Iran Deck Officer (STCW II/2) Certificate of Competency Examination cheat sheet

Great-circle distance: d = R * arccos(sin φ1 sin φ2 + cos φ1 cos φ2 cos Δλ), R = 6371 km or 3440.065 NM.

Initial great-circle course: C = atan2(sin Δλ cos φ2, cos φ1 sin φ2 − sin φ1 cos φ2 cos Δλ).

Mercator sailing: DMP = 7915.7 * log10(tan(45° + φ/2)) minutes; course angle C = atan(Dep / DMP).

Plane sailing for short distances: Departure = Distance * sin Course; Difference of Latitude = Distance * cos Course.

Current vector: set = direction toward which current flows (true); drift = speed in knots.

Tidal height at time t: use standard port height differences and tidal curves; rule of twelfths for approximate rise/fall.

Radar plotting: relative motion triangle; OAW = own ship course/speed, WA = target relative track, OW = target true course/speed.

CPA and TCPA from relative plot: CPA = perpendicular distance from origin to relative track; TCPA = along-track distance to CPA / relative speed.

Stowage factor (SF) = volume per unit weight (m³/t or ft³/t); broken stowage = lost space, typically 10–15% for general cargo.

Cargo deadweight = deadweight − bunkers − fresh water − stores − constant; use for maximum cargo intake.

Draft survey: cargo weight = (displacement after − displacement before) corrected for density, trim, and deductibles.

IMDG segregation table: '1' away from, '2' separated from, '3' separated by one compartment or hold, '4' separated by two compartments or hold, 'X' see segregation flowchart.

Dangerous goods stowage: Class 1 explosives require magazine stowage; Class 7 radioactive material requires separation and dose-rate limits.

Grain stability: angle of heel from grain shift = (total grain heeling moment / displacement) * 12 degrees (approx.); must not exceed 12° or deck edge immersion.

Container lashing: calculate forces from stack weight, wind, and ship motion; use manufacturer's lashing plan and CSS Code.

Ventilation: dew point rule - ventilate if cargo sweat risk (outside dew point lower than cargo dew point) to avoid condensation.

GM = KM − KG; positive GM = stable, negative GM = unstable (loll).

GZ curve: area under curve to 30° ≥ 0.055 m·rad, to 40° ≥ 0.09 m·rad, to 40° or downflooding ≥ 0.03 m·rad (IS Code 2008).

Angle of loll: GM = 0; ship lists to either side; correct by lowering KG (ballast bottom tanks) before adding weight.

Free surface effect: FSC = (i * ρ) / (Δ) where i = second moment of tank free surface; reduces effective GM.

Trim: change of trim = (weight × distance from FP or AP) / MCTC; final drafts from LCF position.

Load line marks: S, W, T, F, TF, FWA; assign fresh water allowance = Δ / (4 × TPC) (mm).

Bulkhead and double bottom: collision bulkhead located at least 0.05L or 10 m (whichever less) from FP, not more than 0.08L or 0.05L+3 m.

Panting and pounding: panting arrangements (stringers, frames) forward; pounding reinforcement in fore peak bottom.

Two-stroke diesel: scavenge air, uniflow scavenging, exhaust valve; firing order and timing; indicator diagram for power balance.

Fuel oil viscosity: HFO heated to 10–15 cSt at injection; viscosity controller set point typically 12–15 cSt.

Boiler: safety valve set at 1.1 × design pressure; water level low-low trip; feed water treatment for scale and corrosion.

Pump types: centrifugal for large volumes/low head; positive displacement for high pressure; NPSH must exceed vapour pressure.

Steering gear: SOLAS requires main and auxiliary; main steering gear capable of 35° port/starboard in 28 s at full speed; testing before departure.

Oily water separator: 15 ppm alarm and automatic stopping device; discharge overboard only with approval and oil record book entry.

Inert gas system: oxygen content < 8% in cargo tanks; deck water seal and non-return valve; pressure 200 mm water column.

UMS alarms: dead man alarm, fire detection, bilge high level, and machinery alarms to bridge and engineer's cabin.

Beaufort scale: force 0 calm (<1 kn), 5 fresh breeze (17–21 kn), 8 gale (34–40 kn), 10 storm (48–55 kn), 12 hurricane (≥64 kn).

Buys Ballot's law: in Northern Hemisphere, stand with back to wind - low pressure is to your left; Southern Hemisphere reversed.

Tropical revolving storm: avoid the dangerous semicircle (right in N Hemisphere, left in S Hemisphere); navigate to safe semicircle.

