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Tasos Karakasis*: Extended Dry Docking (EDD) Scheme utilizing In Water Surveys (IWS)

During last year, our Under Water Services (UWS) department have received many enquiries for IWS from Container vessels and gas carriers of five years old that get extended dry docking (EDD) at their first Special Survey.

This practically means that instead for the vessel to do the Special Survey in Drydock in 5 years, she takes extension of 2.5 years with an in-water survey (IWS) and goes to 7,5 years, provided that specific requirements have been met.

However, older ships can also be considered for the program depending on the flag state, ship type, classification society and other design and operational factors. The result of the IWS plays an important role on deciding the next dry-docking schedule for the ship, even if the ship is under Extended Dry Docking Program. If the results of this survey are found unsatisfactory, then the operator is asked to book a dry-docking within one month of the IWS.

What is revealed through our research with Class Surveyors is that all major Classifications Societies have adopted such EDD scheme programs, but is of utmost importance and potential show-stopper the written acceptance from the flag administration prior entering an EDD scheme.

Nevertheless, the EDD is not a scheme that could be adopted by all kind of vessels, so the following ships and ship types are not eligible for an EDD:
— Passenger vessels
— Ships subject to enhanced survey program (ESP)
— General dry cargo ships subject to extended hull survey program (EHSR)
— Ships fitted with propulsion thrusters, unless machinery condition monitoring is implemented
— Ships where the propeller connection is by means of a keyed taper key.

Especially for tankers (any kind) a major consideration is that, even if class and flag could approve EDD, the subject vessels might be withdrawn from the EDD if this provides market constraints to those very vessels. The industry (oil majors/vetting) might prove reluctant to take on a tanker which has not been dry docked for 7-8 years.

In summary, the EDD is a very good tool for the Owners to keep operating their vessels longer periods among Dry Docking Surveys provided that the vessels are well maintained and the IWS from authorized UWS providers proves the good condition of hull and painting. 

All revelant requirements among other sources can be found in:
a. DNVGL-RU-SHIP Pt.7 Ch.1 Sec.5 1.6 “Extended intervals between bottom surveys in dry-dock” 
b. LR EDD Guidance
c. IACS Rec. No 133 / Nov 2013.

* General Manager Marine Plus SA

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