Faulty dead reckoning cited in Puget Sound yacht sinking

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The following is a marine accident brief from the National Transportation Safety Board (NTSB):

(WASHINGTON) — The National Transportation Safety Board issued Marine Accident Brief 20/20 on Thursday for its investigation of the July 23, 2019, sinking of the recreational vessel Silver Lining.

No injuries or fatalities were reported in connection with the accident that resulted in an estimated $500,000 in property damage when Silver Lining, with eight people on board, struck an underwater rock formation, took on water and sank near the Hood Canal Bridge, Puget Sound, Wash. The NTSB investigated this accident because the U.S. Coast Guard declared the accident a major marine casualty and by statute the NTSB is required to investigate and determine probable cause.

With last week’s observance of National Safe Boating Week, MAB 20/20 brings into sharp focus the actions that led to the accident, including the operator’s loss of situational awareness and failure to use GPS to determine the boat’s position prior to changing course near a known and marked underwater shoal. The contents of the brief provide good lessons learned for recreational boaters, in both the errors made leading to the accident and in the proper emergency measures following.

The accident happened when the owner of Silver Lining, a 71-foot cabin cruiser with eight people on board, was preparing to change the boat’s course to port for passage through the western channel as it approached the Hood Canal Bridge.

As a navigational reference, the owner waited until the dinghy he was towing 100 feet astern passed the navigational marker on the southern part of the Sisters rock formation before slowing the boat’s speed and turning to port 10 to 20 degrees. Shortly after the starboard engine stopped, the engine shutdown alarm activated and the vessel began to vibrate as three loud banging noises came from the hull. The boat then came to a stop and the port engine shut down on its own. After the automatic bilge alarm sounded, the owner checked the engine room and confirmed the vessel was taking on water.

The owner instructed the seven passengers to don life jackets and to depart Silver Lining on the 12-foot dinghy. He then contacted the Coast Guard via the vessel’s VHF radio. The family departed the boat while the owner remained to try to start the engines and move the vessel closer to shore. Meanwhile the Coast Guard, local marine police and a salvage company were responding to Silver Lining’s location.

“There are many lessons for recreational boaters in Marine Accident Brief 20/20,” said NTSB Chairman Robert Sumwalt. “As the nation begins to reopen from stay-at-home orders due to the coronavirus pandemic and as we move toward a new normal, we need to get there safely. This report highlights the need for boaters to practice good seamanship and to know and follow emergency procedures. As boaters return to the water, I want to remind them to boat sober, wear lifejackets, don’t boat distracted, and always operate at safe speeds.” 

Click here to read the complete report.

By Professional Mariner Staff