Interactive Decision Trees

Have you generated or do you need to dispose of sludge?

• Yes, I have sludge to dispose of

  Where is it being disposed of?

  • Port reception facility
    Deliver to the reception facility and obtain its receipt. Record quantity, tank, retained amount and port in ORB Part I C 12.1 under the applicable format; retain the receipt. Go to the Sludge Management topic →
  • Incinerated on board
    Check the approved installation, manual and local restrictions. MARPOL VI/16.4 prohibits burning in boilers or power plants within ports, harbours and estuaries; it is not a blanket ban on every dedicated incinerator. Record incinerated sludge in ORB Part I C 12.3 with quantity, tank, retained amount and times; manage ash under Annex V and record its delivery in the GRB, category E. Go to the Incinerator Operations topic →
  • Transferred to another onboard tank (internal use)
    For transfers between sludge tanks use ORB Part I C 12.2, recording transferred quantity, source, destination and retained quantities. Check tank identification and the approved arrangement; reconcile quantities under the SMS. Go to the Sludge Management topic →
• No, no sludge to dispose of right now
  No disposal entry without an operation, but the at-least-weekly C 11.1–11.3 sludge-tank inventory remains: identification, capacity and retained quantity. Also record applicable manual collections under C 11.4. Any monthly SMS balance does not replace these records. Go to the Sludge Management topic →

Have you observed an unusual event on board or ashore?

• Something happened that caused damage or an injury
  Immediately activate the prescribed alarm and response if danger is ongoing. Protect people, ship and environment; inform the Master/Company, preserve evidence and make required external notifications. Do not wait for final classification before reporting. Investigation, actions and effectiveness checks follow the SMS. Go to the DPA topic →
• Something serious could have happened, but did not (a near-miss)
  Report the near miss under the SMS, describing facts and barriers that prevented harm without assigning blame. Assess causes and preventive measures; a near miss may also reveal a non-conformity, but does not automatically establish one. Go to the Near Miss topic →
• I found that an SMS procedure was not followed
  Document the unmet requirement and objective evidence; control immediate risk. Distinguish immediate correction from action on causes, assign an owner and deadline and verify effectiveness. Categories are not mutually exclusive: one event may be both an accident and a non-conformity. Go to the Non-Conformity topic →

Did you receive a deficiency during a PSC inspection?

• Yes, it must be rectified before departure or within an assigned deadline
  Record the deficiency code, action code, deadline and authority conditions; inform the Master/Company. Rectify, collect evidence and obtain the required verification. If the deadline cannot be met, contact the authority immediately: do not extend it yourself. Integrate cause analysis and prevention into the SMS. Go to the Managing Deficiencies topic →
• Yes, and a detention was imposed

  Are you considering filing an appeal?

  • Yes, the outcome seems unjustified to us
    Follow the national procedure and deadlines specified in the port State’s decision. An appeal does not itself suspend detention; correction and appeal can proceed together. Observe conditions until the competent authority’s formal decision. Paris MoU review is distinct from national appeal. Go to the Appeal against a Detention topic →
  • No, we are proceeding directly with the rectification
    Rectify deficiencies, involve flag/RO where required and submit evidence to the PSC authority. A surveyor’s attendance or statement alone does not release the ship: obtain formal release or any conditional permission from the authority before sailing. Follow SMS actions to prevent recurrence. Go to the Detention and Banning topic →
• The deficiency concerns a missing or expired International Ship Security Certificate (ISSC) or Interim ISSC
  Immediately inform the Master, CSO and competent flag/RSO. Absence of a valid ISSC or Interim ISSC requires involvement of the Duly Authorized Officer under A.1206(34), appendix 20. SOLAS XI-2/9 provides proportionate measures, from inspection to detention or other restrictions; detention is not the sole automatic outcome. A PSCO may also act as DAO if authorized. Go to the Flag State-PSC Coordination topic →

Does your route cross an Emission Control Area (ECA/SECA) boundary?

• Yes, I am about to enter an ECA/SECA area
  Check boundaries, application date and area SOx requirements. Where the ECA limit applies, use fuel at or below 0.10% sulphur m/m or an approved equivalent within its limits. If changeover is needed, complete it before entry under the written procedure; record completion, date, time, position and tank volumes in the flag-prescribed record book. Go to the Fuel Oil Changeover topic →
• Yes, I am about to leave an ECA/SECA area
  If changing to fuel subject to the global limit, start only after leaving; record commencement, date, time, position and volumes as required by MARPOL VI/14.6. The global limit is 0.50% m/m, subject to approved equivalence and stricter local requirements. There is no requirement to stop using low-sulphur fuel. Go to the Fuel Oil Changeover topic →
• No, I am not crossing any ECA/SECA boundary right now
  Check where you are operating: if already inside an ECA, its applicable limit still applies. For the Canadian Arctic and Norwegian Sea distinguish designation entering into force (1 March 2026) from the 0.10% SOx requirement (1 March 2027). NOx requirements have separate criteria: fuel changeover does not demonstrate NOx compliance. Also check the onward route and local rules. Go to the MARPOL Annex VI topic →

What is your ship's situation regarding alternative fuels?

