Underwater Adventures

As all readers of fantasy know, the ocean floor is home to numerous ancient submarine civilizations and dark, green realms of creatures half-man and half-fish. Your players may have heard tales of the mountains of sunken loot that have been collected there over the centuries, of such things as pearls the size of a man's head, of beautiful mermaids with green eyes and blue skin. . . If they should find some way to investigate these stories, how will you handle it? This section deals with methods for conducting underwater scenarios.

BREATHING

The first major concern in underwater adventures is breathable air.

Magic-users have the advantage in this area, as they have access to several spells that can solve the problem of submarine respiration. These include water breathing (which is also a druidical spell), airy water, shape change, or even wish, which might be made to work for the whole party (illusionists would use alter reality). They can also polymorph others into forms that can breathe water. However, most non-magic-users will probably find the use of magic items or potions safer and more reliable. These include potions of water breathing or items like the helm of underwater action or the cloak of the manta ray (which help in movement as well as respiration). The DM may also find it expedient to create such things as "'air pills" or seaweed herbs that confer the temporary power to breathe water when ingested.

Most methods of underwater breathing are of limited duration, so most submarine adventures will be similar to dungeon adventures as regards time actually spent underwater. Players will have to get to their destination, accomplish their mission and return in a matter of turns, rather than days or weeks as in other outdoor adventures. If extended campaigns are desired, the DM will have to ensure that the players can acquire some sort of equipment or comestible that will allow them to stay underwater for an unlimited time.

Campaign Rule. Humanoids can hold their breath for the round they go under plus 1 segment per point of Constitution (10 segments for creatures with no listed score). This assumes strenuous activity, ie. melee combat. If not under duress, this time period is doubled: After the entry round, the humanoid can hold its breath for 1 round plus 2 segments per point of Constitution (20 segments for creatures with no listed score). Once the humanoid can no longer hold their breath, they will begin to asphyxiate, thrashing and drowning, for 3d6 segments. At the end of this time, they will die. If any cure spell is cast on the character within 5 rounds of death, the character will revive to the 1 hit point level. One breath of air taken, from a air bladder or other means, will enable a swimmer to remain underwater for another time period equal in segments to his or her Constitution score. An emptied water skin full of air provides 2 breaths and a specially-made air bladder holds three.

MOVEMENT

There are two possible modes of movement underwater: swimming and walking.

Swimming is not possible in any type of armor heavier than leather (except magic armor), or when encumbered with more than 20 pounds of equipment of any type (add or subtract 1 pound for each 100 g.p. worth of Strength bonus or penalty). Though submersion in water makes everything "weigh less" due to buoyancy, actual mass of equipment is unchanged, and the same density that causes the illusion of less weight also causes a resistance to movement that slows it down considerably. Therefore, movement (either swimming or walking) is the same as the speeds used in dungeons, even though underwater movement is "outdoors". Average movement is a function of encumbrance in exactly the same ratios as in dungeon movement.

Persons able to swim (due to lack of encumbrance, not innate natatorial ability) will be able to move vertically as well as horizontally, and at the same rate of speed. Remember that swimming persons are vulnerable to attack from every direction.

Characters encumbered with more than about 20 pounds of gear will be forced to walk on the floor of the ocean, lake, river, or whatever. They will have to negotiate underwater hills, coral outcroppings, shipwrecks, seaweed forests, etc., in the normal manner, i.e., they will have to go around or through them.

Characters equipped with a ring of free action or other magic item that confers the same power will be able to move normally and cover distance as if in the wilderness—that is, three times dungeon rate.

A4, In the Dungeons of the Slavelords, p.9. Swimming and Drowning: Unencumbered characters can swim underwater 100-ft per round (or 10 ten-foot squares on the detail map): in other words, 10-ft a segment. Encumbered characters (for example, any person holding anything in one of his or her hands) cut movement by 1/3. A character may remain underwater without drowning ("hold his breath") for a number of segments equal to his or her Constitution score. Thus, a character with a 16 Constitution could remain underwater for 16 segments and could swim 160-ft, or 16 squares. After 16 segments (in that character's case), the character would cease all activity and would begin to drown.Drowning takes 3-18 segments, and during this period the character can do nothing but writhe in panic, though it is possible he or she could be dragged to safety. Such a saved character will suffer hit points of damage equal to the number of segments spent drowning. If not brought to air before the segments of drowning are up, the character is dead. If any cure spell is cast on the character within 5 rounds of death, the character will revive to the 1 hit point level. One breath of air taken, for example, from a sealed scroll case or worm tube (see below), will enable a swimmer to remain underwater for another time period equal in segments to his or her Constitution score.

