Explosions

Note: This is a HârnMaster expansion on Explosions. It is a discussion paper, and the rules may be modified in later drafts (if any). Please try out these rules and send me comments.

By the way. Here is one case where a detailed system like HârnMaster has a high price to pay: this is not a quick system. Explosions are complicated and require a lot of resolution. A fast, easy system has evaded me so far...

While explosions are relatively rare in a medievel environment such as Kethira, some of you have indicated that you would like to see the subject dealt with in more detail.

Explosions have attributes that make them somewhat different from other types of strike/strike attempt. The most important of these are:

1. All exposed, in range, body parts are struck by an explosion.
2. Impact drops off with increased range and may be increased if the terrain has a channeling effect.
3. Strike Location(s) are determined by chance and facing (aiming is not possible).

Procedure

[1] Channeling

Range/Impact may be affected by channeling obstructions; an explosion in a corridor, for example, propagates mostly along the channel formed by the walls and ceiling in either direction.
Increase Impact by 1d6 for each direction in which the explosion is blocked (except down - the floor is ignored). Hence, the impact of an explosion next to one solid wall is increased by 1d6. If it occurs under a ceiling, increase it by one more, and so on. Hence, the impact of an explosion in a hallway would be increased by one for each wall and by one for the ceiling (eg. from 3d6 to 6d6) and the impact of an explosion in a normal room would be increased by 5d6.
As an overriding consideration, channeling cannot more than double an explosion's Impact.
For each character, the following procedure is followed:

[2a] Determine Range

Cross-index the character's range (in five foot hexes) from the explosion's epicentre and cross-index it with the modified Impact (above). If the resulting impact is less than 1, the character is more or less unaffected by the explosion. Otherwise, he may be injured.

[2b] Screening Obstructions

Determine whether part(s) of the character are protected by (i) other characters, (ii) low walls, (iii) heavy vegetation, (iv) other blocking features that would (at GM discretion) lessen the impact of the explosion. Any reduction from screening features will be applied to reduce the impact of the explosion, but ony on the specific body parts screened. Note: Shields are treated as plate armour when determining effective impact.

[2c] Instant Kill

Some Explosions are so powerful that they will instantly destroy or fatally shock any organic creature (and many solid objects) in their paths.
If a shortcut is wanted, it may be assumed that an unarmoured character who is subject to a 7d6+ impact explosion is killed instantly. 10d6 impacts are generally fatal regardless of any armour worn.

[2d] Facing

Determine the character's facing at the instant of the explosion. The Hârnmaster combat system presumes that characters are turning and moving constantly in the course of a turn, hence, it is possible for a character to be facing in any direction at any given time. Most likely, however, an engaged character will be facing one or more of his opponents. Facing is primarily a matter of GM discretion, but the following table may be used to determine the side of the character which is affected by the explosion:

01-25 Front
26-50 Left Side
51-75 Right Side
76-00 Back

[2e] Strikes

Explosions affect all exposed body parts. Sometimes, the GM may decide that reflected blast may (to a lesser degree) also affect body parts which are not directly facing the epicentre. In general, the procedure is to resolve a strike against each body part, according to facing, as follows. Numbers in parentheses () indicate that the body part(s) indicated have the percentage chance shown of being struck:

Front

Skull (60%), Face, Neck, Chest, Belly, Groin, Each Hip (75%), Each Leg (70%), Each Arm (60%), Tail (10%), Each Wing (60%).

Side (Left or Right)

Skull (60%), Face (35%), Neck, Arm (75%/25%), Leg (75%/25%), Thorax (50%), Abdomen (50%).

Rear

Skull (65%), Neck, Each Arm (50%), Back, Hips, Each Leg (75%).

Strike by Strike

Types of Explosion (Aspect)

The Aspect of a strike resulting from an explosion is determined by the type of explosion. For the purpose of roleplaying, explosions may be broadly divided into the following types at GM discretion:

Fireballs

A fireball is basically a propagation of intensely hot gasses, at a relatively slow rate, and may not be accompanied by a conventional shockwave. A fireball might, however, ignite flamable material. The Aspect of a fireball is Fire/Burn.

Pure Concussion

Any sudden shockwave. The Pure Concussion effect is not particularly hot and is more likely to put fires out than start them. A concussion's aspect is Blunt. Note that a major implosion will have the same general effect(s).

Shrapnel (Large)

Any explosion which causes large pieces of debris to scatter. The aspect of such an explosion is Tear.

Shrapnel (Small)

Any explosion which causes small (less than 2cm) pieces of debris to scatter. The aspect is Point.

The GM is advised to resolve most dangerous strikes first since, once the character is dead, further determining injuries may be academic.

Significant explosions nearly always cause their victims to loose consciousness.

Impact Table

-------------------------------------------------------
                       Basic Impact d6  
-------------------------------------------------------
 Hexes   1   2   3   4   5   6   7   8   9  10  11  12    
-------------------------------------------------------
  0-2    1   2   3   4   5   6   7   8   9  10  11  12    
  3-5    1   1   2   3   4   5   6   7   8   9  10  11    
  6-8    -   1   1   2   3   4   5   6   7   8   9  10    
  9-11   -   -   1   1   2   3   4   5   6   7   8   9    
 12-14   -   -   -   1   1   2   3   4   5   6   7   8    
 15-17   -   -   -   -   1   1   2   3   4   5   6   7    
 18-20   -   -   -   -   -   1   1   2   3   4   5   6    
 21-23   -   -   -   -   -   -   1   1   2   3   4   5    
 24-26   -   -   -   -   -   -   -   1   1   2   3   4    
 27-29   -   -   -   -   -   -   -   -   1   1   2   3    
 30-32   -   -   -   -   -   -   -   -   -   1   1   2    
 33-35   -   -   -   -   -   -   -   -   -   -   1   1    
 36-38   -   -   -   -   -   -   -   -   -   -   -   1