SEATTLE (AP) — Drowning by people using stand-up paddleboards has increased and authorities say it’s because the victims did not use a life jacket.

The Coast Guard recorded 11 total paddleboard fatalities in the nation in 2017 but three already this year in western Washington. All three involved people who drowned while not wearing a life vest.

The Coast Guard classified paddleboards as vessels in 2008. The agency required users to wear a life jacket or attach it to the board. Paddleboarders younger than 13 must wear the life jacket.

A 2014 study by the University of Washington and the Fred Hutchinson Cancer Research Center said many adults reject life jackets. They call them uncomfortable, consider themselves expert swimmers or make poor choices because of alcohol.

Not wearing a life jacket on a paddleboard can result in an $87 fine.