In Water Survey:
It is an examination of ship’s underwater portion & fittings of the hull instead of intermediate dry docking.
It is carried out by a team of qualified divers employed by a firm, which is approved by the classification society.
IWS survey is to provide the information normally obtained from a docking survey, so far as practicable.
The class will accept an IWS in lieu of the intermediate docking between special surveys required in a five-year period.
IWS notation: in water survey.
IWS notation is a must before conducting. If the vessel has an IWS already, the condition of the high resistant paint is to be confirmed to maintain the notation.
If the vessel needs IWS notation to be assigned by the class, plans & means are to be provided for ascertaining:
→ the rudder pintle & bush clearances to verify the security of the pintles in their sockets with the vessel afloat.
→ The clearance in the stern bush with the vessel afloat.
Eligibility of ship for IWS:
(1) Age of the ship not greater than 15 years.
(2) Ships are not subjected to ESP
(3) Ships must have class IWS notation.
(4) High quality paint coating for (7.5 years) extended dry docking.
(5) Ships must be fitted with effective ICCP & ECCP.
(6) Access arrangements for sea v/v, rudder bearing & pintle clearance
(7) Stern tube wear down measurement, bow & stern thruster sealing checking arrangements.
Preparation:
(1) Application to classification society’s ship-safety division for an IWS program.
(2) Approval from the class for IWS.
(3) Appoint a diving company approved by the class.
(4) Meeting & agreement between owner, surveyor & diving firm about the equipment & procedures for both observing & reporting the survey.
(5) A copy of plans showing the hull & attachments below the water line should be provided to both surveyor & diving firm. One copy retained onboard.
(6) Class (Ship safety office) should be informed about the date, time & location of the survey.
Documents to be prepared by C/E before survey:
(1) IWS notation
(2) Permission for IWS
(3) Risk assessment
(4) Diving checklist fill up
(5) Last DD reports (maintenance & hull painting)
(6) Propeller report
(7) Stern tube report
(8) Rudder clearance report
(9) Last stern tube L.O. analysis Lab report
(10) Reports on anti-fouling system
(11) Anode plan
(12) Statement related damaged condition.
Safeties:
(1) Ship is safely anchored (Preferred weather with min current).
(2) Weather forecast good & suitable for next 3 days.
(3) Toolbox meeting carried out, ship’s crew must be well informed about survey. Risk assessment done.
(4) Lock out, tag out of the main propulsion system. T/G engaged.
(5) Steering Gear motor power should be switch off and lock out, tag out for no rudder movement
(6) Bow & stern thruster same power off & LOTO.
(7) ICCP & MGPS power off
(8) No discharge during survey
(9) Good underwater visibility
(10) Diving company pre-dive to confirm cleanliness of hull, rudder, propeller & chest gratings.
(11) Sea chest suction notified in E/R & ready to change over as per diver’s request.
During Survey:
(1) Diving supervisor, ship’s representative (C/E or master), and surveyor should gather @ CCTV station.
(2) A good two-way communication between divers & surveyor should be provided.
(3) Surveyor should be satisfied by the pictorial presentation of the divers
(4) Inspection area →
(i) Hull condition from fwd to aft
(ii) Hull painting condition
(iii) Any damage, corrosion, deformation of hull
(iv) All underwater hull marking
(v) Bilge Keel condition
(vi) Sea chest condition
(vii) S/T seal condition, clearance & wear down of S/T bearing measurement.
(viii) Propeller condition & nut
(ix) Rudder bearing clearance, intact pintle,
(5) Audio video record of whole survey.
Reports:
Diver’s reports with colored photographs & video recordings should be provided to surveyor, ship safety headquarters (classification society), Owner, and one copy should be readily kept onboard.
S/T bearing clearance & rudder carrier bearing clearance report should be verified by the maker’s reading.
If the IWS reveals damage or deterioration that requires early attention, the surveyor may require that ship to be dry docked. So that a detailed survey can be undertaken & necessary repairs carried out.
After IWS:
(1) Confirm all divers are out of water
(2) Diver supervisor to confirm approval to remove LOTO.
(3) Diver boat cast off.
(4) C/E prepare M/E ready
