The
modern-day journey for one of HRNM’s largest artifacts, a 200-year-old anchor,
began in 1993 (read part 1 about the anchor here). In order to treat the anchor and preserve it for the future, Dr.
Brad Rodgers of East Carolina University constructed a preservation tank in
November 1993. His team built the tank by digging a hole, lining it with cinder
blocks, and then pouring concrete to create the tank’s walls. They built an I-beam
superstructure over the tank that would allow them to raise and lower the
anchor as well as turn it over. The tank held 4,000 gallons of water and was
fourteen feet long, nine feet wide, and four-and-a-half feet deep.
The anchor being delivered to HRNM after preservation was completed. |
Throughout
the process the conservation tank was filled with either distilled water or
rainwater. Once the anchor was submerged in this water, conservationists added
sodium carbonate and placed steel anodes over the shank and arms of the anchor.
The anodes did not make contact with the anchor, but formed a tent-like
structure over it instead. An electrical current then ran through the anodes. This
complicated procedure allowed the corrosion on the anchor to change from its original
state into magnetite or hematite, which reduced the thickness of the corrosion
and allowed chlorides to rinse out of the anchor. Conservationists emptied the
tank halfway and refilled it with fresh rain or distilled water several times
throughout the process. This was continued until all of the salt was removed
from the anchor.
Dr.
Rodgers estimated that five percent of the anchor’s weight, or sixty pounds,
was salt. After the anchor was preserved, it was painted with several
protective coatings. On average, the preservation process takes four to six
years, but a number of hurricanes delayed the process. In 1999, Hurricane Floyd’s
rains contaminated the tank with mud and other debris. After the hurricane Dr.
Rodgers and his team decontaminated the tank and re-started the process from
the beginning. It was not until December 2005 that the anchor’s preservation
was finally completed, and it is now on display at the Naval Museum.
(This blog post was written by HRNM Public Relations Coordinator
Susanne Greene.)
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