A new video documents the fairly unsung work of the San Francisco Bar Pilots, an elite group of local maritime experts and ship captains who board huge container ships and cruise ships to help them safely navigate through the Golden Gate.

If you haven't heard of the San Francisco Bar Pilots, you're not alone. They're a team of 60 skilled maritime pilots who are part of an organization that dates back to 1850, essentially to the founding of the city itself. For as long as ships were traveling into San Francisco Bay, ship captains without the specific local knowledge of currents, winds, and water depths — particularly around the channel leading into the Bay, and the huge San Francisco Bar, a horseshoe-shaped sand bar under the water about five miles out from the Golden Gate.

A new documentary short by Sam Eckholm shows how San Francisco Bar Pilots board massive container ships 11 miles out to sea, with their small pilot boats pulling up along side, and the pilots having to just jump over to a ladder without any harnesses or safety equipment, and climb onto the ship. They then take over from the captain of the ship in order to safely guide the ship through the channel and to one of a half dozen ports in the Bay, including Oakland, San Francisco, Redwood City, and Richmond.

These pilots are responsible for guiding about 8,000 entries and exits in the Bay every year, which amounts to more than $40 billion in annual trade. And as you may recall, it was an intoxicated pilot who was deemed responsible for the Cosco Busan oil spill disaster in San Francisco Bay circa 2007.

Maritime pilots do similar work at the ports of Los Angeles, New York, and Baltimore, and up in Oregon, there are also bar pilots to navigate through the similarly tricky Columbia River Bar.

"There's really no other profession that requires so many different things to be perfected in order to succeed," says Captain Paul Ruff with the San Francisco Bar Pilots.

In the video, Eckhorn explores the two types of vessels that the Bar Pilots use in and outside the Bay, and joins them in treacherous boarding of a container ship 11 miles out, documenting the navigation into the Bay.