The PICO buoy is a small, cost-effective moored ocean observation system that is safely and easily deployed. The enclosed design and low profile discourages boarding and vandalism. Electronics are housed in a central fiberglass well. The patented mooring line has unique shark-bite protection armor and is wound onto an integrated anchor spooling mechanism. The line spools out as the anchor falls to the sea floor. Data is collected by the Prawler, a sub-sea instrument which samples as it descends the mooring line, and then communicates the data via inductive modem to the surface buoy, eliminating the need for multiple instruments on the mooring line. Buoy software allows for flexible sensor configurations. When the Prawler reaches a pre-set depth, usually about 500 meters, a ratcheting mechanism harnesses the wave motion to crawl back up the mooring line. Even light wind-chop will power a climb back to the surface. Instruments on a mooring line measure at discrete depths, but the Prawler measures dense, integrated vertical profiles. The Prawler averaged 20 profiles per day at a deployment location just south of Hawaii. The PICO buoy is small, low cost and easy to deploy and recover. These buoys have been deployed from high latitudes to the tropics, measured nearly 20 tsunamis, and survived Category 5 typhoons.