Jump to content
Free downloads from TNA ×
The Great War (1914-1918) Forum

Remembered Today:

Aiming guns at sea


IanA

Recommended Posts

I have a nasty feeling that the answer to this is going to be obvious but I can't, for the life of me, think what it might be. When shooting with a rifle or land-based artillery, a steady platform is essential. How, given the immense distances involved, did the naval gunners cope with rolling and pitching. It is a problem which must have concerned archers on board mediaeval craft but will have been magnified by the huge range of the 20th century naval gun.

Cheers,

Ian

Link to comment
Share on other sites

Ahoj!

I'm not sure of my English here ..

The rolling (from side to side) is countered by firing at a certain moment of the roll. You aim at such-and-such degree at such-and-such moment of the roll (simplest when it is zero), and only fire then. As the rate of fire of the heaviest guns is BOOM every 30-45 seconds, you do not lose much shots to syncronization with the roll.

The pitch (front to back) is IIRC simply ignored.

The innacuracy of the aiming etc. was countered by firing salvos - the more guns the better - and hoping that "dispersion" of the projectiles will put some in the right spot at the right time

And of course, in heavy seas you simply do not shoot, as it doesn't make sense.

Borys

Link to comment
Share on other sites

Ahoy, Borys! What you are describing would have been familiar to Admiral Nelson but things had moved on a bit through the rest of the 19th Century. Bring on the powder monkey!

H2

Link to comment
Share on other sites

I really don't know how Fire Control shot the big ones, but 5" and under, the gun pointer simply kept the target in his sights and shot when it, the gun, when the sights were "lined up" The gun captain yelled "Fire" and the pointer had the trigger (Which had a "dead mans" switch on it) which actually fired the thing. Therefore, he was really the Big Kahuna.

The pointer kept the cross hairs of his sight on the top, leading edge of the target. (Like below) The cross hairs would actually be just touching the top of the X.

This was "local control" assuming the radar was knocked out. That was certainly no consideration in WWI.

At least that is how we did it on the five inch we manned aboard ship.

DrB

:)

+

XXXXXXXXXXXXXX

Link to comment
Share on other sites

Ahoj!

Ahoy, Borys! What you are describing would have been familiar to Admiral Nelson but things had moved on a bit through the rest of the 19th Century. Bring on the powder monkey!

H2

Some things didn't change that much.

Not by WWI.

Stabilization of guns is still SF at that stage.

Borys

Link to comment
Share on other sites

Ahoj! Borys and other shipmates,

Oh, I am relieved! If this thread stimulates any sort of discussion it can't have been all that stupid! Your theory of firing at the same moment of the roll makes great sense but does seem primitive. As does the idea that if you fire lots and lots of guns at a target then some may hit. Gyroscopes sound promising but I'm not sure of the application. I can't believe the thought of two battleships refusing to fire at each other because of a heavy sea. <_<

If you fire at a certain point of the roll (and this does sound rather appropriate to the Spanish armada) would the upward motion of the barrel cause the shell to overshoot? I suppose you then correct by observation.

More please!

Cheers,

Ian

Link to comment
Share on other sites

Guest KevinEndon

How about they point the ship into the wave thus reducing the roll to almost nil and the pitch would be at a minimum. The guns would fire when at the top of the wave thus giving more accuracy and at a push more distance.

Link to comment
Share on other sites

Wouldn't this severely limit the firepower of the ship? We want a broadside!!

Ian

Link to comment
Share on other sites

I'm no sort of an expert, but I do know that you can't use all your guns if you're pointed at the enemy. I'm also not convinced about your idea that pitch would be at a minimum - try it in a destroyer! :P

I think there's a fair bit of guesswork here but someone out there knows!

Cheers,

Ian

Link to comment
Share on other sites

Ahoj!

Lots of reading material here, boys:

http://www.navweaps.com/

Specifically:

http://www.navweaps.com/index_tech/tech-074.htm

However, I believe this text to reflect WWII or thereabouts situation.

At the very best - very late WWI.

Also, please keep in mind that the Original Question was about pitch and roll in WWI ships (as this is a WWI board), and not long range gunnery in general.

As to effect of roll on gun range:

Barrel lenght - 16 meters

shell speed - c 800 m/s

I don't have the time to do the maths - but the shell doesn't stay in the barrel very long. And - with salvo patterns being 150 by 300 meters - what is a couple of meters this way or the other?

And happy reading ...

If you want to discuss naval stuff, I could point you to two boards dedicated to big-gun warships, but I'm not sure if the board rules allow it.

Borys

Link to comment
Share on other sites

Ahoj! Borys,

Bardzo dziekuje!

