Corin Nemec -- star of the '90s sitcom "Parker Lewis Can't Lose" -- is recovering from emergency surgery ... after he shattered his leg and lost TONS of blood in a bad boating accident this weekend.
Nemec says he was on board a Coast Guard vessel in Belize on Saturday morning -- on his way to shoot a scene for a movie -- when the boat crashed into a semi-submerged barge.
Nemec claims he suffered major injuries in the wreck -- and was transported to a nearby hospital for emergency surgery.
The actor -- who was working on the movie "Poseidon Rex" -- told a local news reporter, "We hit the sinking barge, and that is what filled the boat to one side immediately with an enormous amount of force, and that threw me into the side of the boat where I shattered my femur in 3 places."
41-year-old Nemec says the break was so bad, he lost over half the blood in his body -- and he required multiple blood transfusions to save his life.
"Everybody onboard that boat, including the gentlemen working for the Coast Guard, everyone is lucky to be alive," Nemec said.