barges.

[Tadworth]

Can anyone suggest any design improvements to the hull shape , or rudder arrangement of a cargo carring canal motor barge, 20m x 2m, in shallow water, at low speed -4 mph ?

[JonathanCole]

Got any pictures? More info on the existing setup would be helpful. Pretty slim for a monohull, should be quite efficient motoring.

[Tadworth]

These are called "narrowboats" in the uk, the cargo carring type are called "workingboats", lots of pics on the web.

[CDBarry]

What goal?

Reduced fuel, reduced wash, better maneuvering ...?

[marshmat]

At only 4 knots on a 20m barge you are operating at a speed-length ratio of about 0.49, I think. A modified cruiser stern and a clean sharp entry would probably improve efficiency but at the expense of cargo space. At such low speed you are using so little power anyway that these hulls are already pretty efficient.
What goals do you have in mind?