees to the direction of travel. The angle would be probably between 70 - 80 degrees off the bow/stern.
Interestingly, HMS Dreadnought was originally designed for 14" tubes but was upgraded to 18". The torpedo flats were very small so the forward starboard tube is angled at about 70 degrees, while its port equivalent is at an angle of 80 degrees (all by eye from John Roberts' book).
Submerged tubes would be found on the more recent construction, such as the Elswick built Japanese ACs. Oslylabya had tubes trained 20 degrees aft the beam (70 degrees from the stern), but these were reported unreliable at high speeds in JFS 1905-06.

Above water mounts which were not weather-deck mounted would also be fixed as they had little physical room to be trained in. Due to the centralized pivot mounting the ship would need a large cutout in the hull to be able to train a tube, and these cutouts are just not present in ships of this era.

I think we can safely treat all ship torpedo mounts as fixed unless they are on the weather deck, and having torpedoes fired together from multiple fixed mounts should not be possible.

Someone will now prove me wrong :)

[tone]

As far as I am aware all submerged tubes of this era would have a fixed mount, excluding new German construction mentioned above.
Side tubes would be angled from the perpendicular, i.e. not at 90 degrees to the direction of travel. The angle would be probably between 70 - 80 degrees off the bow/stern.


I see by checking the plans for SMS Kaiser Barbarossa (1901) that her stern tube articulated 30 degrees to either side of straight astern (http://dreadnoughtproject.org/plans/SM_Kaiser_Barbarossa_1901//panzerdeck_100dpi.jpg), but her bow tube was fixed straight ahead (http://dreadnoughtproject.org/plans/SM_Kaiser_Barbarossa_1901//stauungsplan_100dpi.jpg). Her forward and midship beam tubes appear to be angled 10-15 degrees forward (http://dreadnoughtproject.org/plans/SM_Kaiser_Barbarossa_1901//zwischendeck_100dpi.jpg) (a guess: they are not directly indicated, but a gap in the bulkheads appears to have this angle). It's possible the beam tubes could articulate, but they would have had less arc than the stern tube, if any, judging by the leeway allowed them in the gaps in the bulkheads.

This pre-study (http://dreadnoughtproject.org/plans/SM_Linienschiff_C-G_1899//langsschnitt_100dpi.jpg) for what was probably to become the Wittelsbach class shows the same pattern: a similar, moderate fixed forward angle to her beam tubes, a fixed forward tube, and an articulated abovewater "stinger" at the stern.

Skipping later in German ships, the slight forward angling of beam tubes persist up to Friedrich der Grosse, 10-20 degrees or so (http://dreadnoughtproject.org/plans/SM_Friedrich_der_Grosse_1912//langsschnitt_100dpi.jpg).

Some of those plans are pretty much ideal for gauging arcs of gunnery, of course!


Interestingly, HMS Dreadnought was originally designed for 14" tubes but was upgraded to 18". The torpedo flats were very small so the forward starboard tube is angled at about 70 degrees, while its port equivalent is at an angle of 80 degrees (all by eye from John Roberts' book).


I take it you mean from the BOW! Ok, I take much less exception to the statement I disagreed with above. :)


Submerged tubes would be found on the more recent construction, such as the Elswick built Japanese ACs. Oslylabya had tubes trained 20 degrees aft the beam (70 degrees from the stern), but these were reported unreliable at high speeds in JFS 1905-06.


I believe this was a common problem. The arms that would extend out to allow the torpedo to come out freely sometimes bent under the water's rush.


Above water mounts which were not weather-deck mounted would also be fixed as they had little physical room to be trained in. Due to the centralized pivot mounting the ship would need a large cutout in the hull to be able to train a tube, and these cutouts are just not present in ships of this era.

I think we can safely treat all ship torpedo mounts as fixed unless they are on the weather deck, and having torpedoes fired together from multiple fixed mounts should not be possible.

Someone will now prove me wrong :)

I think we are largely in agreement.

it must have been darn difficult to communicate firing information from sighting positions to tubes. It was not until WW-I or so that a real emphasis was placed on building in special transmitter/receiver pairs for communicating torpedo orders below. The RN's 1914 Manual of Fire Control Instruments lists around 12 different devices pertaining to torpedoes: one pair to convey range to target, another to convey course and speed of enemy, a series of ones to support the new gyro angle capabilities (the newest then to anticipate torpedoes settable up to 40 degrees in 5 degree increments), and still others to convey different orders such as "load", "flood tube", "fire", and "fire when the sights come on" (for those stations that had their own sighting equipment).

