Rivergator Appendix XXV:
(under construction -- will finish later in 2015)
Currents. In a river, it is the flow of water usually guided by gravity. Current can also be generated by volume alone, as is the case with the Lower Mississippi River, which descends a mere 315 vertical feet in the 954 miles of its journey to the ocean. A rising river or tide can cause reverse currents into its tributaries.
Cross-currents. Two or more currents intersecting along a line, sometimes called the “sheer line,” often associated with boils, eddies and whirlpools.
- It is a current of water flowing in the opposite direction of the main current, usually in a circular motion. Easy to spot with the debris and foam it traps. They help in paddling upstream.
Whirlpool. A whirlpool is a swirling body of water produced by the meeting of opposing currents. (wiki)
- An upward thrust of water to the surface, usually caused by an obstruction in front of the river current. Example rock dike.
Hydraulics. is a topic in applied science and engineering dealing with the mechanical properties of liquids. At a very basic level, hydraulics is the liquid version of pneumatics. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some part of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry, pumps, turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion. Free surface hydraulics is the branch of hydraulics dealing with free surface flow, such as occurring in rivers, canals, lakes, estuaries and seas. Its sub-field open channel flow studies the flow in open channels. (wiki)
Keepers. Found at Chain of Rocks (ex. rock dams, low head dams). If you go over it and capsize, you would be recirculated in the rotating turbulence at the base of the waterfall, and even if rescuers were on hand, a rescue would be impossible.
VHF Marine Radio. Towboat pilots use VHF marine radios for communication between vessels, and also with harbor tows, lockmasters, the US Coast Guard, and recreational craft. Commercial traffic uses VHF cannel 13 while recreational VHF channel 9. Channel 16 is reserved for distress and emergency “mayday” calls only.
- A tree trunk or heavy limb, embedded in the river bottom and presenting a serious hazard to steamboats.
Flood Stage: The level at which a body of water begins to flow over its banks and onto dry land, usually expressed in feet above sea level.
Levee: Mounds of earth and/or fill, such as sand or gravel, piled along a body of water to prevent it from overflowing onto dry land.
Red “Nun” Buoys = LBD navigation channel
Green “Can” Buoys = RBD navigation channel
Dikes are usually small and low, and placed to protect a specific location; levees are high and usually continuous along a stretch of shore or riverbank. Used to protect against floods, as well as "reclaim" land normally covered by water.
Crest: The highest level of water reached by a flooding body of water, after which the water level begins to drop. Most rivers in flood experience multiple crests as additional snowmelt, rain, or obstructions (such as ice, levees or dams) affect their volume and flow.
Fleeted Barges: Tow companies will anchor barges mid stream for storage as the put together and break apart the massive tows for transportation. Their presence can confuse any paddler. It is sometimes difficult to determine if they are moving or not, especially in high water.
Work Boats: Works boats service the towboats with crew and supplies, and perform repair functions. They are small but the move fast and make big waves. Their wakes typically make steep crashing waves that might upset a small canoe or kayak. Watch for their unpredictable and erratic motions in and around other tows and barges.
Bridge Piers: There are dozens of bridges that paddlers will have to navigate under along the Middle/Lower Mississippi River. Each one is supported by piers and pylons which are anchored into the bedrock below the river.
Wharfing: At least half of the St. Louis Harbor is lined by wharves (and docks) of various sorts, shapes and sizes. For paddlers this means that you have no place to easily pull over in case of wind, waves, or the need to relieve yourself. At low water you might be able to sneak into any number of places between wharves and docks, or in between fleeted barges and docked tows.
Chevrons: The Chevron is a new method of river engineering added to places where navigable access is needed on both sides of the channel. They are basically a rock dike made in the shape of a classic chevron. Chevrns are placed in the in the middle of the river, not connected to either side. Best route: paddle around chevrons (preferably on the inside RBD if there is no traffic) not through them or over them. Waves from upstream tows will rise taller and crash over louder in the turbulent chevron area. In high water their influence is diminished.
- As a verb, for a powered vessel to move an unpowered one, like a barge. Tow may also be a noun, referring to the craft being moved. In the 19th century on the Mississippi River, barges were either towed behind the steamboat on a long line, or lashed firmly alongside. Over time, it was learned that the towing vessel has much better control over its barges if they’re all lashed firmly together and pushed from behind — but they’re still called towboats.
Upstreamers = towboats going up the river
Downstreamers = towboats going down the river
- A narrow board or platform allowing passengers and cargo to move from one boat to another, or from the boat to the shore. A larger gangplank, suspended from above and maneuvered at the bow of the boat, was known as a stage.
- A space set aside for passengers or officers to sleep or change clothes. Passenger cabins were extremely small, as meals and most other activities on board took place in the public areas of the boat, inducing the saloon and on deck. Most passenger cabins were located on the boiler deck, and opened onto both the outside deck and the interior saloon. Charlotte M. Houstoun, recounting her time on Buffalo Bayou on the steamer Dayton in the 1840s, described the bunk in her cabin as a “narrow shelf.”
Pilot House The small, glassed-in structure atop the boat from which the captain or pilot steered the vessel. The pilot transmitted engine orders to the engineers on duty on the main deck below by a series bell rings or by a speaking tube.
Hurricane deck. The deck above the boiler deck, usually the uppermost full deck on the boat. On smaller boats the pilothouse might be situated on the hurricane deck, or there might be a small set of cabins (usually for the boat’s officers) placed there.
Boiler Deck. The deck above the boilers and the main deck, where most passenger accommodations were located — cabins, saloons, etc.
Main deck. The lowest full deck of a Western Rivers steamboat, the one closest to the water. The main deck was where the boilers, engines and most machinery were located, along with stacks of cordwood for fuel, livestock, cargo, and so on.
Quarter Less Twain - ten and one-half feet
Mark Twain - twelve feet (two fathoms)
Quarter Twain - thirteen and one-half feet
Half Twain - fifteen feet
Quarter Less Three - sixteen and one-half feet
Mark Three - eighteen feet (three fathoms)
Quarter Three - nineteen and one-half feet
Half Three - twenty-one feet
Quarter Less Four - -twenty-two and one-half feet
Mark Four (or Deep Four) - twenty-four feet (four fathoms)
No Bottom - over twenty-four feet
Lilly Dipper. A person that isn’t paddling but makes the motion as if they were paddling.
© 2014 John Ruskey
For the Rivergator: Lower Mississippi River Water Trail
The www.rivergator.org is a free public use website
presented by the Lower Mississippi River Foundation.
Re-printing of text and photos by permission only with proper credits.
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