These are specialised weapons for use underwater; many of the standard weapons described above may be adapted to underwater use or even used as they come. As a rule, these weapons will be unavailable on any world with no atmosphere or a hydrographics percentage less than 20%.
Bangstick 18mm
Weight 250g. Length 1000mm. A short pole tipped with an explosive cartridge (usually an 18mm shotgun load), used to discourage (generally in a fatal fashion) underwater predators. Use of the bangstick requires a fencer's thrust to set off the charge against the hide of the predator. Each stick is good for one attack before reloading which takes one combat round.
Electric
Prod
Weight 250g; batteries 25g. Length 500mm. A hand weapon which delivers a powerful charge of electricity when brought into contact with a target. Used to ward off large predators, the electric prod is a pole with batteries in the hand grip which discharges when touched against a target. It is easier to use than a bangstick since only a touch is needed, and the prod doesn't do physical damage to the target which could draw other predators. Unlike most underwater weapons, the electric prod is just as effective against land animals. The batteries are good for 10 discharges, cost Cr10 and take one combat round to change.
Gas
Speargun 10mm
Weight 1000g; spear 250g. Length 500mm; spear adds 200mm. An undersea weapon using compressed air or CO2 gas to fire a spear, the gas speargun is first available at TL 6. Reloading takes one round; changing the gas cartridge (good for five spears) takes three rounds.
Sling
Speargun 10mm
Weight 500g; spear 300g. Length 1500mm; spear 600mm. Similar in principle to a crossbow (q.v.) the sling speargun is a slightly longer-ranged underwater weapon than the hand spear. Available from TL 5, it consists of a tube, a rubber or elastic sling, a trigger mechanism and the spear itself.