"Guns arc of fire" Topic

what where the guns arc of fire on a broadside firing ship?

the hulls of the ships are quite thick would this impact on the arc or was the internal layout more important?

did the arc change from the time of the Galleons in 1650 to the time of ship of the line? ( more guns less room is my guess)

thanks
Lord Ghee

Probably about 22.5 degrees, or less, for many.

Later, a British man came up with a way to rig them so they had a lot more leeway in terms of arcs, and they improved their loading speeds too, so supposedly they could fire 2 – 3 times to every single shot from their opponents.

I believe that was either in the 1700's, or early 1800's.

There are a few reasons why the arcs changed overtime. Ship size, gun carriage design, tactics, weight of barrel, new types of gun.

I don't think there is one particular point or inovation when this occured but a combination of all of thee above.

You're question "what where the guns arc of fire on a broadside firing ship" depends on which period of naval history. Broadside firing began in the wars with the Dutch and finished with Nelson and that's a large slice of naval history.

Having been on the Victory many times I would say 10 degrees at most.

Early carronades were really squat and short. There was a foot or two of daylight between the end of the barrel and the inside bulward of the ship! Think of the problems. However, with evolution, they wre on pivots and slides so it was easy to change angles. From what I can see, the long guns were on carriages that had small wheels which were meant to be strong enough to carry the tremendous recoil forces straight backwards. They were not on casters like an office chair, they were sturdy and only rolled in one direction. It must have been totally brutal work to change the angle of a long gun sticking out of a port. You might guess that sometimes they just fired away if they couldn't wait for "fire as she bears" I wonder if ships were in line of battle but not exactly opposite, if the helmsman would steer in a shallow zig-zag to allow guns to get a better shot. That might not be a "midshipsmans' textbook topic" but might be done by the experienced veteran helmsman manning the wheel during an engagement.

KMH gives about 15 degrees. Sounds about right to me, though I suspect in practice it was more like right in front.

Maybe we have to ascribe more finesse to the people of the time than might be forthcoming from armchair admirals who have never steered or handled the sails on a sailing ship.

There are a lot of things that the smelly, illiterate, underclass did that escaped the attention of the pens of the officers.

Usually a sailing ship is "powered" by a bit of surplus propulsion over the speed that it needs to keep it place and interval in a line of battle. In a line of battle, everybody operates at the speed of the slowest ship, which leaves a lot of surplus speed in hand for everybody else. The helmsman makes constant adjustments to the rudder to maintain the speed- this slightly alters the orientation of the wind to the sheets (and can be done real-time in reaction to each gust or sequence of waves hitting the ship- much quicker and possible to do, in comparision to bracing the yards to a different angle or reefing a sail or adjusting the tension on a corner of a sail). Think of it as he is constantly steering a wiggling course over the surface of the sea.

I don't see any reason why the helmsman would not make slow left and right curves in order to give every gun a better look at the enemy. They usually assigned the best, experienced helmsman to the wheel during a battle. If not for this, I would put an expendable guy there and save the experienced guy for a bad storm situation and stick him in the powder room or the cockpit. +/- 15-20 degrees is not a problem.

The long guns were very heavy beasts and the wooden wheels were axeled to roll in only one direction- carrying the force of the recoil backwards. To pivot the guy around required a 8-10 foot prybar and a lot of brute strength to skid a ~7000 pound (24pder) gun&carriage around.

In my naval games, I allow that if the enemy is anywhere within the 60 arc of the hull of the firing ship, all the broadside guns on that side can fire.

Having reading many accounts of Naval Warfare and now played several Napoleonic games; I can say that having limited arcs is more fun, as like wings of war; you have to get into the best position to fire your guns.

Although I see the merit of 60 degrees; for us; the fun is getting up his chuff for a full braodside from the stern.

As to the helsman (done that role) he does what the skipper or officer of the watch tells him to do thats it.

Also my mate (ex Navy Gunner) was a guide on the Victory for 12 months, and he assures me you'd only move the guns up or down, forget left or right, it wasn't until much later when aiming came in as opposed to just load and fire.

Also, if he's wiggling about all over the place, you'll change the speed of the ship as the point of sailing alters. Kiss goodbye to good station keeping in the Line of Battle.

Apparently some British ships managed 90 degrees arcs of fire from some guns by removing deck supports. Don't think it was widely done though. bgbboogie, I've read some accounts of it being done. Plus, I believe, they did it on the HMS Shannon. Maybe only with smaller guns than on the Victory though?

