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[Call ofCthlhu] Dynamite: damage and blast area

tindriel

Retired User
I'm actually playing a Call of Cthulhu campaign (d100), and I have some doubts regarding explosions rules. The Core Book estipulates that when you double the amount of dynamite sticks, damage and blast area are increased. But the thing is that it gives you no example at all to know exactly how is it done (and the spanish translation isn't as clear as I would love to). Can anyone tell me how can I work out the damage and how It decreased if I use 12 sticks of dynamite, please?

Thank you very much,

Tindriel
 
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nclarke

Registered User
Validated User
The English version is 6e says:
"Calculate effect in terms of the strength of the blast and the radius of effect in yards. Example; a stick of dynamite does 5D6 damage in the first two yards, 4D6 in the third yard, 3D6 in the fourth, and so on. Each victim takes separate full damage. Doubling a charge increases damage by half. "

So 2 sticks do 7.5D6, 4 sticks do 11.25D6, 8 sticks do 16.875D6, 16 sticks do 25.2D6. 12 sticks would do roughly 21D6 or 21 to 125 damage in the first 2 yards/meters, roughly 16D6 in the third yard/meter, roughly 12D6 in the fourth yard/meter and so on. I'd decrease it by four dice for each extra yard/meter down to zero more than 7 yards/meters from the blast.
 

Toadmaster

Registered User
Validated User
Distance should be exponential, double the distance, quarter the damage. This is not stated in the rules, but that is how explosive force works and also makes it easy. The book example is linear which will result in a much larger blast radius compared to the real life numbers. Not a huge deal with small charges, but quickly unmanagable on large ones.

Book example 2yd 5d6, 3yd 4d6, 4yd 3d6, 5yd 2d6 6 yd 1d6 vs 2yd 5d6, 4 yd 1d6.


Taking a Mk3A2 offensive (aka concussion) grenade which holds 1/2 lb of TNT (roughly equal to 1 stick of dynamite) in a non fragmenting fiberboard case. It is listed as having an effective casualty radius of 2 meters in the open (closed spaces increase blast damage). Following the 5d6 for 1 stick of dynamite, exactly following the rules would still have the blast be equal to a rifle shot at 6 yds, while the formula I list has it doing 1d6 at 4 yds (still double the listed effective radius).


So accepting the 12 stick example numbers are correct, you would get 2yd 21d6, 4yd 5d6, 8yd 3d6, 16yd 1d6 following the 1/4 damage for each doubling of range, while the book example would be doing damage out to 21 yds, losing 1d per yard (not sure where the poster above got the drop by 4d6 per yard).

A 500lb aircraft bomb (approximately 200lbs of explosive filler or 400 sticks of dynamite, not even going to do the math) has an explosive blast radius of 13 meters, with effective fragmentation to 40+ meters. -1d6 per yard would greatly exceed both the blast and fragmentation given by the military.
 
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