Army mortars v screw galleys

Darman wrote:

Theemile wrote:Sadly, this has me thinking about a hedgehog launcher - a WWII weapon which was essentially a few dozen mortars mounted together to create a pattern of destruction wherever they are aimed - the shipborne issues would be compounded - except for the accuracy bit, since a hedge hog is an aim-over-there-ish weapon.

This was my thought too. A hedgehog or katyusha-type weapon (although I would not want to be the one firing rockets from aboard any wooden ship) firing shells/warheads with incendiary "shrapnel" might be effective.

Keep in mind that the US Army, when considering coastal defense requirements at the end of the 19th century, considered the smallest number of coastal defense mortars (12" mortars, pre-sighted, fixed fortified positions, fixed aiming points, invulnerable to all incoming fire except mortar fire) to be 4 mortars in a diamond formation. And even that was half a battery. Most coast defense installations built at the time included at a minimum 16 mortars per position to bracket the enemy warship with as many shells as possible. This should give you some idea of the challenges of aiming these mortars from dry land. Add in a ship pitching and yawing every which way? No way. Not with the minimal number of mortars you'd be able to fit on a galleon (i.e. one or two at most). Again, the Army's Coast Defense Artillery expected 16 mortars firing at once from fixed positions at pre-sighted coordinates to be effective at taking out an enemy battleship.

Jonathan_S wrote:Given the difficulty of a direct hit, and the relative ineffectiveness of blackpowder propelled shrapnel from a mortar shell I wonder if you'd be better off trying for something closer to the original hedgehog; underwater explosions using high-explosive. Of course the fuses would have to be changed since the hedgehog was contact fused; it only detonated if it hit a sub. You'd want something that went off at roughly 7-10 feet underwater. But screw gallies have very lightly build hulls; a series "nearby" high explosive underwater detonation might cause significant leaking.

OTOH that requires more resources and time than simply diverting some existing army mortars and ammo onto ships - you'd have to design and build a new mount and ammo. By that point The Cities or KHs should have already shown up - and they've guns that'll blow right through the bow armor on a screw galley. (Not to mention when working in pairs either design has the steam powered mobility split up so a screw galley can't keep it armor pointed at both simultaneously; giving a free shot at the galley's unarmored flank).

JeffEngel wrote:

Jonathan_S wrote:Given the difficulty of a direct hit, and the relative ineffectiveness of blackpowder propelled shrapnel from a mortar shell I wonder if you'd be better off trying for something closer to the original hedgehog; underwater explosions using high-explosive. Of course the fuses would have to be changed since the hedgehog was contact fused; it only detonated if it hit a sub. You'd want something that went off at roughly 7-10 feet underwater. But screw gallies have very lightly build hulls; a series "nearby" high explosive underwater detonation might cause significant leaking.

OTOH that requires more resources and time than simply diverting some existing army mortars and ammo onto ships - you'd have to design and build a new mount and ammo. By that point The Cities or KHs should have already shown up - and they've guns that'll blow right through the bow armor on a screw galley. (Not to mention when working in pairs either design has the steam powered mobility split up so a screw galley can't keep it armor pointed at both simultaneously; giving a free shot at the galley's unarmored flank).

Still - submarines are going to be a wicked threat to surface vessels, and any nation seeking an equalizer against a large sea power is going to hanker after them as soon as it can build a remotely effective one. Having an anti-submarine weapon prepared already is a fine idea, and putting it to preliminary use against something else is a fine place to start. With different ammunition types - timed fuse, contact fuse, or in this case depth fuse - you'd have something that could suit a variety of niche applications. If it's not sucking up a whole lot of tonnage, space, or manpower, it'd be a handy extra for a warship. And if they're built small enough and with mounts that can be moved from the ship to a field carriage without gross trouble, they could swing from ship use to marine shore use as need be.

Theemile wrote:

JeffEngel wrote:*quote="Theemile"*

Sadly, this has me thinking about a hedgehog launcher - a WWII weapon which was essentially a few dozen mortars mounted together to create a pattern of destruction wherever they are aimed - the shipborne issues would be compounded - except for the accuracy bit, since a hedge hog is an aim-over-there-ish weapon.*/quote*
The hedgehog was used for depth charge distribution against a submarine that wasn't localized beyond over-there-ish - you got "accuracy" under those conditions just by hosing down an area with pain. Surface fighting wouldn't have that kind of need except in case of fighting in the dark or thick fog, but the sub could be put out of action or driven off by underwater detonations that may not do much good against a ship when they go off in air.

If the idea is just to rip up sails and rigging, you're in better shape. That said, I've got no idea how bad sheer concussion is on sails or rigging, or how well these charges are going to spread jagged bits of metal to rip them up.

If you don't mind ripping through ammo and you do want to get things done in a hurry, you could use something hedgehog-like - a cluster of mortars firing shells in a narrow fan. While the army can do very good things with mortar accuracy and well-timed fuses for air burst, a ship has to worry about the sea under it pitching it in ways that the army only needs to fear if it takes to fighting during earthquakes.

But in the spirit of varying the exercise some, rockets with timed fuses for air bursts may be another source of indirect fire. I don't think I'd care to try them on any ships with any sails or rigging though.

The British used the Hale rockets on their bombardment ships in the war of 1812 (and Napoleonic wars), and those ships were rigged. I think one of the previous posters was correct, you'd probably need a ship with the appropriate (Ketch) type sail plan for either ordinance type, but I believe the Hale's were used widely in the British fleet for a number of years on most vessels.

Silverwall wrote:Don

In the New Orleans case they were moored in a river/bayou with no waves to speak of, I guarantee you shooting at a galley in a bay/harbour will have more swell to deal with.

Terminal velocity of the shrapnel even with the explosion would be unlikely to be more than 175 mph max or ~255 feet per second. The bursting charge in a shrapnel round is very small, just enough to shatter the outer casing and disperse the shrapnel balls. Do not confuse it with the powerful explosion of a HE round being fused for proximity detonation.

For comparison the 45 ACP round which is famously slow by bullet standards is ~820 fps which is a huge difference in energy and will almost certainly suffer less drag than shrapnel will. 9mm parabellum has a muzzle velocity of about 1250 fps and rifle rounds only go up from there. I therefore stand by my comment that a thin splinter deck of wood will protect against this kind of splinter damage. The lack of velocity of splinter/shrapnel damage is why a 2-3mm thick steel helmet could protect soldiers in the world wars when direct shots went straight through.

Angle guns are long barrel compared to mortars so have much more burn time to fully consume the propellant charge and reach a consistent velocity.

As I said the correct way to fire shrapnel into the rigging is to use a conventional long cannon to fire case shot straight at the rigging. Much easier to aim, more effective and doubles for other purposes.

Hooked wrote:The Go4 has come up with something Russian katyusha rockets from WWII.
Chairis is going to produce a better version using Lewsite(sp?) (like dynamite)
Is it possible to have a multiple rocket launcher on a ship. Enough explosions, even just close to a screw may be enough to damage its hull? It may not be necessary to hit the screw galley. Just like horseshoes, close enough is all you need.