What item was originally designed to help overboard sailors?

When a powerboat is operating at night from which directions must the white masthead light be visible? What are the the three main offshore oil rigs in Canada? How nice is the Celebrity cruise ship reflection? You see a white baby with orange markings and black lettering what type of buoy is this? What main destinations might be included on Baltic cruises? What does a white Non-Lateral Marker with orange circle indicate? How do you reinstall lower unit on a 1974 9.8 mercury outboard motor so it will shift properly? How do you make a pedal boat? In oregon can a passenger drink on a boat? What year did john finch invent the steam boat? What is the Rafter spacing on flat roof mobile home? Whenever the boat is underway properly sized PFDs must be worn by children of what age in Alaska? What would cause a 350 Chevy boat motor to sputter and occasionally backfire at any speed or even when idling but then at other times run fine? How do submarine use Archimedes' principle? How has the development of a periscope changed over the years? What is a 2 masted sailing ship called? How old do you have to be to get a boat license? Does Disney offer a cruise and park vacation package? What year is your evinrude motor model 9322b serial c90901? How can a concrete or metal boat float?