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Navigating locks

Navigating locks
How to avoid panic when locking through
by Vern Hobbs

When we contemplate sailing, our thoughts run to images of open, uncluttered waters. In our idyllic daydream we see full, white sails running before a steady breeze on a blue sea. Nowhere in our lovely fantasy do we see the confines of a navigation lock.

Dealing with locks is not part of my romantic vision of sailing, but sometimes it is very much part of the reality of it. A shortcut across the Florida peninsula or the Isthmus of Panama, as well as a cruise through the Great Lakes, will involve passing through locks. The prospect of locking may be intimidating, but a bit of understanding, preparation, and basic seamanship will see you through.

Navigation locks are among mankind's longest-standing engineering achievements, dating back to the Renaissance. Locks are simply marine elevators used to move a vessel from a body of water at one height to a body of water at a different height. Over the centuries, civil engineers have developed many ways of building locks, from the very simple to the amazingly complex. Regardless of design, all serve the same purpose.

The cleat hitch is not a good idea when locking; it tightens under load. Lines must be able to adjust to a boat's rise and fall.

A safe hitch requires the bitter end to be held so the line may be let out or hauled in as the boat rises and falls.

Start by identifying the best resources

If there is a lock passage in your future, a good place to start is the nautical chart. Locks are depicted on the charts with the word "lock" and a notation of the width and length of the lock chamber. Larger-scale insets with more detailed printed data are often also presented. Sailors should evaluate overhead clearances as well. Power lines, gantries, and bridges are commonly found at or near locks.

More detailed information, including hours of operation and special usage rules, can be found in the appropriate United States Coast Pilot. This series of handy publications supplements information contained on nautical charts and is published periodically by the National Oceanic and Atmospheric Administration (NOAA). Coast Pilots are numbered to correspond with the Coast Guard district to which they apply. The most current editions may be purchased from NOAA chart agents or online at .

Temporary changes to the operational schedule or status of locks will be published in the Coast Guard's Local Notices to Mariners. Local notices are no longer distributed in paper form, but they may be viewed online at

While Coast Guard and NOAA publications provide a great deal of information, it is important to note that most locks in the U.S. are operated and maintained by the Army Corps of Engineers. This agency offers a wealth of information about lock navigation at and in printed publications, mostly free, that may be obtained by writing to: Commander, USACE Publication Depot, 2803 52nd Avenue, Hyattsville, MD 20781, Attn.: CEIM-IM-PD. In addition to general information, details about specific facilities and the procedures mariners should employ at them are provided.

The nation's second-largest operator of locks is the New York State Thruway Authority, which maintains the extensive New York State Canal System. This network of rivers and canals includes the fabled Erie and Oswego Canals, and it allows passage between the Great Lakes and the Atlantic Ocean through the Port of New York. Charts, schedules, regulations, and other vital information may be accessed through its website: .

Outside the U.S., locks are operated by a variety of private and governmental agencies, many of which impose stringent rules, schedules, and substantial fees for lock usage. A current cruising guide, an Internet search, and contact with cruisers who have recently used such facilities are all good resources.

Be observant of signs and signals as you approach the lock, above at left. Instruct your crew to judiciously use lines to maneuver into the mooring point, center. Don't be afraid to use fenders generously when locking, at right.

Prepare your crewmembers

Preparation and forethought are the first steps toward a safe, trouble-free lock passage. Making the boat and crew ready for a lock is not unlike preparing to enter a crowded marina. Think through the process and allow adequate time to have everything ready before reaching the lock.
A sailboat crew should take the following steps to prepare to lock through:
• Revert to auxiliary power. Start your engine, break out your oars, or call the towboat. Sails are useless and hazardous inside a lock chamber. Give your engine time to properly warm up, and check the operation of your forward and reverse gears.
• Take prudent precautions. Locking will require a lot of on-deck activity, which increases the risk of a crewmember falling overboard. Crewmembers should wear PFDs. Throwable rescue devices should be made ready for quick use. The crew must be able to move about freely. Sails, lines, and any unnecessary equipment should be stowed and secured.
• Prepare equipment. Fenders should be generously set along both sides of the boat. You may be required to moor to either side of the lock chamber or possibly even to raft up to another vessel. Corps of Engineers publications recommend a minimum of two 50-foot mooring lines, positioned fore and aft, loosely coiled and ready for use. A springline is also a good idea. In some locks mooring lines will be provided, but the prudent skipper will have his or her own lines ready should these "public lines" be unavailable or unserviceable. A stout boathook should be within reach of each crewmember who will be handling mooring lines. At least one member of the crew should have a sharp knife available in case a line needs to be cut.
• Make a plan and then share it. Evaluate wind and current and how each of these factors might affect your boat. Remember that structures in and around the lock will influence both these forces. The filling and emptying of the chamber will invariably create turbulence and strong undertows. Anticipate them and be prepared to react.

