Gate replacement on Lock and Dam #2

Posted 8/4/21

By Bruce Karnick [email protected] First, let’s get this out of the way. Yes, the tour was a very cool tour if you like machinery and the behind-the-scenes stuff. A HUGE thank you goes out to …

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Gate replacement on Lock and Dam #2


By Bruce Karnick

[email protected]

First, let’s get this out of the way. Yes, the tour was a very cool tour if you like machinery and the behind-the-scenes stuff. A HUGE thank you goes out to the Army Corps of Engineers for their hospitality, especially George Stringham and Tony Frost, the two tour guides for the morning. They gave The Journal almost two hours of their time. Sincerely guys, thank you, thank you, thank you. It was an awesome experience.

One thing that everyone should be aware of anytime you are on the river is water safety. This is not something to take lightly. On average, 14 people die in boating accidents in MN. Not a lot in the grand scheme of things, but even one is too many if it were preventable by wearing a personal flotation device (PFD). That is why every crew member takes safety so seriously. Before stepping on to the barge, I was given a PFD to wear along with the hardhat and safety vest.

Recreational boaters should be aware of the safety requirements on the river.

With the safety piece explained, what exactly is going on at Lock and Dam #2? First, a little history.

The original lock and dam, located at mile 815.2 on the Mississippi River was started in 1928 and finished in 1930. The original lock is the smaller one located furthest from shore. Due to settling, the original lock walls began to tilt severely, so a second lock had to be built. That was completed in 1948 and is the general layout you see today. The site did go under a major rehabilitation project over an eight-year period back in 1987 to 1995.

The lock channel is much deeper than the surrounding navigational channel it can easily handle water up to 25 feet deep. For navigation purposes, the channel is typically dredged to around 11 or 12 feet. This keeps the minimum depth of nine feet much easier to maintain because it requires less frequent dredging.

The dam is 722 feet long with 19 Tainter gates that are each 30 feet long. (Tainter gates are a radial arm flood gate.) The dam also has a 4.4-megawatt power station that is owned and operated by the city of Hastings. 4.4-megawatts is roughly enough to power between 3,300 and 4,400 homes in Hastings per year.

The miter gates that are for the navigational control are the original gates from the construction in 1948. Over time, the gates have been damaged and distressed causing serviceability and safety issues. The gates do get inspected on a schedule and repaired as needed, but the metal can only undergo so many welds and repairs before replacement is needed, and 73 years for metal doors submerged in water 24/7 is a solid run.

The upstream gates are 27 feet tall weighing in around 256,000 pounds each based on the tech specs. The crane operator, ‘Shorty’, said that his scale shows one upstream gate around 245,000 lbs. The downstream gates are 30 feet tall and by the tech specs, weigh around 266,000 pounds each.

The replacement plan started in 2015 with the engineering of the new gates. Once designed, the production took about a year and a half to build just the metal work, that started in 2017 in Alabama. The tolerances for dimensions are down to 1/4 of an inch which is very impressive on a project of this magnitude.

Once that phase was complete, the four gates were shipped to the Quad Cities facility in Rock Island Illinois for the fitment of the hydraulic lines, gaskets and hinges. That phase of the project was completed in a few months. There were other adjustments, tests, fittings, more tests and eventually the gates were put on the barge and brought upriver over the course of roughly four days. There was a little delay bringing them to Hastings because they had to wait for the crane to be available.

The shop and crane are on one gigantic barge. The barge dimensions are 300 feet long by 68 feet wide by 12 feet deep. You could fit two of these barges side by side on Todd Field and they would occupy the entire playing surface between the endzones.

On the front end of the barge is the crane, the back end is the shop, crew quarters, galley, restrooms and showers, locker room, control room and generators. The barge is completely self sufficient for nearly everything. Everything except moving.

The barge displaces approximately 2,850 LTons of water. That is roughly 53,000 gallons of water. 53,000 gallons is also how large the fuel tank is on the barge. Why does this barge have a 53,000-gallon fuel tank when it has no motor to move it? Three reasons: To fuel equipment on the deck of the barge, to run the generators, and to be the backup tank for the pilot barge that pushes it along the river. To put that in perspective, the 53,000-gallon tank takes about six semis and roughly eight hours to fill. The pilot barge only carries around 30,000 gallons of fuel and it can use up to 5,000 gallons per day. How would you like that fuel bill?

Along with the fuel tank, there is a 9,500-gallon potable water tank, a 9,750-gallon sewage tank, motor oil, and hydraulic oil tanks.

The crane is a Seatrax brand crane. Seatrax make cranes that are designed to be used in the open sea, mostly on oil rigs. The advantage of this style of crane starts at the pivot point. The crane sits on a huge cone shaped king post rather than a straight pin or a ball on a pin. This design has two advantages. One, the crane cannot come off excepts for straight up, two, the cone shape allows greater strength for side-to-side tilt. The greater strength to the side means the crane can operate at a maximum tilt of seven degrees versus other cranes that are limited to about three degrees.

