Gun Tackles Positions During Firing

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I know how the tackles are used to bring back the gun to loading position, move it forward to firing position, move to the side for aiming and such, whether using the same sets of tackles or additional sets, and know the function of the breeching cables.

My question is: After the gun is in firing position, what, if anything, would be done to the tackles used to bring it forward? I've watched a number of Youtube videos, most with just breeching cables and no tackles, and some with tackles but either not firing or firing without shot. In short, most larger guns are not normally shot under full powder and shot conditions these days.

My point is that since the breeching cables stop the gun after recoiling, would the tackles used to position the gun be left taunt? If so, might they not break? Might the friction in the blocks when the gun moves quickly backwards cause the ropes to break, or would they thread back through the blocks quickly enough?

While I know nothing about how the gun tackles were used during firing, I can calculate a couple things. According to this source Victory's 32-pounders weigh 3.28 tonnes (barrel and carriage) each, or 7,232 pounds assuming these are metric tonnes (non-metric 2,000 lb tons are spelled ton - although the English may do things differently). And Broadside Cannon states the velocity of a 32-pound cannon ball would be 487 meters per second or about 1600 ft/sec. Now Newton's law of conservation of moment says that m1xV1 = m2xV2, so the velocity of the gun after firing would be V2 = m1xV1 / m2, where m1 = shot weight, V1 = shot velocity, m2 = gun weight and V2 = gun velocity. (Yes, I know the formula uses Mass, not Weight, but the conversions to mass cancel out, and even as an engineer, I'm uncomfortable with units of mass in the English system.) Thus:

Gun Velocity = 32 x 1600 / 7232 = 7.08 ft/sec. And it turns out 7 feet isn't a bad distance for the gun to recoil to until it was stopped by the breeching cable. With little or no friction, then, it would take one second for the gun to recoil to it's stopped position, somewhat more considering friction from trucks, ramping up the deck or friction from the gun tackles. That seems reasonable. And it certainly wouldn't kick back really quickly, like the barrels or actions of more modern recoiling guns. But I wouldn't want to be standing behind it!

So, I would think that at that velocity the gun tackles would be able to move with the gun, the ropes being pulled through at 3 times 7 = 21 ft/sec due to the Double/Single blocks. They'd probably get hot though? And they'd certainly be left loose, with 20' of extra cable ready to thread quickly through the block, and not tied up or neatly rolled up.

Any thoughts on the above? Anyone know if all gun tackles would remain in place during firing, ready to be pulled back, etc? Any thoughts on the physics of the system?
 
I know how the tackles are used to bring back the gun to loading position, move it forward to firing position, move to the side for aiming and such, whether using the same sets of tackles or additional sets, and know the function of the breeching cables.

My question is: After the gun is in firing position, what, if anything, would be done to the tackles used to bring it forward? I've watched a number of Youtube videos, most with just breeching cables and no tackles, and some with tackles but either not firing or firing without shot. In short, most larger guns are not normally shot under full powder and shot conditions these days.

My point is that since the breeching cables stop the gun after recoiling, would the tackles used to position the gun be left taunt? If so, might they not break? Might the friction in the blocks when the gun moves quickly backwards cause the ropes to break, or would they thread back through the blocks quickly enough?

While I know nothing about how the gun tackles were used during firing, I can calculate a couple things. According to this source Victory's 32-pounders weigh 3.28 tonnes (barrel and carriage) each, or 7,232 pounds assuming these are metric tonnes (non-metric 2,000 lb tons are spelled ton - although the English may do things differently). And Broadside Cannon states the velocity of a 32-pound cannon ball would be 487 meters per second or about 1600 ft/sec. Now Newton's law of conservation of moment says that m1xV1 = m2xV2, so the velocity of the gun after firing would be V2 = m1xV1 / m2, where m1 = shot weight, V1 = shot velocity, m2 = gun weight and V2 = gun velocity. (Yes, I know the formula uses Mass, not Weight, but the conversions to mass cancel out, and even as an engineer, I'm uncomfortable with units of mass in the English system.) Thus:

Gun Velocity = 32 x 1600 / 7232 = 7.08 ft/sec. And it turns out 7 feet isn't a bad distance for the gun to recoil to until it was stopped by the breeching cable. With little or no friction, then, it would take one second for the gun to recoil to it's stopped position, somewhat more considering friction from trucks, ramping up the deck or friction from the gun tackles. That seems reasonable. And it certainly wouldn't kick back really quickly, like the barrels or actions of more modern recoiling guns. But I wouldn't want to be standing behind it!

So, I would think that at that velocity the gun tackles would be able to move with the gun, the ropes being pulled through at 3 times 7 = 21 ft/sec due to the Double/Single blocks. They'd probably get hot though? And they'd certainly be left loose, with 20' of extra cable ready to thread quickly through the block, and not tied up or neatly rolled up.

