The collection of cannon that this report will focus on is referred to as the “Cannon Site“, located within the boundaries of Cahuita National Park in the Limón Province of Costa Rica. The Cannon Site has a perimeter of 529 meters and an area of 9,491 square meters. The area experiences a variety of natural factors influenced by the sea, from calm to rough currents, with large swells and heavy surge (Harris, 2015). The farthest point of the Cannon Site is located approximately 257 meters from shore and ends 32.4 meters from shore. The site includes 15 submerged cannons, mostly dived among three areas containing cluster patterns. Below is a map of the cannon in Figure 1.
Figure 1. Map of Cannon locations provided in ECU field report 2015 (Harris, 2015).
When iron artifacts, including cannons, become submerged into the water it begins a process of emerging into the environment. Overtime the iron from the cannon begins to rust underwater and begin a corrosion process. As time passes, the cannons are covered by the mud, shell, and sand mixtures known as concretions.
Figure 2. Cannon# 13 Cannon Site, Cahuita Costa Rica. Photo by. Tyler Ball 2016.
Concretions act as protective barrier from preventing the damaging process of iron corrosion. Routine corrosion rate measurements on a marine site with ferrous objects is immensely valuable to understanding the site formation processes and are an important tool for cultural resource management (MacLeod, 2011). Concretions can only protect artifacts so much. A pattern of frequent interference resulting from tourism and treasure hunting will damage the concretions, as well as the artifacts.
Work Cited
Harris, Lynn et. all
2015 TANTALIZING TALES OF TWO SHIPWRECKS: CAHUITA NATIONAL PARK SITE REPORT. East Carolina University, Department of Maritime Studies. Report sent to Ministry of Environment, Energy and Telecommunications. Cahuita, Costa Rica.
MacLeod, Ian D, and Vicki L Richards
2011 In Situ Conservation Surveys of Iron Shipwrecks in Chuuk Lagoon and the Impact of Human Intervention. AICCM Bulletin 32(1). December:106–122.