"Locks are simply marine elevators used to move a vessel from a body of water at one height to a body of water at a different height. "

Visualize how you plan to moor once inside the lock; for example, you might want to make fast your stern lines first, to check your way from a following current. Once you've made your plan, share it with your crew. Everyone must know what to do and when. Be certain that everyone is able to communicate. Review the commands you intend to give to signal which actions. Consider that voices may be difficult to hear over the length of the vessel. Work out and rehearse some simple hand signals. Finally, remind your crew about general precautions to observe while handling docklines and mooring to structures, especially if you have novice crew or non-boat-savvy guests aboard.

Proceed toward the lock

With boat and crew prepared, you are ready to proceed toward the lock. Identify and follow the marked approach channel so your vessel will remain clear of hazardous areas and will be correctly positioned to enter the lock.

Locks operated by the Corps of Engineers display an "Arrival Point" sign approximately one-quarter mile from the lock. Upon reaching this marker your boat has officially entered the lock approach. If your boat and crew are not completely prepared, stand off just beyond of this point until they are. The arrival point marker is your cue to contact the lock operator by radio.

Operators normally monitor VHF Channels 16 and 13 and may also use other working channels. State the name of the lock, your boat's name, and the VHF channel you are using. If your initial hail is made on Channel 16, expect to be directed to the preferred working channel. Once contact is established, state your position in relation to the lock and your request to lock through. If you have any questions, concerns, or specific requests for assistance, include them in this transmission.

Monitor the working channel

Once you are moored, the
lockgates close behind you. . .

. . . and the lock gates ahead
open as water flows in.

Listen carefully as the lock tender returns your call. He or she will relay important information such as rise and fall of the water level, waiting time, where and how to moor, and signals to listen or watch for. Continue to monitor the working channel until the lock passage is complete.

If you are unable to hail the lock by radio, sound two long and two short blasts with your whistle or horn. Listen for the same signal in acknowledgment and then for verbal instructions delivered by loudhailer. Regardless of your method of communication, remain observant of sound and light signals and posted signs.

Depending upon traffic and other factors, you may be directed into the lock immediately or asked to wait. If delays are encountered, position your boat in the channel to allow safe passage of traffic exiting the lock. The operator may assign priorities to vessels waiting to enter the lock. Corps of Engineer lock operators will give government and commercial vessels priority over pleasure craft. Priority may be based on vessel size, cargo, and mooring accommodations.

When the lock is ready to receive vessels, the operator will give the appropriate signal audibly (by radio, loudhailer, horn) or visually (using lights). Enter the lock slowly but with enough power to maintain steerageway. The helmsman must be alert to changing current and wind conditions, other vessels, and any directions from the lock operator. Deck crew must be in position with their mooring gear ready.

Go far forward

"The objective here is to safely transfer positive control from the helmsman to the line handlers. "

Unless the operator provides specific mooring instructions, proceed as far forward in the lock chamber as is safe. This allows space for following vessels. Select a mooring point with regard to the availability of cleats or mooring bits, the position of other boats, and the lock operator's instructions. Bring the boat to a stop, or near stop, and signal your deck crew into action. The objective here is to safely transfer positive control from the helmsman to the line handlers. Communication is paramount.

If the lock provides mooring lines, bring them aboard and secure a line at the bow and another at the stern by passing each line around a cleat and then holding the loose, or bitter, end. This will allow a line to be let out or hauled in, as necessary, when the boat rises or falls with the water level. Avoid the use of full figure-eight hitches or other knots that will tighten under load.

If you are using your own mooring lines, insure that one end is tied securely to the boat. Pass the other end loosely around the cleat or mooring bit on the lock structure and hold the bitter end, allowing the line to be easily adjusted as the vessel rises or falls.

A springline is useful in maintaining your boat's position and managing the loads on the bow and stern lines. A springline becomes indispensable if you are singlehanding. It is impossible for singlehanders to tend all lines at once. If you are in this situation, tie off with enough slack to afford time to move about and reset lines as the water level changes.

When the lock cycle is complete, the operator will signal for vessels to exit the chamber. As you leave, remember the effects of wind, current, and the actions of other skippers. Communicate concisely with your deck crew. Likewise, ask your crew to clearly signal when their lines are free and secured.

Depart the lock as you entered: slowly but with good steerageway. Keep to the marked channel, avoiding any hazardous areas. When you pass the "Arrival Point" marker directed toward the traffic coming from the opposite direction, your lock passage is complete. Switch your radio back to Channel 16, stow the mooring gear, and get back to living out that idyllic daydream of the sailing life.


