Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Think of it as a spell checker that insults you, as well.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.



Hydraulic recuperator system for muzzle-loading shipboard cannon.

Better late than never.
  [vote for,

There are many problems associated with the efficient operation of cannon on large wooden sailing ships, but BorgCo now have the means to address a significant long term issue.

When a cannon fires, it recoils; the recoil energy is dissipated by friction between the carriage wheels and the deck, and finally arrested by the block-and-tackle which transmits the remainder of the shock to the hull. In itself, this is advantageous; the muzzle needs to be inboard so that the piece can be reloaded. Stopping the recoil while the muzzle is still outside the hull makes efficient reloading impossible. The barrel is then swabbed out, and a fresh charge and projectile are loaded. The block and tackle systems on each side are then used to haul the gun back into battery, after which the priming can be placed and another round fired.

The issues to be addressed are (i) the dissipation of the recoil energy, and (ii) the rapid and efficient return of the carriage to the firing position.

BorgCo armaments engineers have therefore designed a simple yet effective hydraulic recuperator system which can be retrofitted to any man o’ war from a frigate up to a three-decker ship of the line. The materials and engineering are entirely consistent with 18th-century technology and can be installed, maintained and used with no greater skills base than already required for the ship’s guns and pumping systems. No special materials are required.

The existing block-and-tackle assembly is retained as a backup, but is augmented by a ringbolt in the front centre of the truck. From this point, ropes run to two pulleys bolted to the hull on each side of the gunport and then pass down through thimbles (smooth metal tubes to prevent fraying) to the bilge.

In the bilge is the main part of the recuperator mechanism. A two metre long metal-bound wooden lever is secured to the hull frames with a strong hinge. The pair of ropes run to two pulleys below the level of the hinge, then up to an eyebolt set a metre inboard of the hinge point. At the inner end of the arm is a pivot, from which a rod passes down to a piston head placed within a cylinder bored from a section of treetrunk, and bound with wrought iron straps. The piston has a greased leather seal, and the interior of the cylinder is also greased, so that a watertight seal is formed.

A pipe leads from the base of the cylinder to a tall, narrow barrel several times the diameter of the cylinder which is half-full of water, with a lid which has an air vent.

When the gun fires, the recoil forces move it inwards away from the hull. The force is transmitted to the ropes, which transmit the movement to the middle of the lever. Constrained at its outboard end by the pivot, the inboard end is forced down, compressing the water in the piston and forcing it through the pipe into the barrel.

When the gun reaches the limit of its recoil, non-return ratchets in the pulley blocks stop the ropes pulling it back. It is then reloaded; the crew stand clear, and the release lever (which operates both ratchet locks simultaneously) is pulled. Below decks, the water in the barrel is at a substantially raised level and is therefore exerting a force on the base of the piston equivalent to that which induced its original movement; it is a store of potential energy. Using the mechanical advantage of the lever, the water flows back into the piston, pushing it back to its rest position, tensioning the ropes, and hauling the gun back into the firing position, ready to send another 24-pounder roundshot skimming over the waves to inflict untold death, destruction and suffering on whoever’s the enemy of the British Crown today (the waiting room is always full – just stick your head round the door and shout “NEXT !”).

It is said that the military are “always ready to fight the last war”. Now, the navy can be ready to fight not only the last war, but the … eighteenth or nineteenth one before that, too. With the higher rate of fire, and less exertion needed to achieve it, victory in any sea battle between sailing ships armed with muzzle loading cannon is pretty much guaranteed.

8th of 7, Nov 26 2019

For [8th of 7] https://en.wikipedi...ki/Disappearing_gun
Recoil has it's uses... [neutrinos_shadow, Nov 27 2019]

Davis gun https://en.wikipedia.org/wiki/Davis_gun
Innovative and remarkably effective. [8th of 7, Nov 29 2019]


       Why all the faffing around with water? A simple counterweight on your lever will work (and if the water can slosh about, that's a bad thing too, on a ship (or any vehicle, really)). You could even get a little bit clever with mechanical advantage and have "zero initial force" and such.
neutrinos_shadow, Nov 27 2019

       A counterweight gives a constant force with distance; because the head of water rises, the returning force increases with distance.   

       If you lift a 10kg counterweight 1m, the restoring force is 100N at any point in the travel. But with hydraulics, you are increasing the mass of material moved. At rest there is no tension in the rope; for each unit of movement of the piston down the bore, you move l x A x rho kilograms of liquid against gravity.   

       It is in effect a fluid spring, but unlike a metallic or elastomer spring it cannot suffer from fatigue and is self-recalibrating (or can be made so) on each stroke.
8th of 7, Nov 27 2019

       This is a good idea but it's founded on the proposition that a watertight piston could be made using technology at the time. I am currently reading (for the second time) a book about the history of machine tools and it goes in to a lot of depth about the development of early lathes and boring machines.   

       It is interesting to note that military technology of the 18th century was almost entirely restrained by the accuracy of cannon-boring machines. Producing an accurate bore was hugely expensive. Newcomen engines used packing and covered the top of the piston with water which continuously leaked into the lower section. The book also mentions that a huge number of Watt engines were "hand finished", that is, the piston and bore were matched using a chisel and a file. High-pressure steam engines simply couldn't appear before better machine tools were invented.   

       You've proposed a wooden bore and greased leather seals, which might have been fine, but it seems that if you are going to the expense of having another moderately accurate bore, plus all the additional weight of the system described, it may have been easier to simply add another cannon. A mechanical system could use the recoil of one cannon to pull the other cannon into the firing position.
mitxela, Nov 29 2019

       We considered that, but li limits the rate of fire.   

