Low Tech cannons mortars and shells

[Varyon]

Originally Posted by Rupert

Fragmentation damage is 1d per 20mm of warhead diameter if there's enough fragmentation to give a fragmentation effect as GURPS understands it.

I've seen this figure mentioned before, but can never remember it when these threads pop up. Is it actually stated somewhere in the GURPS books, or is it just something that has been extrapolated from existing weapons? Also, what impact should various means of increasing fragmentation (shell walls specifically designed to fragment, having premade fragments inside of the shell, etc) have on this?

Originally Posted by Polydamas

My understanding is that it was only after WW II that engineers go through every exploding munition and systematically design it to kill and maim as many people with fragments as possible, Eg. the old 'pineapple' grenades were designed to be easy to grip with a wet or muddy hand, any benefit to fragmentation was accidental. Its just so much harder to make anything other than a simple casing, and gunners are really really concerned that you get "does not explode in the tube" right.

I think there were low tech attempts to increase fragmentation by including nails or other preformed fragments inside of the grenades, like the Chinese land mine on LT86 (that used lead balls... which somehow do crushing damage instead of the piercing damage of most high-velocity lead balls in GURPS).

Originally Posted by Anthony

That has more to do with the rules for blast damage being broken than with the rules for fragments being broken. Fragment damage being linear in shell diameter is entirely reasonable, the problem is that radius for blast effects should also be near linear in shell diameter, not 3/2 power (what it actually should be in both cases is damage that's linear, and also a wounding multiplier that's linear; a bomb that's 8x more massive produces a given overpressure at 2x the range but also for 2x the duration, and it produces fragments with 2x the penetration but also 2x the wound channel).

So, you're saying that it would be more appropriate for explosions to scale with the cube root of explosive weight (rather than the square root they currently use)? The wounding multiplier would be a bit of a pain to try to work through; it might be better to just have damage scale as the 2/3 power of weight. If already redoing things, it would probably be a good idea to adjust fragmentation so that the skill isn't always 15, but is rather dependent on how much fragmentation the explosive produces (more fragments means higher skill)... and maybe make them pi instead of cut, probably with a poor armor divisor (ideally, the armor divisor would go down with fragmentation damage, to represent larger fragments having more difficulty getting through DR but causing more severe wounds when they do - the latter is already handled by using 2/3 power - but that might be a bit too difficult to implement in practice). Maybe have an option when the explosives are designed to have a tradeoff between fragmentation damage and skill (more fragments means higher skill, but as they are smaller they each deal less damage).