My problem with grenades and big explosions ...

[Dana_Jorgensen]

The question is really how big is the explosion. I was reading Band of Brothers and, during the attack on Brecourt (sp) Manor, Joe Toye had a grenade blow up right between his legs and he was mostly unharmed. Two other grenades blew up nearby and, again, he was ok. In other first hand account I've seen this scene many times: guy runs up to bunker and tosses grenade in through slit, the grenades explode and then the occupants of the bunker come stumbling out the door in a daze surrendering. I've heard there was a problem with the German stick grenade in that the stick acted to direct the blast so, depending on which way the stick landed, you could be very close and end up ok.

I guess I need more information on exactly how big the lethal area of a blast is. I'm not sure where to find that.


I thought about using something similar to the "damage increments". That's how Hero System works.


Finally, the fireball anology doesn't quite hold since every character, regardless of level, carries around two or three grenades. They are just too common to be hyper-effective.


Aaron

The biggest change to grenades in the last 50 years has not been the advent of new explosives to use in them. Instead it has been the advent of new design features to make the dispersal of fragments more uniform.

For grenades in WW2, I'd suggest that when a save is made, roll 1d6. 1-2, the damage is reduced by half, 3-4 the damage is reduced by 3/4, 5-6, no damage. This would help greatly in representing the extremely erratic dispersal patterns of grenades from that time period, which is why some soldiers seemed to be a helluvalot luckier than others.

Hmmm... and I need to update Big Bang Vol. 5 with that particular little rule...

 

[ledded]

The question is really how big is the explosion. I was reading Band of Brothers and, during the attack on Brecourt (sp) Manor, Joe Toye had a grenade blow up right between his legs and he was mostly unharmed. Two other grenades blew up nearby and, again, he was ok. In other first hand account I've seen this scene many times: guy runs up to bunker and tosses grenade in through slit, the grenades explode and then the occupants of the bunker come stumbling out the door in a daze surrendering. I've heard there was a problem with the German stick grenade in that the stick acted to direct the blast so, depending on which way the stick landed, you could be very close and end up ok.

Well, not to pick nits, but in the incident you are talking about he was warned by Winters that a grenade was incoming, and just managed to roll off of where it was between his legs. Still, the grenade detonated within just a few feet of him at most inside of a trench and he didnt even take a scratch, then narrowly avoided a couple more like you said, again not taking a scratch.

But in the same incident remember that Buck Compton (a former college baseball player) and several others threw grenades at fleeing Germans. A couple tossed theirs close and wounded a few germans, but Buck threw his straight into the back of a mans head, literally taking it off (ick).

And there was the BoB incident in Haguenau where they ambushed some Germans in a small house, and one of the paratroopers went through the door before the grenade someone had just tossed in the window went off and it wounded him mortally. Two of the Germans inside were untouched by the blast.

But yeah, I've read a lot of WWII and before incidents like these where someone narrowly avoids a grenade with no injury where another soldier is not even that close to one and dies from a small fragment, and everything in between. Those disperal patterns must have been erratic indeed.

I guess I need more information on exactly how big the lethal area of a blast is. I'm not sure where to find that.

I thought about using something similar to the "damage increments". That's how Hero System works.

Finally, the fireball anology doesn't quite hold since every character, regardless of level, carries around two or three grenades. They are just too common to be hyper-effective.

Aaron

Personally, I use a mechanic like Dana Jorgenson and others mentioned above, and maybe even pick up his Big Bang 5 which is all about grenades. While mostly fairly modern stuff in it, I've found it to be a *very* good and accurate reference for a multitude of grenades if you dont really like the 'all grenades are the same' feel of d20 Modern. He also addresses issues like 'lethal radius/casualty radius' in d20 Modern.

When I ran my WWII game, I did a similar mechanic to that suggested above, plus I also added a simple rule that any thrown grenade goes off immediately on an even natural attack roll, and goes off the next round on an odd natural attack roll. I did that because of the reputed disparity between different fuse lengths, caused by hand cutting or whatnot. It did give PC's (and enemies) the occasional attempt to 'throw it back' like we've often read about and seen in the movies, and it was great fun. I wouldnt do that for a 'modern' grenade, but it seemed to work out well for my WWII game.

