Norway Deck Officer Class 1 (Master Mariner) cheat sheet

Great-circle distance: d = 60 × arccos(sin φ1 sin φ2 + cos φ1 cos φ2 cos Δλ), result in nautical miles when the arc is in degrees.

Mercator sailing: departure = DMP × tan(course); use meridional parts tables or DMP = 7915.7 log10 tan(45° + φ/2) for the sphere.

Mid-latitude sailing: departure = Δλ × cos(mid-latitude); reliable only for legs under about 600 NM and below high latitudes.

Celestial intercept: Ho = Ho from sextant corrected for index error, dip, refraction, semi-diameter and parallax; intercept a = Ho − Hc, drawn toward the GP if positive, away if negative.

Zone time: ZT = UTC + zone description, where ZD = longitude/15 rounded to the nearest whole hour; zone boundaries are political, not strictly 15° meridians.

GNSS fix quality: HDOP above 4 degrades a two-dimensional fix; RAIM must be available for sole-means GPS under IMO performance standards for ocean passages.

Tidal height by rule of twelfths: 1/12, 2/12, 3/12, 3/12, 2/12, 1/12 of the range in each successive sixth of the tidal interval from HW to LW.

ECDIS safety settings: safety contour, safety depth and safety draft must be set for the actual draft; look-ahead and route-check alarms are mandatory for the passage plan.

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

Beaufort scale anchors: force 6 = 22–27 kn, force 8 = 34–40 kn, force 10 = 48–55 kn, force 12 = 64 kn and above; sea state descriptions follow the same scale.

Swell travels with little energy loss; swell direction and period indicate the direction of the generating storm, not the current wind.

Tropical revolving storm avoidance in the Northern Hemisphere: avoid the dangerous semicircle (right of track), and in the navigable semicircle keep the wind on the starboard bow and steer to increase distance.

Fog formation requires a dew-point spread of about 2 °C or less; advection fog forms when warm moist air moves over a colder sea surface.

Wave height in a developed sea scales roughly with wind speed squared; a fully developed sea reaches significant wave height of about 0.025 × wind speed (kn)² metres.

Storm surge plus spring high water is the worst-case combination for coastal flooding; surge is set up by onshore wind stress and low barometric pressure.

Ice accretion: spray icing is most rapid at air temperatures of −2 °C to −8 °C with wind above about 15 kn; the IMO Polar Code sets operability limits by ice class.

GM = KM − KG; a positive GM means the vessel is initially stable, and the righting lever GZ = GM × sin θ for small angles only.

Free surface effect: FSC = (i × ρ_liquid)/(Δ × ρ_water) where i is the second moment of the free surface area about its centreline; it reduces effective GM.

IMO intact stability criteria (IS Code 2008): area under the GZ curve not less than 0.055 m·rad to 30°, 0.09 m·rad to 40°, and 0.03 m·rad between 30° and 40°.

IS Code further requires GZ maximum at 25° or more (30° for some ship types), initial GM not less than 0.15 m, and angle of maximum GZ not less than 25°.

Load line marks: the assigned freeboard is measured from the deck line to the summer load line at the ship's side; seasonal allowances are 1/48 of the summer draft for tropical and winter zones.

Damage stability: the vessel must survive flooding to the margin line under SOLAS subdivision and damage stability requirements applicable to its ship type and date of build.

Shear force and bending moment: still-water values from loading condition plus wave-induced values; the sum must stay inside the class-approved permissible envelope.

Torsion and hull girder strength: longitudinal strength depends on section modulus; loss of section modulus from corrosion reduces permissible bending moments, not just the plate thickness.

Pivot point: at rest it lies near midships; with headway it moves forward, and with sternway it moves aft, so the stern swings out first when going astern.

Bank effect: a vessel close to a bank experiences suction toward the bank at the bow and a cushioning effect at the stern, tending to shear the bow into the bank.