I do know that some of the earliest torpedo control instruments from ABOUT the RJW era were based on hydraulics. Apparently this was judged more reliable than the earliest electro-mechanical ones, but they were really quaint!

tone

[SunScream]

Sorry my post was misleading, I didn't mean the Germans were *only* using trainable mounts, just the sim was replicating something the Germans had developed. :)
Presumably the ball & socket mount was confined to the stern due to water flow and pressure issues when mounting them abeam. Getting an effective watertight seal must have been difficult in the days of indiarubber and leather gaskets. Bow tubes would have to be fixed due to the narrowness of the hull at this point.

Yes, I was measuring off the bow, as mentioned in the previous paragraph of my previous post. I was talking beam in first draft but then went waffling on about bow tubes until the whole section was deleted. I forgot to change back :o

Isolating bow and stern tubes would always be a worry. It only needs someone to shout down the wrong voice-pipe or hit the wrong button and you promptly torpedo the next ship ahead/astern in the line. One reason why bow tubes were just about non-existent in RN ships and those very few with stern tubes had them suppressed when the great war broke out.

Hydraulics are good. You can tell where a break in the system is by the water or oil squirting out, and you may be able to patch it temporarily with a rag and a jubilee clip. Much harder to locate and repair the fault in copper wire coated in lead and stuck to the ceiling.
HMS Invincible was a test bed for electrical operation of the main guns but the lack of precision electric motors and a plague of wiring faults and blown fuses meant she was eventually converted back to hydraulics.

[tone]

Sorry my post was misleading, I didn't mean the Germans were *only* using trainable mounts, just the sim was replicating something the Germans had developed. :)
Presumably the ball & socket mount was confined to the stern due to water flow and pressure issues when mounting them abeam. Getting an effective watertight seal must have been difficult in the days of indiarubber and leather gaskets. Bow tubes would have to be fixed due to the narrowness of the hull at this point.

I'm not convinced that the Germans had any articulated submerged tubes. You'll note that the dirigible aft tubes in the plans cited in my previous post are all mounted above the water line. I wouldn't be surprised that no one would want to compromise hull integrity to the degree required to have a torpedo tube that could articulate underwater. Additionally, there is the need in broadside tubes to have a projecting arm that can be slid out into the wash before the torpedo is fired (or at least this is how the RN systems worked). These were fairly heavy apparatuses, and their projection would have caused considerable aftward torque in a tube that was not firmly fixed in position.

tone

[SunScream]

I have been doing some further digging into German torpedo tubes:
JFS and I agree with you regarding the fixed tubes and the above water stern tube on Kaiser Barbarossa, Wittelsbach and the Braunschweig classes.
The following Deutchland class is mentioned by JFS as having "Torpedo tubes (17.7 inch): 6 submerged (bow, stern and broadside - training)."
"Torpedo notes:- first ships to be fitted with the training submerged tube, 1904 pattern. Stern submerged tube."
It is also noted that the Wettin (Wittelsbach class) was trial ship for the trainable submerged tube.

All well and good but, as has been pointed out before, early Janes are not always that accurate. Possibly Conway has more information.

Just to really put the cat amongst the pigeons I dug out Profile Publications book on Konig (launched 1913) and discovered:
"Three bow tubes and two stern tubes were fitted,* each tube forward having stowage for ten torpedoes plus one in the tube; aft the stowage was nine torpedoes plus one in each tube. These tubes fired a 50cm (19.7 inch) torpedo, and were fitted at an angle 20 degrees before the beam. They were built with gyro angling gear and originally could be set for a 90 degree field of fire from their mountings. Later the tubes were fixed and the angling gear removed."

*i.e. one bow tube and two more on each side.

These were all submerged tubes as shown on the plans, the beam mounts just before A turret and just aft of D turret. It looks like the Germans persevered with the angling method for some time before giving up. Of course, once fixed further protective screens could be built up around them.

This is all interesting stuff :)

[tone]

I have been doing some further digging into German torpedo tubes:
JFS and I agree with you regarding the fixed tubes and the above water stern tube on Kaiser Barbarossa, Wittelsbach and the Braunschweig classes.
The following Deutchland class is mentioned by JFS as having "Torpedo tubes (17.7 inch): 6 submerged (bow, stern and broadside - training)."
"Torpedo notes:- first ships to be fitted with the training submerged tube, 1904 pattern. Stern submerged tube."
It is also noted that the Wettin (Wittelsbach class) was trial ship for the trainable submerged tube.