       You start with all guns loaded and run out. As the enemy comes abeam, you want to either fire a broadside (which inflicts tremendous shock on your own ship) or better, allow gun captains or divisions to "fire as guns bear", actually the preferred technique until the range got really short. That allowed the gunner to hit the enemy "on the uproll", trying to hole their hull below the notional waterline. But that means firing independently at precisely chosen times; you don't want half your ordnance sitting loaded but inactive waiting for its "partner" gun to fire and thus run it out, and if one of the pair is disabled then the other loses its "free return " mechanism too.   

       We know all about the problem of machining cylinders, hence the use of wood, and low-pressure low temperature wet systems which are to some extent self-lubricating and self-sealing.
8th of 7, Nov 29 2019


       Rope two adjacent guns together using a pulley, a bit like a horizontal sash window with a gun on each end of its rope.   

       The fired gun recoils backwards to the refill position. As it does so it pulls the other one forwards to the firing pos. When it can then be fired while the other one is being wadded-up.
bhumphrys, Nov 29 2019

       Did you read the annotation before yours ? Did you ? Any of it ? Where the issue of pairing guns like that was explained and discounted ?   

       No, you didn't. Otherwise you would have grasped why it doesn't work. Either that or you're terminally stupid.
8th of 7, Nov 29 2019

       The whole recoil problem could be much more easily solved by having a double-ended cannon, long enough to poke out of both sides of the ship. The charge is pushed to the mid-point of the barrel, cannon balls are added from each end, and then the thing is fired.   

       This would have the advantage of allowing you to sneak up between two enemy ships and then shoot them both simultaneously.
MaxwellBuchanan, Nov 29 2019

       [+] for the fact that there's somebody besides me who wonders how we could have improved ancient warfare without using modern technology.
doctorremulac3, Nov 29 2019

       It's a way of contemplating alternative history scenarios. If X had had a weapon which was only marginally more effective than Y at the battle of Z, and because of it Y's larger forces were defeated (instead of winning, as they did in actual* history) or even held to a draw, how different might things have turned out ?   

       // a double-ended cannon //   

       The Davis gun; an early recoilless cannon. Versions were carried - successfully- on some WW1 aircraft.   


       *That is, the version of history that the Jesuits, the Illuminati, the Reader's Digest and the Disney Corporation have decided that it's safe and appropriate for you to know.
8th of 7, Nov 29 2019

       Davis gun? Pfah! we say.   

       The Davis gun, according to the linked Wikipedia suffered from the twin drawbacks of being both practical and effective.
MaxwellBuchanan, Nov 30 2019

       //limits the rate of fire//
Ah, but it doesn't really. Either you have x cannon firing every y seconds, or x/2 cannon firing every y/2 seconds, as you are loading etc the "other" set while the first are firing.
neutrinos_shadow, Dec 01 2019

       Careful, neutrinos, or you'll be told.
bhumphrys, Dec 04 2019

       Actually, would a more intelligent use of recoil not be to have all the guns pointing forward? Then you can simultaneously shoot the enemy and retreat rapidly.
MaxwellBuchanan, Dec 04 2019

       When asked why HMS Dreadnought had such limited arcs of fire to the stern, Admiral the Lord Fisher replied "It has never been the policy of His Majesty's ships to run away."   

       Then again, the design of the battlecruisers was explicitly "To be able to kill anything that couldn't run away, and run away from anything that could kill them" - in other words, more powerfully armed than cruisers, but much faster than battleships.
8th of 7, Dec 04 2019

       Yes, but that leaves one options uncovered: killing things that are running away.
MaxwellBuchanan, Dec 04 2019

       ... for which the aircraft carrier was invented.
8th of 7, Dec 04 2019

       Ah yes. I believe we have one of those now, and there's a real prospect of getting some planes to put on it.
MaxwellBuchanan, Dec 05 2019

       Hmm, why not simply have the gun on a ramped track? Upon firing, the recoil drives the gun up and back where it can be reloaded and the crew not standing near an open gun port. Then you send it back down the track. The timing could be controlled with a loop of rope attached to the front and back of the gun carriage running through a ratchet.   

       As a side benefit (of posted idea and mine) You could use the cannons as a mass damper for roll in rough seas, you'd need 1 trained cabin boy per cannon and a supply of saws/peg legs for the inevitable limb issues that go along with big moving masses and free rum.
bs0u0155, Dec 05 2019

       // ramped track //   

       The weapon needs to traverse. If there's an inclined-plane frame, pivoted at the front- as used by later shore-based artillery- then it works, but the lack of headroom limits the height and therefore steepness of the ramp. The gundeck of a first rate has about 1.6m headroom. A longer, shallower ramp means that the tail would interfere with ramps from the opposite broadside. The muzzle needs to stay level with the gunport to allow the mop, scoops nd rammer to be manipulated by passing them out of the port during reloading.
8th of 7, Dec 05 2019

       What about the rope, instead of being connected to that hydraulic stuff, instead passes downward through holes in the centers of cast iron weight plates that are held apart by a frame, finally being attached to the lowest plate? Then, when the cannon recoils, it picks up each plate in sequence from its rest (being of increasing diameters inside a stepped conical frame, or something like that). This causes the restoring force to increase the farther back the cannon goes. I don't remember why you wanted that property, but this has it.
notexactly, Dec 08 2019

       There must be some way of bringing the exceptional rehological properties of custard into this. Then we'll have it cracked.
bhumphrys, Dec 08 2019

       <Notes that [bhumprys] may turn out to be officer material after all/>
8th of 7, Dec 08 2019


back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle