Croatia Master Mariner cheat sheet

Meridional parts: MP = 7915.7 · log10 tan(45° + Lat/2), with Lat in degrees; Mercator course/speed from dLat, dMP and dLong.

Great-circle distance: cos D = sin Lat1·sin Lat2 + cos Lat1·cos Lat2·cos ΔLong; initial course from sin C = cos Lat2·sin ΔLong / sin D.

Composite great-circle vertex latitude is the limiting parallel; use Napier's rules on the right-angled triangle to find vertex longitude and changeover points.

Running fix: advance the earlier position line along the course and distance run, then transfer the LOP parallel to itself before plotting the intersection.

Tidal height by rule of twelfths: 1/12, 2/12, 3/12, 3/12, 2/12, 1/12 of range over the six hours after HW/LW slack.

Vertical sextant angle: distance (m) = 1.856 × height (m) / angle (arcminutes) for small angles; apply index error and dip first.

ECDIS: safety contour, safety depth and look-ahead time are set by the navigator; route planning must be checked against CATZOC and chart datum.

Radar ARPA CPA/TCPA: TCPA negative means target has already passed the closest point; guard zones must be checked against true-motion vectors.

Stowage factor (m³/t) = volume occupied / mass; break-bulk general cargo typically 1.2–2.5 m³/t, grain about 1.3–1.6 m³/t, iron ore about 0.35–0.45 m³/t.

Broken stowage % = (volume lost / total volume) × 100; the stowage factor actually used = nominal SF / (1 − broken stowage fraction).

Deadweight available for cargo = summer deadweight − bunkers − fresh water − stores − constants − ballast retained.

IMDG segregation: codes 1 (away from), 2 (separated from), 3 (separated by one bulkhead or deck), 4 (separated by two), X (segregation shown in the Dangerous Goods List).

Grain Code: list angle, heeling moments from the assumed heel of 12° (or angle of flooding if less), and allowable heeling moment from the ship's Grain Loading Booklet.

Hatch cover weathertightness: ultrasonic testing or hose test at not less than 0.2 bar; chalk test shows compression of packing.

Timber deck cargo: lashings at intervals not exceeding 3 m, securing strength per MSC.1/Circ.1623; crew protection and freeing-port checks required.

Container lashing: stack weight limits, mixed stacking rules and the Cargo Securing Manual are the controlling documents; verify VGM per SOLAS VI/2.

ISM Code: SMS with documented procedures, designated person ashore, master's overriding authority, internal audits and management review.

Watchkeeping under STCW: minimum rest 10 hours in any 24 and 77 hours in any 7 days; watch schedule posted; records retained.

Muster list assigns each crew member to a station; the station bill must cover fire, abandon ship, man overboard, and emergency steering.

Permit-to-work systems apply to hot work, enclosed-space entry, working aloft and over the side, and electrical isolation (lock-out/tag-out).

Shipboard familiarisation must be completed before undertaking duties; drills per SOLAS III: abandon-ship and fire drills monthly, enclosed-space entry drill every two months.

Planned maintenance system: defect reporting, critical equipment list, and spare gear inventory controlled by the chief engineer and superintendent.

Ballast Water Management Plan and Record Book are ship-specific; BWM Convention D-2 discharge standard applies; records kept at least two years.

Garbage Record Book entries for categories A–I; retention on board and discharge receipts must match the Garbage Management Plan.

GM = KM − KG; KM = KB + BM; BM = I / V, where I = LB³/12 for a box-shaped waterplane.

Free surface effect: FSC = Σ(ρ · i) / (ρ_ship · Δ), where i is the second moment of area of each free surface about its own centreline.

Angle of loll: tan θ = √(2·GM / BM) for negative GM; GZ at small angles ≈ GM · sin θ.

IMO intact stability criteria: area under GZ curve ≥ 0.055 m·rad to 30°, ≥ 0.09 m·rad to 40°, GZmax ≥ 0.20 m at ≥ 30°, initial GM ≥ 0.15 m.

Damage stability: SOLAS II-1 subdivision index A = Σ p_i·s_i; probabilistic damage stability replaced deterministic rules for new ships.

Longitudinal strength: still-water shear force and bending moment combined with wave-induced components; permissible limits in the loading manual.

Bulkhead deck, collision bulkhead position ≥ 0.05L and ≤ 0.08L from the forward perpendicular (SOLAS II-1).

Tonnage: gross tonnage from V·(0.2 + 0.02 log10 V) under ITC 69; net tonnage derived from cargo volume formula.

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

Beaufort scale: force 8 = 34–40 kn, force 10 = 48–55 kn, force 12 = 64 kn and above; significant wave height roughly 0.025·V² for fully developed sea (V in knots).

Tropical revolving storm approach: in the Northern Hemisphere, dangerous semicircle is to the right of the track; manoeuvre to put wind on the starboard quarter.

Swell travels ahead of the storm; long-period swell from an unseen source is an early warning of a TRS.

Fog forms when the dew point is within about 2 °C of air temperature; radiation fog over land, advection fog over cold currents.

Semi-diurnal tide: M2 period 12 h 25 min; spring tides at new and full moon, neap tides at quadratures.

Ocean currents: western boundary currents (Gulf Stream, Kuroshio) are warm, narrow and fast; eastern boundary currents are cold and broad.

Ice: first-year ice thickness up to about 2 m; icebergs calved from glaciers drift with the current, not the wind, and 90% is submerged.

Hague-Visby Rules: carrier must exercise due diligence to make the ship seaworthy before and at the beginning of the voyage; 12-month time bar.

Hamburg Rules: carrier liable unless it proves reasonable measures to avoid the occurrence and its consequences; two-year time bar.

Bill of lading is prima facie evidence of receipt; conclusive evidence once transferred to a third party acting in good faith.

General average (York-Antwerp Rules): sacrifice or expenditure intentionally and reasonably made for the common safety; contribution apportioned by arrived values.

Salvage under the 1989 Convention: award based on saved value, danger, success, skill, and environmental protection; no cure, no pay subject to SCOPIC.

Collision liability under Brussels Convention 1910: joint and several liability for personal injury, several liability for property damage in proportion to fault.

Limitation of liability: LLMC 1976/1996 Protocol; tonnage-based limits for claims in respect of loss of life, personal injury and property.

UNCLOS: territorial sea 12 nm, contiguous zone 24 nm, EEZ 200 nm, innocent passage through the territorial sea; hot pursuit must be continuous.

SOLAS chapters: I general, II-1 construction, II-2 fire, III LSA, IV radio, V safety of navigation, VI cargoes, VII dangerous goods, IX ISM, XI special measures.

MARPOL Annexes: I oil, II NLS, III packaged harmful substances, IV sewage, V garbage, VI air pollution; Annex VI sulphur limit 0.50% (0.10% in ECAs).

STCW 2010 Manila Amendments: certificate revalidation every five years; basic safety training, advanced firefighting and PSCRB for all officers.

MLC 2006: minimum age 16, hours of work 14/77, repatriation, accommodation and food standards, complaint procedures; DMLC Part I and II.

ISM and ISPS: ISPS levels 1–3, Ship Security Plan, Ship Security Officer, Continuous Synopsis Record on board.

BWM Convention: D-2 standard, Ballast Water Management Plan, International BWM Certificate; ships must manage ballast before discharge.

Load Line Convention 1966/88 Protocol: summer, winter, tropical, freshwater and timber marks; freeboard measured from deck line to load line.

COLREGs: Rule 5 lookout, Rule 6 safe speed, Rule 8 action to avoid collision, Rule 13 overtaking, Rule 14 head-on, Rule 15 crossing; Rule 19 restricted visibility.

Two-stroke slow-speed diesel: uniflow scavenging, exhaust valve, crosshead; firing order determined by crank arrangement to balance torque.

Specific fuel consumption (SFOC) in g/kWh; typical large two-stroke SFOC 160–175 g/kWh at MCR.

Indicator diagram: area gives indicated power; mean indicated pressure (MIP) relates to power by P = p·L·A·n·k.

Boiler: safety valve lift pressure set at 1.1 × design pressure; water level and feedwater control critical to avoid carry-over.

Pump: NPSH available = (p_atm − p_vap)/(ρ·g) + static head − friction losses; cavitation occurs when NPSHa < NPSHr.

Steering gear: SOLAS II-1 requires two independent power units; changeover within 45 seconds; main and auxiliary steering gear tested before departure.

Fuel oil: viscosity at injection controlled by heating; sulphur limit drives use of VLSFO, scrubbers or alternative fuels; ISO 8217 specifies grades.

Fire main pressure and emergency fire pump: capacity not less than 25 m³/h for cargo ships; located outside the machinery space.

GMDSS sea areas A1 (VHF DSC), A2 (MF/HF DSC), A3 (Inmarsat), A4 (HF); equipment carriage per SOLAS IV.

DSC distress alert: VHF channel 70, MF 2187.5 kHz, HF 4207.5, 6312, 8414.5, 12577, 16804.5 kHz; followed by radiotelephony on 156.8 MHz (ch 16).

NAVTEX: 518 kHz international, 490 kHz national, 4209.5 kHz; reception range about 200–400 nm.

EPIRB: 406 MHz COSPAS-SARSAT, registration in national database; float-free mounting; battery and HRU expiry dates recorded.

SART: 9 GHz radar transponder, range about 8 nm, 12 dots on the radar display; AIS-SART transmits on AIS channels.

Inmarsat-C: store-and-forward, SafetyNET for MSI; Fleet Broadband for voice and data; GMDSS equipment must have a source of energy independent of ship's main power.

AIS: Class A transmits static, dynamic and voyage-related data; CPA/TCPA derived from AIS may differ from ARPA due to update rates.

ECDIS backup: independent backup arrangement or paper chart folio; ECDIS must be type-approved and use official ENC (S-57/S-63).

Fire triangle: fuel, oxygen, heat; extinguishing by starvation, smothering, cooling or chemical inhibition; Class A solid, B liquid, C gas, D metal, F oil fires.

CO2 fixed system: 30% (or 35% for machinery spaces) of gross volume; must not be released until all personnel accounted for and space sealed.

Enclosed-space rescue: never enter without atmosphere testing (O2 20.9%, LEL < 1%, H2S, CO), permit, standby man and rescue equipment.

Man overboard: immediate hard helm to swing stern away from the person, release lifebuoy with light/smoke, Williamson turn or Anderson turn.

Abandon ship: distress alert first, muster, lifeboat launching sequence, life raft painter, EPIRB and SART taken, survival craft water and rations.

Medical: radio medical advice via MRCC or Inmarsat; MEDEVAC decision considers patient condition, distance and weather.

Oil spill response: SOPEP/SOPEP-equivalent, stop source, containment booms, dispersants only with authority approval; report to coastal state.

Emergency generator: must start and supply emergency switchboard within 45 seconds; emergency lighting and fire pump tested weekly.

MARPOL Annex I: Oil Record Book Part I for machinery space, Part II for tankers; entries for each transfer, disposal and discharge.

Annex V garbage: discharge of plastics prohibited; food waste comminuted ≥ 25 mm may be discharged ≥ 3 nm from land (12 nm if not comminuted).

Annex VI: SOx ECA 0.10%, global 0.50%; NOx Tier III for ships built after 2016 in NECA; ODS and incinerator restrictions.

Ballast water: D-2 standard, treatment system, and BWM Plan; exchange at ≥ 200 nm from land and ≥ 200 m depth if D-1 applies.

Anti-fouling: AFS Convention 2001 prohibits organotin compounds; biofouling management plan recommended by IMO.

Safety Management: near-miss reporting, risk assessment, permit-to-work, toolbox talks, and safety committee meetings.

PPE and permit: enclosed space entry requires atmosphere test, permit, standby person, communications and rescue equipment at the entrance.

Pollution reporting: report to nearest coastal state and flag state; PSC inspection may follow; SOPEP and VRP on board.