Low Tech cannons mortars and shells

[Fred Brackin]

Originally Posted by stranger38

So, short answer is yes, and long answer is "they kinda use them"

You need to add in a "but they didn't work very well at all.".Or even an "They were more dangerous to the users than the targets".

[Polydamas]

Originally Posted by stranger38

So, short answer is yes, and long answer is "they kinda use them"

There were weapons in the 15th-17th century which fired exploding shells, but none of the weapons listed in GURPS Low Tech pp. 87-89 had exploding shells as a standard ammunition type. If you need stats, use the Grenade a Main and the Napoleon 12-pounder in GURPS High Tech as a model.

If you see a castle in England with holes in the wall, generally it surrendered in the Civil Wars, had holes dug in it, and was blown up with gunpowder.

[stranger38]

Originally Posted by Polydamas

There were weapons in the 15th-17th century which fired exploding shells, but none of the weapons listed in GURPS Low Tech pp. 87-89 had exploding shells as a standard ammunition type. If you need stats, use the Grenade a Main and the Napoleon 12-pounder in GURPS High Tech as a model.

If you see a castle in England with holes in the wall, generally it surrendered in the Civil Wars, had holes dug in it, and was blown up with gunpowder.

You mean, take the 12lb shot and apply the low explosivo modifier?

Was reading HT yesterday but the damage/weight rateio, i did nota understood

[Polydamas]

Originally Posted by stranger38

You mean, take the 12lb shot and apply the low explosivo modifier?

Was reading HT yesterday but the damage/weight rateio, i did nota understood

GURPS High Tech p. 138 has stats for a Napoleon 12 lbr firing a black powder shell (which they call LE for Low Explosive). This is representative of medium-sized bombs launched by low-tech mortars. Any individual mortar may be bigger or smaller and may have a less powerful explosive charge.

A Low Explosive round from the Napoleon 12 lbr aka. Bourges Mle 1853 does 6d×5(0.5) pi++ on impact (that damage is kind of high) and then explodes for 6d cr ex throwing fragments which do 5d+2 when the fuse burns down. The rules for explosions and fragments are in GURPS Basic Set. In a harshly realistic game, in addition to the variable delay of the fuse which allows people to take cover, run away, or extinguish the fuse before it explodes, give each individual shell a Malf to represent the chance that the fuse fails to ignite, or falls out, or that the shell explodes in the gun. For example, you might give each shell Malf 14 and say that it explodes 1d-2 turns after impact.

The Grenade a Main in GURPS High Tech is representative of small black-powder shells with a burning fuse.

[Anthony]

Originally Posted by Polydamas

If you see a castle in England with holes in the wall, generally it surrendered in the Civil Wars, had holes dug in it, and was blown up with gunpowder.

It's possible to breach castle walls with cannons, but it was done with solid shot. Explosive rounds designed for use against hard targets aren't really a thing prior to the 19th century.

[RGTraynor]

Originally Posted by Polydamas

GURPS Low Tech: Medieval China could be a fun supplement.

Agreed. It'd be eyepopping. Really, world history would be a whole lot different if the Song Dynasty was into aggressive conquest.

[Pursuivant]

Originally Posted by Fred Brackin

You need to add in a "but they didn't work very well at all.".Or even an "They were more dangerous to the users than the targets".

By the 18th century, they were sufficiently reliable and effective that they were part of every artilleryman's arsenal.

You can use the HT stats for a black powder grenade as a basis for a 1 lb. shell.

After that, assume a hollow sphere with 0.375 to 1-inch thick walls depending on shell size and the rest of the volume is black powder. Model volume of powder as 4/3 PI r^3 where R is (shot diameter - (wall thickness x 2))/2. Assuming a density of 50 lbs/ft^3 for black powder you can work out explosive damage based on weight

There is general information about black powder artillery shells in GURPS 3E High Tech 3rd Edition. It says that BP shells do explosive damage based on filler weight, which is usually about 10% of total shell weight. Fragmentation damage is 2d to 12d+ cutting damage per hex within the fragmentation radius. Material picked up from a ground burst material might add 1d-4 to 1d-2 HP cutting.

I consider the GURPS 3E HT rules for shrapnel to be remarkably generous. Unless they were specifically shrapnel shells (shell filled with musket balls) cast-iron shells tended to shatter into just a few pieces. Air bursts directed shrapnel in all directions rather than just towards the ground like modern shrapnel shells. Ground bursts buried themselves in the ground so shrapnel fragments just got buried in the earth or channeled upwards with the blast.

That's not to say they weren't potentially lethal, just not "instant wound/death" as the rules imply. In particular, fuze-timing was a huge issue for pre-20th c. shells, so shells might burst before they reached the target or after they'd passed it by/buried themselves in the ground.

Battlefield archeologists/scavengers regularly collect shell fragments from the ACW and other 19th c. conflicts, which gives you a sense of relative lack of fragmentation damage.

As a SWAG, I'd suggest 1d HP pi++ damage for a low-explosive driven lead ball, 2d cut for a chunk of cast iron shell, with chance of a hit (3d) being 12 for shrapnel, 9 for shells) with normal penalties for range to hit more distant targets. A critical hit means a hit by some sort of shrapnel out to ~2x normal blast radius.

Way too much information on late 19th c. artillery here.

[Polydamas]

Originally Posted by Pursuivant

By the 18th century, they were sufficiently reliable and effective that they were part of every artilleryman's arsenal.

I don't think that the average three- or four-pounder-crew or naval gun crew had explosive shells in the 18th century (which GURPS calls TL 5). Instead, a well-equipped European artillery park would have some weapons with explosive shells.

As late as the Napoleonic Wars, Wikipedia suggests that the only French field guns with a shell were the 6" howitzers https://en.wikipedia.org/wiki/Obusie...ces_Gribeauval https://en.wikipedia.org/wiki/Gribeauval_system (they also had mortars for sieges)

[Rupert]

Originally Posted by Pursuivant

By the 18th century, they were sufficiently reliable and effective that they were part of every artilleryman's arsenal.

And that's early-mid TL5, and they were still not the standard for guns, but a speciality round.

[Anthony]

Late TL 5 they became pretty standard, but that's 19th century, not 18th.