buoy buoys float floating floats lake S sea water waves beach control international larbord lifebuoy nautical old orientation port side red regulation seafaring seaside sign stroke side surface marker buoy assist assistance buoyancy circle circular flotation device help kisby ring life preserver life saving buoy lifebelt lifering lifesaver perry buoy red and white rescue rescue aid rescue device ring buoy safety safety device security anchored data-collecting-buoy dissolved-oxygen electronic-data-transfer estuarine estuary fish-kill-mitigation floating-device fresh-water improving-understanding monitoring-buoys moored oxygen-levels salinity salt-water scientific-advisory solar-panel solar-powered stationary tidal tide water-quality water-quality-management rope sand seashore blue coast harbour reflection sea water mess river stone boat life-buoy saver secure ship