• Already in service with a dual-fuel engine

  Which alternative fuel does it use?

  • Methanol
    Consider both methanol flammability and toxicity. Check detection suited to its poorly visible flame, leak detection, ventilation, exposure protection and training under the approved installation, SMS and MSC.1/Circ.1621 guidance. Visual inspection alone cannot rule out fire. Go to the Methanol Engines topic →
  • Ammonia
    For ammonia check containment, detection, ventilation, emergency isolation, PPE and exposure response under the approved design. MSC.1/Circ.1687 is interim fuel guidance: it does not replace flag acceptance, onboard procedures and specific training. Consider toxicity and flammability. Go to the Ammonia Engines topic →
  • LNG (liquefied natural gas)
    For LNG as fuel check the applicable IGF framework; gas carriers covered by IGC have specific provisions that must not be generalized to other ships. Monitor pressure, temperature and boil-off under the design, with protection against cryogenic, fire and hazardous-atmosphere risks. Do not use venting as a normal pressure-control solution. Go to the Liquefied Gases and IGC Code topic →
• Under evaluation for a new order or a retrofit
  Assess approvals, risks, bunker availability and quality, equipment compatibility, maintenance, training and emergency response. Distinguish regulatory requirements, documented emissions performance and commercial ratings: a rating does not certify safety or compliance. Go to the Alternative Fuels and Operational Readiness topic →
• No alternative fuel currently planned
  Having no alternative-fuel project does not exempt the ship from current emissions, fuel and energy-management duties. Check those applicable to the ship and monitor IMO developments with the Company, distinguishing proposals, adopted rules and requirements already in force. Go to the IMO Net-Zero Framework topic →

Do you have an ongoing emergency involving dangerous goods on board?

• Yes, a fire or incipient fire involves the cargo

  Do you know the IMDG class and UN number of the substance involved?

  • Yes, the class and UN number are known
    Activate the alarm and emergency plan under onboard command; protect people. Identify the IMDG entry and relevant Fire/Spillage EmS codes, considering location, quantity and packaging. Apply the specific instructions integrated into the plan; class alone is insufficient to choose an extinguishing agent. For exposure activate medical assistance and MFAG under the procedure. Go to the EmS Guide and MFAG topic →
  • No, the class is not immediately clear
    Do not delay the alarm, protection of people and planned response while identifying cargo. Use the manifest, documents and stowage plan from a safe position to establish UN number and EmS codes. Do not approach damaged packages to read labels or improvise agents or mixtures; report uncertainty to command. Go to the Dangerous Goods Manifest topic →
• Yes, a spill or leak without fire
  Raise the alarm and follow the plan; safely restrict access. Identify the EmS Spillage code and exposure, fire and reaction hazards. Containment, ventilation, PPE and recovery require procedures, trained personnel and suitable equipment. Activate medical assistance where needed and required notifications without waiting for environmental damage to occur. Go to the EmS Guide and MFAG topic →
• This is not an active emergency, I am planning the response
  Check IMDG 42-24 applicable in 2026, the 2024 Supplement and relevant corrections; keep EmS, MFAG, manifest and stowage plan accessible. Practise alarms, command, communications and schedule retrieval under the SMS. These educational paths do not replace the emergency plan. Go to the EmS Guide and MFAG topic →

An emergency has occurred on board: what type is it?

• Fire or incipient fire

  What type of space is the fire in?

  • Machinery space of category A
    Raise the alarm and apply the fire plan under onboard command. Identify the installed system and its specific procedure: total-flooding CO2 requires evacuation and accounting, prescribed alarms, shutdowns and closures, and release authority. Do not automatically transfer that sequence to water systems or local applications; follow the approved design. Go to the Fixed Firefighting Systems: CO2 and Water Mist topic →
  • Ro-Ro or vehicle space
    Raise the alarm and activate the response for the space. Coordinate protection and evacuation of people with timely system activation under the approved procedure; do not impose the CO2 sequence on all water systems. Consider spread between vehicles, drainage and stability; no unauthorized entry. Go to the Ro-Ro and Vehicle Spaces topic →
• Need to abandon ship
  The general alarm summons people to muster stations: it is not itself the order to abandon ship. Follow the muster list and Master’s instructions, including accounting, assistance and prescribed personal equipment. Embarkation and launching of survival craft take place on order under onboard procedures. Go to the Musters and Abandon Ship Drill topic →
• Security threat (intrusion, security alarm)
  Apply the Ship Security Plan and inform the Master, SSO and CSO under the procedure. The competent authority sets the security level; the crew does not raise it independently. The Master retains authority to take necessary protective measures and coordinates communications with authorities and port. Go to the Ship Security Plan and the ISPS Code topic →

You need to handle a situation involving passengers: what type is it?

