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Pre-Dive Calculation Worksheet

Photocopy this page. Fill in one copy before each dive. Show it to your instructor.

Site & Dive Information

Site name: ________________________________

Date: ________________________________

Dive number (1 / 2 / 3): ________________________________

Expected bottom depth (d): ________________________________ (ft or m)

Selected sonar beam angle (θ): ________________________________ (7°, 20°, or 47°)

Acoustic Calculations (Dive 1)

Footprint diameter D = 2d tan(θ/2): ________________________________

Show your work:

Required lane spacing s = D × 0.70: ________________________________

Rounded lane spacing (round DOWN): ________________________________

Photogrammetric Calculations (Dive 2 or 3)

Camera air-rated half-FOV (α_air): ________________________________

Underwater half-FOV α_water = arcsin(sin(α_air)/1.33): ________________________________

Working distance from subject: ________________________________ (m)

Underwater frame width on subject (W): ________________________________ (m)

Required overlap (O): ________________________________ (0.80 typical)

Baseline B = W × (1−O): ________________________________ (m)

Planned swim speed (v): ________________________________ (0.3–0.5 m/s typical)

Shutter interval t = B/v: ________________________________ (seconds)

Intervalometer setting (round UP): ________________________________ (seconds)

Dive 2 — Orbit Specifics (if applicable)

Orbit radius (r): ________________________________

Angular spacing Δφ = B/r: ________________________________ (rad and degrees)

Frames per 360° = 360 / Δφ_degrees: ________________________________

Add 10% safety margin → plan ____ frames per orbit: ________________________________

Pre-Dive Safety Confirmation

EAN mix analyzed (%): ________________________________

Dive computer set for that mix? ________________________________ (yes / no)

Starting tank pressure: ________________________________

Turn pressure (1500 PSI): ________________________________ (confirm)

Surface pressure (700 PSI): ________________________________ (confirm)

Float and finger spool inspected: ________________________________ (yes / no)

Dive flag visible: ________________________________ (yes / no)

Surface watch in place: ________________________________ (yes / no)

Team role assigned (Photographer / Safety): ________________________________

Abort criteria stated and agreed: ________________________________ (yes / no)

Data and Reference Confirmation

Phone or tablet topside with Surface Data Operator: ________________________________ (yes / no)

App recording and GPS lock checked before data run: ________________________________ (yes / no)

Battery, power, and storage sufficient: ________________________________ (yes / no)

Raw-data backup location: ________________________________

Scale bar / known-distance reference in use: ________________________________ (yes / no)

Control points / checkpoints documented: ________________________________ (yes / no / N/A)

Environmental no-contact plan confirmed: ________________________________ (yes / no)

Instructor sign-off: _______________________________________________

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.