The SOLAS safety construction survey decides whether a cargo ship keeps its Cargo Ship Safety Construction Certificate. For a Chief Officer, the survey is rarely lost on the day. It is lost in the months before, when overdue defects, missing records and untested closing appliances pile up unseen. This guide walks the ship zone by zone, shows how the five-year survey cycle sets your windows, and gives a countdown for the last 90 days before the surveyor comes aboard.
What the Safety Construction Survey Covers and What It Leaves to Other Certificates
Which ships need the certificate and what it certifies about the hull, machinery and equipment
SOLAS Chapter I Regulation 10 sets the surveys of structure, machinery and equipment of cargo ships. A trade guide says the certificate applies to cargo ships of 500 gross tonnage and above on international voyages, and describes it as confirming that design, construction, machinery and stability comply with SOLAS. It is issued by the flag state or a recognised organisation, usually a classification society, after surveys.
Why life-saving and radio items sit outside the construction survey
The regulation excludes items for which a Cargo Ship Safety Equipment Certificate and a Cargo Ship Safety Radio Certificate are issued. Those have their own surveys. Plan the three together where you can, but do not assume that a construction survey will cover life-saving or radio equipment, or the reverse.
The Five-Year Survey Cycle and the Windows You Must Hit
How annual, intermediate and renewal surveys are counted from the certificate anniversary
SOLAS I/10 and the HSSC survey guidelines give the same structure. An annual survey falls within three months before or after each anniversary. An intermediate survey falls within three months either side of the second or third anniversary and replaces one annual survey. The renewal survey is held before the certificate is renewed, and may start at the fourth annual survey and be completed by the fifth anniversary.
Why two bottom inspections in five years drive the dry dock plan and the survey plan together
At least two inspections of the outside of the bottom are required in the five-year validity, no more than 36 months apart, and normally in dry dock. A class document adds that one is to be on or after the fourth annual survey with the renewal. That is why the survey cycle and the docking cycle must be planned as one. Our guides to extended dry docking and in-water surveys cover the options for eligible ships.
What happens to the certificate if a survey window is missed
The HSSC guidance states that a certificate ceases to be valid if the annual, intermediate or periodical survey, or the bottom inspection, is not completed within the required period. A certificate can be extended by no more than three months in the circumstances the guidance sets out. Treat the windows as hard dates in the planned maintenance system.
Which survey guidelines currently apply to the harmonised system
IMO adopted Resolution A.1207(34), the Survey Guidelines under the HSSC 2025, on 3 December 2025. It supersedes A.1186(33). Ask your class society which edition and which class checklist it applies to your survey.
Walking the Ship: Seven Zones, What Is Examined and What to Prepare
Each zone below pairs what the sources say the survey examines with a preparation list. The preparation lists are our suggestions. Class societies publish detailed item lists in the HSSC annexes and their own checklists, and we could not obtain the item-level annex text, so use your class checklist as the final authority for each zone.
Hull structure and the outside of the bottom show age and damage first, so start the file here
SOLAS I/10 requires at least two inspections of the outside of the ship's bottom during the five-year validity of the certificate, with no more than 36 months between any two. HSSC survey guidelines say the bottom inspection is normally in dry dock, and that bulk carriers and oil tankers of 15 years and over must be in dry dock.
- Structure, scantlings and condition, as the regulation describes
- Outside of the bottom at the bottom inspection
- Related items inspected at the same time
- Thickness gauging and coating records
- Damage reports and permanent repair records
- Dry dock plan and class survey window, as our dry dock planning timeline explains
Closing appliances such as doors, hatches and air pipes decide whether the ship keeps its watertight and weathertight integrity
A trade guide to the certificate lists closing appliances and protection against flooding among the areas surveyed, alongside watertight subdivision and bulkheads. Which closing appliances your class examines at each annual survey is set out in its survey checklist, so ask for it early rather than assuming.
- Condition and operation of watertight doors and other closings
- Bulkheads, decks and flooding protection
- Ventilators, air pipes and similar openings where your class checklist includes them
- Test and maintenance records for watertight doors
- Seal, hinge and dog condition notes
- A list of closing appliances by location
Tanks, void spaces, sea inlets and overboard discharges are where hidden wastage and flooding risks sit
Trade guidance lists double bottoms, ballast tanks and protection against flooding through sea inlets and overboard discharges among the areas surveyed. Internal examination depends on ship type and survey, and intermediate surveys of tankers add piping and electrical checks in dangerous zones under SOLAS I/10.
