In-water survey (referred to by various classification societies as IWS, BIS, etc.) is a method of surveying the underwater parts of a ship while it is still afloat instead of having to

dry-dock A dry dock (sometimes drydock or dry-dock) is a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform. Dry docks are used for the construction, maintenance, ...

it for examination of these areas as was conventionally done. For

cargo ship A cargo ship or freighter is a merchant ship that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world's seas and oceans each year, handling the bulk of international trade. Cargo ships are usu ...

s, two surveys are required within a period of five years. One of these can be an in-water survey, provided the ship is eligible for it. :The ship (tanker or bulk carrier) should not be more than 15 years old. :The bottom of the ship should not be painted black before carrying out the survey.

References

Bureau Veritas Classification e-rules on In-water surveys (INWATERSURVEY) in Rules for the classification of steel ships

Turkish Classification Society – see Bottom Surveys
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