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Quick Reference Card

Formulas

Formula Use
D = 2d tan(θ/2) Sonar footprint diameter
s = D × (1 − overlap) Lane spacing for required overlap
B = W × (1 − O) Photogrammetric baseline
Δφ = B / r Angular baseline for orbit
t = B / v Shutter interval from baseline
α_water = arcsin(sin(α_air)/1.33) Underwater half-FOV through flat port
θ_c ≈ 48.8° Critical angle (max underwater half-FOV, flat port)

Gas Limits

  • Turn pressure: 1500 PSI

  • Surface pressure: 700 PSI

  • Mandatory 3-minute safety stop at 15 ft on every dive

Depth Limits

  • Dive 1: 20 ft minimum, 60 ft maximum

  • Dive 2: 20 ft minimum, 60 ft maximum

  • Dive 3: 20 ft minimum, 45 ft maximum

Abort Criteria

  • Lost visual contact with teammate for more than 1 minute

  • Lost float at surface or GPS lock

  • Reached turn pressure

  • Surface conditions deteriorating

  • Equipment failure on sonar, camera, or BCD

  • Any unease about continuing

Data Abort Criteria

  • GPS lock lost or float repeatedly submerged

  • App recording stopped or file cannot be verified

  • Coverage gap larger than one planned lane spacing in the target area

  • Scale reference missing for a scaled photogrammetric model

  • Task fixation causing missed gas, depth, NDL, buoyancy, or team checks

Generated from the Reef Cartographer Student Handbook, version 05.008. The course documents are the authority; if these pages and they ever disagree, the documents are right.