It’s common with in-line ship assist for the aft tug to be used just to keep the brakes on so to speak. Keeps the speed down. That’s the case with tractor tugs at least.
1 Like
The build-up in the water levels at both sides at the bow of the ship in a narrow fairway like the Corinth Canal causes the bank cushion effect. In my opinion it is probably responsible for a self centering effect in the middle of the Canal.
If for instance the ship moves to port the pressure of the bank cushion effect will push the bow back to course. If there is an overshoot this will result in an opposite force until there is an equilibrium reached between the two bank effects.
That saying you will always need a tug because a sudden widening of the Canal at one or both sides disturbs this process and a correction is needed. If the propulsion is lost a tug is also needed. In such a case the current of 1 - 3 knots doesn’t help and could cause the ship to scrape the walls of the Canal.
Only at the last moment, when the ship leaves the canal, a tug appears in sight from under the bow. A short leash…
When retreating from Greece in WW2, the Germans cut the access to the Peloponnese peninsula by blowing the street and railway bridge over the Corinth Canal.
To make the canal itself useless, they dynamited parts of the upper canal walls and plunged heavy rubble into the canal (locomotives, rail cars, tanks, artillery…)
In 1947/8 the US Army corps of Engineers cleared the canal and rebuilt the bridge (for fear of Greece becoming a Soviet satellite). See story by USACE >>>
https://www.usace.army.mil/About/History/Historical-Vignettes/Military-Construction-Combat/056-New-District/
1 Like
What the Army Corps of Engineers did couldn’t be done these days in the civil world because of corruption, incompetence and bureaucracy.
For fear of communism we also gave away almost for free our national gas resources. Italy received about 10 billion m3 of natural gas per year from the Netherlands for decades, paid only the cost price - first 1, later an average of 10 cents per m3 - and thus received a total of 100 billion euros “as a gift”.
It was discovered that in June 1967 the Council of Ministers had “secretly” decided to supply NATO ally Italy, otherwise the country would go to the Soviet Union for natural gas. The Cold War reigned, this had to be prevented but at the unknowing taxpayers expense.
Now Italy is receiving 220 billion euros the biggest slice from an European support fund of 800 billion coming from all the northern countries like ours because they are so poor. But go see life in Rome, Milan, Florence and you will see that they have more to spend then the average Dutch workers. Southern countries have already complained that 800 billion is too little to meet their ambitions,
2 Likes
The “Texas Chicken” or the “Texas Two Step” maneuver is known to mariners who regularly navigate large vessels on the Houston Ship Channel. As two vessels approach from opposite directions, both normally turn to starboard to allow water displaced by their bows to move the ships away from each other and from the channel’s centerline. After they pass, the suction of the displaced water flowing in behind the ships naturally pulls them back toward the center of the waterway.
1 Like
It is also a good tool used in Lake Charles/Calcasiu River as well as Sabine River.
It is called the Texas Chicken or Texas Two Step, an intricate dance step that requires two partners to race head-on, then veer to starboard at a rather close distance.
2 Likes