I'm learning something new. Which year's Janes features this? Conway's does not necessarily have information on that level, either. I have some Naval Annuals that may have some data.

I'm surprised to see that the very detailed plan I have for Kaiser Barbarossa seems to have gone out of the way to avoid depicting any tubes on the broadside. Perhaps their inclusion, and exact nature, was subject to continued disagreement and/or secrecy. The overall nature of the drawing suggests that they'd be depicted.


Just to really put the cat amongst the pigeons I dug out Profile Publications book on Konig (launched 1913) and discovered:
"Three bow tubes and two stern tubes were fitted,* each tube forward having stowage for ten torpedoes plus one in the tube; aft the stowage was nine torpedoes plus one in each tube. These tubes fired a 50cm (19.7 inch) torpedo, and were fitted at an angle 20 degrees before the beam. They were built with gyro angling gear and originally could be set for a 90 degree field of fire from their mountings. Later the tubes were fixed and the angling gear removed."

*i.e. one bow tube and two more on each side.


This seems to agree with the FdG drawing referenced above.


These were all submerged tubes as shown on the plans, the beam mounts just before A turret and just aft of D turret. It looks like the Germans persevered with the angling method for some time before giving up. Of course, once fixed further protective screens could be built up around them.

This is all interesting stuff :)

Well, giving up on the gyro angling, but not having the fixed tubes angled to fire ahead at a moderate angle, which makes sense as it would forgive you from having to get as far ahead of the ship you wanted to trouble with a torpedo shot. I wonder if the early German gyro systems were causing some trouble?

Good digging!

tone

[SunScream]

I'm using JFS 1905-06.
All the German predreadnoughts show both fore and aft beam tubes in the forward half of the ship.
For the Kaiser Barbarossa, have a look below the belt immediately beneath A turret, adjacent to the magazine, and another just aft of the fore funnel.
You may find a large enough compartment there.

Without knowing how the gyro system works it is hard to judge it, but it sounds complex, possibly too complex. Presumably it allowed the tube to follow the layers aim while the ship was manoeuvring, like a stabilized tank gun. I would love to know just how they managed that :)
At high speed the water pressure must have jammed the mount almost solid, and probably made it leak like fury too.

[tone]

I'm using JFS 1905-06.
All the German predreadnoughts show both fore and aft beam tubes in the forward half of the ship.
For the Kaiser Barbarossa, have a look below the belt immediately beneath A turret, adjacent to the magazine, and another just aft of the fore funnel.
You may find a large enough compartment there.


Yes, I saw those, and guessed their angle. They seem to show bulkheads that were omitted to allow the tube. I don't know why, however, they did not draw the tubes themselves when they did so for the aft and fore tubes.


Without knowing how the gyro system works it is hard to judge it, but it sounds complex, possibly too complex. Presumably it allowed the tube to follow the layers aim while the ship was manoeuvring, like a stabilized tank gun. I would love to know just how they managed that :)


You have it backward. The gyro did not steer the tube. The gyro angle setting was a means by which you could tell the gyro in the torpedo, "When you get free of the tube, steer your torpedo 10 degrees to the right".


At high speed the water pressure must have jammed the mount almost solid, and probably made it leak like fury too.

I really have trouble believing anyone ever fitted an articulating submerged tube and left it there. I'll ask around a bit.

tone

[SunScream]

You have it backward. The gyro did not steer the tube. The gyro angle setting was a means by which you could tell the gyro in the torpedo, "When you get free of the tube, steer your torpedo 10 degrees to the right".



I really have trouble believing anyone ever fitted an articulating submerged tube and left it there. I'll ask around a bit.

tone

I know the Germans introduced the gyro-angled torpedo in about 1908-ish, but given that it was a lot simpler to turn the torpedo rather than turn the tube, I'm wondering why they then deleted the gear from Konig.
There is some possibility that JFS 1905-06 had suffered some misdirection over the training tube to cover up for the angling torpedo, but no matter how I read the paragraph on the Konig's torpedo armament I keep coming back to the sentence "Later the tubes were fixed and the angling gear removed", which seems pretty unambiguous.
If you find out anything please post it, I want to know now :)

[Bullethead]

Side tubes would be angled from the perpendicular, i.e. not at 90 degrees to the direction of travel. The angle would be probably between 70 - 80 degrees off the bow/stern.

It REALLY used to bug me trying to figure out how those old guys 100+ years ago could launch a torp underwater more or less perpendicular to the direction of travel. Obviously, water began slamming into the side of the torp the instant its nose appeard outside the hull, and the further out the fish got, the more bending moment was applied to the part still in the tube. You'd think the fish would break, get bent, or would jam in the tube instead of firing correctly.

