Practical reference
Quick look-ups you actually need on watch — the conventions and codes that govern shipping, the signals and lights you read off other vessels, and the everyday units and scales of the trade. Each page is a single self-contained reference: enough detail to answer the question, with cross-links to the related pages and to practical help where applicable.
127 reference pages, grouped below.
Conventions & frameworks
- SOLAS chaptersSafety of Life at Sea — Chapters I–XV with subsidiary codes.
- STCWTraining, Certification and Watchkeeping — chapters and Manila amendments.
- MARPOL annexesPollution prevention — Annexes I–VI.
- MLC 2006Maritime Labour Convention — five Titles, DMLC, financial security.
- COLREGsRules of the Road — index of Rules 1–38 by part.
- ISM CodeSafety Management — 16 elements, DOC and SMC, the DPA.
- ISPS CodeShip and port facility security — levels 1/2/3, SSP, SSAS.
- Port state controlParis/Tokyo MoUs, USCG, AMSA — targeting, inspection, detention.
- ITF & IBFSeafarer unions, FOC campaign, IBF Framework, TCC scale.
- Load linesPlimsoll mark — TF/F/T/S/W/WNA, zones, freeboard.
- Tonnage measurementGT, NT, DWT, LDT, displacement — the 1969 Tonnage Convention.
- CO₂ regulationIMO CII, EEXI, EU ETS, FuelEU Maritime, IMO GHG Strategy.
- Hague-Visby & RotterdamCarriage of goods by sea — Hague, Hague-Visby, Hamburg, Rotterdam Rules.
- Arrest of ships1952 and 1999 Arrest Conventions, maritime liens.
- Polar CodeCategories A/B/C, ice classes PC1–PC7, PWOM, POLARIS risk method.
- IGF CodeLow-flashpoint fuels — LNG, methanol, ammonia. STCW V/3 competence.
- OPA-90 (US)US Oil Pollution Act — VRP, OSRO, COFR, double-hull, NRC reporting.
- MARPOL Annex V (garbage)Garbage categories, plastic prohibition, GMP, GRB, special areas.
- IMSBC CodeSolid bulk cargoes — Groups A/B/C, schedules, TML declarations, Master's right to refuse.
- IMSBC Group A — liquefiable cargoesLiquefaction physics, TML/FMP, iron ore fines, nickel ore, bauxite, casualties.
- International Grain CodeDocument of Authorization, grain shift stability, trimming rules, GZ curve.
- IBC CodeChemical tankers — cargo categories X/Y/Z, ship types 1/2/3, MARPOL Annex II.
- IGC CodeGas carriers — LNG, LPG, ammonia as cargo. Tank types, BOG, secondary barrier.
- SOLAS Chapter XI-1Special measures to enhance maritime safety — RO Code, ESP enhanced surveys, IMO number, CSR.
Legal & compliance
- Sanctions complianceUN, OFAC, OFSI, EU maritime sanctions — SDN screening, dark fleet, Iran, Russia, North Korea.
- Russia oil price capG7+EU+AU $60/bbl cap on Russian crude — attestation tiers, P&I declarations, enforcement.
- War zones & JWLAJoint War Committee listed areas, BMP5 transit, war risk insurance, Houthi crisis, crew rights.
- ITF wage-claim toolkitPractical steps — documents, inspectors, Letter of Demand, Notice of Intent to Arrest, IMO/ILO database.
Commercial & insurance
- Classification societiesIACS members, class notations, surveys, role under SOLAS.
- P&I and hull insuranceInternational Group P&I clubs, hull, war risk, MLC financial security.
- Charter partiesVoyage / time / bareboat / CoA — BIMCO standard forms.
- Laytime & demurrageNOR, WWD/SHINC/SHEX, demurrage and despatch.
- SIRE 2.0 & TMSAOCIMF tanker vetting, TMSA 4, RightShip, DryBMS.
- Salvage & LOFLloyd's Open Form, SCOPIC, salvor's lien, places of refuge.
- Bunkering & fuelBDN, ISO 8217, sulphur cap, sample retention, scams.
- Draft surveyCargo quantity by displacement — procedure and corrections.
- INCOTERMS 2020FOB, CIF, FCA, DAP — risk and cost transfer points.
Communications, navigation, signals
- GMDSSGlobal Maritime Distress and Safety System — Sea Areas A1–A4.
- AISAutomatic Identification System — Class A/B, MMSI, status codes.
- IMO signal flagsInternational Code of Signals alphabet flags.
- Morse codeMaritime Morse usage including SOS.
