Punt Gun Possibilities

Yes, the trail plays a role, as does the elevation screw and position of the trunnions.

I remember a good thread on the old boards where "Gun Jump" was discussed at length, with some really good good links and information.

I can't find any references for muzzle loading era artillery Gun Jump. modern day gun jump is well understood.


Modern era Gun Jump is well understood.

From the link:

Gun Jump - Defined as the variation in the angle between the gun bore axis and the effective line of projectile departure. Round-to-round variations in the line of departure result from movement of the gun barrel during firing and round-to-round changes in barrel droop due to thermal heating. Investigations have shown that one of the primary causes of gun jump is bending oscillations during firing. Optical measurements have shown that gun barrels are driven into high frequency oscillation caused by the changes in gas pressure as the projectile travels down the barrel. This means that the particular oscillation phase existing at the instant when the projectile exits the barrel is passed on to the projectile. The barrel oscillation has the effect of causing the projectile to leave the muzzle at an angle (relative to the original axis of the bore) corresponding to the instantaneous oscillation phase. In addition, the projectile is given a transverse velocity which is proportional to the angular velocity of the barrel. Thus, gun jump has both a horizontal and vertical component. The horizontal component generally varies by one to two minutes of angle from round-to-round and accounts for a large part of the deflection dispersion. The mean of the horizontal component is generally zero; therefore allowance for it is not made in firing tables nor in the aim of the gun. The component of jump in the vertical plane does not average zero, as barrel droop changes with gun elevation, which changes the frequency of oscillation and the transverse velocity; therefore these effects are accounted for in firing tables and the aim of the gun.

The punt gun wont "Rotate" much on any axis, because its held in place by a lever , which is held in place by a rigid frame, the lever action then dispenses thrust down through the frame, rotational forces of anything is therefore resisted by the buoyancy of the craft, as trying to lever one end of the craft below water and the other end up out of the water is a lot harder than you can imagine using the lever abilities of the gun mount.
The rotational forces that do get to the boat frame are therefore transmuted(?) into thrust on a horizontal plane, as in, they add to the thrust pushing the craft "backward" in the water.
The main part of the thrust is going through the shoulder of the person firing it.
That person then acts as a sort of shock absorber, and most of the forces then end up being transmitted via friction of clothing and footrests again into the frame of the craft, pushing backwards.

Just for the record, the question on the worlds greatest inventions by people who just didnt know what they were doing that PP asked me to elaborate.
ONE example.
Electricity.
In the beginning, and forget all that flying a kite in a thunderstorm "legends", the real guys who found that frogs twitched, just what did they think they were doing?...
Did they have physics manuals to go by?...
No, they were the one WRITING the manual.

what gauge of metal tubing? and is this individual tubes, or the equivalent of a monocoque body?

and I remind you again - if the gun is properly placed in the boat, the boat is not going to be rigidly restrained there will certainly be resistance, but not as if the boat is against a wall.

(for some back details - according to the videos I saw, the breech of a naval gun is not on an elevation screw - it is resting on the carriage structure. and the jump of an older field gun is because the trail angles below the centerline of the barrel, so it is like muzzle climb on a rifle. (and what the stock design of the M-16/AR-15 was developed to reduce.)

13,000 fps? I think your figure is out by an order of magnitude. I'd expect a 6-pdr MLSB cannon to have a muzzle velocity in the 1,200~1,500 fps range. For comparison, even a modern 120mm tank gun only has a muzzle velocity of 5~6,000 fps.

Also earlier in the thread (discussing the Royal Navy's boat operations) you stated that "the largest of those boats could only take a six pound carronade".
I think that's unlikely for several reasons;
1. I've never seen reference in any literature to a carronade with that calibre. The smallest that is listed in any of my sources is 12 pounds. [Under the Admiralty's carronade establismnent of 1779, the smallest calibre carronade issued to ships was the 12-pounder.]
2. One of the advantages of using carronades was to remove the need to carry smaller calibre shot. A 12, 18 or 24-pounder carronade could share shot with the ship's main battery.
3. A document listing the armament of HMS Defence in 1803 (Public Records Office, Admiralty records 160/154), includes the armament of the ship's launch which is given as an 18-pounder carronade. In the same collection, a document listing the armament of HMS Victory in 1808 also gives the armament of that ship's launch, which is similarly an 18-pounder carronade.

Yes, I think I may have had a brain fart and added an extra zero to the muzzle velocity.

1; It is possible that the smaller carronades were not included in a ships establishment as they could not (or were not) used by the ship, only by the boats. It is also possible that such guns were obtained by Captains through other sources, carronades were after all originally intended to be defensive weapons for merchant ships which very rarely carried anything heavier than a six pound cannon (and more usually four pounders).

