17-Aug-2006 -- We have completed the discharging of our Peruvian cement at Baton Rouge (Louisiana) and yesterday we steamed down the Mississippi. Of course the obligatory photo has been taken when passing New Orleans, passing the typical uncountable barges, and finally left this noble river through its "Main Gate", the Southwest-Pass.
A word about the Mississippi
For me as an ocean going seaman the Mississippi ends at Baton Rouge, the capital of Louisiana and situated 234 miles AHP (376 km). "AHP" means "Above Head of Passes", and all distances on Mississippi River are given in US statute miles from this reference point (1 US statute mile = 1.61 km). AHP, however, is not really where the river begins – or ends. The Delta of Mississippi River extends many miles into the Gulf of Mexico in a general SE direction. The diverging mouths of the Mississippi, known as "Passes" and shaped like fingers are narrow banked deposits of sand and clay brought down by the river current.
The principal entrance to the river is the "Southwest Pass" which offers the greatest depths. Other Passes are "South Pass", "Main Pass", "Pass a Loutre", but they are not used by ocean going ships. Additionally, there is an artificial canal, the "MGOC", or Mississippi River–Gulf Outlet Canal, which ends at New Orleans exactly at the confluence 30N 90W.
At the "Head of Passes" all the natural passes do meet, and it is about 33 km above the SW Pass. Thus the navigable distance for ocean going ships from the SW Pass to Baton Rouge is 409 km.
The Mississippi River carries trade from numerous cities located in the Mississippi River valley and along its major tributaries. It raises in Lake Itasca (Minnesota), at 2,145 miles AHP (3,452 km). It is navigable for inland ships as follows:
- with a depth of 2.7 metres (9 ft)
- to Minneapolis (1,578 miles AHP – 2,540 km)
- to Chicago for 278 miles on the Illinois River
- to Pittsburgh for 852 miles on the Ohio River
- during the navigable season a depth of 1.8 m (6 ft) is available in the Missouri River for 660 miles to Sioux City.
The most important means of transport on the river is the "Barge". For those not too familiar with shipping: A barge is a kind of pontoon, or better - a floating container, mostly without own propulsion. The huge inland navigation system of the United States makes barges very common and economic. Often they do link up to 40 barges together and pushing them all over the rivers everywhere. Barges carry mainly coal, cement, grain, fertilizer, minerals, ore and containers.
Being a captain on a "Barge Pusher" is a well reputed job and has an old tradition. They know the whole river, and many of them are acting as pilots for the ocean ships up to Baton Rouge, too.
Our next employment is loading a cargo of potash at Beaumont (Texas). Beaumont is located quite inshore on Neches River, which is reached by ocean going ships through Sabine Lake and Sabine Pass. The open Sea trench, i.e. from the Southwest Pass to Sabine Pass is 300 nautical miles (555 km) long and leads through numerous offshore oil fields. As everybody knows, the US Gulf is rich of oil.
This morning we visited 28N 92W, a Confluence without view to land, but there are numerous fixed platforms and structures for the exploitation of oil around.
To the SE there are three platforms, named "AHC-MI-192-A", "MO-SMI-205-A", and "MO-SMI-205-B", whilst to almost exactly South there are the "SHELL-GB-128-A", "SHELL-GB-172-B", and some smaller structures.
The Gulf of Mexico, the Caribbean Sea, and the Western Atlantic are full of seaweed, called "Sargasso", which often forms quite huge fields.
Sargasso was the first sign of near land which Columbus sighted during his voyage.