In what would be a sea change for the boating public, the U.S. Coast Guard is weighing whether it should require recreational boaters to wear life vests, not simply carry them on board.

The Coast Guard also is considering requiring recreational boat owners to complete a boater safety course.Both initiatives would be aimed at reducing boating accidents that caused 709 deaths nationally in 1996 - 500 of them from drowning. Of those who drowned, 440 were not wearing a "personal flotation device," commonly known as a life vest or life jacket.

"In most boating accidents, it's not like you can say, `Oh gosh, we're sinking. It's time to put on a life jacket.' Usually, it's wham!, something happens, and all the sudden you're in the water," said Lt. Gary Bracken, a Coast Guard spokesman.

"There's no doubt that wearing personal flotation devices would save lives."

Carl Perry, project manager for the proposed rule changes, said the requirements were only one idea under consideration for reducing boating deaths. The Coast Guard has not yet considered details such as what size boats might be exempted from such a requirement.

Both proposals ran into public opposition in a public comment period that ended Friday.

Concerning a life-vest use requirement, 315 of the 416 individuals or groups who responded by April 1 were against it. Sixteen supported it and 73 favored limited federal requirements, such as requiring that children wear them.

Regarding the boater safety proposal, the Coast Guard received 95 responses as of May 15, and the majority opposed it, even though no specifics have been released.

Dan Van Wormer of Ophelia, Va., who runs a sports-fishing and charter service in the Chesapeake Bay, said he has offered passengers life vests throughout his eight years in business. Almost everyone has refused it, saying it is too hot, bulky or restrictive.

In light of complaints about the discomfort of standard life jackets, the Coast Guard last year started approving inflatable vests for recreational users.