Naval Gunfire 'Fingerprint'?

Discussion in 'History' started by sea_mine, Feb 28, 2010.

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  1. List,

    While posting on the Thomas Kennedy's RN Service Record thread last night, I was reminded of another post over on the Battlebus forum (see thread here), where I spend the other half of my life :lol:

    There is a location in the American airborne sector of Normandy just north of Carentan where lock gates control the flood waters of the Douve River. The lock is known as 'La Barquette' and was taken and held against very strong German opposition on D and D+1 by elements of the U.S. 501st Parachute Infantry Regiment.

    The area in question is within the red rectangle here:


    During the battle, NGF was called in on the German position by a Forward Observer from the USS Quincy II. I was intrigued by the forum administrator, Paul Woodage stating that the USS Quincy II had a pattern to her salvos. I have uploaded a zoomed view of the red rectangle, showing what I suspect he refers to with shell holes 1-3 in a straight line with hole 4 offset here:


    The lock is at centre left, with the N13 to Cherbourg running SE to NW at bottom left.

    Can anyone confirm that salvos would have patterns like this? If so, were such patterns the result of deliberate gun laying or did each ship have her own 'fingerprint'?


  2. In the RN the "Forward" controller would direct the ships salvos until they were on target, and then call for "fire for effect". He would do this by conning the ships guns on to the target using increments of say 100 yards, until the target was bracketed. The distance between 1 and 2, and between 2 and 3 look consistent, but 4 looks
    odd. If you follow the line of 1-2-3 there is another hole about double the distance from 3. could this be 5 and 4 fell into the canal?
  3. Onions & List,

    You could well be correct - one of the rounds may have fallen into the river. When I was on site in 2007, the hole you refer to north of the river was the closest one to me - the owner was not known to the Battlbus guide so we stayed on the public road.

    When the Forward Observer first called for fire support, would the USS Quincy II have fired a salvo or a single shot?

    I see from this page that she was equipped with 9 x 8-inch guns, I presume in three turrets - once the FO had the range, would all nine guns be fired in salvo or one or two guns from each turret?

    The targets would have been infantry in the open and 88's firing air bursts.


  4. List,

    I just found this image of the Quincy firing in support of the invasion of southern France in August 1944:


    She appears to have three guns in each turret.


  5. Seaweed

    Seaweed War Hero Book Reviewer

    Salvo or broadside? it would depend upon USN doctrine at the time, and how many rounds the FOB thought were necessary to deal with the problem. If the rounds are landing in soft mud then it may take rather a lot to destroy a target but perhaps what was wanted was for the enemy there to remove themselves.

    It is moot whether Quincy would have had programme time to correct her ballistics via a firing practice. Individual guns will wear at different rates and this can make quite a difference in range when firing at relatively close targets given the flat trajectory of naval guns with their high muzzle velocity. If this action was relatively late in the campaign then variations in barrel wear would of course have been exacerbated. But not to the point observed of Russian guns at the battle of Tsushima (1905) where Russian shells could be seen tumbling end over end in the air. As the rifling wears an ever-increasing amount of propellant gas escapes without doing anything useful.
  6. (granny)

    (granny) Book Reviewer

    Not sure if the Americans followed the RN pattern of Gunnery, but the spread appears to me to be a possible 'up ladder group' fired to determind the target. The spotter would call for another 'up ladder' group until straddling target, then 'Fire for Effect' when all guns would open up in 'broadsides'.
    Just a thought.
  7. Seaweed

    Seaweed War Hero Book Reviewer

    In the picture Quincy is firing broadsides and it appears the right gun of each turret is firing fractionally last (inevitably there will be miniscule differences of time between actual ignitions in the different barrels). This means that the left gun will fire on the assigned bearing but will slew the turret slightly so that the round from theright barrel is slightly left for line. For this reason by the time 4.5 Mk 6 turret (the square one) came along in the RN in the 50s doctrine was (1) always to fire salvoes and not broadsides EXCEPT for the first ranging rounds in NGS, to give the FOB a betetr clue where to look by having two explosions to see instead of one and (2) to gate the rate of fire down to say 16 rounds per gun per minute so that the turret could recover bewteen rounds. Incidentally 22 RPM was about the max for a 4.5 loader for a short burst in AA but a crew could keep 16 up for a sixty round burst, no bother (shell weighed 56 lbs). In a British 6" Mk 23 turret (Colony Class cruiser, 132 lb shell) 6 rounds a minute was the max sustainable. As chaps will have seen in the Bismark film (separate thread) in a battleship shells had to be handled mechanically as they would weigh up to a ton.
  8. Seaweed, (Granny), Onions and List,

    The fire mission was on D-Day afternoon. I found a description of the USS Quincy II's part in the action here - I have pasted in the relevant section below:

    Onions, excuse my lack of knowledge in gunnery matters, but can I ask what is the difference between a broadside and a salvo? - is it just the number of rounds fired?


  9. Seaweed

    Seaweed War Hero Book Reviewer

    A broadside is when all guns that will bear fire together. A salvo is one gun only from one or more turrets.

    Further to my earlier posts, the fire control equipment has also to correct for convergence. If firing on bow or quarter, the muzzles of the forward and after turrets are a considerabel distance apart for range, which willbe reflected on the ground if not corrected by very slight changes in elevation, and also at closer ranges guns have to be toed in so that the fall of shot is not dispersed for line. And corrections for earth's rotation and latitude and alll sorts of other things before you even begin to sorry about stabilisation in that the ship's hull is not dead horizontal etc. In the doubtful weather of D-Day there will have been considerable movement on the ship and of course there will be a slight lag in the heavy barrels responding to the necesary corrections. I hope all this dispels any idea that all the rounds are going to land in the same hole.

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