A simple, relatively portable, and inexpensive spar buoy has been constructed to provide a platform for supporting instrumentation above and below the ocean's free surface. The buoy is 18.9 m long and weighs 76 kg in air; the combined ballast and instrument payload weigh 65 kg. The buoy consists of buoyant sections that are easily dismantled and may be varied in number to alter the buoy's overall length, draft, and payload....