Ballast-free cargo ships

[Guillermo]

In a search to eliminate non-native creatures to sneak into the Great Lakes from overseas, the U. of Michigan jointly with Japan's National Maritime Investigation Institute are developing ballast-free ships by means of longitudinal ducts alnong the hull which, as a secondary benefit seems to produce significative fuel savings due to a better flow of water on the propeller.

See more at:
http://www.great-lakes.net/lists/glin-announce/2008-03/msg00048.html

[chowdan]

Looks interesting!

Great concept! Can't wait to see those in operation! I wonder how they are going to prevent rust on the inside of the hull where the water passes through?

[MikeJohns]

Interesting but a lot of complexity to have 'bow' and 'stern' doors underwater that must seal when the ship is not in ballst. Presumably they will also need to partition this space into multiple tanks for the usual uses of ballast tanks for loading, correcting trim counteracting flooding etc . I think the cost of the complexity might make it unfeasible.

Chowdan
As for corrosion you would do the same as you would for the external hull and the ballast tanks...paint and anodes , no problem there.

[chowdan]

Ohhh i never thought about that. AHahah good thanks for that. :) But yea will be interesting what happens.

[Guillermo]

You're right Mike, a lot of expensive complexity may prove the project to be not viable, although they say it is economically feasible. Interesting the 7% fuel saving thing.

I would have called the concept "flowing ballast", instead of "ballast free" which is not.

Cheers.

[capt vimes]

funny thing... place some waterjets in the ducts and you'll get the 'Red October'! ;-)

[Luckless]

So, how is this going to work in port for loading? It doesn't look like you have any quadrant control, but rather you are stuck with balance along your center line only.


How hard would it be to refit existing tanks with better filtering systems, and high intensity UV lighting? Or even just use a double tank method, empty one while filling the other to maintain weight in a given area, taking on fresh sea water as you go. Should be able to be done with minimal conversion to existing ballast tanks.

[ancient kayaker]

I assume the principle is the rapid flushing of the tanks prevents organisms from fastening on for the trip. Seems a bit risky, suppose those big doors get knocked in by a storm. Or simply spring a leak. Several car ferries have been lost due to door failure and ferries do not venture out into serious ocean with serious storms too often.

Also, those ducts are full of air when the vessel is loaded: all that buoyancy low down could be destabilising.

I would have thought a simple method of filtering could be retro-fitted to existing vessels.