380 m – 420 m · contested

The Brassgate

A contested-zone meeting station at ADS depth, maintained jointly by the Conservancy, the Tyrian Court, and the Pearled Council as the formal point of inter-faction contact.

I have not been seconded to a Brassgate session and may not be. The entry is a description of a structure I have read about in two Conservancy briefings and seen, once, in approach, from an ADS sortie that did not dock. I include it in the chapter because the working country includes the protocols it does not quite admit me to.

The Brassgate is a protocol, given a location. Between three hundred eighty and four hundred twenty metres, in a depth band where humans can arrive only by ADS and Pelagines can ascend only briefly and at physiological cost, the three principal parties to the current contact agreements maintain a shared structure. It is not a town. No one lives here for long. It is the place where the parties meet when they must, and where the agreements governing meeting are themselves renegotiated.

The structure

A central pressure hull with three separately keyed access collars — one sized for human ADS suits, two for Pelagine ingress at the dimensions documented in the second-contact protocols. Internal atmosphere is maintained at a compromise pressure that satisfies neither party's physiology fully: humans operate at depth-equivalent saturation conditions; Pelagines are at the high end of their comfortable ascent range. Encounters are brief by necessity, formal by convention.

Why here

Because this depth is the only one at which unmediated contact is possible. Above three hundred metres, the physiological cost to Pelagine visitors becomes unsustainable for sessions of any duration. Below five hundred metres, the human side has no working tool except a sealed ADS suit, which makes the kind of direct exchange the Brassgate is designed for impractical. The depth is not negotiated; it is calculated.

What happens here

Formal delegations. Instrument calibrations. The occasional dispute resolved under the standing arbitration clause. Nothing informal. The Tyrian Court and the Pearled Council have, on record, met here in sessions with no human representative present, using the human access collar as a neutral waiting room while the other two collars were in simultaneous use. Whether this is anomalous is not established.

The depth is calculated, not negotiated. That sentence is the first thing I learned about the place that felt true on its own terms.