The PSC ship risk profile: what decides how often you are inspected
The Paris and Tokyo MoUs don't inspect ships at random. Each ship gets a risk profile, and the profile sets a window: when the window opens the ship becomes due for inspection, and once it has passed the ship has priority. In the Paris MoU region, port States reported 51,797 deficiencies in 2025, 4,744 of them detainable, according to its annual report. The profile is how the MoUs spread those inspections across ships that need them most.
High, standard and low risk
A ship is classified as high risk, standard risk or low risk. Roughly, the windows in the Paris MoU regime are:
- High risk: every 5 to 6 months, and expanded inspections are more likely.
- Standard risk: every 10 to 12 months.
- Low risk: every 24 to 36 months.
The Tokyo MOU uses the same idea with its own parameters and windows. Check the exact current values on each MoU's site before you plan around them.
What goes into the profile
The calculation mixes things about the ship that you can't change quickly with its recent history.
Generic parameters
- Ship type. Some types (passenger ships, oil, chemical and gas tankers, bulk carriers) start with a higher weight.
- Age. Older ships score higher.
- Flag. The flag's position on the MoU's white, grey or black list.
- Recognized organization. The performance of the class society doing the statutory work.
- Company performance. The ISM company's detention and deficiency record across its fleet, over the last 36 months.
Historical parameters
- Deficiencies. The number found in inspections over the last 36 months.
- Detentions. The number of detentions over the same period.
The 36-month window is the reason one bad inspection follows a ship for three years. It's also the reason a clean run of inspections pays off: the profile improves as old deficiencies drop out of the window.
What you can influence
You can't make a ship younger, and changing flag or class is a large decision. The parameters you work on every day are the history ones and, through them, the company's performance:
- Fewer deficiencies per inspection. Most come from the same short list: fire safety, life-saving appliances, safety of navigation, MLC paperwork, cleanliness, ISM. A pre-arrival check of those areas (preparing for PSC) is the cheapest improvement there is.
- No detentions. A single detention weighs more than several minor deficiencies. Closing items before departure (code 17) instead of letting them grow into code 30 matters for the ship and for the whole fleet's company rating.
- Fleet consistency. Company performance is calculated across all ships under the same ISM company. One weak ship pulls the others' profiles up.
Tools and lists
The MoUs publish calculators and lists that show where a ship stands: the Paris MoU's ship risk calculator on THETIS, the flag and RO performance lists, and the Tokyo MOU's list of under-performing ships. Use them with the ship's real data before a voyage into the region, not after the first inspection.