More than 180 volunteers answered the Jacksonville Fire and Rescue Department’s call for more boats in the search for missing firefighters Brian McCluney and Justin Walker Tuesday. Today is the sixth day of the search, and officials warned that the efforts were reaching a critical stage.

On Tuesday, more than 70 boats launched from Mayport at the mouth of the St. John’s River— double the number of vessels from Monday’s volunteer effort, according to Action News Jax.

Today volunteers sallied from Jacksonville, Brunswick and Savannah as officials asked for help from anyone with a boat with sufficient range to travel 60 miles offshore and back. The offshore forecast was favorable, calling for 5 to 10 knot southwest winds and 2-to-3-foot seas.

McCluney is a member of the Jacksonville Fire and Rescue Department and and Justin Walker is a member of the Fairfax County Fire and Rescue in Virginia. The two left from Port Canaveral for a day of fishing at what is known as the 8A reef.

On Monday, a search volunteer search found one of the missing men’s tackle bag about 50 miles off the coast of St. Augustine, the only clue found so far.