Cannon of the 'tall ships' ?

[blackball229]

I'm not sure any liner will last from one generation to the next. As a fabricator for one of the premier themeparks, I've built many projects where we were forced to reevaluate our thought on absolutes, when it comes to safety.Absolutes only last untill that one occurrance happens that our egos wouldn't let us look at. Time will only tell how long something will last. I've done restoration on various historic projects where the original builder or designer had great innovation but stopped short on thinking the technology all the way through, or stopping short and saying this will suffice. When other lives are at stake over thinking is really the best policy.The shock from repeated firings over time will effect most metals unless the sidewalls are extremely thick. My concern is that we have liners 1/4 inch thick press fit into castings with a seal issue around the touchhole. The repeated firings and cleanings would be forcing gasses, carbon aluminum oxides into the gap. However small it is, when the guns are washed, moisture will sit there and begin to oxidize the sidewalls building pressure between the the two. Add the shock of repeated firings, there are some unknown factors created. There is a point where it could become dangerous.

The particular guns that are mentioned being hollow cast in bronze with the steel liners are the ones I will be refering to.

The liner is proofed prior to the gun being built so the porosity or weakness of the casting around the bore becomes irrelevant. The touch hole is a concern since it would be drilled thru bronze aluminum and steel which is a poor combination to say the least. As an alternative it is possible to tap the steel inside and have a threaded touch hole and have a piece threaded into the sleve that would be able to be replaced the same as a musket or pistol. As for longevity the guns that we build are made to last from one generation to the next and on down the line.

[Commodore Swab]

All of the guns the Viceroy builds are built to last from one generation to the next. The problems you mentioned are not prevelant in many of the smaller guns since they are cast the same as some of the newer originals solid then bored out. As for the difference of metals if a touch hole is threaded in it would be replaceable and would isolate the the charge completly from the various metals. Of course the large guns "could" be cast as a solid bronze and then bored out but $$$$

[blackball229]

I still think "one generation to the next" might be a bit too optomistic and could be a liability in the long run. Wow these barrels must be better than what our military uses because they have a finite number of cycles.

All of the guns the Viceroy builds are built to last from one generation to the next. The problems you mentioned are not prevelant in many of the smaller guns since they are cast the same as some of the newer originals solid then bored out. As for the difference of metals if a touch hole is threaded in it would be replaceable and would isolate the the charge completly from the various metals. Of course the large guns "could" be cast as a solid bronze and then bored out but $$$$

[Cascabel]

I still think "one generation to the next" might be a bit too optomistic and could be a liability in the long run. Wow these barrels must be better than what our military uses because they have a finite number of cycles.

The reason that the modern military guns have a finite number of cycles is that they are subjected to much higher pressures than the pressures generated by black powder. They are also relatively thin walled compared to the pieces that we use to make them lighter in weight.

>>>> Cascabel

[callenish gunner]

The major difference between a period gun and a modern military field piece is the level of compression and barrel design... the metal fatigue that occurs in modern weapons is caused mostly due to the repeated intense compression inflicted on the metal of the barrel with close fitting diameter of the modern rounds used and the amount of propellant used to fire the projectile the distances required in modern warfare. Liability is for weaselly lawyers

Edited June 26, 2009 by callenish gunner

[blackball229]

Wasn't really comparing the two, just that all barrels have a life expectancy. Even at lower pressures there is a a shock factor every time the gun fires creating fatigue.If I fire it 20-50 times a day for the next fifteen years, your saying that barrel will be in perfect shape? You say liability is for "weaselly lawyers"? If my wife an son are shooting on the crew or anyone else for that matter,your damn right I would want to know how far anyone has thought this through. As a fabricator and designer for one of the largest and most famous themeparks in the US, this is what I do professionally.

The major difference between a period gun and a modern military field piece is the level of compression and barrel design... the metal fatigue that occurs in modern weapons is caused mostly due to the repeated intense compression inflicted on the metal of the barrel with close fitting diameter of the modern rounds used and the amount of propellant used to fire the projectile the distances required in modern warfare. Liability is for weaselly lawyers

[gunner Gordon]

Ahh, wonderful to find some true knowledge on this subject

My group is firing sleeved barrels, several shows per weekend, and then doing the usual cleaning at the end of the weekend, pouring water down the barrels, brushing and using bore butter. As a fabricator and a son of a master machinest, my questions are these.