Estarriol, if the base speed is 8 knots and you have sails up for 10 knots, you can wiggle and keep to the fleet 8 knot speed. Fleets in line of battle traveled at the speed of the worse sailer. There were dozens of ways to put up "surplus" sail and then leave some slack in the sails, or yards braced non-optimum, or reefs or one corner of the sails slack. Undoing one of these on a sail and wiggling the path to allow bearing on an enemy is no more complicated than a couple of soccer players timing a through pass.

try it in a sailing boat and see what happens ;) Admittedly, I've never tried it in anything square rigged, but I can't for the life of me see why it would make a difference.

It's a nice idea, and I can totally understand the theory you're putting forward, I just can't see it working in real life (outside of single ship actions)

Dear Estarriol,
Hundreds of thousands of men spent many millions of hours figuring these things out. They didn't know anything about how to set up an internet account, but they had brains the size of ours and used them fully. They knew much stuff we don't have a clue about. Read throught the following two accounts and I think you will see that they certainly had a lot more ability and flexibibility than our early sets of naval wargaming rules imagined.

hnsa.org/doc/luce/index.htm

PDF link

PDF link

"A skilful captain with a well-trained crew could go both ahead and astern, yaw and accelerate and decelerate with
precision and subtlety as the occasion demanded"

Is, I'm assuming, your point. But that would require a lot of men available to work the sails, which would be problematic with guns manned in action, no? As I said, I understand the theory, but I just can't see it working in the line of battle.

Thank you for providing the documents, though. They look interesting and will have to do more than skim read them!

Actually, it really didn't require that many men to handle the sails. Taking in all sails or lowering all sails would take a number of men for a short period of time. But the large number of men on a ship of war were mainly for having 5-10 men on each gun. Most of the sail handling could be done from the deck with ropes and pulleys (blocks). Ships often fought from reduced sails or "fighting sails" where the says and rigging were augmented by chains and anti-boarding netting and overhead netting (to keep falling stuff from killing the deck gun crews). You might be surprised by the small size of the crews that were needed for commercial cargo carriers.

A ca. 200 ton schooner might sail with a crew of 5-7 men- and that is for 7 days a week, 24 hour a day sailing, which includes runing into a severe storm.

link
link

(okay- that is an extreme case- that is a small ship, an economical rig and they can lay to when challenged).

Handling the sails was not very man-power intensive for a manned ship of war. I think that taking on tenth of the men off the guns for a few moments would handle any situation. So we can "allow" our toy ships to use almost all of the sailing capabilities that our researching uncovers. If you (me) think about it, I can't recall any examples of a after-battle report where a captain reported not being able to do any extreme sailing move because of lack of crew.

I have a home set of rules ("Hearts of Iron, Ships of Oak) that started as a combination of the early "Ships of the Line" and "Hearts of Oak" games, but has been through so many revisions that it is now a different game. The prior to present version used 1/2000 ships (Valiant) and a 1/10,000 sea scale, with ships using a 60 degree firing arc (+/- 30 degrees from centerline). (ships move in two pre-written "legs" per turn and can fire (with reloading restrictions) at any time during each leg). Although the game plays quite well, I had some concern in that the players found no need to sail in close line of battle, nor was there a particular exhibited tactical need for close range firing. Looking at period paintings, (easily found on-line) it appeared that line of battles did involve close spacing and close approach. Perhaps, this might just be an artist's convention to be able to cram a battle picture into one painting? Looking at some period general orders, the reality seemed to be that they were close.

cf:

_FINAL FORM OF THE DUKE OF YORK'S ORDERS, 1673_. _With the additions and observations subsequently made_.[1] [+G. Penn, ,Memorials of Penn+]

James, Duke of York and Albany, Earl of Ulster, Lord High Admiral of England, Scotland, and Ireland, Constable of Dover Castle,Lord Warden of the Cinque Ports and Governor of Portsmouth & c.

_Instructions for the better ordering his majesty's fleet in fighting_. Instruction XIV.[13] In time of fight, if the weather be reasonable, the commanders of his majesty's fleet shall endeavour to keep about the distance of half a cable one from another; but so as they may also(according to the direction of their commanders) wavy that distance as the weather shall prove, and as the occasion of succouring any of his majest'ys ships or of assaulting those of the enemy shall require"

as well as:

LORD HOWE 1782 (Admiralty Library 252127+)

Instructions respecting the Order of Battle and conduct of the fleet, reparative to and in action with the enemy
'''''
X. When the fleet is sailing in a line of battle ahead, or upon any other bearing, and the signal is made for the ships to keep in more open order, it will be generally meant that they should keep from one to two cables' length asunder, according as the milder or rougher state of the weather may require; also that they should close to the distance of half a cable, or at least a cable's length, in similar circumstances, when the signal for that purpose is put abroad.

