BD Deck Officer Class 3 (OOW) cheat sheet

Great-circle distance: cos D = sin φ1·sin φ2 + cos φ1·cos φ2·cos Δλ; distance in nautical miles = D° × 60.

Mercator sailing: departure = d.long × cos mean latitude; use for short legs where rhumb line is acceptable.

Plane sailing approximation valid only for distances under about 600 nm and low latitudes.

Speed–time–distance: distance (nm) = speed (kn) × time (h); 1 knot = 1 nm/h = 1852 m/h.

Current triangle: set is the direction the current flows toward; drift is its speed in knots.

Radar range in nautical miles: R = 1.23 × √(antenna height in metres) + 1.23 × √(target height in metres).

True bearing = relative bearing + ship's heading (add 360° if negative; subtract 360° if over 360°).

Course to steer to counteract current: apply current vector opposite to drift direction over run time, then re-solve for speed made good.

Buys Ballot's law (Northern Hemisphere): with back to wind, low pressure lies to the left; reverse in the Southern Hemisphere.

Standard atmosphere: 1013.25 hPa at MSL, temperature 15 °C, lapse rate 1.98 °C per 1000 ft up to tropopause.

Pressure tendency falling more than 1.6 hPa in 3 h indicates a rapidly deepening system approaching.

Beaufort 8 = fresh gale, 34–40 kn; Beaufort 10 = storm, 48–55 kn; Beaufort 12 = hurricane, 64 kn and above.

Fog forms when air is cooled to its dew point: radiation fog overnight over land, advection fog over cold sea areas.

In the Northern Hemisphere, tropical revolving storms recurve poleward and are deflected right of their track; the dangerous semicircle is the right-hand side.

Swell travels beyond the generating wind area; its direction indicates the origin of the weather system.

Isobars closer together indicate a stronger pressure gradient and higher wind speed; wind crosses isobars at roughly 10–30° over the sea.

GM = KM − KG; positive GM gives a righting moment, negative GM means initial instability.

Righting lever GZ = GM × sin θ (valid for small angles, typically up to 10–15°).

Free surface effect reduces effective GM by FSC = (i × ρ)/(Δ), where i is the second moment of area of the free surface.

Archimedes: displacement (t) = L × B × d × Cb × 1.025 for salt water at that draught.

TPC = (WPA × ρ)/100, where WPA is waterplane area in m² and ρ in t/m³.

MCTC = (W × GM_L)/(100 × L), where GM_L is the longitudinal metacentric height.

Angle of loll: ship with negative GM rolls to an angle where GZ = 0; correct by lowering G or adding ballast to reduce KG.

Load line marks: S = summer, W = winter, T = tropical, F = fresh water, TF = tropical fresh water; freeboard increases from S to T.

Stowage factor (m³/t) = volume occupied per tonne; breaks bulk cargo down into heavy (low SF) and light (high SF) grades.

Broken stowage = (volume of hold − volume occupied by cargo)/volume of hold, expressed as a percentage.

IMDG segregation codes: 1 = away from, 2 = separated from, 3 = separated by one compartment, 4 = separated by two compartments, X = no general segregation.

Draft survey: displacement is corrected for density, trim, and deflection; deduct deductibles to obtain cargo weight.

Hatch cover weathertightness is tested by ultrasonic or hose test; chalk test detects contact only, not tightness.

Cargo sweat and ship sweat: ventilation with dew-point comparison prevents condensation on cargo or structure.

Timber deck cargo requires lashings and a stowage factor check; it raises KG and reduces GM.

Dangerous goods in port must comply with the IMDG Code and the port authority's local regulations.

STCW rest hours: minimum 10 h rest in any 24 h and 77 h in any 7 days; rest may be split into no more than two periods, one at least 6 h.

Muster list must assign each crew member a station and duty; it is posted in conspicuous locations.

Permit-to-work systems apply to enclosed spaces, hot work, and working aloft.

Enclosed space entry requires atmosphere testing for oxygen (20.9% normal, entry minimum 20%), hydrocarbons, and toxic gases before and during entry.

Toolbox talk precedes non-routine tasks and records hazards, controls, and personnel involved.

Near-miss reporting is a leading indicator; the safety management system requires investigation and corrective action.

Fatigue risk is managed by watch scheduling, minimum manning, and documented hours of rest records.

Shipboard drills: abandon ship and fire drills monthly; enclosed space rescue drills every two months per SOLAS III/19.

Rule 5: proper lookout by sight and hearing and by all available means at all times.

Rule 6: safe speed depends on visibility, traffic density, manoeuvrability, background light, and state of the sea.

Rule 13: overtaking vessel keeps clear until finally past and clear; any doubt means overtaking.

Rule 14: head-on meeting - both alter course to starboard and pass port-to-port.

Rule 15: crossing - the vessel with the other on her starboard side gives way.

Rule 19: in restricted visibility, reduce speed to minimum steerage way and avoid altering course to port for a vessel forward of the beam.

Rule 7: risk of collision exists if the compass bearing of an approaching vessel does not appreciably change.

Rule 10: traffic separation scheme - cross on a heading at right angles to the general direction of traffic flow.

Two-stroke slow-speed diesel: scavenge air enters via ports, exhaust via a central valve; power stroke every revolution.

