Pedal boats are designed for gliding on freshwater bodies such as lakes, ponds and calm sections of rivers. They don’t handle well in currents or strong winds and the materials and components are not designed to withstand saltwater abuse.
Using a standard pedal boat in saltwater can cause it to deteriorate rapidly as most of the component will rust and wear out fast when exposed to salt water. If you would like a pedal boat you can take out in saltwater, choose one with a stainless steel package that can resist corrosion and damage by saltwater and be diligent about rinsing it out with fresh water after every ride.