Squat: for open water, squat ≈ Cb × V²/100 metres with V in knots (approximate rule); in shallow water squat increases markedly and is greatest when the under-keel clearance is small.

Interaction between ships: in a passing encounter, the vessel overtaking is drawn toward the other; both should reduce speed and keep clear in ample water.

Stopping distance and crash-stop time depend on displacement and added mass; a typical loaded merchant ship needs several ship lengths and 10–15 minutes for a full crash stop.

Tug use: bollard pull is the design measure; effective pull falls with increasing towline length and angle, and indirect towing uses the ship's own momentum.

Anchoring: scope of about 5–7 × depth in moderate conditions; the holding power of the anchor depends on the seabed and on the catenary, not on the anchor alone.

Turn rate and rudder: a vessel turning at constant rudder angle settles to a steady rate of turn proportional to speed and inversely proportional to turning circle diameter.

STCW rest requirements: minimum 10 hours of rest in any 24-hour period and 77 hours in any 7-day period, divided into no more than two periods, one of at least 6 hours.

Watch handover must include position, course and speed, traffic, machinery status, drafts and stability condition, weather, and any standing orders in force.

Master's standing orders must be in writing and signed by the OOW; the OOW calls the master when in any doubt or when the situation is not covered by orders.

Bridge lookout: a dedicated lookout is required when conditions so demand; sole lookout is only permitted in daylight with good visibility and under defined conditions.

At anchor, the OOW maintains a continuous watch, checks the anchor bearing and position at intervals, and monitors weather, tide and dragging risk.

Bridge checklists: pre-departure, pre-arrival, pilot boarding and emergency checklists are completed and signed; the bridge team briefs the passage plan before departure.

Passage planning must be berth to berth and include no-go areas, abort points, contingency anchorages, and minimum under-keel clearance for the whole leg.

BRM: closed-loop communication, challenge and response, and a shared mental model are the core tools; the OOW must speak up when a plan is not being followed.

Rule 13 overtaking: any vessel overtaking any other shall keep out of the way until finally past and clear, regardless of the other vessel's activity.

Rule 14 head-on: both power-driven vessels alter course to starboard and pass port to port; a vessel in doubt must take early and substantial action.

Rule 15 crossing: the vessel with the other on her own starboard side is the give-way vessel and must keep out of the way; the stand-on vessel keeps course and speed.

Rule 19 restricted visibility: no stand-on vessel; every vessel proceeds at a safe speed, and a vessel detecting another by radar alone must take avoiding action in ample time.

Rule 6 safe speed factors: visibility, traffic density, manoeuvrability, background light, sea state, and stopping distance and turning ability of the vessel.

Rule 7 risk of collision: if there is doubt, risk is deemed to exist; a steady bearing and decreasing range indicates risk, and a bearing change is not always sufficient.

Rule 8 action to avoid collision: positive, made in ample time, with due regard to good seamanship; a succession of small alterations is to be avoided.

IALA buoyage Region A: red can buoys mark the port side of the channel on entry from seaward; green conical buoys mark starboard.

Slow-speed two-stroke diesels drive the propeller directly; medium-speed four-strokes usually drive through a reduction gearbox.

Specific fuel consumption for a modern two-stroke is roughly 160–180 g/kWh; a four-stroke is roughly 175–195 g/kWh, so fuel planning must use the actual test-bed figure.

Scavenge and turbocharging: exhaust-gas turbochargers raise charge air density; charge air coolers then reduce its temperature to increase mass flow into the cylinder.

Fuel oil changeover: MARPOL Annex VI requires low-sulphur fuel in ECAs; the changeover procedure must be documented and completed before entering the area.

Auxiliary boiler and exhaust gas economizer supply steam for heating and tank cleaning; loss of feedwater or low water level trips the burner.

Steering gear: SOLAS requires two independent power units; a full rudder movement from 35° one side to 30° the other must be possible within 28 seconds.

Emergency generator must start and take load automatically within 45 seconds of a main power failure, and supply emergency lighting and radio for at least 18 hours.