 

[takyris]

Howdy, not-military-knowledgable-person here:

If you want stuff to be slightly lower on average and very random, you can model this very easily by changing the damage dice. Instead of 4d6, use 3d8, 2d12, or even 1d20. The fewer dice you use, the more random things get, meaning that people are more likely to either get pulverized or take a really low amount of damage.

As an outsider, I also like the blast increment rules. If you made the blast increment something like 10 feet, and dropped the damage by 4 points from 11-20, 8 points from 21-30, and so forth, you could still conceivably get somebody 30 feet away who takes (from 2d12) 24-8 = 16 damage, fails his MDT, and drops like a rock. (I'm modelling the drop-damage thingie off of the shotgun rules in the core book).

But again, no military knowledge whatsoever.

 

[Aaron2]

Personally, I use a mechanic like Dana Jorgenson and others mentioned above, and maybe even pick up his Big Bang 5 which is all about grenades. While mostly fairly modern stuff in it, I've found it to be a *very* good and accurate reference for a multitude of grenades if you dont really like the 'all grenades are the same' feel of d20 Modern.

I have BB#5 already.

When I ran my WWII game, I did a similar mechanic to that suggested above, plus I also added a simple rule that any thrown grenade goes off immediately on an even natural attack roll, and goes off the next round on an odd natural attack roll.

That's rule is also in VforVictory, which is what I started off using.


After much consideration here's what I'm gonna do ......

First, I'll lower the grenade damage down to 2d10. This damage represents a hit by a fragment. I'll try to keep all explosive's damage to an even number of dice.

I'll use the Blast Range Increment as discussed above. The Reflex save DC will drop by 2 for each increment.

When a bomb explodes, everyone within 10 Blast Range Increments will make a Reflex save. Those in the first increment will take 1/2 damage on a success and double damage if they fail. This represent the concussive blast effect. In the second through fifth increment, a successful save will take no damage and a failed save will take full damage. On the sixth and higher increments (more than 1/2 the max range) a failed save will only take 1/2 damage.*

Things like splitteringes (sp) and bazookas through walls will only affect the DC. A bazooka will normally have a really low DC so its effect will be minimal outside of a direct "hit".

That's how I'm currently thinking.


Aaron

*My thought on this is that most of the larger, more deadly, fragments do not travel as far as the smaller ones. 1d10 (1/2 the damage of a grenade) can still kill a low level character but that will be rare. This is similar to how DJ does it in BigBang#5.

 

[JPL]

Well, honestly, grenades are weird things. I've seen them blow up next to someone, and that person only get the wind knocked out of him, while the man twenty feet away took a little chunk of steel in the chest that killed him.

And a first hand account? Grenades make shredded meat out of people. Most don't die immediately, but hey, they were too busy dying to worry about what was going on around them.

I take it you were in the service?

Or had a difficult childhood?

 

[billd91]

I should have stated that I'm running a WW2 game so I actually want to emulate the lesser effectiveness of that era. Esp. the germans whose grenade had pretty poor fragmentation but could upgrade them with a splittering (sp).

One of the things I've read about German potato-masher grenades is that they were designed for more close-in use by the German shock troops. They'd throw them and move up quickly and so they wanted something with a smaller destructive profile. If you're down-grading the grenades to capture the feel of WWII, then you might want to drop the German grenades by an additional die and a little radius.

 

[skippy_the_witch]

I run a techno-magic science fantasy campaign, and one of the solutions I use is that modern armor is affective as damage reduction against firearms and explosives. But even with this, you are right, first level characters are pretty much dead if caught in an explosion. Then again, they are equally dead when facing a goblin with a short sword who rolled a crit. Or by falling down the stairs and rolling a one. Life can suck.

