The buoy can float at the surface (lasting 3–4 years) or lie subsurface to avoid detection and surface hazards such as weather and ship traffic. Subsurface FADs last longer (5–6 years) due to less wear and tear, but can be harder to locate.
Buoys can stay on the water's surface for 3-4 years or be submerged to avoid detection from weather and ships. Submerged buoys endure longer (5-6 years), but are more difficult to find.