Bilge and ballast systems: high-level bilge alarms, oily-water separator of 15 ppm or less, and the oil record book entries are surveyed items under MARPOL Annex I.

IMDG Code classes 1–9: class 1 explosives, class 2 gases, class 3 flammable liquids, class 4 flammable solids, class 5 oxidizers and peroxides, class 6 toxic and infectious, class 7 radioactive, class 8 corrosive, class 9 miscellaneous.

Segregation in the IMDG Code uses the terms away from, separated from, separated by a complete compartment or hold from, and separated longitudinally by an intervening complete compartment or hold from.

The dangerous goods manifest and stowage plan must be on board before loading; the master must be informed of all dangerous goods and their stowage.

Solid bulk cargoes: the IMSBC Code requires a shipper's declaration, and group A cargoes (liquefaction risk) require a transportable moisture limit certificate.

Grain stability: the International Grain Code requires an approved grain loading document and, where relevant, the vessel to be upright after a heeling moment from a shift of grain.

Container lashing: stack weight and lashing capacity are checked against the cargo securing manual; the CSM is ship-specific and approved by the flag administration.

Draft survey: displacement is obtained from the hydrostatic table at the mean of the six drafts corrected for trim and deflection, then deducting lightship and stores.

Reefer cargo: pre-trip inspection, set-point and defrost records, and continuous monitoring of return air temperature are the evidence trail for claims.

UNCLOS zones: territorial sea 12 NM, contiguous zone 24 NM, exclusive economic zone 200 NM, measured from baselines.

Innocent passage through the territorial sea: the vessel must not threaten the peace, good order or security of the coastal state; submarines must navigate on the surface and show their flag.

SOLAS chapters: Chapter I general, II-1 and II-2 construction and fire, III life-saving, IV radiocommunications, V safety of navigation, VI cargo, VII dangerous goods, IX ISM, XI-1 and XI-2 special measures and ISPS.

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

STCW certification: the certificate of competency is issued by the flag administration; the certificate of proficiency and endorsements follow the STCW code tables.

Flag state duties: survey and certification, issue of statutory certificates, and investigation of marine casualties; port state control verifies compliance in port.

MARPOL Annex VI sulphur limits: 0.50% m/m global and 0.10% m/m in ECAs; the Mediterranean Sea became an ECA for sulphur from 1 May 2025.

Bunker Convention, CLC and Fund Convention provide strict liability and compensation for oil pollution; the certificates of financial responsibility must be carried on board.

Muster list must be posted and include the duties of each person; drills are held at intervals required by SOLAS, with abandon-ship and fire drills monthly on most ships.

Fire triangle: fuel, oxygen and heat; fire tetrahedron adds the chemical chain reaction; extinguishing removes one side.

Fire classes: A solid, B flammable liquid, C gas, D metal, F cooking oil; water is prohibited on class B, C and F fires and on live electrical equipment.

Lifeboat launching: the on-load release gear and the hydrostatic interlock must be checked; the fall inspection and the annual and five-yearly tests are mandatory.

SOPEP and the oil record book: the SOPEP must be on board, and the record book entries are made without delay for every Annex I operation.

Garbage record book: entries are required for each discharge, incineration or delivery ashore; the record book is retained for two years on board.

Man overboard: immediate helm hard over toward the person's side, release the lifebuoy with light and smoke, and mark the position on the chart.

Emergency power, radio and lighting are tested weekly; the emergency fire pump and the emergency generator are checked at the required intervals.

Fatigue risk factors: cumulative sleep debt, circadian low between 02:00 and 06:00, and long tours of duty; STCW rest hours are a minimum, not a target.

Situational awareness levels: perception, comprehension and projection; loss of SA is the most common precursor in accident reports.

Authority gradient: a steep gradient silences junior members; a flat gradient can cause indecision; the effective bridge team has a clear but open gradient.