Okay, how to represent this on the tabletop. An issue is that with a 1/2000 ship and a 1/10,000 sea scale, the ships are too big to represent the close line of battle, even when placed bow to stern in line. …. (note that a cable length is 200 yards and a half cable (LOB spacing between ships) is 100 yards.) …. At a scale of 1:4800, 1"(tabletop)= 4feet x 100= 133 yards, and 1.5"(tabletop)= 200yards (a cable) and 0.75"(tabletop)= 100 yards (half cable). My 1/2000 Valiant SOL's are based on a 1.5" long stand, but the actual SOL are somewhere around 60-70 yards long or ~ half a cable. Therefore if I use a tabletop scale of 1/4800 (or ~ 1/5000), my ship stands, placed bow to stern are the right scale for a half cable separation, which matches the fighting instructions. To all-true-scale there should be a ship's length between them but that would really cramp moving the ships around on a wargame table.

Okay, I now can represent the ships pretty well in LOB with nearly correct spacings. What else can be done to the wargame rules to force players into more historical tactics. But this should come from the mechanics of the game system and not from arbitrary rules. The next posting in considering the question, What were the real arcs of fire?

Hi 1968Billsfan, you wrote
"What were the real arcs of fire?"

I'm a total TMG newbie, so thanks for resurrecting this interesting thread from the archives. Comments as follows -

Arc of fire for a broadside gun depended upon: (a) the size and nature of the gunport; (b) the spacing between the guns; (c) the geometry of the training tackle. Arc of fire of an individual gun in the 18th C was <<<approximately>>> +/- 2 points. But not all the guns of the ship's broadside battery covered exactly the same +/- two point arc of fire; there was a slight divergence of arcs at the forward and after extremities of the battery due to curvature of the ship's side.

That having been said, Sir Charles Douglas (a noted 18th C gunnery specialist and innovator) is credited as having developed a means of expanding the arc of fire of a broadside gun to +/- 4 points by trimming away sections of the gunport framework and revising the layout of the training tackle. Rodney's flagship at the Battle of the Saintes (Douglas was Flag Captain) is recorded as having fought to advantage in this configuration; two other ships in Rodney's fleet had adopted certain of Douglas's various gunnery modifications, but I am not certain if expanded gun arcs was among them. I have not run across this feature ever having reappeared at any time thereafter, however.

Re ground scale – My AoS rules (Steer to Glory – unpublished, but frequently played at conventions) features true ground scale relative to the models. By use of movable "sea tiles" on the tabletop, we have been able to do some pretty big games in 1:2400 scale – the Battle of Grenada easily fit on a 6 x 12 ft table, even at one cable intervals between ships. I had originally adopted the true scale convention for aesthetic reasons, but it was remarkable (a) how many fiddly mechanical ship movement issues disappeared, and (b) what sorts of tactical subtleties emerged.

You also wrote –
" What else can be done to the wargame rules to force players into more historical tactics. But this should come from the mechanics of the game system and not from arbitrary rules."

Here is how we approached that knotty problem. Intervals between ships are specified as part of the pre-game set-up and are then randomized to one degree or another according to crew quality. In terms of movement, a ship is free to attempt any action physically possible to it given its point of sailing and the condition of its masts, spars and sails ….. for example, a ship on a Beam Reach may wish to both Back Sail and Turn to avoid a collision ….. BUT, it must dice against its crew skill level for each action attempted. It may succeed in both, one or neither. Movement for each ship is completed in succession.

Games over the years show that the worse the crew skill rating the more difficult it is to operate, either in very close intervals or in tight maneuvering situations. Skilled crews can operate much more efficiently, but, if they are "pushing the envelope", one bad die score can throw an entire division into confusion.

FWIW.

Happy holidays to all.

B

Your mention of Charles Douglas is key.

He did not trim the ports, but he identified a different layout for the gun tackle that greatly increased the ability to point the guns fore and aft.

Reason this is not mentioned later is that it became adopted as standard practice across the British and other navies very quickly as the tactical advantages were readily apparent.

In wargame terms this is very important in a linear action as it means that you can practically engage an opponent that is not directly broadside to broadside. Rather less important in smaller engagements where you can maneouvre to bring the guns to bear.

So, for accuracy restricted arcs across the board before 1782, and expanded arcs after that.

Mark Barker
The Inshore Squadron.

Mark,

Can you refer me to a source for the broad adoption of Douglas's gun arc improvements by the RN after the AWI? I'd be interested.

