Docking + IWS Surveys

Frequency:
Ships less than 15 years of age, intervals at least twice in a 5-year period. In between surveys cannot exceed 36 months.

Items to check:
•Condition of underwater hull
– Welding seams and butts
– Deformation assessment (Buckling, deflection etc.)
– Coating/ Cathodic Protection (Corrosion, wastage of anodes etc.)
– Appendices (Bilge keels, fins, ducts etc.)
•Integrity of hull openings
– Seachests, shell/ bottom penetrations,
– inlet/ outlet valves,
– storm valves,
– scuppers,
– thruster ducts)
•Conditions of rudders/ stabilisers
– Pintles and bearings,
– shaft flanges,
– rudder body tightness/ crackless)
•Anchors and Chains
– Anchor head/ stock connection,
– shackles to chain links,
– thickness measurement)

Docking intervals can be prolonged in the following cases:
o if high resistance paint is used for the underwater hull, extension can be up to 2.5 years.
o For ships operating in saltwater for less than 6 months in a year, extension could be up to 3 years.
o For ships operating solely in freshwater, the interval can be prolonged from between 2 to 5 years.
o Extension of period for drydocking may be granted under special circumstances (normally granted if underwater inspections are carried out by a competent diver under the supervision of a surveyor)
o Alternate drydocking may be carried out provided and in-water survey is done when the vessel is afloat & examination is done by a diver or a surveyor. (Here, an underwater inspection is carried out in lieu of a docking survey)

In-Water Surveys
Accepted in lieu of one of the two docking surveys required in a 5-year period, on ships where IWS notation is assigned. The IWS survey is to provide the information normally obtained for the docking survey. Generally, consideration is only given to an in-water survey where suitable high resistance paint has been applied.

Conditions:
1. Size of ship (beam)
2. High resistance paint
3. In water visibility
4. Suitable draft
5. Effective communication b/w diver and surveyor
6. Done by recognised firm and competent diver in the presence of a surveyor