Any thoughts on the above? Anyone know if all gun tackles would remain in place during firing, ready to be pulled back, etc? Any thoughts on the physics of the system?
Hello Seal, see if these images can help you

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88.jpg

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90.jpg

91.jpg
 
The gun tackles would be unhooked from the carriage just before firing, Carriage recoil is stopped only by the breaching rope. The gun tackles are extended and re-hooked to the carriage during or after loading and used to move the carriage forward to position it for firing again. The illustrations previously posted do not make these steps clear. Also, the train tackle at the rear end of the carriage is usually not necessary during the firing operation if the ship is level. It is only used if the ship is heeled such that the carriage wants to move forward on its own. On 17th century ships, there probably were no train tackles at all, and one of the gun tackles was unhooked from the bulwark and hooked to a deck ring far behind the carriage if the gun was required to be rolled rearward away from the gun port for any reason.
 
The gun tackles would be unhooked from the carriage just before firing, Carriage recoil is stopped only by the breaching rope. The gun tackles are extended and re-hooked to the carriage during or after loading and used to move the carriage forward to position it for firing again. The illustrations previously posted do not make these steps clear. Also, the train tackle at the rear end of the carriage is usually not necessary during the firing operation if the ship is level. It is only used if the ship is heeled such that the carriage wants to move forward on its own. On 17th century ships, there probably were no train tackles at all, and one of the gun tackles was unhooked from the bulwark and hooked to a deck ring far behind the carriage if the gun was required to be rolled rearward away from the gun port for any reason.
Hi Kurt, there may be some news in this book about the handling of the "Ordnance_instructions_for_the_United_Sta SW" guns.
 
Kurt alias @DARIVS ARCHITECTVS is explaining it very well

In Volume IV of Jean Boudriots 74-gun ship book on page 123 ff are the orders of handling a 36pdr gun described.


and I guess there other publications where it is also described
 
The gun tackles would be unhooked from the carriage just before firing, Carriage recoil is stopped only by the breaching rope. The gun tackles are extended and re-hooked to the carriage during or after loading and used to move the carriage forward to position it for firing again. The illustrations previously posted do not make these steps clear. Also, the train tackle at the rear end of the carriage is usually not necessary during the firing operation if the ship is level. It is only used if the ship is heeled such that the carriage wants to move forward on its own. On 17th century ships, there probably were no train tackles at all, and one of the gun tackles was unhooked from the bulwark and hooked to a deck ring far behind the carriage if the gun was required to be rolled rearward away from the gun port for any reason.
Kurt, I agree with all that. I was just wondering what the logic was in unhooking the tackles before firing. It seems the recoiling speed would not unnecessarily stress the tackles. And of course the crew would have to "stretch" them back to their longer length before being able to move the gun forward again, whereas if they remained attached (and didn't fail, of course) that step would be unnecessary.
 
Kurt, I agree with all that. I was just wondering what the logic was in unhooking the tackles before firing. It seems the recoiling speed would not unnecessarily stress the tackles. And of course the crew would have to "stretch" them back to their longer length before being able to move the gun forward again, whereas if they remained attached (and didn't fail, of course) that step would be unnecessary.
The gun tackles are perfectly capable of stopping the recoil of the carriage, or at least reducing it to a very short distance, and the recoil would not run them all the way out. using them that way would damage the blocks, because they are strong enough to move the carriage, but impact from recoil may shorten their life. If they were sufficient to handle recoil, you wouldn't need a breaching rope. The size difference between the gun tackles and breaching rope is evidence of this. It's amazing that breach loading gun operation remained essentially unchanged for over 400 years.
 
And of course the crew would have to "stretch" them back to their longer length before being able to move the gun forward again, whereas if they remained attached (and didn't fail, of course) that step would be unnecessary.
All seamen at a gun had their special task to do.
There were often more than 10 seaman at one gun, so I guess during the loading of the gun, there was enough time for this.....

Nice video of gun drill on the USS Constitution - btw they do not remove the tackle
 
All seamen at a gun had their special task to do.
There were often more than 10 seaman at one gun, so I guess during the loading of the gun, there was enough time for this.....

Nice video of gun drill on the USS Constitution - btw they do not remove the tackle
Hello Uwek, I believe that this text can give explanations about the various maneuvers of a cannon in action "Gunnery instructions _ simplified for th - Barrett, Edward, 1828-1880 "
 
I had always examined these from the standpoint of the tackles, but I'm looking at the shifting of the men more closely. Very interesting. What, exactly, does the statement "only one side being manned by a full crew" mean. I see that the 10/14 men are moving between the guns as required. I know that gun crews normally would be fighting on only one side of the ship, but had to switch to both should they be attacking from both sides, which halved the crew. Which is this? Halving the crew, I assume?
 
The more I think about it, I'm betting that they do not remove the side tackle during firing. Tackles such as these (double/single) work great in their intended operation: pulling a single rope through 3 sheaves to move the single pulley and hook, with a 4:1 mechanical advantage, usually attached to something. But not so great going the other way: lifting and pulling a 9" wood single block with iron hook attached, pulling the loose rope through 3 sheaves with a mechanical DIS-advantage of 4:1. If it took 10 pounds of force to pull the rope through the tackle, pulling along just the tackle (not attached to anything), then it would take 40 pounds to pull it back grabbing the pulley & hook only, far more. Not to mention that several men can grab the rope; it would be hard for more than one man to hold the pulley and hook and pull it, until it could be once again hooked onto the carriage. As long as the recoil would not damage the tackle, it would be FAR easier to leave it attached.

