Artificial Gill Suit[1] Edit

A specialized form of breathing apparatus is called an artificial gill suit (AGS) or simply a “gillsuit”. Unlike a tank-style breathing apparatus that holds compressed air, or a backpack-worn "gillpack" that extracts oxygen from water , an AGS covers the wearer’s entire body. It is made of a material similar to that used in skeinsuits, and may be left transparent or colored as the manufacturer desires.

Much of the exterior of an AGS is covered by a series of microfilters, all made of tough, translucent, porous plastic. These micro-filters draw oxygen from the water, pumping the gas mixture through small tubes to the area of the body where the wearer inhales air. The waste gases produced are released directly from the suit.

AGSes for humans, yazirians, and vrusks conforms to their basic physical shape. An AGS designed for dralasites will stretch to accommodate their shape-changing abilities. A yazirian AGS covers the glide-wing membranes without hampering their use in swimming.

The whole system is regulated by a computer chip and powered by a small energy cell good for five hours before it needs to be recharged. An AGS also has a small digital display which can easily be seen by the wearer. The display shows the diver’s depth, time in the water, and the amount of power left in the suit’s energy cell. The suit also has a built-in low-frequency radio system, which has a range of one kilometer.

An AGS will absorb one-fourth of all damage caused by projectile and gyrojet weapons, fragmentation grenades, explosives, and melee weapons. It cannot be worn with any other suit of armor, but a modified defensive screen may be used with it (+100 Cr to the cost of the screen and powerpacks for waterproofing). When an AGS has taken 35 points of damage, it will be ruined and useless as armor.

Normal goggles may be worn with an AGS by human, vrusk, and yazirian divers. Due to the thermal properties of water, such goggles may not have infra-red capabilities.

A normal AGS weighs five kilograms and costs 800 Credits. If characters need to dive deeper than their safety limits (see below), they will have to use an AGS designed for greater depths (or a submarine).

Special AGSes must be used if the characters are going to dive in waters which contain dangerous chemicals or poison. These AGSes must be tailor-made for the body of water in which the characters are going to dive. Such suits cost an average of 1000 Credits.

If the characters dive in water with extremes in temperature, an AGS can be bought with a heating/cooling system. This system is powered by a small energy cell which works for four hours before needing a recharge. The system protects the character in water with temperatures ranging from -35 to 70 C. This modification costs 100 Credits extra and adds two kilograms of weight to the AGS.

Cost: 800 Cr (standard) / 1000 Cr (Deep/Contaminated water)
Mass: 5 kg
Heating/Cooling system: +100 Cr
Mass: +2 kg

Using an AGS[2][3] Edit

An AGS can be safely used at a maximum depth of 110 meters on Earth-like planets. If a deeper dive is attempted, there is a cumulative 5% chance per 10 meters below the safe limit that the AGS will malfunction.[4] This chance must be rolled for every five minutes, with an additional 1% chance of failure added for every additional five-minute period spent beyond the first.

The wearer will also take one point of damage for every 10 meters he dives past the maximum safe depth.[5] This damage will be taken every minute and is caused by increased pressure. Dralasites will not start taking pressure damage until they reach a depth of 160 meters, due to their elastic abilities.

There is also a 10% cumulative chance per 10 meters of depth beyond the maximum safe limit, that a human or yazirian character will have vivid hallucinations for five minutes as a result of nitrogen narcosis. [6]This chance is checked for every 10 minutes. A check against the character’s Logic score lets him disbelieve the hallucinations.

If an AGS malfunctions, the character wearing it must hold his breath until he can reach the water’s surface. A character can hold his breath for a number of turns equal to the character’s Stamina score divided by five.

If the character is still underwater after running out of breath, the character will take 2d10 damage for every turn spent under water until death occurs from drowning.

If a character dives deeper than 10 meters, the character must ascend slowly (at a rate of five meters per turn) or risk getting a case of the bends. Bends are caused by nitrogen bubbles forming in the bloodstream, due to the quick change in pressure.

This can cause intense pain, doing one point of damage per round until the character is placed in a freeze field or a decompression chamber to stop the loss of Stamina points. Freeze fields do not work underwater, so the character must be on the surface. The damage from decompression will never exceed 40 points, though death can still occur as a result of it.

There is a chance of dying as a result of the bends, independent of the amount of damage taken, as per the table below. Dralasites do not get the bends.

Rate of Ascent Chance to get the Bends

Chance of Death

6 m/t 10% 8%
7 m/t 40% 16%
8 m/t 60% 24%
9 m/t 80% 32%
10+ m/t 100% 40%

If death is indicated, it will occur in 10 minutes. During these 10 minutes, the character will lose one-tenth of his current hit point value (rounded up) every minute. This procedure can be stopped by a freeze field or a decompression chamber.

A character must stay in a decompression chamber for a number of minutes equal to the lowest depth in meters that the character reached. If a character dives below 60 meters, even if he did not contract the bends, he must spend some time in a decompression chamber. If the character does not do this, he will get a case of the bends as described above within 1d5 hours. Again, dralasite characters will never contract the bends due to their unique physiology.

Notes and References Edit

  1. First released in "Going for a Swim?", Dragon Magazine #110
  2. I used the depth numbers as given in the article, despite their being a bit off. Using real life dive safety tables, a normal AGS or gill pack would be safe to use up to about 66m. Below that depth, the risk of oxygen toxicity becomes too high. Compressed atmosphere divers working between 66 and ~100/m require the use of so-called "Tri-mix" breathing gasses (replacing Nitrogen with Helium). Anything deeper than that would require the use of an Atmospheric Diving Suit (essentially a hard-shell armored suit that avoids the issue by maintaining 1 standard atmosphere in pressure inside). ADSes have a maximum operating depth of roughly 610 meters (2000 feet).
  3. These rules should also apply to using any underwater breathing apparatus.
  4. The natural gravity of a planet will also affect the pressure at deeper depths. For every .1 less than 1g, the AGS is able to dive 10 meters deeper before a chance for malfunction occurs. The opposite is true if the gravity is greater than one.
  5. This amount should be modified as per the note regarding AGS malfunction. IE: add 10m for every .1 less than 1g, subtract 10m for every .1 more than 1g.
  6. again, modify as per above
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