If the combatant is engaged in melee while immersed, that is standing in water that is above half-way up the character's calves, then both movement and the combatant's attack dice will be affected.
Penalties are adjusted at five points up the body: at the knees (mid-calf to knee-cap), at the hips (thigh to groin), at the torso (across the belly), at the chest (above the belly to the arm pits) and at the neck (submerged shoulders and up). In each case, use what seems the best description of the water surface as compared to the body. If the surface is below the level of the eyes, enabling the combatant to see, treat this as the neck. Immersion above the level of the eyes (and above the ability to push off the ground to temporarily gain vision), should be treated as submerged.
Adjustments to MovementAs parts of the body are immersed, a certain amount of the body becomes buoyant; additionally, movement through the water becomes a matter of pushing an additional weight of water in order to thrust the body forward, thus increasing the expenditure of action points (AP) for the combatant.
In the interest of establishing a universal impact on creatures of all sizes, movement through water (or thicker liquid) will be treated as an increase in encumbrance ~ or rather, a decrease in the base mass of the combatant due to buoyancy. Whether or not this is scientifically true (and I don't know that it is), the overall effect should be that the combatant's number of AP should fall as the combatant's immersion is increased.
This will mean that the character's encumbrance must be recalculated when entering the water for a loss in weight; it will also mean that the character's movement can be restored somewhat by dropping equipment once entering water. Below is given the amount of mass lost at each point of immersion, for this calculation:
- Knees = 10% loss.
- Hips = 25% loss.
- Torso = 50% loss.
- Chest = 80% loss.
- Neck = 90% loss.
Note that the above movement can be counteracted while swimming; however, when swimming the character should treat their effective encumbrance mass at 5%, if they do not wish to sink or drown.
If the character is immersed in something thicker than water, then compare the specific gravity of the liquid with water and increase the loss of body mass by that degree. For example, quicksand has a specific gravity of 1.156, or 15.6% higher than water. This would mean that a character immersed to their belly would lose 57.5% of their body mass for encumbrance purposes, not 50%.
If, then, encumbrance was so much that the character had no AP on account of it, the character would drown in quicksand in a completely helpless manner. As well, if the character could not effectively unload their gear, due to their lack of AP, in order to reach an edge, while sinking steadily 1 foot per round, the character would again succumb.
Adjustments to Attack DieIf the combatant is fully submerged, the adjustment to attack dice is -8. Therefore, the effects of immersion are staggered to compare with this extreme. Attacks performed while sunk to the knees are done at -1; at the hips, -2; at the torso, -4; at the chest, -6; and at the neck, -7.