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