Punt Gun Possibilities

As far as blanks and grapeshot are concerned, yes, a blank charge has much less recoil than a projectile. I believe it is Mr. Newton who is to blame for that. nothing exiting the barrel at 1000 FPS has less reaction than a pound of something leaving the barrel at 1000 FPS.
but the projectile needn't be grapeshot - it can be the finest birdshot they can buy.

There is always the danger of when a page turns that relevant information gets lost, people don't get to read it. just in case

Punt guns usually use large shot such as BB or A, equivalent to US #1 or BB. At normal punt gun muzzle velocity BB would travel around 325 yards, size A around 375 yards. If these ranges are considered excessive then using smaller shot, say US #8, would reduce the maximum range to less than 200 yards. And those ranges are with the gun fired at an elevation of 35 degrees, so if the gun is fired near horizontaly the shot will travel considerable less than those distances.

So with reasonable care there would be no danger from the shot.

Nothing to prevent them from firing small shot from a cannon, the gun won't know if it's firing one round ball or thousands. All they need is a shotcup - not likely to find one that would fit a six pound cannon in the local gunshop, but not difficult to make.

I like the idea of a portable swimming pool as it could have a multitude of uses, but a trench beside the lake would be cheaper. And self filling, most likely, if it's close to the shore.

They'd probably have to make both the punt and the gun, but considering some of the things they've built neither would present problems.

What is required is a normal charge that is allowed to build up pressure as the black powder burns. like naval signal guns. If the normal shot is in a bag or something else that disintergrates mabey a bag of sawdust will suffice.

The recoil is a result of the momentum of the gases and the mass of the projectile. Without a projectile the amount of recoil is significantly reduced. In firearms blank adaptors use various tricks to increase the pressure in the chamber enough to allow it to cycle, but the overall recoil is still significantly lower than for firing a live round - which is why in films the hero can stand there and fire a rifle or machine gun on full automatic without falling over or ending up with the muzzle rising and smacking them in the face.

In theory you could duplicate recoil by increasing the amount of powder used in a blank round. However there is a limit to how much powder you could put in a cartridge, and the amount you'd need to duplicate the recoil would require a far larger cartridge, which would require a larger chamber which would mean you are no longer using the original firearm.

Basically the only way you can test to see if the recoil of firing a punt gun (or any other firearm) would be capable of moving a boat backwards is to use live ammunition.

Thankfully live ammunition in this case doesn't have to mean solid shot. Shotgun/grape type rounds would be fine as long as the overall mass of the pellets is equal to the mass of a solid round. In fact this would be desirable not just because such rounds have a considerably shorter range, but because the myth itself comes from punt guns which fired such rounds. (You'd have to be one hell of a shot to hit a bird in flight with a one pound shot fired from a six to eight foot long gun that is bolted to a boat....)



Making their own gun may be a lot cheaper and safer, as this would allow them to overcharge it without having to worry about the owner hitting them with the remains of a burst gun. Nothing to stop them from bringing in someone who owns such a gun and having them test the idea out, but as I said if they have their own they can do far more with it.

Range figures are most likely the effective range, although I'd suspect that for grapeshot the maximum range wasn't much further than that. Either way firing at hills some 500-600 yards or more away would be more than safe enough, as long as no one was stupid enough to be standing there - and even then I suspect that the odds of hitting someone at such a distance would be small due to the spread of the shot at such ranges.

Mind Drift...

Geostationary Multi blade model helicopters, you know the things, four blade, they come as platforms for Camera;s and the like...


Take the software, minus the height bit (Obviously?... Duh!) connect to four sized mini propellers, and build a rig to hold the boat in geostationary place on that lake...

I know drill platforms use the self-same mechanism for deep sea drill work, so why cant ya do that with a canoe?...What, no one has done that before?...

GRANT!... I give you the idea, go play with it.

ALSO, if you are replacing the weight of a Human with the power pack for this idea, you have plenty of ability to get it to "Come home" when it needs re-loading?....

I just think the ideas now and again.... is this any good?....

As for the after effects of firing the thing, they had no problem with "rocket" powered Greek fire missiles did they?...
Did they?...



Jamie and a JCB (Back-hoe) for the trench they built for swimming in treacle, syrup, custard....
Just this time it only needs 6 inch to a foot depth...
No seriously, I bet you could float the thing in six inch of water...
My own canoe with just me in it could do that.
So you dont need a deep trench at all?...

In fact "Paddling pool depth" is just about right, as it would enable the crew to service the boat in Wellies... or Waders.....

Why do you need eight foot deep when the boat floats in 8 inches?...


