How Locks Work

Chris Riley by Chris Riley Updated on July 31, 2019. In

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Locks are used to move boats between bodies of water that have different levels. This example, the St. Lucie Lock, is one in a series of five locks that allow boats to traverse the Okeechobee Waterway across the State of Florida from Stuart to Ft. Myers. When going east to west, you are lifted up by two locks to get to the Lake Okeechobee level and then after leaving the lake you are lowered down again by three different locks to get back to sea level at Ft. Myers.

As you approach a lock you should contact the lockmaster via VHF radio. The channel the lockmaster monitors may vary from area to area. There should be a sign posted at the entrance of the lock with instructions as to how to contact the lockmaster.

Use caution as you approach the lock and pay attention to the “traffic signal” at the lock entrance. If the signal is red you should stay well clear and keep an eye out for boats leaving the lock. Once the gates to the lock entrance are fully open and all traffic has exited the lock, the signal will turn green indicating that it is safe to enter the lock.

Prior to making your entrance, you should rig fenders on both sides of your boat and have lines ready at both the bow and the stern. Although many locks, such as the St. Lucie Lock, have lines available where they want you to tie up, you should be prepared and have your own lines should you need them.

Once you have entered the lock, like the two boats pictured here, the lockmaster will indicate where he or she wants you to stop. In the case of the St. Lucie lock, the lockmaster drops you two lines; one for the bow and one for the stern. Be careful as the lines are dropped and don’t let them hit you in the face. You should hold your arms outstretched and the lockmaster will drop the lines on your arms. You should take a wrap around a cleat on both the bow and stern and have a crew member at each position. Once secure, you should turn off your engine and, if equipped, turn off your radar.

Once all boats are secured in the lock, the lock gate that you entered is closed and the gate at the other end of the lock is opened slightly to allow water from the higher level into the lock in order to raise the boats in the lock to the new level. (Or out, lowering the water level, depending on the direction you are traveling.) As the water level rises (or falls) the crew members manning the lines on the bow and stern will have to take up the slack to keep the boat stable and in the correct position. You may experience a bit of current pushing the boat around caused by the incoming stream of water. Just be sure your fenders are secure and that your rub rail is not sliding up the side of the lock.

The difference in levels at the St. Lucie lock is approximately 15 feet. It is quite a site to watch; one moment you are looking down on a boat that has entered from the lower level and a few minutes later you are at eye level with the passengers.

Once the lock is at the new level, the exit gates are opened completely. You should start your engine before the lockmaster takes back the lines. Once clear of the lines, follow the direction of the lockmaster and exit the lock slowly. Be cautious of other boat traffic which may be waiting to enter the lock from the other side.

When you are finally clear and underway, take in the fenders.


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