Dye Dispensing Towed Vehicle

Fluorescent dyes are ideal for tagging the water column to aid in determining water motion and transport. The tagging of water is relatively simple when it is a small stream, but more difficult if the water to be marked is below 100ft in the open ocean. A vehicle can be towed from a surface vessel to deliver dye to the water column as appropriate for the particular study. Two possibilities exist for dye dispensing at depth in the ocean: pumping the dye from the surface to the towed vehicle or carrying the dye on board the towed vehicle. Supplying dye to a vehicle at depth from a surface vessel is possible, but ultimately complicated and often messy. A simpler approach is to carry the dye supply to depth in the towed vehicle and to equip the towed vehicle with its own pumping and distribution system. To complicate matters it is generally desired to have a wide range of pump rates and multiple methods of distribution, such as point and line sources. The two methods of dye distribution are compared. The design of a very successful dye depressor is presented, along with discussions of depressor design, handling, pump rates, distribution methods, and towing considerations.