I recall SOMEONE trimming away gunport framework. Thought it was Douglas, but perhaps it was Broke.

B

Broke carved sighting marks, I'll get you some references for Douglas.

Mark B

Found the reference I was seeking re Douglas. It was not gunports that he would have trimmed away, but the ship's knees where they interfered with training of a gun.

B

You are so right about some problems literally 'going away' when you move the ground scale in line with the miniatures. And you can do this with 1/1200s, as well (for small battles and single ship actions) since the engagement ranges were, generally, short (several hundred yards, at most).

As for the Douglas reforms; my one (and very bad, I'm thinking) source says the reforms weren't fully implemented until after 1815 (which makes absolutely no sense, given Douglas died in 1789!). I too would like to know when the reforms were adopted.

Coastal – 'Tis true. It is possible to play small actions in true 1:1200 scale. We consider max tactical gun range to be 1200 yards, which is only 36 inches. Then there are those excellent re-configurable sea tiles which eliminate edge of the world problems.

B

Hi all,
I was expecting to continue my post above {at 21 Dec 2014 5:11 a.m. PST} quickly and follow with my answer to the question posed at the end:

"What were the real arcs of fire?"

That will follow in the next couple of hours. I had to leave for church and then our weekly wargame before finishing.

A comment on Blutarski's posting at {21 Dec 2014 9:18 a.m. PST}. He quotes the arc of fire as being 2 points. With 360 degrees around the compass and 32 compass points around the compass, a point represents 11.25 degrees and two points only 22.5 degrees. I think this arc is way too small, but if you meant +/- 2 points from the perpendicular to the axis of the ship, then the gun arc would be 45 degrees. (This agrees with what I calculated (see a following post with the gory details) from the size of the gunports and diameter of a cannon barrel. By the way, I can not unequivocally agree that all the guns on a ship's side would point at slightly different arc's (relative to the centerline) due to the fact that the ship's bow was curved and not parallel to the centerline. It is true that if the gun port's were all cut the same into the shipside, that they would have differently directed arcs of fire. However, if they were cut at different angles and all perpendicular to the ship 's centerline, then they would have the same directed arcs and the guns themselves would not recoil into each other as much. I don't know the answer to this and will look at some pictures or diagrams of gun batteries. That should give the answer. Certainly it would make sense for at lease some extreme guns to be pointed ahead or astern as bowchasers.

link

Well the next thing was to consider if the limiting fact of the arc of fire was due to the cannon sides being restricted by the lateral size of the gunport from being angled to the side. Obviously the gunport was big enough for the barrel to go through it and obviously the gun could not be angled to fire at a 90 degree angle to a perpendicular to the ship- the limit is somewhere inbetween. Maybe this might be a limiting factor and cutting a wider gunport was the flash of genus by Douglas.

Getting back to the question: "what was the arc of fire of a Napoleonic sailing ship's guns" I looked a bit for an answer from my available source including sailing training manuals, midshipman exaime test reviews and a small library of ship books. Not anything there, not even any diagrams of guns trained to their maximum deflection. I guess some such concerns were too simple to bother explaining at the time. All the details of gun crew workings, show the gun nicely pointing straight out the gunport, with the crew widely spaced, relaxed and without any crowding from the neighboring guncrew. Next I looked for some guidance from the published size of guns and gunports with some calculations from high school plane geometry.

First, on the size of gunports. In the pre-computer and pre mechanical engineering days, a lot of shipbuilding was done by various rules of thumb and scaling ratios, based upon things that were found to work. A source that has some of this on gunports is:
American Sailing Ships: Their Plans and History
By Charles Gerard Davis (see link )
Some pertinent abbreviated sections are:

By experience in handling the cannon aboard ship, certain miniums sizes of gunports had been arrived at accepted by shipbilders of and prior to 1755, as a rule to be followed in framing a ship's topsides.
…………………….height……….breadth…….height of sill above deck
42 pound gun……2'10"………3' 2"……..2' 4"
32 pound gun,,,,,,2'8"…………3' 0"……2' 3"
24 pound gun…..2' 6"…….…2' 10"……2' 1"
18 pound gun……2'5"………..2' 8"…….2' 0"
Etc………….

