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The Key to Locks

Inland waterway cruising often involves passages through multiple locks. Here’s how to handle them.
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A  determined boater could spend a lifetime navigating the inland canals in the United States, with more than 25,000 miles controlled by the U.S. Army Corps of Engineers alone. Early canal builders quickly realized that connecting bodies of water at different elevations would only result in draining the higher into the lower, so locks were invented to hold the higher water back while still allowing a vessel to pass through. Nationally, the Corps maintains 239 locks as part of its responsibilities.

Safely handling a boat through a lock requires planning and familiarity, as not all locks operate the same way.

Locks are operated by lockmasters, who control and manage vessel traffic. Lock tenders see thousands of boats pass through, and they know what it takes to keep a boat safe in their lock.

Bob Peek, a retired lockmaster on the Dismal Swamp Canal in Virginia, described his job in The Virginian-Pilot: “The bottom of the lock gate is called a sill, where the gates come together. Once your boat crosses that sill, that is my boat, until you cross my other sill. You may be the captain of your boat, but I am the master of the lock. If I ask you for a particular line on the boat, a bow or a stern or what have you, these aren’t whimsical requests. There’s a reason why I ask for certain things, and it’s important that they follow my instructions.”

Locks in areas of heavy commercial traffic may operate 24 hours a day. In waterways with primarily recreational boat traffic, locks will typically be limited to daytime hours. Be sure to check the lock schedule, especially at the end of the day. It would be unfortunate to arrive at a lock past its operational hours with no place to tie up for the night. The lockmaster determines the locking priorities, with commercial vessels and tow boats having priority over recreational boats.

Locks typically monitor VHF channel 13. Just like when approaching a drawbridge, you must call the lockmaster with a request to pass through. Most locks will also have a pull cord hanging down on the entrance fender system, to notify the lockmaster of your interest to lock through.

And, locks have signal lights to indicate when it’s safe to enter the lock. Always wait for a green light before proceeding into the chamber. A red light indicates that the lock is in use, or is cycling to your depth. Do not wait directly outside the lock chamber; boats locking in the opposite direction need clearance to exit. It’s like waiting for an elevator: You have to stand aside and let people out before you can step in.

All locks require persons out on deck to wear life jackets. The lockmaster will instruct you about which side of the lock to tie your boat, and where in the lock to tie. Fenders are your friend. You can’t have too many. Lock walls are typically rough concrete or steel, which would damage the most durable rubrail. Your boat will be held close to the lock wall as it rises or falls, so fenders are necessary to protect the boat’s sides.

Locks with a slight rise or fall may only require you to secure your boat to bollards or cleats on the top of the lock wall. Locks with a significant change may have lines hanging down the inside wall. You will wrap those lines around a cleat on your boat, and take the lines in or let them out as needed. Lockmasters may ask you to take the line to an outside cleat, as it will hold your boat closer to the wall. Some locks will have floating bollards recessed into the lock wall; those bollards will rise and fall with the water level.

Regardless of the arrangement, a boat should have multiple crew members to handle the lines at the bow and stern. Durable, waterproof gloves will come in handy, as the lines that hang in the lock chamber can be pretty foul.

Some locks use valves below the water level to fill or empty the lock chamber from below. In these locks, other than the rise or fall of the water level, you will perceive very little movement while the lock is filling or emptying. Other locks simply open the doors on one end to allow water in or out. In these locks, the turbulence inside the chamber can be significant. Attachment to a strong, well-backed cleat is important to hold the boat steady.

In busy areas, you may not be locking through alone. Most locks are sized to accommodate multiple boats. If locks are holding boats on both sides of the lock, then it may be a good idea to place fenders on both sides of your boat. In some waterways, it is not uncommon to share the lock with canoes or kayaks. In these instances, be extra cautious, as it is easy for them to be below your line of sight. You may also be sharing the lock with marine life passing through. In Florida’s Okeechobee Waterway, for instance, manatees regularly accompany boats in the lock.

Locks can be gateways to new cruising grounds. With careful preparation, you can pass through them safely to new adventures that await on the other side.

This article was originally published in the September 2022 issue.

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