- Condition of tanks and void spaces within the survey scope
- Sea inlets, overboard discharges and their valves
- Piping and safety devices on tankers
- Tank cleaning and gas-free plans
- Previous tank inspection reports
- Valve overhaul and test records
Main and auxiliary machinery, boilers and pressure vessels are examined for satisfactory condition and fitness for service
SOLAS I/10 says the intermediate survey covers the structure, boilers and pressure vessels, machinery, equipment, steering gear and control systems, and electrical installations. A propeller shaft survey may be done with the bottom inspection, with no more than 60 months between surveys, according to the class guidance we reviewed.
- Propulsion and auxiliary engines
- Boilers and pressure vessels
- Shafting and rudder systems
- Overhaul and running hour records
- Pressure vessel and safety valve certificates
- Outstanding defect list with dates
Steering gear and its control systems must be proven, because they sit inside the intermediate survey scope
The steering gear and control systems are named in the intermediate survey scope in SOLAS I/10. Keep test records, and be ready to show how the system behaves if a component fails.
- Steering gear and control systems
- Alarms and changeover arrangements
- Maintenance condition
- Steering gear test records
- Alarm test records
- Hydraulic oil and seal condition notes
Electrical installations and emergency power must work as a system, not as separate equipment
The intermediate survey includes electrical installations, and the trade guide lists main switchboards, generators, distribution, emergency lighting and backup power. For tankers, SOLAS I/10 adds insulation resistance testing in dangerous zones. Our emergency generator and black-start test guide covers the controlled blackout test in detail.
- Main and emergency switchboards
- Generators and distribution
- Emergency lighting and backup power
- Blackout test records
- Insulation resistance readings
- Battery and charger records
Fire protection, fire doors and means of escape are the most frequently found weakness in port state control data
Paris MoU 2025 gives fire safety under SOLAS II-2 as the largest recurring area of noncompliance at 16.8%, with fire doors at 3.1%. The trade guide lists structural fire protection, fire-resistant divisions, fire doors, detection, suppression and means of escape among the areas surveyed.
- Fire-resistant divisions and fire doors
- Detection and suppression
- Means of escape and access
- Fire door test and closing records
- Detection test records
- Escape route and signage checks
The 90-Day Preparation Countdown Before Survey Day
A seven-stage countdown from confirming scope to closing findings after the survey
This sequence is our suggestion. It gives the Chief Officer a fixed rhythm so that gaps surface at 60 days, when there is still time to fix them, instead of in the week of the survey.
What Surveyors and Port State Control Flag Most Often
Reading the Paris MoU 2025 figures as a checklist for hull, electrical and fire protection items
The Paris MoU 2025 annual report, as summarised by IIMS, recorded 16,474 inspections, with 9,879 showing deficiencies and 688 detentions, a detention rate of 4.18%. Fire safety was the largest recurring area at 16.8% of noncompliance, and structural and electrical items under SOLAS II-1 followed at 11.6%. These are port state control figures, not survey findings, but they point to the same zones. A trade guide adds that the safety construction certificate is among the first documents checked in port state control, and that deficiencies can lead to detention.
A Readiness Scorecard to Run Two Months Before the Survey
Scoring each zone by the share of checklist items that already have current evidence
Score each zone out of 100 using your class checklist: one point for each item that has a current record, test or photograph. The scores show where the next 60 days of effort should go. The example below is illustrative.
Mistakes That Turn a Routine Survey Into a Condition of Class
Six preparation gaps that repeat from one survey cycle to the next
Systems That Keep Survey Windows, Defects and Evidence Connected
How a single tracker links survey dates, certificates, findings and dated photographs
Survey readiness depends on dates and evidence staying linked. Marine Inspection supports certificate and survey tracking, a dated photo repository linked to findings, and observations turned into tasks with owners, deadlines and evidence, as described in its dry docking guide for project work. For a Chief Officer, that means one place to see each survey window, each open remark and the proof that it was closed.