However, they did manage it. I kept poking around and finally read enough here and there to convince me it actually worked. The speed of the launching ship was the main limitation, but over time the tech improved so the speed at which broadside submerged tubes could be fired kept increasing. Unfortunately, I can't at this point remember when in time a certain speed at launch became possible. For some reason, however, I'm thinking that in RJW times the launching ship could be moving up to about 15 knots, maybe a little more. By WW1, it was up to 20 knots or so (I think). IOW, always just a little bit less than the top speed possible for a battleship of the day.

I recall reading somewhere that the Brits in WW1 spent a lot of time and effort trying to perfect a method of launching broadside submerged tubes at 30 knots. IIRC, this was for the Renown class BCs. I believe, however, that after much trouble and expense, the best they could do was about 28 knots. But then they scrapped that whole project and put above-water tubes on the Renowns anyway. Go figure.

The reason for trying to keep using submerged tubes as ship speed kept increasing was protection. A room full of torps is a magazine, so you want it down below the water and the armor just like the shell magazines. However, as the Brits showed above, there was a physical limit to how fast a ship could go and still launch submerged broadside torps. Also, submerged tubes necessitated large compartments that had to be outside bulges and other forms of underwater protection, so were easily flooded, and this could endanger the ship. The Germans nearly lost several capital ships in WW1 due to flooding torp rooms from mines and grounding.

Therefore, by the end of WW1, everybody had pretty much given up on submerged tubes and gone to above-water mounts. However, the danger from torps exploding in their tubes remained. In WW2, quite a few DDs and cruisers suffered severe damage when hits caused their above-water torpedoes to explode. This was especially true for IJN ships, due to their bigger warheads, oxygen fuel, and high number of torps carried. The Japanese had recognized this risk in the design phase, and built in some features to try to mitigate it, but events showed these were insufficient.

BTW, the way submerged broadside tubes coped with the movement of the launching ship was kinda strange. Most of them had a sort of arm that stuck out of the tube upon firing. This steadied the torp until it was completely clear of the tube. But this only worked up to a certain point, beyond which the pressure of the water bent the arm.

Above water mounts which were not weather-deck mounted would also be fixed as they had little physical room to be trained in. Due to the centralized pivot mounting the ship would need a large cutout in the hull to be able to train a tube, and these cutouts are just not present in ships of this era.

You're assuming the tubes pivoted in the center, but that wasn't the case :). While there were some fixed above-water broadside tubes, most of them pivoted. They did this at the muzzle of the tube, right at the ship's side, with the breech of the tube swinging in a wide arc on a roller race set in the deck. Thus, the tube could pivot and still require only a small opening in the ship's side.

This type of tube mount was actually one of the very first deployed, in the 1870s and 1880s, which isn't surprising because this is how most guns of that time were mounted. In fact, this mounting predates even true torp tubes. When it was developed, torps were fired from open frames called "carriages", again using the gun analogy. But when true tubes came along, they continued to be mounted this way.

This end-pivot mounting was just for large ships like BBs and cruisers. The center-pivot tubes only appeared later, for TBs and DDs. These ships were narrow enough that 1 tube could cover both sides, just like some guns had done on small ships in the 1860s to 80s. BBs and cruisers were too wide for this to work, however.

[tone]

Trainable above water mounts generally pivot under the center of gravity of the loaded torpedoes, to reduce their desire to bind, and to distribute their weight evenly around the roller track (this is also why heavy gun turrets tend to have massive armor on their back face -- not for protection, but to even out the rotational load imposed by the frontal armor). This often is a little abaft their midpoint. They also tend to have grooves on their sides or tops into which lugs on the torpedo engage. The point here is to prevent the torpedo's nose bending down and trying to snap the body as soon as it emerges from the tube. For reasons I'm not quite sure of, the RN tended to use side lugs (S.L.) tubes for above water fire. It seems to me that top lugs would provide the best support for the longest duration, as tubes tend to have those "spoons" that extend farthest along the top. A puzzler.

For submerged fire, the tubes were "H.B.", or hook bracket. I'd have to go look to see exactly how that was meant. If anyone is extremely interested, I could try to find out and produce an image or three. I do a lot of research of this stuff, despite the schooling received above on the trainable German submerged tubes! ;)

tone

[SunScream]

I think side lugs make sense for above water tubes. Although I imagine there would be little risk of the torpedo actually jamming in the tube due to the speed of ejection, a few lugs on either side of the torpedo would ensure the torpedo would strike the water horizontally. A horizontal landing is critical, as a nose first entry would cause porpoising as the torpedo tries to regain its depth setting, and for beam tubes impart a rotation to the torpedo knocking it off course by a few degrees as well. Vertical lugs make sense on a submerged tube as they would stop the torpedo trying to twist in the water flow as it is ejected and also would prevent the torpedo spinning in the flooded tube as its engine was started.

