395 - 01/05 - Possible Change in Water Depths -Malacca Straits and Indian Ocean


We would like to bring to the attention of Members a circular we have received from the Republic of the Marshall Islands:

"You will have heard of the terrible consequences of the recent underground earthquake off the western tip of Sumatra and the resultant tidal waves. The effects on shipping to date have been restricted to those unfortunate ships in port.

One of the unseen consequences MAY be a change of water depth as a result of sand waves created by the tsunami, particularly in the Malacca Straits.

We all have a responsibility to the shipping community in general to observe any depths that may have changed and to make the appropriate reports.

The following procedures are recommended:

  1. Listen for broadcasts of changes in depths from shore stations and report them to your DPA immediately if any such reductions are reported.
  2. Turn on the ship's echo sounder recorders during transits through the Straits, especially in the vicinity of One Fathom Bank, carefully marking times on the recorder paper together with GPS positions, and note any depths less than charted.
  3. Advise VTS traffic control of any depths less than charted.
  4. Notify Hydrographic services directly of any depths less than charted. As a reminder, Marine Notice 7-041-3, Hydrographic Information: Cooperation with Hydrographic Services provides guidance on reporting changes in aids to navigation and other Hydrographic data.
  5. Consider broadcasting a SECURITE message if serious reductions in depths are noted.

Ship managers are asked to consider the foregoing guidance and incorporate these actions into watchstanding procedures, especially aboard deep draft vessels transiting the Malacca Straits".

Source of information:

Republic of the Marshall Islands

Office of the Maritime Administrator


Staff Author