Okay, the diameter of a 24 pound gun, where it sticks through the gunport could be as large as 12", so we have the material to play with geometry and trig to estimate the training angle allowed by the gunport.
Consider a diagram of the overhead view of the barrel sticking through the gunport, with the gun "tilted" the maximum amount to the left. The left edge of the gun strikes the upper right (a.k.a. outer left) corner of the left edge of the gunport and the right edge of the gun strikes the lower left (a.k.a. inner left) corner of the right edge of the gunport. There are two triangles of interest formed by this figure: one is defined by the edge of the left gunport, the inboard distance from the edge of the gunport to the cannon, and the length of the cannon between these two points,,,,,,, and the second is (hypotenuse) across the cannon between the two edges of the gunport, from the right edge of the gunport touching the cannon to the perpendicular line to it from the left edge of the cannon. The interior angles of these two right triangles are equal which allows the statement of the following three equations:
D1= 24 x cotang(angle)
D2= 12 x cotang(angle)
D1+ D2 = 32" = the width of the gunport.

Solving for angle, it is found to be 48 degrees. So
(a better guess as to the diameter of the 24 pound gun might be Diameter = 1.75 x 5.547" = 9.71"
link
which would allow even a LARGER angle of training- so the width of the gunport doesn't seem to be the issue. It appears that you could train the gun to a +/- 42 arc (or more) or a total arc of close to 90 degrees.

Nope, that's not it. But notice that in the pictures of firing position cannon, the carriages seem to be almost fully drawn up against the side of the ship. You could then keep the cannon steady in position by applying tension to the recoil-arresting block and tackle, so it couldn't start rolling towards the middle of the ship as the ship rocked.
Hmmmmmm.

The following picture suggests that perhaps the limitation was not the arc of the barrel of the gun, but of the gun carrage butting up against the side of the ship. See

link

page 10. You can move the breech of the gun back and forth with handspikes, (http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/50_years/Ch_15.html page 256) but at some angle a couple of problems arise.

One is interference with the neighboring gun (you have to consider the crews getting in each other's way as well as the location of the gun after it recoils)- not the biggest factor, but it will be considered later,,,,,,

Another is that the gun, when run up to the side of the ship at an angle will be pushed inboard quite a bit because the front edge of the carriage (which always are square for some reason) will contact the side of the ship first. Having more of the gun inboard is not the best idea, splintering and stressing the edge of the carriage is not a good idea and the fact that the edge of the front of the carriage is about 8" wider a side than the edge of the barrel. A solution is to have a rounded bulge tacked onto the side of the ship where the carriage butts up against it. Then when the gun is run out against the side of the ship, there is a point of contact that is directed down the gun axis rather than an odd angle of the edge.The center of the front of the carriage is the contact point. See the sixth figure in link which shows this detail and the "normal" arrangement and connection point of the recoil absorbing block and tackle.

Another problem that is easy to anticipate is that if the gun is severely angled, the very significant recoil forces, which are contained by the block and tackles attached to the ships side (as well as by the inertial mass and small, high friction wheels), is going to be uneven on the two sides. One side is going to have a short length of manila rope, the other a large length. Although the mechanical advantages on both sides are the same for static weights, the different sides are going to act very different. Rope is stretchy and passing the strain over a medium length of rope and a proportionally very short length of rope, means that one side will brake VERY much different from the other (also the pulleys act different with different stresses on them). {{I did work for a short period of time unloading ships with block and tackle- way before container ships. I quit because the people and gangs were way too dangerous}} What is going to happen with that close B&T setup is that the gun is going to overturn when it fires. (By the way, this was a fairly common problem with these cannon, especially when the crews were tired and equipment damaged in battle). A way around this problem is to place the eyebolts for the B&T further away from the gun, so there was more stretchy rope and so the lengths of rope were of a more similar ratio. See two figures later in that same reference- "Fig 9" for how the gun would be set up for wide angle firing.

If these two figures are to scale and the 32 pound gun is 128" long, then we can calculate the separation of the eyebolts from the center position of the cannon. For the broadside firing cannon set up they are 31" to the side, and for the wide angle cannon setup they are 114" to the side. OR two foot 7 inches versus nine foot 6 inches. Since gunports were about 7 – 14 feet between guns, you would have a lot of trouble putting in the wide angle setup (needs 19 foot between cannon) without reducing your broadside or compromising the safety.

As to the maximum angle of arc, we can look at this same last figure and simply measure the maxim angle shown. The total arc is 54 degrees. That is for what I think is a Douglas system that was not really implemented fully and I believe not implemented until well after the Napoleonic wars. So for my wargame (the point of this entire epistle) I am going to be happy with a 45 degree (+/- 22.5 degree) broadside arc.

(Isn't that what "Top Gun Ace" said in the second post in this thread?!………)

In terms of sources there is an excellent diagram and discussion in Tunstall and Tracy's Naval Warfare in the Age of Sail – The Evolution of Fighting Tactics 1650-1815.

