ROCKLAND — Saturday will be a busy day in and around Penobscot Bay and the Midcoast, as the Emergency Management agencies of Knox and Waldo counties will play host to a multi-agency emergency drill on and around Lasalle Island and points in Camden, Rockport and Rockland.

Maine State Police, U.S. Coast Guard and Maine Marine Patrol units, collectively called Unified Command, will work with local emergency responders in this final event, capping a months-long exercise series of planning events.

The scenario involves responding to a downed passenger airline, which emergency responders will be told has made an emergency water landing near Lasalle Island on the morning of Oct. 13.

"We are conducting this exercise to validate planning and response protocols, which would be used in coordinated response to a variety of multiple-victim type accidents on the waters of Penobscot Bay," said Knox County EMA Director Ray Sisk in a briefing. "We have chosen the aircraft scenario, but the response would be similar for accidents involving ferries, schooner or cruise-type vessels."

The full-scale exercise will involve emergency responders from Knox and Waldo counties, as well as State Police, Marine Patrol, U.S. Forest Service, Coast Guard and the American Red Cross. Ham radio operators are being utilized to help maintain communications, with a base of operations to be set up atop Mt. Battie in Camden Hills State Park.

Responders will include mainland and island-based emergency medical service entities, search and rescue teams and members from area local fire departments. Overall, Sisk estimated there would be approximately 75 exercise participants, including exercise players (actors), responders, managers, evaluators and safety staff.

Sisk said the most visible part of the exercise, which will involve boat activity in the bay around the island, as well as between Lasalle and Rockland Harbor, will occur between 8 a.m. and 2 p.m. Saturday. Harbor Park in Rockland, Pen Bay Medical Center in Rockport and Camden Hills State Park will be three of the active mainland locations viewable by the public.

"We are ferrying some exercise victim-actors to the island on the M/V Betselma from Camden Harbor. An incident command post will be operating from Harbor Park and responders will be departing from there on their assigned missions. Waterborne rescue personnel will travel to the physical exercise location on Lasalle Island by a variety of state, local and federal agency boats," said Sisk.

A Unified Command Post will be set up at Harbor Park in Rockland, with Knox County EMA and affiliated staff operating from the County Emergency Operations Center at the EMA offices at 62 Union St. in Rockland.

For those wondering what to expect to see, Sisk said at least one state Mobile Command Vehicle and a communications support trailer would be set up near the marine stage at Harbor Park. From there, participants will gather and receive incident briefings at 8 a.m. , and those leaving for the island would be departing by 8:45 a.m. by boat.

Those people would be returning to Harbor Park around noon for debriefings and exercise wrap-up, said Sisk.

The largest privately-owned residential yacht, The World, is set to drop anchor in Rockland Harbor around 1 p.m. Friday, Oct. 12, and stay through 8 p.m. Sunday, Oct. 14. The 644-foot-long vessel and its nearly 200 passengers will be sharing the public pier with the entities involved in Saturday's training, but Sisk said arrangements have been made to allow for security and ease of movement for both activities. The ship's captain and crew have also been briefed on the exercise in order to apprise passengers that the emergency activity they will be witnessing "is only a drill."

Anyone with questions or concerns is asked to contact Knox County EMA at 594-5155 or Waldo County EMA at 338-3870.

"We welcome observers and if you would like to participate in any way, please contact us," said Sisk.