Measuring the current is trickier than it looks. Our crew members learn that waves rippling across the water's surface are actually caused by the wind (and, with practice, can even be used to estimate wind speed) — but those ripples don't tell us anything about the current's speed or direction.
Waves may not tell us about the current, but debris floating in the water can. To measure the current, students toss a small piece of wood (cut down to size from driftwood) into the water, then time how long the marker takes to float down the length of the weather deck. Some quick calculations are then needed to determine in what direction, and how strongly, the water is pushing us.
On this voyage, the research team of Hayley, Jason, and Morgan studied current speed and height of tide for their research project on tidal patterns, collecting their data while the ship remained docked at Constitution Island. Our position proved problematic, however, since unseen eddies and inconstant currents would sometime draw our current marker straight away from the ship, often resulting in the marker never crossing the "finish line." Whether these currents are caused in part by nearby World's End, the deepest point on the Hudson River, we cannot say.