So can you fit one of them to a punt gun?... would it change the recoil?...

how about a ball of cotton wadding as a round, one that would just open up like a parachute when fired so it doesnt go far?...

Interesting, but a bit too time consuming and complex I should think. What is needed is simply a way to make sure that the boat (and hence the gun) remains pointing in the right - ie safe - direction. A simpler physical rig, be that guide wire or just a narrow pool would be a lot simpler and isn't going to run the risk of malfunction.

I'll come to the canoe comment in a moment.



I ball parked five feet in depth.

The reason for the depth is because a canoe alone would not be suitable if they intend to supersize the myth by using a bigger gun. A canoe is likely to become VERY unstable if you were to put even a small cannon or carronade into it, since the weight would be being carried fairly high up on a narrow hull. Add to this the force of the recoil and the need to secure the gun to the boat and chances are that firing a larger gun would result in a canoe rolling over or its hull shattering - if not both. Bare in mind that the largest sized gun that could be safely fired from the largest ships boat circa 1800 was the humble 6 pound carronade (which would have been about 1/3rd the weight of a six pound cannon - I can't find specific figures but would estimate the weight at around 300-400 pounds). Even though the boats themselves were quite cable of carrying much heavier guns, and the ships anchors. In the latter case the weight would be around one and a half tons - although it seems this was usually carried under the boat rather than on it.

In order to run tests with a larger gun, or to have that option, they would need a much wider and more stable hull and account for increased draft due to the additional weight. The hull of an airboat *might* be ideal for this, but given the lack of airboats in the SF area they may decide that it is cheaper or easier to use whatever is available locally. Chances are that this would mean a much deeper drafted hull design.

Of course my five foot figure probably is a little too deep, four feet or maybe even three feet would probably suffice here. But it would be better for them to have too much depth than too little. A deeper pool than is required is not really a problem as it will have no effect on the testing. A shallower pool however would cause problems if it turns out that the draft of their boat, if loaded with a heavy gun, is greater than the depth of water it is sitting in.



As I said above, the recoil of a gun is a measure of the speed and mass of whatever is coming out of the barrel. Such momentum is more affected by mass than by speed - which is why a 9mm pistol round has less energy than a .45 calibre pistol round even though the former has a greater muzzle velocity.

Blank firing adaptors simply increase the pressure within the firing chamber, bringing it up to the point where it will cycle the action - usually this is done by restricting the width of the chamber or barrel where they meet (at least for guns used in film). This will, however, not give the gun a greater recoil and certainly not anything close to what would be caused by using a live round.

The same holds for using lighter 'ammunition', as it is the mass of the projectile(s) coupled with the speed that denotes the momentum and hence the recoil. So in order to fully test the amount of recoil you have to fire the gun using live (and heavy) ammunition. In theory you could use 'soft' ammunition, but one pound of (say) cotton would take up much more space in the barrel/chamber and probably either get stuck in the barrel or create so much resistance that the pressure would cause the gun to rupture. So in terms of practicality and safety you'd want to use real shot.



Probably, in fact one of my first thoughts on seeing a punt gun was the question as to how it was loaded. Clearly a gun which is that long and secured to the bow of a long narrow boat could not be a muzzle loader, since trying to climb over to reload it would either capsize the boat or require you be in the water.

This just leaves the logical assumption that punt guns are/were breach loaders. To me this makes sense - the swivel gun fired a one pound shot - usually grapeshot rather than a solid round - and was typically a breach loader even though they were mounted on ships and around two feet long at most.
In fact I can't help but muse that the punt gun was inspired by the swivel gun (which was often carried on a ships boats). This would make sense - a sailor put on shore and who loved hunting might well have decided to see if a swivel gun could be used for hunting (they could probably have got a swivel gun from a ship that had just been sold out of service, especially towards the end of the 1800's).

On the point of pool depth:

I think it would be a good idea to silence the critics before they even get warmed up, by making sure pool depth is never considered an issue as far as the results go.

Remember that the water offers resistance to the movement of the boat (mass displacement) and let's say you make the waterproof trench design that's been proposed. Whatever the result is (boat goes far/boat doesn't go far), if the pool is too shallow, critics will complain that the boat either didn't meet the full resistance of the water but just slid along the plastic on the bottom of the pool if it goes far, or that it hit the bottom and was slowed/stopped if it doesn't go very far.

Ensuring a proper depth/width/length of the pool will squash all that before people even think about it.

I still think the canal/trench will work. It just needs to be deep/long/wide enough that the amount of water never becomes an issue. A platform on either side that goes over the trench can still keep the boat in place and ensure easy access.