Locking Through, an informational brochure published by the U.S. Army Corps of Engineers,
Jacksonville District

NOAA United States Coast Pilots
Online sources of information

The author:
Vern Hobbs and his wife, Sally, sail a 1974 35-foot Bristol cutter along Florida's Atlantic coast and the Intracoastal Waterway. Their day jobs pay the rent, but Vern's work as a local artist specializing in maritime subjects finances the boat projects.
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post #2 of 22 Old 10-31-2007
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One thing missing here is what to do in small locks like those on the Erie Canal. When calling ahead to the next lock when locking up, ask for a "slow fill." Most lockmasters are happy to comply, if they can. When water enters the lock, it hits the keel and pushes the boat against the wall. [Motorboats don't have this problem, since they bob like a rubber duck in a tub.] Wish I had learned this before I was half-way up the Erie Canal!
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Another point not mentioned is that it is prudent to hang an 8 foot 2x4 outside your bumpers. This provides a long flat surface contact with the lock wall, making it easier to stabilize the boat, and keeps the muck found on the lock walls here on the Mississippi from fouling those pretty white fenders!
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post #4 of 22 Old 01-09-2008
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Not having personally ever been through a lock I found the article and comments very interesting and helpful. Some day I hope to spend some time on the Great Lakes and this information will be useful.
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post #5 of 22 Old 04-02-2012
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Re: Navigating locks

Went through some locks in Italy and France recently. Interesting experience. We communicated with the lock operators by pulling on a rubber tube to signal our desires. The operators signaled back with red and green traffic lights. Some of the locks dated back to Napoleonic times. When we were going upstream, we had to climb a metal ladder in the stone wall to take a mooring line up and around a bollard. Going down stream, we could tie off to a metal ring with a highwayman's hitch then use a deck cleat as a clutch until we were ready to get underway. I was great fun. I only got pulled off into the water once.
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post #6 of 22 Old 04-02-2012
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Re: Navigating locks

The most interesting locks we have done were on the Canal du Sud in southern France. This canal opened in 1680 (really a remarkable feat of engineering for the time) and the lock sides are curved outward several feet to form an arch - I guess that thought it would be stronger. Does make it interesting to line up to.

After the refit we have decided to sell Ainia. We want something smaller that would be could for the light summer winds of Lake Ontario, although we plan to spend at least a couple of winters in the Caribbean before heading north.
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post #7 of 22 Old 04-02-2012
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Re: Navigating locks

I'm glad this thread was revived, I hadn't seen it. We navigate the locks from the sea to the fresh water lakes in Seattle. There are two separate locks, one large and the small one at the same location. Generally, the smaller is the one most often used except for busy summer weekends and for large commercial traffic. The biggest hassle isn't the locks themselves, it's the railroad bridge just on the salt water side of the locks that is invariably down meaning that sailboats have to mill around in the strong currents either upstream or down until it opens, while dodging all the power boats. It seems like there is always one boat completely unprepared and inexperienced every time we lock through which provides the entertainment for the day, as long as they aren't tying up next to you:-((

SV Laurie Anne

1988 Brewer 40 Pilothouse

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post #8 of 22 Old 04-08-2012
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Re: Navigating locks

Navigating locks is truly an experience. Here's what happens with our Finnsailer 35. We try to time the lock so we don't have to hold position or scramble to secure ourselves to a dolphin. Of course we have the mast down, so I don't have much to hang on to when I'm on the bow with my boat hook.When we went through the Champlain, Dismal Swamp, and Okeechobee waterway locks, we were usually alone. Then once we are in, I start grabbing for lines(in the South) or wrapping around a pole, etc (in the North), and Captain Bob reminds me that he has to get the entire boat in the lock for this to work. So I throw the lines back to him until he finally grabs one that suits him or point out each possible tie up until he nods. It's at this point I am envious of the big cruisers with chest high gunwales. Then once I have the line, I hold on for dear life. By that time Captain Bob has wrapped his line around a winch to pull in the back end. He reminds me that it's easier for me to slacken my line than for him to try to pull in 13,000 lbs. I get the message. Then the water comes in/out. We go up/down. The gates open, and off we go. With a sailboat, each lock offers a unique experience. In one of the Champlain locks, the wind caught us before I could secure us, and we did a 360. Oh, the adrenaline rush that was. Fortunately no other vessel was in the lock. In the North, you supply your own lines. In the South, the lockmaster will throw you the lines and chat you up. I keep thinking with having more 30 lockings logged, the procedure should get easier. I hasn't. Maybe I have recessive genes for locking. Then again, maybe locking a boat is like landing an airplane. If you are still able to stand afterwards, it was a good one.

Last edited by helenwiley; 04-08-2012 at 03:20 PM.
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Re: Navigating locks

What a wonderful post! If you don't write professionally, you should. Thanks
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Re: Navigating locks

I wish the lock was the only thing I had to deal with. Once I get through the lock, then I have to contend with a low bridge immediately on the other side. That means I have to plan my trips by tide cycle. If the water is too high, I can't get back to the house where my dock is. Most of the time I just trailor it down the road to the public boat launch to avoid this issue.
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