Closed-loop communication: sender transmits, receiver repeats back, sender confirms; this is the standard for orders and helm and engine commands.

Human error types: slips and lapses (skill-based), mistakes (rule- and knowledge-based), and violations; each needs a different corrective approach.

Just culture: honest error is distinguished from reckless or intentional behaviour; reporting is encouraged and protected, and blame is reserved for wilful acts.

Safety management: the ISM Code requires a safety management system, designated person ashore, master's authority, and internal audits and reviews.

Team briefing and debriefing before and after critical operations improve shared mental models and surface concerns before they become incidents.

Voyage estimate: voyage result = freight earned − (bunker cost + port charges + canal dues + agency + commissions + crew and other voyage costs) − fixed costs for the period.

Time charter vs voyage charter: a time charterer pays hire and bunkers and takes commercial risk; the owner provides the ship and crew; a voyage charterer pays freight per tonne.

Laytime and demurrage: laytime is the allowed time for loading and discharging; demurrage is the agreed daily rate for time beyond laytime; despatch is a half-rate reward for early completion.

Off-hire: hire stops when the vessel is unable to perform the service due to breakdown, dry-docking or deficiency; the off-hire clause defines the exact conditions.

Bills of lading: a clean bill states goods received in apparent good order; a letter of indemnity is used when a clean bill is issued against a known discrepancy.

Hague-Visby Rules: carrier liability for cargo is limited per package or per kilogramme, whichever is higher; the package limitation is 666.67 SDR per package or 2 SDR per kg.

Crew administration: seafarer employment agreements, medical certificates, and the Maritime Labour Convention 2006 cover hours of work, wages, accommodation and repatriation.

Piracy and war risk: additional war risk premium (AWRP) and kidnap and ransom cover are negotiated for high-risk areas; the crew's rights under MLC continue during detention.

Radar: range resolution improves with shorter pulse length; bearing resolution improves with a narrower horizontal beamwidth and a larger antenna.

ARPA target acquisition and tracking: a target is acquired automatically or manually, and the trial manoeuvre function predicts the effect of a course or speed change.

AIS data: the vessel's identity, position, course, speed and destination are broadcast; AIS is a supplement to, not a substitute for, radar and visual lookout.

ECDIS: the electronic chart must be an official ENC or a raster chart from an approved service; the display must show the safety contour and the vessel's own position.

Integrated bridge systems: the conning display, gyro, autopilot and ECDIS must be cross-checked; a single sensor failure must not remove all position input.

DGPS and GNSS accuracy: the position is degraded by ionospheric and tropospheric error, multipath and satellite geometry; RAIM detects and excludes faulty satellites.

Echo sounder and speed log: the Doppler log measures speed over ground or through water; the electromagnetic log measures speed through water only.

Voyage data recorder: the VDR must record bridge audio, radar, ECDIS, AIS and engine data, and the annual performance test is mandatory.

Synoptic chart: isobars spaced closely indicate strong wind; the geostrophic wind is parallel to the isobars, and the surface wind is backed about 20–30° over the sea.

Frontal systems: a cold front brings a sharp wind veer, a temperature drop and squally showers; a warm front brings a gradual veer and steady rain.

Weather routing: the optimum track minimizes the sum of fuel and time cost, and the route must avoid the maximum significant wave height the ship can safely handle.

Sea state: significant wave height is the mean of the highest third of the waves; the maximum wave in a record is roughly twice the significant wave height.

Ocean currents: the Gulf Stream and Kuroshio add 1–3 kn on the favourable side; the current is strongest at the axis and weakens toward the edges.

Tropical cyclone structure: the eye has calm winds and low pressure; the eyewall has the strongest winds; the storm moves toward the pole and then recurves in the Northern Hemisphere.

Ice: first-year ice is thinner and weaker than multi-year ice; the ice edge and iceberg limit are plotted on the chart and in the Polar Code water.