Seven degrees of tilt does not sound like that much, but according to Frost, it’s enough to cause a little panic on a barge. “It was steep. Water was close to coming over one side and the other side was almost out of the water. I don’t want to make it sound dramatic, but it was pretty high. It exposed a lot of the one side, so it would be a good time to paint it.”

Keep in mind, the barges are about physically 12 feet tall and this one likes to sit with about five and a half feet of draft. Draft is what is in the water. Seven degrees of tilt is enough to almost push one side into the water and the other side completely out, that’s dramatic.

The barge uses large ballast tanks in the hull to offset the weight of the crane and the cranes load. The ballast tanks can also change where the barge rides in the water. If the barge, while moving from site to site, encounters a lower bridge, the engineers can lower the draft by almost six feet from normal running. That means 11 feet out of the 12 feet can be in the water to sneak under a bridge.

The shop holds all the tools that a normal shop on land does plus the additional things needed on a moving vessel like riggings to tie loads down. There are even small shop vehicles to haul heavier parts and equipment from one end to the other. The floor of the shop has a large cargo door bolted down to access the lower level of the barge. The door takes about an hour to open and close because it has to be bolted every few inches to maintain its watertight seal. There are three cargo doors to access the lower level in total. The largest one could fit a small passenger vehicle.

Along side the shop is the galley, or kitchen. The kitchen can comfortably seat seven crew at a time. It has everything your home kitchen has. Plenty of counter and cupboard space along with a stove, microwave and large fridge.

Next to the galley are the bathrooms and showers. It was a bathroom, on a barge. Think about the bathroom at most retail stores and add a shower. They were nice and clean, but nothing fancy.

The control room is also attached to the galley. The control room really is the brains of the entire barge. Two touch screens control the systems on the barge. On each screen, engineers can see fluid levels in all the tanks, including the ballast tanks. This system allows the ballast tanks to be filled or drained as needed to keep the barge as close to level as possible. Besides the automatic, computer-controlled system, there is a redundancy built in for each part of the barge with mechanical switches, that control panel is also in the control room. Just off the control room is the generator room. The generators were surprisingly small for the amount of power they put out, a bonus of ever advancing technology according to Frost.

Below deck is just as surprising as above. Well organized, well laid out and a very open floor plan. It was the open space that surprised me. When ever you see a movie where there is stuff going on in ships, the space is always so cramped and confined. Not on this barge. The locker room was spacious with professional sports sized lockers, the below deck tool and parts rooms were huge with excellent organization. There were four separate winch rooms with 1.75-inch cables to lift massive anchoring spikes off the riverbed. There were the standard bulkhead doors to separate each section off as needed if there were a hull breach as well.

The craziest thing down there was the small inspection doors for the various ballast tanks and the inspection areas for the bed spikes. The doors looked as though anyone over 200 pounds was not going to fit. Those kinds of spaces are what Frost referred to as ‘confined requirement spaces.’ That means, to go in those spaces, it takes a team of people to ensure the safety of the crew member that goes in. They need to have a sniffer in the area at all times, which is a device that detects the air quality and composition for safe levels of oxygen and for levels of dangerous gasses. They also have to have an extraction system and team in place on the chances that something goes wrong, and they need to be in constant contact with the crew member in the confined area.

Back on the deck, there are multiple fuel stations for moving fuel into the storage tank as well as refueling equipment on deck.

The crane, it was already touched on, but what else can be said about this marvelous machine. Seatrax has a unique design where the boom winches are built into the arm which makes keeping the load steady much easier on a floating surface. The boom is 170 feet long to the main hook and it can lift 500 tons out to a 55-foot radius, 276 tons at 60 feet while fully revolving. There is a 470,000-pound counterweight on the backside, and it is run by a 950 horse Caterpillar C27 engine.

The gantry of the crane can be folded down to allow the barge to be under 46 feet tall top to bottom. The folding of the gantry takes about one minute.

The cockpit of the crane sits about 25 feet in the air, is climate controlled and quite spacious. The controls are laid out to be very simple, but do not let that fool you, it takes skill to operate something this big.

Outside the cockpit are the catwalks to do the various maintenance tasks, including access to the engine room and the boom. If you ever want to feel small, get a tour of a giant crane. Remember the description of the cone shaped center pin? To put it in perspective, think of a traffic cone. Got it? Now, visualize the traffic cone 30 feet tall and 15 feet wide at the bottom, made out of metal, with over half a million tons of metal sitting on top of it.

The crane sits on that cone and is rotated by a few small electric motors on the outside of a giant gear.

Seeing the technology behind the scenes of this kind of operation was so cool. I would say it is definitely a fun career highlight so far for me. There is no way I could give you every little detail I learned in a 2,200-word story. I did grab a bunch of pictures, I’ll share the images on our Facebook page so you can see them in high resolution. Search for ‘The Hastings Journal’ Thanks again to George and Tony for the awesome tour and to all the other folks that popped in and out and said hi or gave their expertise to me. I won’t forget the tour. Stay safe on the water!

The massive 256,000-pound upstream gate is lifted from the water to allow workers to more quickly make adjustments to it. Photo by Bruce Karnick