When traveling through uncharted waters, one of the most basic questions a ship's crew needs to be able to answer is also one of the most important: How deep is the water? In fact, as Juet's journal entries show, Captain Hudson and his crew repeatedly faced the danger of running aground while exploring the river that would bear his name.
Monitoring water depth is just as important for us on board the Replica Ship Half Moon. Of course, in 21st century the Hudson River has been throughly charted and (unlike Captain Hudson) we have experience navigating this river, but that doesn't mean there are no uncharted waters for us to explore. On Day Two, we chose to travel down the narrow, secondary channels between Cementon and Kingston.
When in doubt, we take soundings (measure the water's depth) with the same tool Hudson's crew would have used: a lead line (or sounding line). Flags attached to the lead line mark depth in 6-foot increments (fathoms). The Half Moon has a draft of 8-1/2 feet (extending that far underwater), so it needs at least a fathom and a half of water to stay clear of the bottom.