The new arrangements allowed the cannon to be pointed without the knees interfering. As the knees were one of the primary structural load paths of the ship, they were not the sort of thing to be carving chunks out of !

Mark B

1968BillsFan wrote – "A comment on Blutarski's posting at {21 Dec 2014 9:18 a.m. PST}. He quotes the arc of fire as being 2 points."

Sorry for my imprecision of language and the resulting confusion. My use of the term "+/- 2 pts" was intended to define a broadside arc of fire ranging in general from 2 points before the beam to 2 points abaft the beam (i.e. – 45deg inclusive).

Re the diversion of gun arcs at the extremities of the gun deck battery, I based my comment upon my visits to USS Constitution (I live about 10 miles away). "Old Ironsides" – An Illustrated History of USS Constitution" by Thomas Horgan has a good planform diagram of Constitution's gun deck which shows the effect; in fairness, we are not talking anything really dramatic – a few degrees at best and at the very extremities. It's a miniscule point, really.

B

Re trimming away portions of the knees by Douglas, Padfield cites it in "Guns at Sea". I quite agree that the knees are important structural elements, but nothing implies that the trimming was so dramatic as to compromise structural integrity.

B

1968BillsFan – I did a little more checking in my library and I found a plan-form diagram of a British frigate gun deck battery in Robert Gardiner's book, "The Heavy Frigate" that shows uniform parallelism of guns from bow to stern at 90deg to the keel line, with the sole exception of the two foremost guns. Assuming that the diagram is an accurate representation, it indeed appears that the British pursued a different mode in this respect than did the US.

B

Okay, now I've concluded that a 45 total arc is correct for non-altered broadside guns, its time to consider the implications and effects on lines of battleships bombarding each other. Using scale drawings on excel (or I could have used paper cutout of scale ships), I looked at what could be hit from ships spaced at a half cable (100 yards) and one cable separation in line.

Method: [1] Set firing ships in line and draw line of fire arc at 80% and 20% of ship length. (e.g. about a full broadside) [2] Draw a parallel line to the line of ships at a distance of 100,200, 300 and 400 yards. [3] estimate the percent of those lines at the distances which is included within the arc. [4] at some ranges, the "target" lines are included with two broadside arcs- note that as well…………….do for a half cable and full cable ship space of firing ships.

Doing this gives the following table of results:
(please realize that there are different density of firers and targets in the two cases- which makes the understanding a bit confusing)

…Percent coverage by ships with a HALF CABLE separation.
range……..%shot by one ship..% shot by two ships….
100 yards…….70%………………………
200 yards…….100%……………..20%
300 yards…….100%……………..60%
400 yards…….100%……………..95%
500 yards…….100%……………..100%….5% by three

…Percent coverage by ships with a ONE CABLE separation.
range……..%shot by one ship..% shot by two ships….
100 yards……..30%………………………
200 yards……..60%……………..0%
300 yards……..83%……………..0%
400 yards…….100%……………..5%
500 yards…….100%……………..33%

Okay, I will interpret the table this way. At 300 yard separation,if a shooting formation is at a cable's separation, only 83% of the water at 300yards is covered by fire (because of the separation between ships). While it is true that if faced with an opponent's line (them at half cable), that ever shooter will probably have a target, BUT there will be enemy ships that are not fired on, who can reload or return fire in peace. 60% of the time there will be TWO half-cable opponents firing at one full-cable ships. ……At yardarm range (100yards) it is true that each one-cable ship has a target, but 70% of the half-cable line is not under fire. If the fleets are traveling in opposite directions, then the full-cable ships are going to receive continuous, "rested" broadsides AND the half-cable ships are each going to receive half the number of broadsides as their foes. ……….Of course the full-cable line of battle is much longer, but it history seems to show it rare that this would lead to an advantage………………………………………………….Another aspect of the two different spacings is the size of the "dead spaces", (outside of any firing arc)in the two systems. The full cable arrangement leaves a lot of dead spaces between the far-spaced arc of fire for opponent ships to sail into without being raked in order to "break the line", rake the opponent line and double up on the full-cable ships. For the two cases, we have

…………..WIDTH OF DEAD SPACES AT SEVERAL RANGES

range……..half cable case….full cable space
====================================================
100 yards……100 yards……..250 yards
200 yards…….20 yards……..130 yards
300 yards…….none *………..70 yards
400 yards…….none *………..0 at 380 yards

*= two half-cable ships could fire at such a ship wheeling to charge in an attempt to break the line.