1 Since the barrels are pressure fit into the casting and the touchhole drilled afterward, there is no true seal between sleeve and casting. there will be a buildup of powder residue and rust over time. Having rebuilt historic machinery and architecture pieces for years, I've seen how this type of buildup can cause expansion pressure. How safe is this over time?

2 How many actual firings would be considered safe before retiring barrels?

3 There was also a mention of honecombing of barrels over time. Is this just relative to cast iron? what about the sleeves, how do they react over time to firing?

4 Shouldn't our master gunner be keeping a detailed log of firings?

5 We use aluminum foil for our charges, you mentioned an incident involving aluminum foil. What are the pros and cons of foil charges?

I'm relatively new to the group, and the people in charge have been lording their methods and knowledge as absolute. Me, having been a machinests son,a fabricator and a shooter since I was 12 have some serious doubts about the safety of the group.

What are your thoughts, and what else should I been considering?

The problem with an unknown core casting, gun cast with the liner in place , is many fold. The liner and the breech plug in the liner should be of a construction to fire the charge without the iron around it. In such a casting the molten material can cool off too quickly on contact with the steel liner ond become weak or porous .The vent when drilled may not be true but have spark hiding cavities. There have been attempts to solve these problems, but the best way to build a sleeved gun is to cast it solid,better trunnions too, and bore the tube then press the properly breeched liner into the tube. If you don't know the maker you don't know the construction of the gun. Then an X-ray such as used for aircraft castings is about the only positive way to be sure. Proof firing an unknown gun only tells you it's safe through the last shot. I too know two one armed gunners, one involving the use of aluminum foil, there are no small cannon accidents. Think, what would be the acceptable percentage of failures? One of the true examples of zero tolerance for accidents.

I'm truly sorry that it has taken so long for me to get back to you, I work in the motion picture and government sector with special weapons(class3 and destructive devices) I alo teach a coast guard approved gunnery class for tall ships in southern CA as well as running guncrews on two of these ships. Please contact me on my profile PM and I would be happy to share my experiances with you.

[Black Hearted Pearl]

It seems to me the ships that have 'Quakers' are also ones who have been used for Movies. Most likely the Quakers were bought by the production companies (cost vs effect) and then 'donated' back to the ships. This is the case with the Rose (aka HMS Surprise). Even though the Rose came with full firing replicas, the production company choose to purchase larger Quakers for visual effect (the screen adds 10lbs) but with cost savings (no recoil, less safety issues). However for the purposes of live re-enactment, Quakers don't do it for the VIPs and most of the Quakers become stagnant movie props. Anyone for some fiberglass door stops for your barn?

[gunner Gordon]

Don't forget a few styrofoam cannon balls to go.

[Crudbeard]

The major difference between a period gun and a modern military field piece is the level of compression and barrel design... the metal fatigue that occurs in modern weapons is caused mostly due to the repeated intense compression inflicted on the metal of the barrel with close fitting diameter of the modern rounds used and the amount of propellant used to fire the projectile the distances required in modern warfare. Liability is for weaselly lawyers

I agree with the concern over the safe life of a cannon. As a former rigging engineer, we always used to say that it is not a question of whether rigging will fail, just when it will fail, as it will always fail eventually. The trick is to inspect, maintain, repair if possible, and retire the damn thing before someone gets hurt.

In regard to the concern about drilling the touch hole in a sleeved gun, and just about all modern manufactured cannon are sleeved of course, I think the concern is quite valid. There are many things that could cause a cavity in the vent, movement of the sleeve being one, and porosity of the breech wall another. Quality manufacturers try in various ways to make sure this does not happen, but my feeling is that the safest thing is to sleeve the vent with a softer bushing such as copper that has some give to it to make sure the vent doesn't open into the wall of the breech. This way if the sleeve does move due to thermal expansion or gap between the sleeve and casting, or anything else, there will be some tolerance for this condition. And copper bushings are just the way they did vents back then, when the inevitable erosion of of the vent needed to be repaired.

The Viceroy (Lawrence Campbell) and I plan to thread a copper vent bushing into the hardened steel sleeves of the big bronze pieces mentioned above, since there is no doubt that the steel, aluminum, and bronze, having different coeffeficients of thermal expansion, will not want to move together as the temperature of the gun changes. So better safe than sorry.

Crudbeard