Freeboard? What's that?!

This [Nguyen Che Linh] channel is full of such stuff. Often there’s a big crowd trying to get through the sluice and often they don’t have enough power to make it:

Here’s one with more of a crowd:


Isn’t that a Lynyrd Skynyrd song?


This is a job for… the Ocean Clean Up Crew!!!

8 posts were split to a new topic: Texas Cold Snap

Not to worry, Biden will soon implement a new US tax to subsidize the purchase of more clean green engines in Asia. It’s for the Planet! Who could be against it?

The future of tug boating on the Mississippi without the Jones Act.


you’d think that just maybe if these BOOBS didn’t load their scows so deep they might have adequate horsepower to get through that opening?

effing Asian CLOWN CIRCUS!


I did a little research with the help of the Admiralty Coefficient on the effect of the ship weight or displacement on the ship’s speed. The result is shown in the graph. The outcome is a bit disappointing as the effect is much less then expected.

Bear in mind that the deadweight tonnage (DWT) is the displacement at any loaded condition minus the lightship weight.

That formula is for open water. May not apply in that narrow opening.

You have a good point there, it lacks accuracy but I think that the general idea that the effect of less cargo doesnot translate into a large difference in speed is still valid.

Those ships (boats?) are acting as plugs in the dam as they transit the sluice. The bigger the plug the more force is required to push it through the choke point.


I was thinking about putting a 32 meter beam ship into a 33.6 meter wide lock. Have to drive into the lock on a dead slow bell when it seems like the ship should just go in on a stop bell. Then when stop is rung up the ship will drift backwards unless some lines are put up quick or if the locomotives weren’t holding the ship.

Water in the lock got no place to go.

A similar example is transiting the Panama Canal and ringing full ahead to enter the locks.

The same effect as what @Chief_Seadog calls putting a plug in the dam. You need considerable power to overcome the pressure of having to push away that fast flowing amount of water. My point is to show that as it seems less cargo doesnot add much to the speed.

IDK, seems like it might have more to do with the dimensions of the vessel relative to the opening than displacement. Less draft would give more room for the water to go around the hull.

I’d think that the depth of the opening would matter as to which was more critical, draft or displacement.

I’ve watched a few of these and the place they get stuck is routinely when the stern section is approaching the upstream end of the sluice. They back out and try again and often on the third or fourth try they make it through.

When the sluice is running fast there’s a pronounced declivity in the same upper section – boats coming downstream dig their bows in partway through.


What would happen to the boats bow wave going downstream into the opening?

These guys are just like the accountants at American companies.

Once you get away with doing too much with too little the first time, they expect you to just do it again and again every time. Then they don’t understand “your screw up” when something eventually goes sideways with disastrous results.

1 Like

It isn’t so much speed that is lacking, it is acceleration (or lack of it in this case) and that relies on raw horsepower, more required for deeper draft and heavier weight.

1 Like

I’m sure I saw a Harbor Freight trash pump or two.