The Coast Guard has released the results of a study of ice accretion and ice accumulation on fishing pots, specifically crab/cod pots used in the Alaska/Bering Sea fishery.
In December 2020, a Coast Guard Marine Board of Investigation requested Coast Guard Research and Development Center (RDC) assistance for the study following icing factors involved in the loss of the fishing vessels Scandies Rose in 2019, and the Destination in 2017.
The board noted that initial evidence suggested vessel icing, including the possibility of asymmetrical icing, was a causative factor in the Scandies Rose loss of stability and, ultimately, its sinking. The MBI also noted the investigation into the 2017 loss of the Destination revealed that excessive icing directly contributed to the vessel loss of stability and rapid capsizing.
Due to the repetitive nature of these accidents, the MBI requested RDC assistance in determining how ice accumulation occurs on the non-solid surface of the pot cage, the netting, and gear within the pot, as well as the added weight of ice accumulation over time.
RDC conducted initial tests with the Coast Guard Cutter Polar Star during an Arctic Winter West patrol. Operating limitations prevented an in-depth analysis, so RDC planned a full series of follow-on tests in a controlled environmental chamber at U. S. Army’s Cold Regions Research and Engineering Lab.
The experiments showed that in certain situations:
- a single trap could accrete more than its own weight in ice,
- ice accretion thickness could be a rough indicator of weight gain,
- and covering a pot or stack of pots with a tarpaulin (“tarp”) prevents ice accretion on the frame, mesh netting, warps and floats.
“It is our hope that these findings inform industry and policymakers to make decisions to prevent future casualties as a result of asymmetrical icing,” said Captain Greg Callaghan, Eleventh Coast Guard District Chief of Prevention, and FV Scandies Rose Marine Board of Investigation Chairman. “We are grateful for the team at RDC who worked tirelessly to support the Scandies Rose MBI, from our initial interaction to coordinate the experiment on the Polar Star, to the planning and execution of the Ice Accretion Study. Their efforts have provided significant insight critical to saving lives in this industry.”