Wolfhag | 18 Jan 2019 11:27 a.m. PST |
I now that WWI battleship turrets can traverse at about 2 degrees per second. If the ship was turning at 1-2 degrees per second could the guns stay on target good enough to fire? If the ship started to turn or maneuver would firing have to cease until a new course was settled on? Thanks, Wolfhag |
Virtualscratchbuilder | 18 Jan 2019 1:09 p.m. PST |
I would say it would not fire. As your ship is turning, it is changing aspect in at least six dimensions – moving, turning, heeling with the turn, rolling with the seas and pitching (the rates of both changing as you go through the turn), and rotation of the turret – I suspect this would be too much for the gunlayers of the time. Even if they got a gun nominally on target the time lapse between the fire command from the director and the actually triggering of the gun would result in a significant bearing change. The other thing is the turret rotation speed is steady as far as I know – it does not have an accelerator or brake, so you would not be rotating and tracking a target, but rather rotating to a point and then waiting for the target to move into the crosshairs, either through its own motion or through the turning motion of your ship. If you were firing as the turret rotated past the target, you would have to have instantaneous response when firing the gun, and you would have to reverse the turret for the next firing opportunity. If you want an illustration on how difficult this is, stand with your arm out in front of you and use your finger to site something off in the distance, like 30 feet. Now squint and look at your finger with one eye, and then taking tiny shuffle steps rotate your body counterclockwise and try and keep your finger on the target. |
StoneMtnMinis | 18 Jan 2019 1:12 p.m. PST |
True, but even while turning or conducting other navigational maneuvers any incoming fire, accurate or not, can have a supressing or disrupting effect on the target. |
Virtualscratchbuilder | 18 Jan 2019 1:18 p.m. PST |
I do not think battleship gunfire is rapid enough or accurate enough to have such effects. I have never heard of a ship being straddled being disrupted. On the other hand I have heard of ships maintaining accurate fire while taking hits themselves. |
Blutarski | 18 Jan 2019 8:04 p.m. PST |
In WW1, fire was customarily ceased when a ship undertook a turn of any significant degree. The main reason was that the fire control computers of the time required both firing ship and target ship to be travelling upon straight courses in order to compute range and deflection. In addition, a sharp turn by the firing ship would introduce heel that the director technology of the era had difficulty compensating for. Certain later models of FC directors were provided with a limited means of dealing with minor own ship course alterations (one or two points under easy helm); these were described as possessing "helm-free" capability … which rather over-stated the true utility of this feature. I have, in one case, been able to corroborate this fact by correlating the maneuvering of one of the BCs in the Run to the South with the ship's gunnery log; it could be seen that the ship ceased fire during the period of time under which it was turning. In addition to the above, the points presented by virtualscratchbuilder are (IMO) valid ones – especially with regard to the degree of controllability of a fine rate of traverse of a heavy gun turret by the matching pointers method. FWIW. B |
Wolfhag | 19 Jan 2019 9:37 a.m. PST |
Yes, turning does present a number of issues that throw off your range keeping which will degrade your chance to straddle. However, it may not keep you from firing. IIRC capital gun turrets had firing circuits that would only close when the ship was level, it was an attempt at stabilization. If you are turning enough that the ship heels to port or starboard enough it may keep the circuits open even if the firing button was pressed. In Campbell's book on Jutland, it reports times when ships fired and there are entries that show a ship ceasing fire and then opening fire again a few minutes later but it does not always clarify the exact reason why. I can see a ship taking evasive action to get out from under multiple straddles would force all batteries to cease fire. IIRC the German BB's and BC's "snaked" back and forth while in a column to throw off the range keeping but I don't recall the course changes and frequency or if it affected firing. If a ship was changing course by 1 degree per second would it heel over too much? If not would the "Follow the Pointer" system enable it to keep the turret on the target good enough to fire? Wolfhag |
Blutarski | 20 Jan 2019 7:23 p.m. PST |
"IIRC capital gun turrets had firing circuits that would only close when the ship was level, it was an attempt at stabilization." The first primitive attempts at vertical stabilization (by which I mean that, when the trigger was pulled, the guns would not discharge until the ship had rolled to a vertical position). The IGN were evaluating the Petravic system and Lutzow (IIRC) had one experimentally fitted at Jutland, but it suffered a mechanical breakdown very early in the action. The British were also working on a vertical stable device (Henderson device) but it did not reach the fleet until some time after Jutland. Up through the Jutland period, it was the director operator who determined at what point in the roll he fired the guns. Some chose to fire at the end the roll toward the target, when the ship would momentarily hang motionless before commencing to reverse roll direction. Others opted to fire at "the top of the roll" when the ship was most nearly vertical; the roll rate was highest at this point, but the angular rate of change was least. My guess is that a lot had to do with the weather/sea state. FWIW. B |
Wolfhag | 20 Jan 2019 7:58 p.m. PST |
Interesting. So without director control how was it done from each turret? This would have really strung out the salvos. Wolfhag |
Blutarski | 21 Jan 2019 12:26 p.m. PST |
Wolfhag wrote – "Interesting. So without director control how was it done from each turret? This would have really strung out the salvos." Zackly! Fire of ships w/o a director was controlled from the Transmitting Station. When the required/desired number of "Gun Ready" lamps were lit, the firing gong/buzzer was sounded and the gun-layer in each turret would fire as his sights rolled on to the target. Discharge of three or four guns from separate turrets was rarely instantaneous for various reasons; every instant of time difference between gun discharges would serve to "loosen" the density of the salvo fall of shot. That is one of the reasons why introduction of the director was so welcomed; Peter Padfield's "Guns at Sea has a wonderful little graphic illustrating the difference in shot spread between director controlled versus non director fire in a competitive evaluation in 1908 or so (when the director was first being formally evaluated). B
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Mobius | 25 Jan 2019 6:35 p.m. PST |
I think that the ship would train its turret to where it should be to fire at the target after the turn and not try to match the turn rate. |