The repeated, rapid scurrying of a hand over paper interrupts the faint squeak of an eraser that had broken the silence of the pilothouse only moments before.

The slight scratch of a pencil follows.

The timid sounds, like those of a mouse scampering through the walls of an old house, are the only noises that betray a human presence in the dimly lit room.

The low, red glow of a night lantern illuminates the chart in front of Petty Officer 2nd Class Christopher New. He performs a quick calculation, adjusts the compass legs to a wider setting, and smoothly arcs a pale circle around the ship's current position -- a prediction of their location one hour in the future.

New is one of seven enlisted navigation personnel who serve aboard amphibious transport dock ship USS San Antonio (LPD 17). Their job is to safely navigate the ship through the world's oceans, paying attention to a vast amount of data encompassing everything including the depth of the water, ocean currents, ship's speed, territorial boundaries, and even the weather.

Since humans first began sailing the oceans, navigation has been critical to the success of any voyage. Consequently, the job of a quartermaster has existed in some form or another for tens of thousands of years before New became one of San Antonio's navigation personnel.

Even with the advent of GPS and satellite imaging technologies, the job is no less important or demanding. The U.S. possesses one of the world's few blue-water navies capable of sustained maritime operations worldwide. As such, these Sailors who specialize in navigating are expected to be able to direct the ship in waters that are wholly unfamiliar.

"We still use paper charts as our primary navigation tool [aboard San Antonio]," said New. "When we begin voyage planning, we have to determine where we're going, and then find out if we have the charts for that area on board. If not, we have to order them."

From there, they work with the ship's navigation officer to determine the track of their voyage, which will sprawl across many charts as they navigate around hazards, through straits, and keep outside of foreign territorial waters -- sometimes by only the breadth of several hundred feet or yards. It's a daunting mathematical task that offers little room for error.

"Planning is the most difficult part of the job," said Lt. j.g. Charles Cahoon, the ship's navigation officer. "We have to predict where we will be on the route at a specific time on a specific date days in advance, and things change so quickly. One day we might slow down to do flight operations, and then we have to readjust everything."

The Sailor on duty, known as the quartermaster of the watch, is responsible for recommending course corrections and for periodically marking the ship's position. They also determine dead-reckoning positions, which are predictions of the ship's future location. The dead-reckoning is updated every hour and every time the ship's speed and course are adjusted. This can mean dozens of small adjustments, erasing, and re-plotting in the span of an hour.

"We also gather weather information like temperature, sea state, and barometric pressure," said New. "Every six hours, we compile that into a report to send out."

Since the mid-2000s, the Navy has been in the process of converting entirely to digital navigation. This began with the introduction of the Electronic Chart Display and Information Systems-Navy (ECDIS-N) standard, utilizing the Voyage Management System (VMS) software.

The process has been delayed due to budgetary constraints in equipping the many ships of the fleet. San Antonio is one of the last ships to still utilize traditional paper navigation -- something that is scheduled to change very soon.

"This is the last year we'll be using paper," said Chief Petty Officer Jussuam Cardoso, the navigation department leading chief petty officer. "When this deployment is over, I'm sending my guys off to school to learn the new systems. When they get back, it'll take us a couple months to become qualified with the new VMS, and then we'll be entirely digital."

Charts and the open sea have gone hand-in-hand for centuries. The compass, protractor, triangles, and dividers have been iconic of nautical navigation from time immemorial.

The modernization of the Navy's navigation systems is inevitable and will lead to more efficient navigation. Until then, San Antonio will be plotting a course according to the scale of the chart -- one inch at a time.

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