The lobster boat, the Miss Melinda, caught fire just after 4:00 p.m.
It took firefighters quite a while to knock the fire down because the boat was in the harbor, several feet away from shore.
Rockport fire chief Bruce Woodward says the department used the harbor master’s boat to get as close to the Miss Melinda as possible.
Witnesses say thick black smoke could be seen for miles as crews worked to anchor the boat and knock down flames.
Eventually, the boat was brought closer to shore and sprayed with foam to extinguish the fire.
The two people on board the Miss Melinda were rescued by some nearby boaters. No one was injured, but two sail boats were also damaged by the fire.
There is no word on what started that fire.