| Plate Fleet
Shipwrecks |
| |
- History: |
| |
|
- |
| |
|
- |
| |
- |
|
| |
- |
|
| |
- |
|
| |
- |
|
Florida Keys
National
Marine Sanctuary |
| |
- |
|
| |
- |
|
| |
- |
|
| |
- |
|
|
|
|
|
A badly corroded
cannon from the 1733 fleet |
As you drive along the Overseas Highway
through the Keys, look for iron cannons and anchors
in front of restaurants, strip malls, marinas, and in
roadside parks. These artifacts were salvaged from 1733
fleet wrecks and other ships before the consequences
of removing waterlogged objects from the marine environment
were realized. If you stop to inspect the artifacts
you’ll see the effects of long-term
corrosion. Large pieces of the metal are literally peeling
off and rusty flakes and chunks pile up under the remains
of the cannons and anchors. Eventually, they will crumble away to nothing. The reason for this deterioration is lack of proper conservation when the object was taken from the sea. Iron and other metals react with
|
Poorly preserved anchor with ballast stones attached |
seawater forming, over many years, a
hard covering of corrosion products called concretion
that often includes sand, shell, and coral from the surrounding
environment. If the object is taken from the water and
not conserved to remove salts and stop the corrosion process,
it will quickly begin to fall apart. Ceramic, glass, and
organic materials such as leather, rope, wood, and bone
also require conservation to remove absorbed salts, to
preserve their appearance, and to stabilize for curation
and exhibition.
Conservation methods depend on the type of artifact and include soaking in fresh
water and treatments with various chemicals to prevent
warping, crumbling, and shrinking. Metal artifacts often
are treated by electrolytic reduction to remove concretions
and restore the metal. In the case of large iron objects
such as cannons and anchors, conservation treatment can
take years and become extremely costly. For these reasons,
archaeologists often prefer to leave cannons and anchors
on shipwreck sites. Over time the artifacts reach a state
of equilibrium with their environment and, if not disturbed,
will last for centuries. Wouldn't you rather see a shipwreck looking as it did when it wrecked with its cannons in place instead of rotting on the roadside?
|
|
 |
|
|