Wilderness Survival Guide. p.43. Holding One's Breath. The base amount of time that a character can hold his breath underwater is a number of rounds equal to ½ of his Constitution score (rounded up). This assumes that the character has a chance to take a deep breath before submerging and does not perform any strenuous physical activity while he is underwater.Normal movement (underwater swimming, diving, or surfacing) is allowed; so are activities such as opening a locked chest, searching for a secret passage, or casting a spell (if being underwater does not prohibit the casting to begin with).If the character did not have a chance to fill his lungs with air before going under, the time he can hold his breath is cut in half (rounded up). If he engages in strenuous activity (such as combat), the time is also cut in half. These penalties are cumulative with each other, so that a character who is abruptly dumped into the water and then forced to fight can only hold his breath for one-fourth as long as he could under more favorable circumstances.Any character is able to hold his breath for at least one round, regardless of the effect of these penalties.When the time limit for holding one's breath expires, the character does not automatically expire as well. He can stay alive as long as he makes a successful Constitution Check once per round; each check after the first is made with a cumulative +2 modifier to the die roll. For example, a character with a Constitution of 12 can hold his breath underwater for 4 rounds under the most favorable circumstances. After 4 rounds, he has run out of air but can still survive. If he makes a Constitution Check at the end of the 5th round, he is alive and can still be pulled to the surface. At the end of the 6th round, the check is made with a +2 modifier to the die roll; at the end of the 7th round, the modifier is +4, and so on.A character who has not run out of air can get to the surface either by swimming (if he has proficiency) or by remaining still and allowing his body's natural buoyancy to carry him upward (the only way that a non-swimmer can surface). Such a character is in control of his faculties and is able (for instance) to divest himself of extra weight to bring himself to the surface more quickly. When a character runs out of air, he is unconscious and cannot move under his own power. To survive, he must be pulled or otherwise moved up to the surface before he fails a Constitution Check.

C2, Ghost Tower of Inverness, p15. Every character who falls into deep water will be able to "tread water" for 2-7 (d6 + 1) rounds before becoming exhausted and drowning. This base number of rounds is modified by exceptional characteristics:— Strength: +½ round per point above 16; -½ round per point below 5— Constitution: +½ round per point above 16; -½ round per point below 5If a character has not begun to swim freely (unencumbered by heavy items or non-magical armor) by the time indicated, that character is considered to be unconscious and can no longer attempt to remove encumbering items. In three more rounds, that character will have drowned. If the base roll plus modifiers indicates a time which includes ½ of a round, round up and assume a 50% chance of lapsing into unconsciousness during the last round.The base time to remove armor and possessions while "treading water" is given by the table below:

general possessionsleatherstuddedringscale

1 round1 round1 round2-3 rounds2-3 rounds

chainpaddedplatebandedsplint

2-4 rounds2-4 rounds4 rounds4-6 rounds4-6 rounds

The base time is modified by Dexterity as follows:-½ round per point of Dexterity over 16+½ round per point of Dexterity under 5If a character is removed from the water unconscious, a cure light wounds spell will awaken him or her and cure any ill effects from swallowing water, etc. However, if used in this way, the spell will not restore any lost hit points.

VISION

Distance of vision will vary according to depth (available light) and obscuring objects.

Basically, characters will be able to see objects and movement up to 50-ft away in fresh water and 100-ft away in salt water.

The depth limit of vision is the same as the distance limit: characters can see until they go below 50-ft in fresh or 100-ft in salt water. Below this depth vision will be obscured. You may wish to vary the distance as a function of depth to make this slightly more accurate, so that characters in fresh water could see 50-ft at a depth of 10-ft, 40ft at a depth of 20-ft, and so on in segments of 10-ft until vision is 0-ft at 60-ft of depth.

The same formula would apply to salt water, starting with 100-ft of distance at 10-ft of depth.

Use of a light spell would allow vision up to 30-ft distance regardless of depth, or add 10-ft of vision to any distance shorter than 60-ft (whichever is greater).

The visual capability of a helm of underwater action will quintuple normal vision as pertains to both distance and depth.

Infravision and ultravision are useful underwater, and their distance limits are the same as in dungeon settings.

There are some problems, however: infravision users may become confused due to shifting currents and layers of different-temperatured water, as water exchanges heat more slowly than air and therefore is of a less even temperature.

Distance of ultravision is halved at 100-ft depth and reduced to zero below 200-ft, as ultraviolet "light" does not penetrate beyond that depth in sufficient quantities for sight.

Other objects will also obscure vision. Seaweed or sea grass will reduce vision to 10-ft or perhaps nil for those within it, depending on its density. Sea grass can be anywhere from 3-ft to 30-ft in height, while seaweed can take practically any size or shape the DM desires. In any case, shoals of either will totally obstruct vision, and anything may be hiding within! Schools of fish can also blind and confuse with their masses and quick movements.

Mud can also be a big problem, especially as pertains to combat on the bottom, where violent movement may kick it up in great clouds, totally blocking vision as long as the movement lasts and for 7-12 (d6 + 6) rounds afterwards, unless there is a current to carry it away. Even light sources cannot penetrate the muddiest water.

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