Short answer: A marine survey is a professional inspection of a vessel by a marine surveyor to assess its condition, identify defects and record the findings for a specific purpose. The main types are pre-purchase surveys, insurance surveys, damage surveys, valuation surveys, and class and statutory surveys; refits often add a scope-definition survey. Depending on the agreed scope, a marine survey may include document review, inspections afloat and ashore, operational checks, specialist testing and a sea trial. The report should identify the work completed and any limitations.
“Marine survey” is a broad term. The scope changes with the assignment: a pre-purchase survey, an insurance survey and a class renewal survey look at the same yacht through different lenses and produce different outcomes.
What Is Done in a Marine Survey?
The exact work follows the survey brief, but a full condition or pre-purchase survey of a yacht usually runs through these stages:
- Brief and documents. The surveyor agrees the purpose and scope with the client, then reviews the yacht’s certificates, class and flag status, maintenance records, previous survey reports and repair history.
- Out-of-water inspection. With the yacht hauled out, the surveyor checks the hull, appendages, rudders, propellers, shafts, seals, through-hull fittings and coatings. Steel and aluminium hulls may be checked with ultrasonic thickness gauging; GRP hulls with moisture readings and tap testing.
- Inspection afloat. Machinery, electrical systems, steering, tanks, piping, HVAC, safety equipment, navigation and communication equipment, deck gear and accommodation are inspected and, where possible, run.
- Sea trial. Where the brief includes it, the surveyor attends a sea trial to see propulsion, steering and systems working under load.
- Specialist checks. Larger yachts often add specialist inspections, such as engine surveys by the manufacturer’s service network, oil analysis or rig inspection on sailing yachts.
- Report. The surveyor issues a written report with observations, defects, photographs and recommendations.
Ultrasonic thickness gauging on a hull during survey work at KRM Yacht.
Types of Marine Survey
| Type | Purpose | Usually requested by |
|---|---|---|
| Pre-purchase survey | Establish condition, defects and risks before a purchase | The buyer |
| Insurance or underwriting survey | Support the insurer’s risk review: condition, safety and insurability | The owner, for the insurer |
| Damage survey | Record the nature and extent of damage after an incident and support the claim and repair planning | Owner, insurer or loss adjuster |
| Valuation survey | Assess the vessel’s market value, often for finance or insurance | Lender, insurer or owner |
| Class survey | Assess compliance with the applicable classification rules so the vessel stays in class | Owner, through the classification society |
| Statutory survey | Assess compliance with the applicable statutory requirements so certificates can be issued or renewed | The flag Administration or a recognised organisation acting on its behalf |
| Refit-entry or scope-definition survey | Confirm actual condition and turn assumptions into a workable refit scope | Owner side or yard |
A pre-purchase survey assesses condition for a prospective buyer. Insurance and damage surveys serve different purposes; their scope and depth depend on the agreed brief and any insurer requirements.
Who Carries Out a Marine Survey?
A marine surveyor is the professional who inspects the vessel and writes the report. Independent surveyors work for buyers, owners, insurers and lenders; class surveyors work for the classification society and survey against its rules. Many independent yacht surveyors belong to professional bodies such as the International Institute of Marine Surveying (IIMS) and the Yacht Designers and Surveyors Association (YDSA) in the UK, or the Society of Accredited Marine Surveyors (SAMS) and the National Association of Marine Surveyors (NAMS) in the United States. Membership can be checked in each body’s online directory.
When choosing a surveyor, look for experience with the yacht’s size, build material and type, a clear written scope, professional indemnity insurance, and independence from the sale and from any repair work.
Marine Survey vs Class Survey vs Surveyor
| Term | Meaning |
|---|---|
| Marine survey | The inspection and reporting process, carried out for a specific purpose |
| Marine surveyor | The professional who carries out the survey |
| Class survey | One specific type of survey, carried out by a classification society against its rules to keep the vessel in class |
| Statutory survey | A survey by or on behalf of the flag Administration, often delegated to a recognised organisation such as a classification society, to issue or renew statutory certificates |
A class or statutory survey checks compliance; it does not replace an independent condition survey for a buyer.
What You Receive at the End
The usual output is a written report. Depending on the survey type, it may include:
- Vessel identification and the scope and limitations of the survey
- Observations by area, with photographs
- Defects and deficiencies, often graded by priority or safety
- Recommendations for repair or further testing
- Compliance-related findings
- A valuation where the brief requires one
A useful report tells the reader what was inspected, what was not, what was found, how serious it is and what needs to happen next.
Why Marine Surveys Matter in a Refit
In refit work, survey findings often decide whether a package stays small or grows into a wider yard period. A survey may uncover steel renewal, coating breakdown, pipe wastage, machinery wear, electrical issues or certification items that were not visible at the quoting stage. Once defects are verified, the team can define access, arrange specialist attendance, involve class or flag where needed and build the scope on confirmed condition rather than assumptions. A yard’s scope assessment serves refit planning; it does not replace a buyer’s independent pre-purchase survey. That is where a clear refit brief and measured checks such as hull thickness measurement and non-destructive testing come in.
If the findings are feeding directly into technical work, the next step is usually to turn the report into a defined yard package through tests and surveying.
Measured readings such as plate thickness turn survey findings into a defined repair scope.
Frequently Asked Questions
What is a marine survey?
A professional inspection of a vessel by a marine surveyor to assess its condition, identify defects and record the findings for a specific purpose, such as a purchase, insurance, a claim or compliance.
What is done in a marine survey?
Depending on the agreed scope, a marine survey may include document review, inspection of the hull and underwater parts out of the water, checks of machinery, electrical and other systems afloat, operational and specialist testing and a sea trial, followed by a written report with findings, recommendations and any limitations.
What are the types of marine survey?
Pre-purchase, insurance or underwriting, damage, valuation, class and statutory surveys. Refits often add a scope-definition survey.
How long does a marine survey take?
Timing depends on the vessel’s size, complexity, access and the agreed scope. Confirm the inspection time and the report delivery time separately with the surveyor.
Do I need a survey to insure a yacht?
Requirements vary by insurer and policy. Confirm whether a survey is required and whether the proposed surveyor and scope are acceptable to the insurer.
I am buying a superyacht. What survey do I need?
A full pre-purchase survey by an independent surveyor experienced with yachts of that size and build, usually with a haul-out, a sea trial and specialist checks such as engine surveys. Review the class and flag status and recent survey reports as well; a class survey does not replace an independent condition survey for the buyer.
Is a class survey the same as a marine survey?
A class survey is one type of marine survey, carried out by a classification society against its rules. An independent condition or pre-purchase survey is carried out for the client and covers the client’s brief.