So we can see that a full-cable line would have a serious tactical hole, in that opponents could easily duck between their arcs of fire and move to close range. This tells why ship station keeping was such an obsession.

Okay, in terms of my little "Hearts of Iron, Ships of Oak" game, I think that the geometries should foster correct period tactics by the gamers. However, they always find the hidden flaw…..

Spot on, BillsFan.

We backed into a similar epiphany by observing events during game play. Assuming one cable interval between ships in a defending line, it was not possible to concentrate the fire of two ships upon the lead ship of a Nelsonic attacking column. If that lead ship was approaching directly for the gap between two defending ships, it was actually immune to any fire at all within 200 yards.

Like they say, the devil is always in the details.

Merry Xmas to all / B

Merry Christmass everyone!! One of my presents was the book "Fortune's Favorite, Sir Charles Douglas and the Braking of the Line", by Christopher Valin, Fireship Press, (2009). I highly recommend this book to everyone's library! Although much of the book is on defending the view that C.Douglas was the father of the idea of breaking the line of battle (see also
Naval Evolutions: A Memoir by Howard Douglas and Christopher J Valin but also read Fighting Instructions, 1530-1816, Volume 29 By Sir Julian Stafford Corbet)
One of Charles Douglas's innovation was a means of increasing the arc of fire (ruminated about above to an extent) and some extracts from that book are quoted below. It mentions the use of much wider spaced restraining tackle, perhaps a close look at some of the original sources would likely show that a beveled gunport and a rounded protuberance on the ship's side for butting up of the gun carriage were also part of the system.

Douglas also wanted to add three 24 pounders to each side of the quarter-deck "where the rigging is not in the way". He went on to describe how he had figured out a way to allow the guns to swivel easier and wider:
"By the means, then, of bolts placed in side, right in the middle between every two guns, into which we occasionally hook their tackles, we are able to point all of them, without using a crow or handspike, where knees called standards do not interfere, full four points before or abaft the beam, which I presume is to a degree of obliquity until now unknown in the navy". (Laughton, p 268) .
This was an understatement. Until then, guns basically pointed straight ahead at right angles to the ship's head, and had to be fired when the target was passing by Douglas's rigging allowed guns to swivel ninety degrees (forty-five degrees to each side) which made a huge difference not only in aiming the guns, but in the guncrew's ability to fire at targets that were approaching or moving away. The Naval Institute's SEA POWER describes the enhancement in this way:
The old rule had been "two or three quick broadsides in passing", but now the special tackles enabled British gun crews to train their guns up to four pints ahead or astern of the beam. The result was that the British ship would fire two or three broadsides both before and after the guns of a French ship could be brought to bear, and , while the were oppositie, the British were able to fire a great deal more rapidly (E.B.Potter SEA POWER (Annapolis: Naval Institute Press, 1981, p 49)

Other improvements… a wedge with a cleat at the top placed behind the wheels of the truck, the gun rides up these and then pushes them backwards, reducing the recoil distance, …. Adding metal metal band springs to the recoil breeches line to help take up recoil, ,,, perforated goose quills for priming devices, redesigned breech holes to lessen spillage of powder, flannel cartridges, ..

"After the success at the Battle of the Saints, the entire British fleet eventually made most of the changes Douglas had implemented although there was some resistance from certain captains, so the changes were not immediate.

Now there a number of things that are now confusing to me. One point is that the existing ancient sailing ships do not seem to be rigged this way- how did this method become lost? Another is that the book says quite strongly that this method was quickly adopted after the Battle of the Saints (1782), so that it would have certainly had time to be implemented by the time of the Napoleonic wars in all ships- but I am not sure of the evidence of this. If so, then perhaps in Napolonic wargame rules we might give the British a 90 degree arc of fire, while the French/Spanish get 45 degrees (rather than other sweeteners for the Biritish?)? Another is that they claim at NINETY degree arc of fire was achieved, although I have never seen any diagrams of this extreme an arc- 60 degrees is the largest seen. The so of Charles Douglas, (Howard Douglas) wrote an often republished book (Treatis on Naval Gunnery) where "extreme training" (see link page 510) is presented as a rare rather than a routine procedure. Also, if you look at the spacing of the guns of a typical SOL ( hms-victory.com/things-see) or big frigate ( link ) it is hard to see how the extreme offset tackle could have been used.

Any help in this would be appreciated !