I'm not working from any data here, it just seems to be a logical conclusion.
Top lugs on a above water tube would only make sense if the lugs were T shaped and running in a slot. I'm assuming that lug is equvalent to that on a shell, i.e. just a soft metal stud sticking out from the projectile body.

If you can get pics I would love to see them. The less history lost the better!

[Bullethead]

Trainable above water mounts generally pivot under the center of gravity of the loaded torpedoes, to reduce their desire to bind, and to distribute their weight evenly around the roller track

That's definitely true for mounts on DDs and TBs, but not for tubes on BBs and cruisers. As mentioned above, those had a pivot on the end next to the ship's side and rollers under the other end. This didn't cause an imbalanced binding problem because both ends of the tube were equally supported.

Here's a pic of such an end-pivot BB mount, in one of its earliest forms (taken from The Black Battlefleet by Adm. Ballard):
http://people.delphiforums.com/jtweller/TorpTube.JPG

HMS Alexandra was the 1st Brit BB to be built with torpedoes, although several older BBs had already had torps added to them by this time. Alexandra was commissioned in 1877 and was a central battery ironclad of the old school, with sailing rig, wrought iron armor, and muzzleloading guns. Originally, she had 16" torps of the original Whitehead design, launched from open carriages, but these were replaced in 1880, during the refit between her 1st and 2nd commissions, with the 14" true tubes shown above.

As you can see in the picture, the tube fired out one of the non-gun ports on the main deck outside the armored gun battery. This port was only about 2' square and was otherwise exactly like all the others outside the battery, which were used for ventilation and lighting. Because all BBs of that time had such ports, adding torps to such ships was quite easy--just a minor modification to the port for the pivot, and perhaps adding a race on the deck for the rollers at the rear of the tube.

This type of above-water tube mount continued in wide-spread use throughout the ironclad and predreadnought eras, due to its simplicity. You'll see advertisements for them (of newer model and larger size but otherwise the same) in the old Jane's editions from this period.

[tone]

I think side lugs make sense for above water tubes. Although I imagine there would be little risk of the torpedo actually jamming in the tube due to the speed of ejection, a few lugs on either side of the torpedo would ensure the torpedo would strike the water horizontally. A horizontal landing is critical, as a nose first entry would cause porpoising as the torpedo tries to regain its depth setting, and for beam tubes impart a rotation to the torpedo knocking it off course by a few degrees as well.


Surely the goal was a flat entry, but the nose tended to hit first. Prior to gyro torpedoes, the destroyers had tables drawn up that cross-indexed their speed by the relative firing angle of the torpedo to indicate how far aftward it would be deflected by its nose's slightly early entry. When done really well, these tables were non-trivial, as they included the bow wake's effect on the firing.


Top lugs on a above water tube would only make sense if the lugs were T shaped and running in a slot. I'm assuming that lug is equvalent to that on a shell, i.e. just a soft metal stud sticking out from the projectile body.

Here is a plate from the RN's Torpedo Manual of 1909, Volume III showing both the sturdy and streamlined bar (on right side), and the lug grooves within it along which the torpedo would guide its way out upon firing.

http://dreadnoughtproject.org/images/submergedtube.jpg

The manual also spells out that the RN tried trainable submerged tubes (in the "old Inflexible", otherwise no date given) but had quickly given up on them. By 1909, it was noted that submerged torpedoes could be fired at speeds up to 20 knots, but non-gyro torpedoes would deflect 3 degrees aft upon leaving them, despite the projecting bar (the issue was that the tail would still be in the lee of the bar when the lugs came free).

tone

[Bullethead]

By 1909, it was noted that submerged torpedoes could be fired at speeds up to 20 knots, but non-gyro torpedoes would deflect 3 degrees aft upon leaving them, despite the projecting bar (the issue was that the tail would still be in the lee of the bar when the lugs came free).

Excellent stuff, Tone. Thanks for correcting me on the speeds for launching, too :).

[SunScream]

Thank you to both of you for the information, its all really interesting.

Referring to the German trainable submerged tubes, JFS 1905-06 mentions that there was "nothing novel in the idea". Clearly they were aware of Inflexible's tube trials.