How did cannons work on curved decks?

[PopDavid]

What was done to make a cannon mounted on the skyward curving decks of the early galleons to keep it in place?  If the deck angles sideways, what stops it from sliding downhill?  How could it ever be fired or aimed?  Randoms thoughts after looking at the 18th/19th century flatter gun-decks.  Maybe no one has ever though about this.  I am building the Artesania "San Fransisco" galleon kit.  The gun-ports are square to the deck and this looks off.  It is an early issue from the 90's and I am less than happy with it, struggling.  I have seen the various build logs.

[jud]

The guns of the time you are dealing with, were short ranged, smooth bored, and very inaccurate, requiring ranges to be short for effective results. Modern firearms like to be horizontal because the line of sight needs be in agreement with the bore when aimed especially if sighted in with the line of sight directly above the bore, desired because the force of gravity effects the fall of the shot but not the line of sight, even offset sights are adjusted with the gun horizontal. Those old guns and sights had not been developed to the point where tilting would have effected the fall of the shot enough to be noticed. Typically a gun will not move from recoil forces until the projectile clears the bore, so recoil over a sloped deck will have no effect on the shot, just need to make provisions to let the gun recoil without damage, if it slips down the slope a bit, not a problem, after reloading, run the thing back out and use the hand spikes to correct the position the gun in the port, aim, then touch her off again.

 

 

Edited November 28, 2019 by jud

[Mark P]

Good Evening Pop;

 

If you are referring to the very early days of artillery on ships, Henry VIII up to the early 17th century, the gun carriages were very different to those with which we are more familiar. Some of those recovered from the Mary Rose were designed to lay flat on the deck, strapped to a baulk of timber, with a removable breech section, which was wedged in place before firing. As these were the lighter ones, they may well have been used on the more upwardly-curved parts of the upper decks. I am not sure how the recoil was contained. Look up the guns in the Mary Rose museum. This design would be unaffected by any sideways lean from the angle of the deck.

 

This degree of curvature would not have been repeated on the lower decks, where the heavier guns were located, because these decks were actually built with a step downwards towards the stern, giving a split-level deck. This was very common prior to around 1620. When full-length unbroken decks were introduced, they became known as 'over-leaping' decks, from which we derive the word 'orlop'. In the early 17th century, this term was applied to all continuous decks. A ship could contain 2 or 3 orlop decks, known as the upper and lower orlop, etc. 

 

How far into the Elizabethan era this type of gun continued in use I am not sure, but shipbuilders gradually reduced the amount of sheer (curvature) so any problems caused by this would have diminished. And for large parts of those times, and well into the 17th century, guns were often not fitted to the upper most parts of the stern or the forecastle on most ships.

 

All the best,

 

Mark P

[Baker]

Do not think that modelkits from 16th and 17th  century ship models are always correct.

"skyward curving decks" The decks are indeed a little curved but not skyward curved

 

some info about armament 

https://www.academia.edu/20120786/The_Arming_of_Late_16th_century_Merchantmen._A_Masters_Thesis_from_the_Maritime_Archaeology_Programme_University_of_Southern_Denmark

 

Shipbuilding

https://nautarch.tamu.edu/pdf-files/Myers-MA 1987.pdf

 

More info: see my Golden Hind build.

Or in this book

 

 

 

 

[CapnMac82]

If we look to the era of "trucked" guns, the wheels ("trucks") were made different diameters so that the carriage had an upward angle, so that the gun barrel could be parallel to the waterline as a general rule.

 

"Proper" loading of cannon wanted a wadding (dry) over the powder, and again over the shot (greased).  In the old texts you come across "load on the roll" to where the powder was loaded as the barrel pointed "up" and the shot as well.

 

When the shots were touched off varied by ship and nation--somewhat.  Royal Navy tended to fifre on the bottom of the roll, to put rounds into the enemy's hull.  French practice was to aim high, into sails and rigging (both of those only in the most coarse sense, and neither absolute nor specific).  Firing of guns in salvos, or "as they" bear varied by the Navy, too.

 

The "downhill" camber of the decks helped hold the guns against the spirketting, which kept them somewhat fixed in place, or enough that the gun tackles could take up the slack while loading and firing.

[allanyed]

I am not sure what you mean by skyward.   Decks generally had deck beams with rounding of various amounts although the Orlop often did not.   The below is from a fourth rate of the late 17th century.    When you describe skyward I was thinking  it to be concave, not convex which I don't think would be correct on any ship of any era.

Allan

 

 

 

[PopDavid]

I mean like the drawing  from Backer.  Where the bow and stern curve up, the deck slants down towards the middle of the ship.  The gun would have left-right tilt on one side and the opposite on the other.  The x-y motion of the carriage for aiming is rotated or tilted.  When the gun is fired and recoils inward, it would want to slide in and down hill.  Unless restrained by something to prevent the downhill motion, yet allowing the inward motion.  I will try not to think about aiming and hitting a specific target with a gun mounted this way.  Operation should be better down in the center of the decks. left-right is leveler.  The gun port have parallel sides, as they should.  To match the gun to the port, it would need different size wheels or be on a leveling platform to keep its x-y axles aligned with the opening.  Maybe just a case of too much education, the lesser schooled gunners would just step up and fire way.  Then muscle the reloaded gun back into position pointing out the port and wait.  Target is close enough!  Not considering ship motion at this point.

[PopDavid]

I think I found the answer.  The rigging would catch the gun whenever recoil pushed it.  Training would include " see the scuff marks and scratches on the deck.  Don't stand there when we light this puppy off"😀

[jud]

The answer I saw that seemed the most logical was, cannons were not used from those fighting castles, bows, pikes and swords with some early Fire or wheel lock weapons were probably in abundance up there.

 

[dafi]

Don´t be too scientific about the early years of gun use. No experience yet, no calculations yet, no trained crews yet, no long range yet, just shoot if you think you can 🙂

 

Here is the Vasa, best example of what used too be, even if the decks were not curved as extreme as in the galleons any more: curve still quite visible.

 

 

And if one think that things need to make sense the way we believe in today, have a look at the main top that is as declined that it is even difficult to stand straight!

 

XXXDAn