2; Errm, no ships still ended up carrying at least two, more usually three and probably four different sizes of shot. Carronades were either the main armament of a ship, in which case the chase guns would be of smaller calibre as such vessels tended to be smaller brigs and sloops (Say a six pounder gun for a 12 pounder carronade vessel.) As secondary weapons they were of larger calibre than the ships great guns - a typical 18 pounder frigate would have 32 pound carronades. But then the larger ships would also have chase guns, and these would be yet another calibre - in the above case of an 18 pounder frigate probably 9 pound cannon or possibly 12 pounders. So that would be at least three different sizes of shot carried by a typical frigate.
On a first rate ship of the line such as Victory you'd be carrying 12, 18/24, 32 and 68 pound shot for the various guns.
Which is to say that carronades were always of a different calibre to a ships great guns.
The sharing of shot may have been in relation to simplifying the logistics of supplying the fleet as a whole. Prior to the introduction of the carronade a fleet - meaning not just the line ships but everything down to cutters - would have needed at least 9 weights of shot (not including the more specialised types of shot available). Even if you then discount the 2 and 42 pound guns as being rare, and therefore not needing much in the way of supplies, store houses still needed to stock them just in case.
With the Carronade however you suddenly have a situation where the smaller vessels, which had been limited to four or six pound cannon, were now using 12 pound carronades - the same calibre as many frigates of that time. So instead of having to provide and manufacture 9 types of shot by 1805 you only needed to produce 5 types of shot, one of which (the nine pounder) didn't have to be produced in large amounts since by this time guns of this size were more or less used purely as chase guns. In fact it is probable that by 1805 there was no need to produce 6 or 9 pound shot at all, as the existing stores should have been more than adequate for the limited number of shot such guns would have gone through even on the most active ships.

3; The number and size of a ships boats was set by the ships size and rating - both Victory and Defiance were line ships. I have a feeling that the confusion here is because the mentions of six pound carronades seem to come from actions carried out by Frigates and smaller ships - which were more active than the line ships and made extensive use of their boats. The smaller ships would have fewer and probably smaller boats, and these may not have been up to handling the weight of an 18 pound carronade.
Of course it is also possible that while 18 pound carronades may have been issued, this may have been done by some bright spark who didn't bother to check with the men who had to use them. Best guess here would be that frigate captains, who as I said made extensive use of their boats, quickly realised that the big 18 pound carronades were simply too large, heavy and unwieldy to be practical for operations at sea. Certainly I would not want to have been in the Atlantic in a ships launch that was carrying an 18 pound carronade. As such they may have acquired smaller carronades for their boats - just as those captains who could afford to do so often acquired additional ships boats to supplement those officially issued to a ship.

Shock absorbers, dampers, springs, smoke and mirrors....

Dont get me wrong here, and accepted there is room for error, in my original post where I mentioned some form of restraint that was not "Fixed", I knew the problems of trying to affix a boat to a cannon.

Does anyone know the lbs-ft torques of a Bugatti Veyron?... 1,000 horse power, and I use this as an engineering example here of how to harness such power.
100 pit ponies, even if you have to round up some right scraggy ones that couldnt rip the skin of a rice pudding, just to get the 1,000, 1,000 of them are going to rip the transom off of any decent craft at a MILD pull from a standing start....

So we dont have complicated clutch mechanisms, or even a "Launch control" magic button, but we do have US, and in that, come on folks, we on here MUST have some form of communal effort with the occasional brain fat for entertainment, we must have fun doing this, but in the end, we MUST be able to harness the power of a six pounder.....

So, get some high compression bounce a Bowler off a 10ft drop shock absorbers, mount the cannon to a sledge and put the shocks between the sledge and the boat.....

Bowler, in case anyone doesnt know, make these....


I aint saying the only four shocks will do the trick, maybe more, maybe just BIGGER, but if you can land one of them without knocking your teeth out, I am sure it should give us the idea.

Its not the compression we are after, its the rebound.
The rebound section of the shocks action will be the part that gives us thrust and momentum.

and yet when a line of sled dogs takes off, they don't rip the front off the sled.
yes, I am treating the gun and the boat as being, for all intents and purposes, as being a single object. that is why I approved of the selection of a boat that had motor mounts designed to hold a 600# plus motor assembly 4 feet off the bottom of the boat.

I am aiming for halfway in between having the gun chained to anchors on the sides of the canal, and having the gun just rattling around loose on the boat.


Guns recoil in line with their barrel. what converts the linear recoil to torque is having your anchor point out of line with the barrel. hadguns tend to have a lot of torque, because the grip is below the barrel. traditional rifles have some torque, because the shoulder stock is angled below the barrel. However, the torque rotates it around the point of contact between the stock and the shoulder. an M-16 rifle is designed such that the intended point of contact is directly in line with the barrel, in a deliberate effort to eliminate the torque.

old Moses will have torque, but the torque will be centered around where the trail is in contact with the boat. if you use a naval gun, then the torque will be centered on the point where it is in contact with restraints. if you use the rings for the breeching lines, I would presume that they have been designed in such a way as to minimize the torque. If I ultimately end up doing the .50 cal in a cookie sheet - it has a naval carriage.

This is a very poor video regarding lack of details - but it shows live fire from a carronade and the resulting recoil.

I won't swear to it but if I were a betting man I'd say that was a small calibre conventional cannon rather than a carronade. Carronades weren't simply small cannon, there were a number of features (internal and external) that differentiated them from conventional cannon. The gun shown in the video certainly lacks the distinctive shape of a carronade. The muzzle especially looks wrong. It's also rare for a carronade to be mounted on a conventional carriage (since the most common models, which were produced after the American Revolutionary War, lacked trunnions).