D&D Companion: The Encounter

"Part 5: The Encounter" should include rules for underwater movement and actions, including combat and spell casting.

Illustration by Jim Roslof

Underwater Encounter Distance

When determining encounter distances underwater, two factors need to be taken into account: sight and hearing.

Sighting enemies: To determine the distance at which approaching creatures are first seen, roll 3d6 and multiply by 10 to find the distance in feet.  If the number rolled exceeds the current visibility distance, the encountered creatures are seen only when they enter the range of visibility.

Hearing enemies: Underwater, sound carries farther than light.  It is quite likely that characters will hear approaching creatures before they actually see them, particularly when operating at great depths.  Assume that characters can detect approaching creatures out to a range of 180' (3d6 x 10') on a successful Hear Noise roll.

Underwater Combat

Unlike most normal fights, underwater combat almost always takes place in three dimensions.  Once the distance has been determined, the plane of attack needs to be considered.  This may involve attacks from above or below, as well as attacks from the back or sides, or even a combination of the two.  The diagram below is a handy way of determining the plane of attack:

The "0" represents the position of the adventurers.  To discover the height of the encounter and its direction relative to the adventurers, roll 1d8 and consult the diagram.  A roll of 1 = an attack directly from above; 2 = from behind and above; 3 = an attack from behind; 4 = from behind and below; 5 = an attack from below; 6 = from in front and below; 7 = from directly in front; 8 from in front and above.

Underwater Movement and Actions

A normal person cannot move or fight as well underwater as he can on land.  He is -4 to hit with any weapon such as a sword or axe.  Missile weapons are only -1 on hit rolls, but they have only half their normal range.

Underwater Spell Casting

It is impossible to speak clearly underwater.  Unless a cleric or magic-user has waterbreathing (either through the spell or a magic item), he cannot cast spells underwater.

Even if a cleric or magic-user can breathe underwater, some spells will have strange results or side effects underwater (as described in module X7 "The War Rafts of Kron")

Saving Throws: 

Expanded tables for higher level characters.

Combat Tables:

Expanded tables for higher level characters.

Missile Fire Ranges:

Reproduced with heavy crossbow and composite bows.

Variable Weapon Damage:

The Greyhawk supplement introduced variable weapon damage for both man-sized as well as larger opponents, which could be included as a way to differentiate between the new weapon options, instead of using the Weapon Mastery system from the D&D Master Set.

Unarmed Combat:

The Cook/Marsh Expert rulebook describes a simple approach to striking (characters who engage in combat without a weapon will do 1-2 points of damage plus any strength adjustments for a successful attack).

A method for grappling/wrestling may be derived from Gary Gygax's Combat Example from The Strategic Review #2.  (Revised approaches to both striking and wrestling are presented in the D&D Companion rulebook, for those preferring the BECMI approach.)

Jousting:

Rules for jousting in D&D based on the system in Chainmail were described by Jon Pickens in The Dragon #17 (August, 1978).  (A simpler system is described in the D&D Companion rulebook.)

Mass Land Combat:

The Cook/Marsh Expert rulebook suggests using the Swords & Spells supplement for large scale battles.  Gary Spiegle's War Machine rules* are better, although I would not feel the need to reproduce them.

*see also "War Machine revisited" in The Dragon #109 (May, 1986)

There are basic rules for sieges in Swords & Spells, based on Chainmail.  These appear to have been revised in the AD&D 1e Dungeon Masters Guide, although the Siege Machine rules in the D&D Master Set are more playable.