Operational guide · Certification & surveys

Bottom Survey and In-Water Survey (IWS)

Cargo and passenger ships follow distinct bottom-inspection regimes; an ordinary IWS depends on Administration/RO acceptance and UR Z3 and is not Extended Dry-Docking.

bottom surveyIn-Water SurveySOLAS Chapter Iship's bottom

Operational Explanation

Cargo and passenger ships follow distinct bottom-inspection regimes; an ordinary IWS depends on Administration/RO acceptance and UR Z3 and is not Extended Dry-Docking.

Regulatory Reference

SOLAS I/10 cargo; SOLAS I/7 and HSSC passenger; IACS UR Z3 general class bottom/IWS; Rec.133 only for EDD.

Scope of Application

Cargo: at least two bottom inspections in five years and maximum 36 months. Passenger: annual bottom inspection, normally two out of water in five years; any eligible non-ro-ro reduction needs specific Administration acceptance.

Procedure / How to Complete It

Classify cargo/passenger and survey regime.
Confirm Administration/RO/class IWS acceptance.
Apply UR Z3; use Z10 only for the specific ESP category.
Separate ordinary IWS from EDD and its approvals.
Do not apply Rec.133 EDD to passenger ships.

Practical Example

A cargo ship may replace one inspection by accepted IWS without entering EDD; a passenger ship follows its annual/HSSC regime.

What Typically Goes Wrong

Applying I/10 to every SOLAS ship, using Z10 as the general IWS source, or calling every IWS Extended Dry-Docking.

Common Mistakes Mistake Library

Mistake	Consequence	How to Avoid It
Applying I/10 to every SOLAS ship, using Z10 as the general IWS source, or calling every IWS Extended Dry-Docking.	Non-compliant decision or treatment	Follow the approved arrangement and applicable sources

What the PSCO Checks

Evidence of the approved arrangement, procedures, records, competence, defect management and consistency with statutory/class/maker requirements.

Operational Tips

Separate current requirement, class/maker, SMS and voluntary guidance.
Do not improvise tests, thresholds or intervals.
Record deviations and corrective action.

Preparation checklist

Ship type distinguished
Correct I/7 or I/10
UR Z3
IWS accepted
EDD separate

FAQ

Do cargo and passenger ships share one rule?

No.

Is an IWS automatically EDD?

No.

Which is the general UR?

UR Z3; Z10 only within its ESP scope.

Bottom Survey and In-Water Survey (IWS)

Operational Explanation

Regulatory Reference

Scope of Application

Procedure / How to Complete It

Practical Example

What Typically Goes Wrong

Common Mistakes Mistake Library

What the PSCO Checks

Operational Tips

Preparation checklist

FAQ

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