Mackinac Island is a National Historic Landmark located in Lake Huron, one of the Great Lakes of North America. The small island (3.8 square miles or 9.8 square kilometers) is part of the state of Michigan and is located at the eastern end of the Straits of Mackinac.
In a twist to traditional open water swimming relays and a nod to the "carbon-neutral" option, four swimmers swim - and walk - around the island during the Great Turtle Relay Swim Around Mackinac Island. This year's event will be held tomorrow, July 27th.
The four swimmers of each relay rotate in the water every 20 minutes. When it is not their turn to swim, the swimmers walk around the island. Each relay member swims for 20 minutes and then walks for 60 minutes until they finish the approximately 11-12 mile circumnavigation of Mackinac Island.
Relay exchanges are done in the water and each team is escorted by a kayaker. Wetsuits are allowed with the water temperature expected to be 63˚F (17˚C).
This swim-walk relay, escorted by a kayak around an island that bans nearly all motor vehicles is another example of the growing "carbon-neutral" open water relay phenomenon. Whereas the Mackinac Island Relay is a swim-walk relay, the "carbon-neutral" option first established by Doug Woodring in the 15K Clean Half relay in Hong Kong is a swim-paddle relay where swimmers have the choice to swim and paddle in an outrigger canoe.