As one of my players so eloquintly put it when they had destroyed 17 out of 20 goblins with a well placed concusion grenade throw, "Guys, we are all one grenade away from dying."

skippy

 

[3catcircus]

As it is now, grenades do 4d6 point of damage with a burst radius and a Reflex save (DC 15) for 1/2 damage. This is fine for normal games, but I’m running a military game where grenades are the smallest explosive around.

Here’s my problem. Once damage reaches 6d6, it kills first level characters regardless of whether they make their saves or not (half damage is still over 10 hps). Outside of the burst area is perfectly safe while inside is instant death. What I want is to create a zone around where it is possible to be killed but also possible to escape unharmed; this is an attempt to simulate fragments flying about. So, first off, I was thinking of having a part of the explosion damage represent fragmentation. Instead of a Burst Radius, the attack will have a Burst Range Increment and the Reflex* DC will drop by 2 for every increment past the first. This should be around 2d6 or 3d6 of damage; save for no damage (i.e. didn’t get hit).

The second aspect of the explosion, the concussion force, is a bit more difficult. I would prefer that except for massive explosion, this be an unavoidable but small amount of damage (say 1-2d6) but have a stunning kinda take-your-breath-away type of effect. I’m not sure what to do. Maybe a Fort save vs stun.

Overall I’d like to do this with the minimal amount of rolling per blast but keep these same effects. Any ideas? Any other d20 games do explosions differently?


Aaron

*Instead of a Reflex save, it should probably be a built in attack bonus like dart traps.

Unfortunately, I don't think d20 can properly model this as-is. This is where I start my Twilight:2000 Rave... They used a system that included both blast and fragmentation. Depending on whether you were in the primary or secondary blast zone would determine how much (if any) blast you would take, and would also determine how many (if any) fragments you would get hit by. Their system also applied blast damage to each body part while fragmentation damage was applied to a specific body part.

Something else to keep in mind - the blast radius is probably not correct.

For the M61/M67 Fragmentation grenades, killing radius is 5 metres and casualty-producing radius is 15 metres, but fragments can disperse up to 230 metres away.

For an offensive grenade like the Mk3A2 concussion grenade, all the damage is caused by the blast (no fragments) - and has more of a blast than the M61/M67 - but the kill radius is only 2 metres, but fuze fragments and secondary missiles can be propelled up to 200 metres away.

This is how I would approach it:

1st - separate blast and fragmentation damage - for the frag grenade, make it 2d6/2d6. Next change the blast radius/range increment - 5 metres (15 feet) primary (blast & fragmentation damage), followed by a secondary zone of 15 metres (45 feet) where you only suffer fragmentation damage. Third, consider having blast damage be nonlethal and/or subdual with the following house-rule: if it exceeds the massive damage threshold, subtract it from hit points. If it doesn't exceed the massive damage threshold, then act as per the massive damage threshold rules as they exist now.

 

[Aaron2]

This is where I start my Twilight:2000 Rave... They used a system that included both blast and fragmentation. Depending on whether you were in the primary or secondary blast zone would determine how much (if any) blast you would take, and would also determine how many (if any) fragments you would get hit by. Their system also applied blast damage to each body part while fragmentation damage was applied to a specific body part.

I'd like to do something like that. OTOH, I don't want a 5-cm mortar shell to land near the squad and have to make 50 die rolls just to figure out that one guy is slightly wounded.

For the M61/M67 Fragmentation grenades, killing radius is 5 metres and casualty-producing radius is 15 metres, but fragments can disperse up to 230 metres away.

From what I understand, there is a certain distance after which any flying fragments are just too small to be considered lethal. The bigger, more deadly ones won't travel nearly as far.


Aaron

 

[nobodez]

Wow, I can't believe that nobody mentioned the grenade rules from Spycraft. All explosives have something called a blast Increment, usually 5 or 10 feet, though sometimes more. Eavery blast increment you are away from the blast, you take half as much damage. So, for example, a 24 pt explosion with a 5 foot blast increment deals 24 points at 5 feet, 12 up to 10, 6 up to 15, 3 up to 20, and finally, 1 up to 25 feet away.