How big should cannon be (compared to what's available)?
{Ronald L. Ambs}

I'm pretty sure that the lengths quoted by fittings companies run from the muzzle to the end of the cascable. To account for the extra distance from case, you need to add two and a half calibers to the "official" length. One caliber, for this purpose is equal to the size of the bore.

Further complicating the issue is that smaller guns -- 9, 6 and 4 pounders -- come in a variety of lengths, even during the American Revolutionary Wars and early French Revolutionary/Napoleonic period. (The larger guns also started coming in different lengths during the late Napoleonic period, but thankfully, he appears to be looking for lengths prior to that period.)

So here goes:

These values are based on the Blomefield pattern gun of 1796, used by the Royal Navy. My source is The Arming and Fitting of English Ships of War by Brian Lavery.

	Units	24 lbr	18 lbr	12 lbr
Full Size Length	inches	108	108	90
Bore	inches	5.823	5.292	4.623
Overall Length	inches	122.5	121.2	101.5
1/8" Scale (1:96th scale)
Length	inches	1.125 (1-1/8)	1.125 (1-1/8)	0.9375 (15/16)
	mm	28.6	28.6	23.8
Overall Length	inches	1.27 (1-1/4+)	1.26 (1-1/4+)	1.057 (1-1/16)
	mm	32.3	32.0	26.9

(Note that the overall length was the length + 2.5 * bore.)

One thing you may notice is that the standard 24-lbr gun and the standard 18-lbr gun were the same length. The 18-lbr was a smidge thinner. The 24-lbr had max. diameter of 21 inches, while the 18-lbr had a diameter of 19.5 inches. At 1:96 scale, this is 0.015 ("1/64"), the proverbial "hair."

My recommendation is go for the 30 mm guns for the 24 and 18lbrs, and the 25 mm for the 12-lbr. Put a thick coat of paint on the 24lbrs, and a thin coat on the18lbrs.
{Mark Lardas}

One of the best places to find odds and ends about naval guns is Robert Gardiner's article on Guns and Gunnery in The Line of Battle in Conway's History of the Ship Series. (IMO, this is the best encapsulation of this topic to be found). The table he gives is not exhaustive, but gives these figures.

CANNON OF SEVEN	7 inches bore	47 lb shot (replaced by the 42lbr)
DEMICANNON	6	25 lb (replaced by 32lbr)
CULVERIN	5	18 lb
DEMICULVERIN	4.5	9 lb (Ancestor of the 9lbr)
SAKER	3.5*	5 lb (replaced by 6lbr)

[Murderers] are small iron or brass pieces, which have chambers put into them [i.e. breechloaders] and most usefully used at the bulkheads of the forecastles, halfdecks or steerages. And they have a pin of iron named a pintle which is put into a stock of wood, and so they are fastened and traversed. And the main employment of these murderers is to scour the decks; that is to murder such men as enter upon the decks at an enemy's boarding.
- (Nathaniel Boteler's Six Dialogues for the Sea Service.)

With this definition, (at least in Russia) the caliber of a cannon in inches was twice the cubic root of the conventional weight of the ball: e.g. the caliber of 12, 18 and 24 pounds cannons was equal respectively to 4" 37/64, 5" 15/64 and 5" 49/64, or in millimeters 116.3, 133.1 and 146.5, very close (only a little bit bigger) than the figure reported in the post of Marc Lardas for English ships.

Typical characteristics of naval guns (English, French and American) are reported also in the book The line of battle (Conway) for the period 1650-1840. For example, referring to the Napoleonic period some figures are:

	Calibre (in/mm)	Length (in/mm)	(ft-in/m)	Gun weight (Cwt/kg)	Shot weight (lbs/kg)	Powder Weight (lbs/kg)	Remarks
24pdr	long gun American	5.8/147.3	9-4/2.84	48/2439	24/10.9	8/3.6	Upper deck armament of big frigates
24pdr	congreve British	5.825/148	7-6/2.29	42/2133	24/10.9	8/3.6	Lightweight short gun used to up-gun

In the scale 1/8" (=1:96) it means about 3 cm. Of course you have to take into account also the shape, material and appearance of guns: much simpler iron guns in Napoleonic time, complicated and decorated bronze guns in XVII century. In the first half of the XIX century often ships of the Royal Navy had carronades on the upper deck and, beginning from the Napoleonic time, also French ships has similar guns.
{Davide Ruggi}

The French Navy of the pre-Napoleonic period still used a duodecimal system of linear measurement, and weights expressed in pounds and ounces; however, modern readers familiar with the 'anglo-saxon' measurements of today are in for a rude surprise if they believe that old French feet or pounds or pints are the same as those to which they are accustomed!...As a very rough guide (and by no means always appicable), French measures are often about 10% larger than their English counterparts.
- (from the introductory notes)

A French pound (livre) weighed 489 grammes; thus an 18-pdr gun fired a ball weighing 19.42 English pounds (8.81 kgs); 12-pdrs were equivalent to 12.94 English pounds (5.87 kgs),...
- (Note 3, Chapter 2, p 21).

Long Guns and Carronade

An 18 pdr long gun with a charge of 5lb of powder was capable of penetrating nearly 2 feet six inches into oak at a range of 400 yds. and over 1 foot at 1000 yds.

By ricochet firing ranges could be increased considerably :- At 1deg elevation the 800 yds for a 32lb long gun could be increased to 2900 yds after 15 grazes. Contemporary notes add:- Ricochet firing requires a perfectly smooth sea. The closer the gun is placed to the water, the farther it ranges the shot. It might be advisable to heel the ship over by running in the opposite guns. Ricochet firing is not used for shells because the fuzes are always extinguished when so used.

The carronade was a short gun developed by the Carron Company, a Scottish ironworks, in 1778. Half the weight of an equivalent long gun, it could throw a heavy ball over a limited distance as shown in the following table This lack of range was frequently a disadvantage, allowing an opponent with conventional guns to stand off and fire without the British vessel being able to reply.

To allow for irregularities and lack of roundness in cannon balls and the difficulties in boring out long cannon there was always a large gap between the ball and the bore. This was known as "windage" and could be almost 0.2" in a 32 pdr. long gun. The Carron Company managed to reduce the windage to 0.073" in their 32 pdr carronades with a corresponding increase in efficiency.

Carronades

Weight	Weight	Length	Diam.	Charge		Range at elevation (yds)
(ball, lbs)	(cwt)		Bore	lb	oz	1deg	2deg	3deg	5deg
42	22	4'6"	6.84"	3	8	430	700	900	1200
32	17	4'	6.25"	2	8	380	600	800	1170
24	13	3'9"	5.68"	2	0	360	580	770	1120
18	10	3'4"	5.16"	1	8	340	550	745	1050
12	6	2'8"	4.52"	1	0	310	520	715	970

{Bruce Bardell}

So, my advice would be to vary the length factor of your guns a little bit, taking into account the year and the gun size. There is a general downward creep in length (and in thickness of metal as well) during the 1700s for all calibres of gun, where data is available.

The general configuration of guns in other countries would match the Danish pattern quite nicely - there is a gaping hole in the Danish data between 1692 and 1786 simply because they kept on producing guns to the 1692 pattern throughout that period; the rather short 1786 models were inspired by earlier French and especially English developments however.

Denmark used 36-pound guns, while the Royal Navy used 32- and 42-pounders; the Danish 36 would be an English 39- or 40-pounder or so. The very short 18-pounders of 1792 and 1804 are a local Danish speciality, and should be overlooked.
{Staale Sannerud}

(From Hahn's book: 'Ships Of The American Revolution And Their Models'.

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