OFFICER IN CHARGE OF MARINE INSPECTION PUGET SOUND ADVISORY

FUTURE USE OF NON-CORROSION RESISTANT ALUMINUM PLATE

Exfoliation and fracturing problems observed on the high speed passenger vessels JET CAT EXPRESS and HULA KAI recently lead to the discovery that ALCAN ALUMINUM CORPORATION 5083 H321 cold rolled aluminum plate used in both vessel’s construction is not guaranteed for marine application, as it is susceptible to corrosion. This has raised some concern for the continued use of this material. As a result, the following interim guidance is provided with regard to this material:

For New Construction:

1) It is strongly recommended that shipyards only use corrosion resistant aluminum plating in vessel construction.

2) It will be required that corrosion resistant plate be used in those areas where exfoliation corrosion is of concern (e.g. bilge spaces, chain lockers, etc.).

3) If non-corrosion resistant aluminum plating is to be used in other areas, it will be required that the plate be protected and inspected in a manner similar to that outlined in the DNV High Speed and Light Craft Rules.

4) It is strongly recommended that shipyards be very precise in their purchasing specifications and request a “marine grade – corrosion resistant” aluminum plate for future applications.

For Existing Vessels (those already in operation or in an advanced stage of construction):

1) We will work with local yards and operators to determine what vessels operating in this zone were constructed with the ALCAN 5083 H321 cold rolled aluminum plate.

2) Inspect those existing vessels in operation to see if there are any signs of similar exfoliation or fracturing.

3) Develop on a case-by-case basis the need for more frequent inspections and/or plate protection (e.g. coating the plate if it is not coated).

If you have any questions, please contact Lieutenant Commander Tom Miller of my staff at the above address or phone number.

M. R. MOORE
Captain, U.S. Coast Guard
Officer in Charge Marine Inspection