The Asperida, a Copper-Nickel Sailboat after More than Thirty Years in Seawater
Harold T. Michels and Kenneth P. Geremia
Copyright NACE International. All rights reserved. Paper Number 05238 reproduced with permission from CORROSION/2005 Annual Conference and Exhibition, Houston, Texas.
The Asperida is a 16 m pleasure sailboat that was launched in 1967. The hull
is made of solid 4 mm thick copper-nickel alloy UNS C71500, which is supported by a 6 mm frame made of the same alloy. During its lifetime, the Asperida has had a few mishaps, including groundings and hitting submerged rocks. Although the hull
is dented and a small portion of the keel
is crumpled, the hull plates have not ruptured and the welded joints have not fractured. Biofouling resistance has been reported to be good, except for one incident in a notoriously problematic harbor in Spain
a few months after being launched. A plastic pot scrubber easily removed any growth on the rare occasions when biofouling occurred. Some areas of the hull have lost
a measurable amount of thickness, as determined by ultrasonic measurements, but overall, the loss has not been excessive. No meaningful corrosion
or localized attack was observed when the hull was inspected in June 2004. However, weld defects related to trapped gas were found. In summary, the hull, which is believed to be the oldest copper-nickel hull in existence, was in surprisingly good condition...
The final conclusion, in the report:
"... In view of its many attributes, UNS C71500 should be considered seriously as a hull material for pleasure boats, commercial ships and naval vessels."