Also, I was wondering what the rope tied to the ring outside the gun port is being used for:
1648566054597.png
 
I had always examined these from the standpoint of the tackles, but I'm looking at the shifting of the men more closely. Very interesting. What, exactly, does the statement "only one side being manned by a full crew" mean. I see that the 10/14 men are moving between the guns as required. I know that gun crews normally would be fighting on only one side of the ship, but had to switch to both should they be attacking from both sides, which halved the crew. Which is this? Halving the crew, I assume?

I had always examined these from the standpoint of the tackles, but I'm looking at the shifting of the men more closely. Very interesting. What, exactly, does the statement "only one side being manned by a full crew" mean. I see that the 10/14 men are moving between the guns as required. I know that gun crews normally would be fighting on only one side of the ship, but had to switch to both should they be attacking from both sides, which halved the crew. Which is this? Halving the crew, I assume?
Signet, here is the title of a book as it can clarify some passages "Artillery instructions _ simplified for th - Barrett, Edward, 1828-1880"
 
The Swedish naval gun drill of ca 1700 specifies that the tackles are to be unhooked and laid on the deck clear of the recoil. When we tested a full-scale 24-pounder from Vasa (1628) in 2014, this is what we did. To complement the calculated figures in the post above, I can add the following real-world data, which we measured using high-speed video.

The Vasa 24-pounder weighs about 1600 kg with carriage. When fired with a service charge and 24-pound solid iron shot (close to 10 kg), it recoils about 7 meters on a flat, hard surface before coming to a halt, unless restrained by breechings. It reachs a maximum recoil speed of about 12 kmh, but it accelerates to this speed in less than 0.2 seconds. The problem for the breech tackles, if left taught, is that this is an enormous shock load, not a smoothly accelerating pull of the line through the blocks. While the tackle might survive this, it would be a needless strain on the equipment.

The gun was restrained by a breeching 50 mm in diameter which allowed the gun to recoil about 1.5 meters before bringing it up short. The ends of the breeching were fixed to a pair of large steel slabs with lots of contact area with the ground. Each slab weighed 1000 kgs, and each round yanked the slabs backwards over the ground about 5 cm.

You can look up Vasa cannon on Youtube for video footage of the tests.

Fred Hocker
Director of Research, Vasa Museum
 
Many Thanks to Fred for these additional information - just checked youtube and found these videos






and btw also this:

we joined Fred Hocker in the Admiral's Cabin. As Director of Research, Fred is an endless source of knowledge!

 
Thanks a lot, Fred and Uwe. Very interesting. While the recoiling speed isn't very high, as you say, it reaches that speed very quickly, so that would wear on the tackles.

The engineer in me can't help but do the math:

Momentum = 1600 kg x 12 km/h = 24/2.205 kg x Shot Velocity
so Shot Velocity = 1600 x 12 / 24 / 2.205 = 1764 km/h = 1096 mi/h = 1608 ft/s, the same velocity I found and was used in my calculations above. Great corroboration.

I do have one question about the second video posted:

In the first and third firings, the gun recoils far back, as Fred mentions. In the second video, it only recoils back a fraction of the distance before stopping. I don't think it's a partial video; the rod in the foreground continues to vibrate and smoke continues to move. Yet I don't see a restraining cable or anything preventing movement. Do my eyes deceive me?
 
Thanks a lot, Fred and Uwe. Very interesting. While the recoiling speed isn't very high, as you say, it reaches that speed very quickly, so that would wear on the tackles.

The engineer in me can't help but do the math:

Momentum = 1600 kg x 12 km/h = 24/2.205 kg x Shot Velocity
so Shot Velocity = 1600 x 12 / 24 / 2.205 = 1764 km/h = 1096 mi/h = 1608 ft/s, the same velocity I found and was used in my calculations above. Great corroboration.

I do have one question about the second video posted:

In the first and third firings, the gun recoils far back, as Fred mentions. In the second video, it only recoils back a fraction of the distance before stopping. I don't think it's a partial video; the rod in the foreground continues to vibrate and smoke continues to move. Yet I don't see a restraining cable or anything preventing movement. Do my eyes deceive me?
Actual muzzle velocity for this round, as measured by doppler radar, was 360 m/sec (1296 km/h); there are a lot of losses of energy in the recoil process, since the axles are not greased and part of the recoil energy is pushing the breech down instead of back. The second video shows the very first proof round, with a charge only 1/3 of the service charge. This produced only about 2 meters of recoil with the gun unrestrained. To proof the gun, so that it was safe to fire, we started with a 1/3 charge (1.11 kg), then 2/3 (2.22 kg), then a full charge (which in modern powder generates considerably more push and pressure than 17th-century powder). The full charge of 3.33 kg was then considered the overproof charge (it results in almost 10 m of recoil), and we were limited to a portion of this. Our adjusted service charge was 2.65 kg, which generated a muzzle velocity in the transonic range, which corresponds to what we can deduce from contemporary shot tables.
 
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