Very interesting but though it starts by talking plain English, (thank goodness not Polish!) it deteriorates quickly into 'tilt of the trunions across the beam' and suchlike stuff. It may be that I am looking for an easy answer when five year's training may be of more use!

Ho hum!

Ian

Link to comment
Share on other sites

Or, the seafarer's quatrain:

"Roll, roll, you mean old b....h. The more you roll, the less you pitch.

Pitch, pitch, g.....n your soul. The more you pitch, the less you roll.

DrB.

:)

P.S. Heading into the waves will not reduce the pitch. 'Twill increase it.

Link to comment
Share on other sites

I can't believe the thought of two battleships refusing to fire at each other because of a heavy sea. <_<

If you fire at a certain point of the roll (and this does sound rather appropriate to the Spanish armada) would the upward motion of the barrel cause the shell to overshoot? I suppose you then correct by observation.

IanA

If you have ever been to sea in really heavy weather then you would apreciate that no, you would not waste ammunition in trying to hit the other target. At some point with bad weather you might not even put to sea at all!

The point at which you shoot when rolling is surely a question of judgement (I am talking WW1 era). The guns were not gyro stabilised in those days.(See modern tanks which have their guns 'locked' onto their target and remain so despite the tank hull pitching and rolling).

Ian

Link to comment
Share on other sites

See modern tanks which have their guns 'locked' onto their target and remain so despite the tank hull pitching and rolling.

On the old Chieftain, the gun was pointed at the target and 'locked on', and as stated, the gyro then compensated for pitch and roll, but not vertical and horizontal movement. If, after 'locking on', the tank rose 30ft up a hill, the shot would overshoot by 30ft, or if it moved parallel to a stationary target for 100 metres, it would miss by 100 metres. There was lots of room for error, so it took a good gunner to make these small adjustments in the close confines of a tank while being bounced around cross-country.

Given the extreme distances in naval gunnery, the inherent errors (perhaps as much as 2-3%) of this type of fire control must have meant a miss by up to 700 yards, and I don't think British gunnery is that bad.

So being as equally intrigued as IanA, I asked an ex-Matelot, the same question; - but, being a cook and a CPO, he was doubly disqualified from having an answer.

His only contribution to the issue was "All I know, is that when the 6" guns kicked off, all my ******* bread loaves went flat".

Regards.

Gordon.

Link to comment
Share on other sites

Ian,

Why with a computer of course?

The gunnery in the Great War was controlled by the Gunnery Officer who was in the director, this was an optical range sight (9ft) which when aimed at the target corrected the train and elevation angles to correct for own ship roll and pitch.

Combine this with the Plotting Room which used Girocompasses to determine own ships course and targets course to determine range and position when the projectile would arrive, (advanced range). Taking into account, variations in atmospheric temperature, pressure, barrel erosion, propellant weight and projectile weight.

To cut a long story short the information was fed into a fire control computer system (Argo clock a mechanical analogue computer) and with the spotter entering the corrections on splashes a hit was made.

Each gun did have its own layer that had optical sights and the experience to fire over open sights. Standing by for flak.

Regards Charles

Link to comment
Share on other sites

Very good try Charles but I'm still left scratching my head (Damn these splinters!) :blink:

The 'computer' I have heard of and I can imagine (note, not understand!) this making corrections for ship's speed and course plotted against the target's estimated speed and course. I can also understand the value of observed shots just like land-based artillery. What is still really stumping me is that if a shot is registered while the ship is over on its port beam and corrections made, these corrections are going to be meaningless if the next shot is fired when the ship has rolled onto its starbord beam. Would the gunners hold fire until the ship was level? I suppose in something like a battleship the roll would be fairly slow and predictable.

What we need is an ancient mariner. (Cooks and CPOs need not apply :D )

Cheers,

Ian

Link to comment
Share on other sites

IanA,

Just guesswork, but the ship would have an inclinometre (or the gun control would) so that reference (or actual moment of firing) could be taken when the ship is upright.

The fall of shot would be 'up two hundred, down two hundred', etc depending on the observed distance between splash and target, irrespective of how your ship was healing over when the fall of shot was observed.

Ian

Link to comment
Share on other sites

Ian,

Basically using pointers and wheels! the information put into the 'computer' which was very nearly real time IE if the director moved so did the pointers in the turrets, and consequently if the advanced range changed so did the pointer. The gunlayer had two wheels, range and direction, he just matched the pointers. They would always shoot on the up roll at the same angle this differential being put into the computer, and if all the inputs where correct a hit would be made, maybe.

Regards Charles

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...