Tick 10 — 2026-05-22 05:46 UTC

Thread: R11 (maritime / through-bulkhead sensing) Verdict: Physics scrutiny re-frames "through-bulkhead" to "through-seam" — the romantic submarine-radar vision is impossible at WiFi bands; the actual product category is gasket-leakage sensing.

What shipped

• examples/research-sota/r11_maritime_propagation.py — pure-numpy skin-depth + lossy-dielectric saltwater + slot-diffraction physics for 7 maritime scenarios.
• examples/research-sota/r11_maritime_results.json — machine-readable predictions.
• docs/research/sota-2026-05-22/R11-maritime-sensing.md — research note with the physics, verdicts table, feasible/infeasible verticals, honest scope, composition with prior threads.

Headline (verdict table)

Scenario	Verdict	Margin
Man-overboard surface @ 200 m	✅	+25 dB
Through 10 mm closed steel door	❌	-938 dB
Through cabin door 2 mm seam	✅	+31 dB
Through cabin door 5 mm seam	✅	+39 dB
Container w/ 30 mm vent slot	✅	+45 dB
Submarine 30 mm pressure hull	❌	-929 dB
Head 30 cm underwater	❌	-231 dB

Key physics: steel skin depth = 3.25 µm at 2.4 GHz (impassable). Saltwater = 853 dB/m. The loophole is slot diffraction through gasket seams.

Feasible verticals catalogued

1. Man-overboard surface detection (200 m range)
2. Through-seam crew vitals (lone-watch monitoring without compromise)
3. Container tamper detection (cargo security)
4. Hatch-seal integrity audit (predictive maintenance)
5. Engine room thermal-anomaly detection (via condensation envelope)

What this matters for the loop

R11 is the first thread that explicitly debunks a romantic 10-20y framing. The "through-bulkhead" terminology used in the original PROGRESS.md is physically wrong; the actual category is "through-seam". Replacing one vision with a more honest one is the kind of progress this loop is meant to surface.

Composes cleanly:

• R6 Fresnel envelope + slot diffraction = narrower composite envelope
• R10 link-budget primitives reused unmodified for air-side maritime
• R7 multi-link consistency essential for adversarial-resistant maritime
• R14 privacy framework transfers directly to crew-cabin monitoring

Honest scope landed

• Best-case ignores vessel vibration, engine ignition noise, salt-spray, multipath
• Vibration (5-30 Hz) is in-band with R10's gait frequencies — maritime gait-classification harder than land
• No GPS in steel compartments — alternative positioning needed

Coordination

ticks/tick-10.md. No PROGRESS.md edit. Branch research/sota-r11-maritime.

Remaining threads

R3 (cross-room re-ID), R4 (federated), R13 (contactless BP — likely negative-result candidate), R15 (RF biometric).

~6.3h to cron stop. 10 threads landed.