Barometer: a rapid fall of 1 hPa per hour or more indicates a developing low; a rise indicates improving conditions but may bring strong winds behind the front.

Damage stability: the vessel must survive flooding of the assumed damage extent with the margin line not immersed and with positive residual freeboard and GM.

Permeability: the assumed permeability of a compartment depends on its use; a machinery space is about 85%, a store about 95%, and a void space about 95%.

Flooding effect: added weight lowers GM and increases draft; the loss of buoyancy from a flooded compartment reduces reserve buoyancy and can heel the ship.

Cross-flooding arrangements: they reduce the angle of heel after damage but take time; the time to equalize must be within the required limits.

Loading computers: the approved loading instrument must be used for every departure and arrival condition, and the results must be within the permissible envelope.

Bending moments: hogging puts the deck in tension and the keel in compression; sagging is the reverse; the still-water and wave components are combined.

Corrosion and wastage: the class rules set allowable diminution for each structural member; exceeding it requires renewal or a reduced permissible stress.

Bulk carrier hold structure: the side frames and the lower stool are high-stress areas; hold cleaning and inspection records support the structural survey.

Masthead lights: a power-driven vessel under way shows two masthead lights, the forward lower than the after; a vessel over 50 m shows a second masthead light.

Side lights: red on the port side and green on the starboard side, each showing from dead ahead to 22.5° abaft the beam.

Stern light: a white light showing from dead astern to 67.5° on each side; a vessel under 50 m may show one masthead light and a stern light.

Fog signals: a power-driven vessel making way sounds one prolonged blast at intervals of not more than 2 minutes; stopped, two prolonged blasts with an interval.

Sound signals in sight: one short blast means I am altering course to starboard; two short blasts means I am altering course to port; three short blasts means I am operating astern propulsion.

Rule 18 responsibilities: a power-driven vessel keeps out of the way of a sailing vessel, a vessel not under command, a vessel restricted in her ability to manoeuvre, and a vessel engaged in fishing.

Rule 10 traffic separation schemes: a vessel must cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.

Distress signals: a gun fired at intervals of about a minute, a continuous sounding of the fog signal, and the spoken word MAYDAY are distress signals under Annex IV.

Pneumatic and hydraulic control: the control air must be dry and oil-free; water in the control air causes sluggish or erratic valve response.

Fuel oil treatment: settling tanks, purifiers and filters remove water and solids; the purifier bowl and the gravity disc are selected by fuel density.

Lubricating oil: the alkalinity reserve (TBN) must match the fuel sulphur; a low TBN with high-sulphur fuel leads to corrosive wear.

Cooling systems: the central cooling system uses a low-temperature and a high-temperature circuit; the sea water cooler and the fresh water cooler are separate.

Boiler water treatment: the phosphate and hydrazine levels are controlled to prevent scale and corrosion; the water is tested daily.

Main engine control: the governor limits fuel to prevent overload; the scavenge fire and the crankcase oil mist detector are protection devices.

Electrical: the main switchboard is split into sections; the preferential trip and the emergency generator changeover are tested at the required intervals.

Pumps and valves: the bilge pump, ballast pump and fire pump are separate; the fire pump must be able to supply the required pressure at the hydrants.

Inert gas system: the tank atmosphere must be kept below 8% oxygen by volume; the inert gas plant and the deck water seal are surveyed items.

Gas detection: the combustible gas indicator and the oxygen analyser are calibrated before each use; the tank entry requires a permit and continuous monitoring.

Crude oil washing: the COW system must be approved, and the operation is recorded in the oil record book; the tank is washed with crude oil, not water.

Static electricity: the flow rate is limited during the initial filling of a tank, and the tank is bonded and earthed before loading.

Bulk cargo liquefaction: group A cargoes can liquefy and shift; the moisture content must be below the transportable moisture limit before loading.

Cargo hold ventilation: the dew point of the hold air and the outside air determine whether ventilation is safe; condensation on the cargo causes damage.