- Navigation lightsCOLREG vessel light identification.
- IALA buoyageLateral, cardinal, isolated danger, safe water marks.
- Sound signalsCOLREG fog and manoeuvring signals.
- Distress proceduresMayday format, GMDSS basics.
- Distress frequenciesVHF channels, MF/HF, GMDSS.
- Passage planningSOLAS V/34 four-stage process — Appraise, Plan, Execute, Monitor.
- ECDISElectronic chart system — ENC vs RNC, RCDS mode, type-specific familiarisation, S-100.
- Tide tablesReading harmonic constituents, primary vs secondary ports, time/height interpolation, datums (CD/MSL/LAT).
- Magnetic compass adjustmentVariation, deviation, Coefficients A–E, Flinders bar + soft-iron spheres, swing + deviation table — SOLAS V/19.
- CPA & ARPAClosest point of approach, TCPA, relative vs true motion, radar plotting — COLREGs Rules 7-8, SOLAS V/19.
- Under-keel clearanceStatic vs dynamic draft, squat, heave, tide window, company UKC policy — SOLAS V/34.
Operations, cargo, deck
- IMDG classesDangerous goods classes 1–9 with packing groups.
- KnotsBowline, clove hitch, sheet bend, and more.
- Ship typesTankers, bulkers, container, RoRo, offshore taxonomy.
- Vessel stabilityGM, GZ curve, IS Code 2008, free-surface effect.
- Mooring & anchoringOCIMF MEG4, line types, snap-back zones, anchor watch.
- STS operationsShip-to-ship transfer — fenders, approach, MARPOL Annex I Ch 8.
- Cyber security at seaBIMCO + IMO MSC-FAL.1/Circ.3, ISM cyber requirement (2021).
- Draft survey procedureReading 6 draft marks, trim/heel correction, density correction, deductibles, cargo mass calculation.
- GZ curve — intact stabilityRighting arm vs heel angle, IS Code 2008 criteria, dynamical stability area, severe wind/rolling.
- Lashing forces — CSS Code Annex 13External forces by sea area + ship length, MSL vs BL, balance-of-forces method.
- Anchor holding powerHHP coefficients, seabed types, scope ratio, chain catenary, dragging-anchor warning signs.
Cargo operations by ship type
- Tanker cargo operationsOil & product tankers — inert gas, COW, load-on-top, ODME, ISGOTT, ship-shore checklist.
- Chemical tanker operationsIBC Code categories X/Y/Z, ship types 1/2/3, compatibility, coatings, N₂ padding, prewash.
- LPG carrier operationsIGC Code — pressurised / semi-ref / fully-ref, cooldown, reliquefaction, BOG, gassing-up.
- Bulk carrier cargo operationsIMSBC Code, loading sequence & hull stress, alternate-hold loading, trimming, BLU Code.
- Container ship operationsBay plans, twistlocks & lashing bridges, VGM (SOLAS VI), IMDG stowage, parametric rolling.
- Container stowage planningMaster bay plan, GM target, stack-weight & lashing limits, DG segregation, OOG & reefer access.
- Reefer cargo operationsIntegral vs conventional reefer, set-point vs supply air, CA/MA, PTI, the cold chain.
- Ro-Ro operationsPCTC/RoPax, ramps & hoistable decks, door integrity & subdivision, vehicle-deck free surface.
- Ro-Ro vehicle lashingLashing points, web vs chain lashings, chocks, mafi trailers — CSS Code + Cargo Securing Manual.
Choke points & canal transits
- Suez CanalSea-level canal, convoy system, SCA tolls & pilots, Ever Given grounding, Red Sea security.
- Panama CanalPanamax vs Neo-Panamax locks, ACP tolls, Gatun Lake water crisis, mandatory pilots + mulas.
- Strait of MalaccaMalacca-max, TSS, piracy, the world's busiest strait — Singapore, Phillip Channel.
- Strait of HormuzGulf oil chokepoint, TSS in Omani waters, tanker-war history, transit security.
- Bab-el-MandebRed Sea southern gate, Houthi threat, war-risk routing, Suez-vs-Cape arbitrage.
- Cape of Good HopeThe Suez alternative — added distance & bunker cost, southern-ocean weather routing.
- Bosphorus & Turkish StraitsMontreux Convention, TSS, pilotage, tanker queues, Bosphorus & Dardanelles transit.
Engineering & MARPOL Annex VI
- BWM ConventionBallast Water Management — D-1 exchange, D-2 performance, BWMS type approval.
- EGCS / scrubbersOpen-loop, closed-loop, hybrid; washwater bans; SOx compliance.
