A friend of mine posted a picture of a Carmagnolle diving suit (c. 1880), and there's no way that it isn't actually a golem. So I created Chimera stats, like one does:
Golem, Diving (construct)
Lvl 3; MR 0" (10" submerged); WL 4 (M); DF 4 (+1); AT 2 claws (1d8), 1 ink cloud (see below); AB Athletics, Engineer (maritime equipment and vessels only), Sense; SP Alert, Fearless, Grip (1d8), Immune (see below), Night Vision, Resistant (edged, piercing), Unstoppable
The diving golem is a construct designed for use on the sea floor, employed to protect divers and aquatic explorers, perform underwater repair work on docked ships, or carry out salvage detail on sunken vessels. Like all constructs, the diving golem is immune to poison, disease, fatigue, called shots, and enchantment powers. Immobile on land, the golem is activated via an intricate mechanism on its back (-1 to reprogramming attempts). Once submerged, the diving golem sinks to the seabed where it may move and act freely, returning only after its task is complete or if someone it's supposed to protect must be returned topside. As the golem moves about underwater, it surrounds itself with a bubble of breathable air (treat as the 3rd-level endure power in a small blast template centred on the golem); there is sufficient air for one person to breathe for one hour (half-hour for two people, 20 minutes for three people, etc.). A pair of articulated, pincer-like claws allows the golem to perform engineering work and to defend itself; on an attack roll of 13+, the golem may grip its foe to cause damage each subsequent turn. Its field of vision is a full 180 degrees, and it cannot be surprised by anything that approaches from the front, either above or below. The golem may also release an ink cloud (treat as the 1st-level obscure power) to confuse foes or mask the presence of itself or those it's protecting.
If you're looking to introduce this into your setting, I'd recommend the diving golem as a tech level 6 automaton, in the steam-punk vein, though anything earlier than that could certainly be the result of magic.
