Mark Everett Coates III, of Havre de Grace, was last known to be operating a 10-foot jon boat near the Hatem Memorial Bridge (US 40) around 5 p.m. on Wednesday, Nov. 4, according to the Maryland Natural Resources Police.
Coates had launched the vessel from the Water Street Boat Ramp in Havre de Grace before heading onto the river.
On Thursday morning, Nov. 5, officers were dispatched after the boat was discovered overturned near Garrett Island, prompting a search involving multiple agencies.
The US Coast Guard, Susquehanna Hose Company, Harford County Emergency Services, Harford County Sheriff's Office, Chesapeake Search Dogs, and other agencies are assisting Natural Resources Police, with dive teams and aviation resources deployed.
Coates was last seen wearing a chartreuse long-sleeved shirt and blue jeans.
Authorities are asking anyone who may have seen boating activity in the area or knows where Coates may have been since leaving Havre de Grace to contact the Maryland Natural Resources Police at 410-260-8888.
Boaters are also being urged to avoid the stretch of the Susquehanna River between the US 40 and I-95 bridges while search operations continue.
The circumstances surrounding the capsized boat remain unclear.
Check back for updates.
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