"We were about a mile and a half offshore when all of a sudden this boat came up lickity split, came up against the port side of the boat and slammed into us," Barry McKay said.
McKay, who is a doctor, said he feared for his life when he saw more than a dozen men in Mexican Navy uniforms aiming machine guns at him.
"I think we're in deep trouble, I thought they were going to shoot us and kill us and take the boat," he said.
McKay said the men eventually let him go when he showed I.D. and a fishing license. It was unclear as to why he was detained.
The 27-foot boat shows signs of damage on the exterior, as well as the interior. It could cost more than $2,000 to repair the boat.
He said he won't be going down there again anytime soon.
Some say incidents off the coast of Mexico are becoming more common.
Last April, a larger boat carrying a group of scuba divers off the coast of Mexico was detained for two hours.
"More people seem to be avoiding foreign waters at this point. The word among boaters is caution, caution, caution," boat mechanic Dan Stuart said. "The sad part is you're relying on the authorities in Mexico, but then you don't know are they really authorities or just people in uniform?"