….. This is opinion based upon the "dog that didn't bark" school of logic. I have read widely on the Age of Sail – from Allen, Beatson, James, Clowes and the Naval Chronicles up through the Naval Records Society, Lavery, Gardiner, Willis, Rodgers, Padfield, etc. The common themes mentioned in connection with British gunnery superiority are inevitably rate of fire, close action, targeting of the hull, gun locks, better powder quality. Mention of unusual arcs of fire always seems to be confined to Douglas. Padfield ("Guns at Sea") reproduces a diagram from an early 19th C "gunnery notebook" that indicates the tackle fixed to the bulwark in the traditional manner quite close to the gun port .

I would not bet a large sum of money on it, but my guess FWIW is that Douglas's training scheme either (a) did not spread through the fleet, or (b), if it did spread, it was not found to be of such a decisive nature as to merit mention by commentators and historians. I'm absolutely ready to change my mind on this if presented with references to the contrary, but this is my view as things currently stand.

Best holiday wises to all.

B

I'm thinking the same thing. Reading the actions as described by William James and others, you just don't get any sense of an enhanced arc of fire (by either side). Additionally, as you noted, none of the well known works mentions it. So I'm not sure if Douglas' rigging was used that much.

BTW, looking at some of the contemporary drawings and photos of still existing ships (ie, Victory), the additional ringbolt between adjacent gunports is evident. But looking at the arrangement of a gun at full deflection, the area it takes up is substantial (and moreso in recoil). Add in the obstructions (such as knees, etc), and the arc would be less than the optimum +2/-2 points.

Unless some source can shed more light on this, I'm inclined to concur; it either wasn't as important a factor in practice or it just wasn't as effective due to the practical restrictions of construction and space available. But, I too am open to changing my view.

Right now, I just gotta agree completely with you Blutarski. The weight of evidence is so overwhelming, even from son Howard (indirectly) that we are in the 99.999% range that the extreme training method was not the fleet standard and was in the rare and seldom-seen category. I think that the advantage of having twice or three times the density of guns along the broadside was a better choice than a dubious alternative of allowing a larger arc of fire. By the way, playing with my scale cut-out type models of ships and ranges, the C.Doughlas-based quotes of (in effect) 'we get 2-3 extra broadsides on the approach and retreat of an opposed sailing line of battle, compared to 2-3 broadsides during the normally-assessible fire', would only be at ranges of 300 yards or more. (e.g. with constant speeds of the ships, at that range, the extra distance (and time) for a 90degree arc over a 45 degree arc, gives that much more time for extra BROADSIDES.) So (at least in my rules), 300 yards is somewhere between medium and short ranges. Close than that, there is less advantage for the increased arc. Since Napoleonic British tactics were to close to the enemy to very close yardarm range, they (if they really adopted C.Doughlas's system) didn't think it was the dominant decider in tactics. Heck, If I could get a 3-1 advantage in firepower delivered, I would always stay at 300 yards and blaze away. (If you look into the "point blank range" of the big guns used and the angle subtended by a 300' long ship there was not a big problem in hitting it).

I think this topic is starting to wind down. A 45 degree arc and close-spaced gunports is the model that I think we should work on for the reality of Napoleonic sail practice.

Much of your pen-and-paper analysis was done by Clerk of Elgin before Nelson's time, it is worth a look to see what conclusions he draws. His book was required reading in the fleet at the time.

A 45 degree arc should do you fine. Closer spaced gunports were down to the increased use of iron in construction (you can see it coming in on Victory and the real effect on Unicorn/Trincomalee) allowing thinner structural timbers.
(See Lambert, Lavery etc on ship construction).

There are two things mentioned on the discussion that rarely or never happened:-

Firstly, the mention of 'Nelsonic column'. Nelson never attacked an opposing line of battle in column, the Trafalgar attack is far more complex and subtle.

Secondly, you mention broadsides. Ships fired by divisions of guns in a ripple or as the battle wore on, singly as they managed to reload taking into account fatigue and casualties. The force on a ship's side from the simultaneous discharge of all guns was prohibitive, so determining arcs of fire from a single point in time is unnecessarily restrictive.

Finally I suppose is that all this analysis is OK from the armchair but remember what we are trying to replicate. From our fleet commander position we might want that ship to engage a target 150 yards ahead of it because it suits the tactical situation better.

For the individual gunners, they are going to blast away at whatever is closest and in line with their gun until told to stop and that is what any set of rules needs to encourage.

Our Clear for Action computer system works on 22.5 degrees fore and aft of the length of the ship – i.e. a 45 degree arc total and that works for us.

In helping with the Flying Colors boardgame system for GMT there is an increased firing penalty for "partial" shots at the edges of the gun arcs for actions before 1782 to reflect the narrower arcs but it is not a major consideration.

Mark Barker
The Inshore Squadron