Hatch covers: the hatch cover is the main source of water ingress; the ultrasonic or hose test and the compression bar condition are checked before loading.

Dangerous goods stowage: the segregation table in the IMDG Code must be applied, and the class 1 and class 7 cargoes have additional stowage requirements.

Statutory certificates: the safety construction, safety equipment and safety radio certificates are issued under SOLAS and are valid for five years with annual and intermediate surveys.

Class surveys: the special survey is at five-year intervals, with annual and intermediate surveys; the class certificate is separate from the statutory certificates.

Port state control: the PSC officer checks certificates, the ISM and ISPS records, the oil record book and the crew's STCW certificates.

Detention: a ship is detained when a deficiency is clearly hazardous to safety, health or the environment; the detention is reported to the flag administration.

Flag administration: it may delegate surveys to a recognized organization (class society) but retains responsibility for the certificate.

Documentation: the continuous synopsis record, the crew list, the minimum safe manning document and the certificate of registry must be on board.

ISM Code: the safety management certificate is valid for five years, and the document of compliance is issued to the company and verified annually.

ISPS Code: the ship security plan is approved by the flag administration, and the ship security certificate is valid for five years with an intermediate verification.

Fire fighting: the fixed CO2 system must be released only after all personnel are accounted for and the space is sealed; the release is recorded.

Fire main: the fire pump must supply the required pressure at the hydrants, and the emergency fire pump must be able to supply the fire main independently.

Abandon ship: the order is given by the master; the crew musters at the muster station, the lifeboat is launched, and the EPIRB is activated.

EPIRB and SART: the EPIRB transmits on 406 MHz to the COSPAS-SARSAT system; the SART responds on 9 GHz to a radar.

Oil spill response: the SOPEP contains the contact list and the response actions; the spill is reported to the coastal state and the flag administration.

MARPOL Annex V: garbage is segregated by category; food waste may be discharged outside special areas at the required distance from land.

Drills: the abandon-ship and fire drills are held monthly; the enclosed space entry and rescue drill is held at intervals required by SOLAS.

Accident reporting: the marine casualty or incident is reported to the flag administration; the report includes the nature, the position and the assistance rendered.

Bridge team roles: the master has overall responsibility, the OOW conducts the watch, the pilot provides advice, and the helmsman and lookout support the team.

Pilotage: the pilot's presence does not relieve the master or OOW of responsibility; the master must intervene if the pilot's actions endanger the ship.

Challenge and response: the helmsman repeats the order and the OOW confirms; the order is not assumed to be executed until confirmed.

Fatigue: the OOW must report fatigue to the master; the master must adjust the watch schedule to maintain the required rest hours.

Situational awareness: the bridge team must monitor the position, the traffic and the ship's systems; the loss of one input must be detected and compensated.

Error management: the crew must be trained to detect and correct errors; the near-miss reporting system is part of the SMS.

Cultural factors: language, rank and national culture affect communication; the bridge team must use a common working language and standard phrases.

Emergency leadership: the master takes command, the team is briefed, and the emergency checklist is followed; the decision is recorded in the log.

Freight: the freight rate is per tonne or per cubic metre; the freight is earned on delivery of the cargo, subject to the terms of the charter party.

Laytime: the laytime commences when the notice of readiness is accepted; the notice must be tendered when the ship is ready in all respects.

Demurrage: the demurrage rate is agreed in the charter party; the time is counted in running days or working days as specified.

General average: a sacrifice or expenditure intentionally made for the common safety is shared by the ship, cargo and freight in proportion to their values.

Particular average: damage to the ship or cargo that is not a general average act is borne by the party that suffered it.

Hull and machinery insurance: the policy covers damage to the ship; the deductible and the insured value are agreed in the policy.

P&I insurance: the protection and indemnity club covers third-party liabilities, including crew injury, cargo claims and pollution.

Crew wages and repatriation: the seafarer employment agreement and the MLC 2006 set the minimum standards for wages, hours and repatriation.