Huge buoy washes ashore in Delaware Seashore State Park
Story Location:
Conquest Road
Rehoboth Beach, DE 19971
United States
The sedan-sized buoy of a mooring used to anchor an experimental, wave-powered desalination machine off the Delaware coast washed up near Conquest Beach in Delaware Seashore State Park recently.
The machine was deployed by Maryland-based Murtech approximately four years ago. In an email Sept. 27, Robert Murtha, Murtech president and founder, said the buoy was installed a little longer ago – five years. It was located approximately one mile offshore, in roughly 30 feet of water, just north of the Indian River Inlet in the permitted testing area, he said.
Murtha said the movement of the buoy’s anchor chain on the seafloor is what caused wear that led to a break.
“The buoy has bobbed up and down millions of times with the wave activity over the past five years,” said Murtha.
There is a 2-inch-diameter anchor chain holding the mooring in place, which is attached to the bottom of the float on one end and an anchor lying on the seafloor on the other, said Murtha. One link broke during a recent storm at the pivot point of the chain’s lifting and dropping on the ocean floor, he said.
The failure of the anchoring line occurs with all moorings, and they have to be replaced after many years of wave cycles, said Murtha, adding the company estimated a five-year-period before chain failure. Murtech can now establish performance data and apply it to projected inspection and maintenance approaches for future deployments, he said.
Murtha said he and his team had a reasonable expectation the buoy would wash ashore on a beach somewhere near the mooring location.
“The predominant wave direction close to the shore as we are gives us some idea where it might go. There is a very strong longshore current – current running parallel to the beach – that moves up and down the Delaware coast,” said Murtha.
The anchor and chain are still on the ocean floor. The company will be replacing the chain from the worn link point and then putting a refurbished buoy back on station in the coming months, Murtha said.
Murtech will be ready to start additional system evaluation and validation in spring 2022 on its wave energy converter, where fresh water is being made using wave energy to desalinate sea water, said Murtha.