• Embarkation just completed, before departure
  Check voyage duration and the applicable regime. SOLAS III/19.2.2 requires newly embarked passengers to muster before or immediately upon departure when their scheduled stay exceeds 24 hours. Distinguish the required safety briefing for new passengers and any stricter onboard rules; do not use the former 24-hour deadline to postpone muster. Go to the Passenger Musters at Embarkation topic →
• Several cases of gastrointestinal illness within a few hours
  Immediately inform medical staff and command; initiate surveillance, case recording and health-plan measures under clinical direction. Do not assume a cause or diagnosis. Apply prescribed isolation, hygiene and notifications: an unusual pattern requires assessment without waiting for a numerical threshold. CDC/VSP thresholds apply within their jurisdiction, not universally. Go to the Managing a Gastrointestinal Outbreak topic →
• Emergency underway: passengers need to be mustered

  Do you need to verify that all passengers have been counted?

  • Yes, a final headcount at the assembly stations is needed
    Reconcile the count with the current list of people actually on board and the designated system, including passengers without cabins and assistance needs. Avoid duplicates and immediately report missing people or uncertainty to command. Cabin lists are supporting information, not the sole basis; any searches are coordinated and performed only safely. Go to the Passenger Accounting topic →
  • No, the flow toward the assembly stations needs managing first
    Position trained staff as planned, maintain clear communications and direct people along safe routes. Assist those who need help under the plan; report obstructions and reroute under onboard command. Flow management and accounting can proceed together, without waiting for movement to finish before reporting problems. Go to the Crowd Management topic →

You need to manage a cargo operation or an access to a ship space: what is the situation?

• I need to authorize entry into a potentially enclosed space
  Stop entry until procedural conditions are met. MSC.581(110) considers a potential hazardous atmosphere or oxygen deficiency together with at least one characteristic: limited access, inadequate ventilation or not designed for continuous occupancy. Assess connected spaces too; arrange isolation, ventilation, representative tests, permit, attendance and rescue. One satisfactory test is insufficient; no improvised rescue. Go to the Enclosed Space Entry topic →
• I need to determine the quantity of cargo loaded/discharged
  Choose a method suited to the cargo and agreed for the purpose: draft survey is not universal. Where appropriate, use reliable hydrostatic data, corrected readings, density and consistent deductions between initial and final surveys; document conditions and uncertainties. Other cargoes may require weighing, tally or tank measurements. Go to the Draft Survey topic →
• I need to plan the loading/discharging before operations
  Check stability, local loads and stresses at every stage, coordinating ballast and sequence. For solid bulk under SOLAS VI/7, Master and terminal agree the plan before starting, with signatures and lodging under applicable requirements. Changes are possible: reassess and agree the revision before implementing it; stop operations if safety is compromised. Go to the Loading/Discharging Plan topic →

You have found an anomaly in the electronic navigation equipment: what type is it?

• GNSS signal lost, unstable or suspicious (jamming/spoofing)
  Inform the Master and apply the contingency procedure while preserving safe navigation. Compare appropriate radar, visual references and dead reckoning: two displays using the same GNSS are not independent sources. Assess effects on connected equipment; exclude suspect input or change configuration only under the design, procedure and bridge-team assessment. Record and report. Go to the Electronic Navigation and GNSS Resilience topic →
• The ECDIS position does not match visual/radar references
  Treat position as uncertain until verified. A discrepancy may arise from sensor/GNSS, datum, antenna offsets, radar alignment or chart data: do not immediately diagnose datum shift. Check independent sources and equipment data; do not apply manual offsets merely to align displays without an established cause and procedure. Go to the Datum Shift and Chart Reference in ECDIS topic →
• BNWAS does not trigger the expected alert or gives false alarms
  Notify the Master, maintain a safe watch and check configuration, reset and alarm sequence under the manual without bypassing. Required BNWAS must operate whenever the ship is underway at sea; it does not replace lookout and watchkeeping. For failure, record and arrange repair and compensating measures with the Company and authorities where required: additional bridge staff alone are not an exemption. Go to the BNWAS and Anti-Collision Alert Systems topic →

A critical problem has occurred in the engine room: what type is it?