- NOx tiersMARPOL Annex VI Reg 13 — Tier I/II/III, NECAs, SCR, EGR, EIAPP.
- Ballast water exchange — D-1Sequential / flow-through / dilution, 200 nm + 200 m rule, D-1→D-2 transition, BWRB.
- Fresh water generatorFlash evaporator vs RO, salinometer cut-off, chlorination, MLC Reg 3.2 potable-water testing.
- Scrubber washwater dischargeMARPOL Annex VI + EGCS Guidelines — pH ≥ 6.5, PAH limit, turbidity, local discharge bans.
Crew, watchkeeping, weather
- Ranks & ratingsDeck, engine, catering — STCW certificates per rank.
- Career pathwaysCadet → OOW → Chief Mate → Master + engine equivalent.
- Watchkeeping & rest hoursSTCW 10/77, watch rotations, UMS.
- Beaufort wind scaleForce 0 to force 12.
- Douglas sea stateVisual sea state scale 0–9.
- Unit convertersKnots, NM, fathoms, °F↔°C, mb↔inHg.
- PEMEPre-Employment Medical Examination — ENG1, ML5, STCW A-I/9, ILO/WHO standards.
- Repatriation insuranceMLC 2.5 financial security for abandonment — P&I blue card, claim process.
Tools & calculators
- Distance & bearingGreat-circle and rhumb-line between two positions, plus passage time.
- Nearest port locatorPaste a lat/lon — get the 10 closest UN/LOCODE ports.
- Mayday script generatorFill 5 fields → printable Mayday call ready to read on Ch 16.
- Watch rotation timer4-on/8-off countdown with browser notification when watch ends.
- Lights quizIdentify COLREG navigation light configurations — STCW oral prep.
- Sound signals quizListen and identify COLREG Rule 34/35 patterns.
- COLREGs rule pickerPick vessel × encounter × visibility → applicable rule + action.
- MLC compliance checkerWalk a contract through the most-violated MLC 2006 provisions.
- Dead-reckoning calculatorLast fix + course + speed + elapsed → estimated current position.
- IMO number validatorPaste a 7-digit IMO number → checksum verify with calculation steps.
- Demurrage / laytime clockNOR + laycan + rate → running laytime + accruing demurrage.
- MARPOL discharge legalityCargo class × zone × distance → permitted / restricted / PROHIBITED.
- UTC ↔ local timeDST-aware converter for every major port.
- Sunrise, sunset & twilightCivil/nautical/astronomical twilight per position and date.
- Squat estimatorShallow-water sinkage via Barrass / Hooft / ICORELS formulae.
- CII rating estimatorIMO Carbon Intensity Indicator A-E rating with Z-factor by year.
- Magnetic variation referenceVariation, deviation, compass error, WMM2025.
- ECA / Special Area checkerPaste lat/lon → applicable MARPOL ECAs and special areas.
- Box-girder GM checkSimplified GM estimate from L × B × d × KG. Cadets only.
- IMO flags quizIdentify flag → letter or meaning. STCW oral-exam prep.
- IMDG class quizIdentify the hazard class from the placard.
- Beaufort scale quizWind description ↔ force number.
- Multilingual phrasebookBridge / engine / safety phrases in EN / TL / HI / RU / UK / ID / ZH.
- Printable lights chartAll 14 light configurations on one A4 — laminate for the bridge.
- Passage time + bunker reserveDistance, speed, departure → passage time + ETA + voyage fuel + reserve at IMO 48h margin.
- Ballast exchange timeSequential / flow-through / dilution time vs pump rate + tank volume — BWM D-1.
- Stowage factor & hold useCargo mass × SF + broken stowage → hold volume needed; commodity quick-picks.
- Lashing force — CSS Code Annex 13Cargo mass + sea area + ship length → Fx / Fy / Fz external forces.
- Deviation table — swing8-heading swing entry → magnetic, deviation, Coefficient B + C estimates.
- SOLAS fire quizChapter II-2 + FSS Code — 21 questions on fire integrity, detection, CO2, fireman's outfit.
- COLREG decision quizScenario-based rule + action picks — 18 scenarios covering Rules 8–19, 9, 10, 13–18.
- Cargo securing quizCSS Code + IMSBC + Grain + TDC + RoRo lashings — 18 questions on MSL, TML, lashings.
- Abandon-ship drill walkthroughSOLAS Reg III/8 + III/19 + LSA Code — 18-step drill chronology with primary citations.
- Distress wallet cardVHF / MF / HF + Mayday script in credit-card-size laminate format.