Four-stroke medium-speed diesel: one power stroke per two revolutions; separate inlet and exhaust valves.

Indicator diagram shows compression, combustion, expansion, and exhaust phases; area represents indicated work.

Fuel oil viscosity is controlled by heating to the injector's specified range, typically 10–15 cSt for residual fuels.

Turbocharger uses exhaust gas energy to drive a compressor, increasing scavenge air density.

Oily water separator alarm limit is 15 ppm; discharge overboard is prohibited in special areas.

Steering gear: SOLAS requires main and auxiliary gear capable of putting the rudder from 35° one side to 35° the other in 28 s at full speed.

Bilge system: branch lines lead to a main line and bilge pump; non-return valves prevent flooding through the system.

MARPOL Annex I: oily water discharge permitted only under 15 ppm with an oil filtering and monitoring system outside special areas.

MARPOL Annex II: noxious liquid substances categorised X, Y, Z, OS; discharge rules depend on category and area.

MARPOL Annex IV: sewage discharge beyond 12 nm from land, or treated effluent beyond 3 nm.

MARPOL Annex V: garbage discharge prohibited within 3 nm; food waste comminuted beyond 3 nm, and outside special areas beyond 12 nm.

MARPOL Annex VI: sulphur limit 0.50% globally, 0.10% in ECAs; ECA areas include the Baltic, North Sea, North America, and US Caribbean.

Annex VI NOx Tier III applies to new ships in NOx ECAs; Tier II applies elsewhere.

Ballast Water Management Convention: D-1 exchange (at least 200 nm from land and 200 m deep) or D-2 treatment standard.

Oil Record Book Part I entries must be made for every ballasting, transfer, and discharge operation and signed by the officer in charge.

SOLAS Chapter I: applies to ships on international voyages; certificates issued under flag State authority.

MARPOL: 6 annexes, entry into force depends on ratification thresholds; Annexes I and II mandatory.

STCW: sets minimum standards for certification, watchkeeping, and rest hours; certificates of competency and endorsements.

COLREG 1972: 38 rules in five parts plus four annexes on lights, shapes, and signals.

UNCLOS: territorial sea 12 nm, contiguous zone 24 nm, exclusive economic zone 200 nm, and continental shelf.

LLMC and CLC: limitation of liability and civil liability for oil pollution damage; compulsory insurance certificates.

Hague-Visby Rules: carrier duties of seaworthiness, care of cargo, and the nautical fault exception.

MLC 2006: minimum living and working standards, including accommodation, wages, and repatriation.

GMDSS sea areas: A1 within VHF DSC range, A2 within MF DSC range, A3 within Inmarsat coverage, A4 outside all.

DSC distress alert: VHF Channel 70 or MF/HF 2187.5 kHz; follow with voice on Channel 16 or 2182 kHz.

Distress frequencies: VHF 16, MF 2182 kHz, HF 4125/6215/8291/12290/16420 kHz.

EPIRB: 406 MHz Cospas-Sarsat; float-free mounting; registration with the flag State required.

SART: 9 GHz radar transponder; range about 5–8 nm from a ship's radar; 12 dots on the radar display.

NAVTEX: 518 kHz international, 490 kHz national, 4209.5 kHz HF; message types A–Z with priority categories.

GMDSS watchkeeping: continuous DSC watch on VHF 70 and MF 2187.5, plus NAVTEX and SafetyNET/Inmarsat.

False distress alerts must be cancelled by DSC or voice and reported to the coast station or RCC.

Fire triangle: fuel, oxygen, and heat; extinguishing removes one leg; chemical chain reaction is addressed by dry powder.

Fire classes: A solid, B liquid, C gas, D metal, E electrical, F cooking oil; water is unsuitable for B, C, E, and F.

CO2 extinguisher: black label; safe for electrical fires; asphyxiation and static discharge risks in confined spaces.

Abandon ship: distress signal, muster at station, launch lifeboat with sea painter, clear the ship's side.

Man overboard: hard a-starboard (or as appropriate), release lifebuoy with light and smoke, post lookout, and manoeuvre.

SOLAS lifeboat capacity and davit requirements; lifeboat drills monthly, mustering within 5 minutes of the alarm.

Emergency generator must be capable of starting and supplying emergency loads within 45 seconds.

Fire main pressure and hydrant locations must be shown on the fire control plan; the plan is posted at the gangway and in accommodation.

Primary survey: danger, response, airway, breathing, circulation (DRABC); call for help and start CPR if unresponsive and not breathing.

CPR: 30 compressions to 2 ventilations, rate 100–120 per minute, depth 5–6 cm; use AED as soon as available.

Recovery position for an unconscious but breathing casualty; monitor airway continuously.

Hypothermia: handle gently, remove from cold, insulate, and avoid rapid rewarming; do not give alcohol.

Drowning: rescue breathing is the priority; start CPR with ventilations before compressions.

Severe bleeding: direct pressure, elevate, and use a tourniquet as a last resort; record the time applied.

Burns: cool with running water for at least 20 minutes, cover with sterile non-adherent dressing, and do not remove adhered clothing.

Seasickness and dehydration: oral rehydration salts; monitor for signs of shock.