Fog formation: radiation fog over land at night; advection fog when warm moist air moves over cold sea.

Sea state: significant wave height = average of highest one-third of waves; swell direction independent of local wind.

Ocean currents: Gulf Stream, Kuroshio, Agulhas; use pilot charts and current atlases for route planning.

Weather routing: use synoptic charts, 500 hPa charts, and wave forecasts; avoid heavy weather damage and parametric rolling.

Ice: icebergs drift with current; ice accretion from freezing spray raises KG and reduces stability.

ECDIS: safety contour, safety depth, route monitoring, and alarms; must not be relied upon solely for navigation.

Radar: X-band (9 GHz) for high resolution; S-band (3 GHz) for rain penetration; range scale and sea/rain clutter adjustments.

AIS: Class A mandatory for SOLAS ships; provides MMSI, course over ground, speed over ground, and navigational status.

Gyrocompass error: check by azimuth of sun or terrestrial bearings; repeaters aligned to master.

Automatic Identification System (AIS) data: not to be used for collision avoidance alone; use radar and visual lookout.

Watchkeeping: STCW rest hours - minimum 10 hours rest in any 24-hour period and 77 hours in any 7-day period.

Bridge resource management: challenge and response, closed-loop communication, and prioritisation of tasks.

Echo sounder and speed log: check against charted depths and GPS; speed log calibration.

Rule 5: proper lookout by sight and hearing and all available means; no relaxation.

Rule 6: safe speed - consider visibility, traffic density, manoeuvrability, background lights, and state of sea.

Rule 13: overtaking vessel keeps out of the way until finally past and clear; any doubt = overtaking.

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

Rule 15: crossing - vessel with other on her starboard side gives way; avoid crossing ahead.

Rule 19: restricted visibility - reduce speed, sound fog signals, and if risk of collision, take avoiding action; no right of way.

Rule 8: action to avoid collision must be positive, made in ample time, and large enough to be readily apparent.

Rule 10: traffic separation schemes - cross at right angles, avoid entering separation zone, and keep clear of inshore traffic zone.

SOLAS: minimum safety standards for construction, fire protection, life-saving appliances, and radio communications.

MARPOL Annex I: oil pollution prevention; Annex II: noxious liquid substances; Annex III: harmful substances in packaged form; Annex IV: sewage; Annex V: garbage; Annex VI: air pollution.

STCW: certification, watchkeeping, and rest hours; 2010 Manila Amendments.

MLC 2006: seafarers' working and living conditions; minimum age 16; hours of work and rest; repatriation.

COLREG: Convention on the International Regulations for Preventing Collisions at Sea, 1972.

Flag State: jurisdiction over ships registered; Port State Control inspections under regional MOUs.

ISM Code: safety management system, designated person ashore, emergency preparedness.

Bunker Convention: strict liability for oil pollution from bunkers; certificate of insurance required.

SMCP: Standard Marine Communication Phrases - use for safety communications; avoid colloquial language.

Distress: MAYDAY (spoken), repeated three times; urgency: PAN PAN; safety: SÉCURITÉ.

GMDSS: DSC on VHF Ch 70, MF/HF; distress alert via Inmarsat or DSC; follow with voice on Ch 16.

Radio telephony: use phonetic alphabet (Alfa, Bravo, Charlie...) and figure spelling (One, Two, Three...).

Message markers: QUESTION, ANSWER, REQUEST, INSTRUCTION, ADVICE, WARNING, INFORMATION, INTENTION.

NAVTEX: 518 kHz international; 490 kHz national; 4209.5 kHz tropical; receive MSI broadcasts.

EPIRB: 406 MHz Cospas-Sarsat; register with flag state; test using self-test only.

Signals: distress flares, smoke, and sound signals; use Table of Life-Saving Signals for shore communication.

Fire triangle: fuel, oxygen, heat; fire classes A (solid), B (liquid), C (gas), D (metal), E (electrical), F (cooking oil).

Firefighting: CO2 for electrical, foam for oil, water for class A; never use water on electrical or oil fires.

Emergency procedures: muster list, abandon ship, man overboard, fire, and pollution response drills.

Life-saving appliances: lifeboat capacity, davit inspection, and weekly/monthly checks; immersion suits.

Pollution prevention: SOPEP, garbage management plan, oil record book, and ballast water management plan.

SOPEP: Shipboard Oil Pollution Emergency Plan; includes reporting procedures and contact list.

MARPOL Annex V: garbage discharge restrictions; special areas; placards required.

Personal survival: immersion hypothermia, HELP position, and survival craft rationing.