THERMOCLINE

You have no windows. Everything you know about the ocean arrives as a smear of noise on a paper roll, and everything the ocean knows about you, you gave away yourself.

How it works.

1. Trim the boat. Below about 5 knots the dive planes do nothing. Depth is held with water, not with steering — flood to get heavy, pump to get light. You get heavier as you go deeper, and lighter when you cross into the cold water under the layer.
2. Spend silence carefully. Speed is noise, and cavitation is a scream. The shallower you are, the slower you cavitate. Pumping ballast is a transient anyone can hear.
3. Use the layer. Sound is trapped on the side of the thermocline it starts on. Sit under it and the surface world goes quiet — including the escort's sonar looking for you.
4. Solve the triangle. Bearings alone will never give you range. Steer a new leg, gather more bearings, and fit range, course and speed until the residuals go flat.

Keyboard — space hold/run · 1 2 3 time rate · ←/→ steer 10° · ↑/↓ ordered depth · f/p flood/pump · n next track