• Total or partial blackout
  Raise the alarm and immediately coordinate engine room and bridge. Follow the plant-specific blackout procedure: verify emergency supply and designated services, identify/isolate the fault and restore main generation and loads in the authorized sequence, avoiding repeated reclosure onto a fault. The emergency generator does not automatically supply propulsion. Preserve logs and times for analysis. Go to the Blackout and Failure Management topic →
• Critical spare not available for an urgent repair
  Make the equipment safe and inform the Chief Engineer and Company. Verify compatibility, certificates and traceability of any alternative with the maker and competent parties; a sister-ship loan does not prove equivalence. Temporary repair or operating limitation requires assessment and class/flag acceptance where applicable. A PMS entry does not authorize exemptions from statutory or class requirements. Go to the Critical Spare Parts Management topic →
• Anomalous behavior in the automation systems (suspected intrusion)
  Activate the cyber/SMS response, inform command and Company contacts and preserve essential services. Containment, segmentation or transfer to local control must be coordinated and checked against plant dependencies: indiscriminate disconnection may remove control or protections. Preserve evidence where safe; recover from a trusted configuration under the plan without improvised restarts or changes. Go to the Cyber Risk Management topic →

During the dry dock survey you found an anomaly: what type is it?

• Plate thickness below the minimum allowed limits
  Suspend close-out of the affected scope. Confirm component identification, location, calibration and repeatability; compare applicable limits and measurement history, extending examination as required. Class/competent authority determines renewal, repair or another acceptable disposition. Record drawings, readings and tests and obtain required close-out before concealing the area or returning it to service. Go to the Thickness Measurement (UTM) topic →
• Anomalous play or suspected wear on the tail shaft
  Suspend the affected sequence and inform the Chief Engineer, Company and surveyor. Check measurement, maker/class tolerances, lubrication, trends and shaft arrangement. Examination, any withdrawal, repair and tests depend on the arrangement and applicable Rules, not an automatic rule. Document results and acceptance before reassembly or return to service. Go to the Tail Shaft Survey topic →
• Coating damage beyond the acceptable threshold
  Map location, extent and type of deterioration, distinguishing coating damage from metal thickness loss. Check the Coating Technical File, PSPC where applicable and survey/maintenance criteria; agree preparation, coating-system compatibility and repair checks. Update the CTF where required. Do not infer a universal repainting threshold or treat painting as a structural repair. Go to the Coating and PSPC topic →

What type of survey/certification deadline or situation are you handling?

• A regular certificate deadline is approaching
  Identify the certificate, Convention, expiry date and required surveys with flag/RO. The HSSC three-month rule concerns retention of the new certificate’s validity basis in the specified cases, not a universal prohibition on earlier renewal. Check endorsements and documents to be issued; booking a survey does not extend a certificate. Any extension requires a legal basis and competent authorization. Go to the Renewal Survey and Certificate Renewal topic →
• An interim certificate is needed (new ship, flag change, class change)
  Identify the exact document: interim ISM/ISPS, temporary statutory documents and class certificates are not equivalent. Check eligibility, authorized issuer, validity, outstanding checks and restrictions. A new ship or change of flag or class does not automatically qualify for every interim certificate; agree the route to the definitive document without assuming coverage of other certification. Go to the Interim Certificates topic →
• A Condition of Class has been opened
  Record the Condition of Class scope, deadline and restrictions; assign responsibility and plan work and verification. If the deadline is at risk, contact the society before expiry: no unilateral extension. Retain evidence and formal closure confirmation. Effects on class status and statutory consequences must be checked separately with class and flag/authorized RO. Go to the Condition of Class and Recommendations topic →

Regarding current environmental obligations, what is your ship's situation?

• The ship's CII rating is D or E (low)
  Check the verified rating and history: E for one year or D for three consecutive years triggers a corrective action plan in SEEMP Part III, to undergo competent verification and be implemented. An isolated D does not alone meet that threshold, but requires attention to the trend and SEEMP measures. Assign actions, owners and monitoring to achieve C or better; the document alone does not demonstrate improvement. Go to the CII (Carbon Intensity Indicator) topic →
• The ship operates on routes subject to EU ETS/FuelEU Maritime
  Check each regime’s scope, derogations and calendar separately. EU ETS requires monitoring/verification and allowance surrender: surrender in 2026 covers 70% of covered 2025 emissions; for 2026 emissions phase-in reaches 100% and includes CH4/N2O. FuelEU, applicable since 2025, concerns lifecycle GHG intensity of energy and its compliance balance/document, not a second allowance surrender. Coordinate data and duties with the Company and verifier. Go to the EU ETS and FuelEU Maritime topic →
• Ballast Water Management compliance needs checking
  Check applicability, any valid exemptions, certificate, approved plan and current BWRB. For ships subject to the ordinary D-2 implementation schedule, transition ended by 8 September 2024. Check BWMS operating limits, alarms, maintenance and records: type approval alone does not demonstrate compliant discharge. For failure or unsuccessful treatment, inform the Company and relevant authorities and agree the prescribed measures; do not unilaterally replace D-2 with D-1 exchange. Go to the Ballast Water Management Convention In Depth topic →