Rowing boat

[spacechimp]

Haven't got the first clue how to model something:

if I have a rowing boat with an oar on each side, and one oar pushes with one power, and the other pushes with some fixed proportion of that power (each parallel with the sides of the boat and each the same distance from the boat etc.) how do I model the path the boat takes? I'm assuming it'll look like some sort of Spirograph pattern but I'd like to be able to stick this in Excel or Autograph and see the path for a given oar separation etc.

Any ideas?

[Teddio]

You need to consider the force not the power. Consider two parallel forces equidistant from the centre-line of the boat. If the forces are unequal then the resultant force will not lie parallel to the boat's centre line. You need to draw a force diagram where the length of the line is proportional to the force, then construct the resultant. Alternatively you can calculate the magnitude and direction of the resultant force.

[spacechimp]

So always a circle, just bigger the smaller the difference between the moments, right? I'm not feeling very clever atm..

[jomifl]

An added complexity is the hydrodynamic properties of the boat hull. The longer and deeper the hull the more it will tend to go in a straight line. This is however affected by the underwater shape which on a short and shallow boat can cause the boat turn sideways. Unless you can assign some values to the properties of the hull you will have an insoluble problem. Is there any specific reason for solving this? If so another approach might be a good idea.

[spacechimp]

Nothing specific really. Just thinking about the metaphor of one person not pulling his weight.

Thanks for responses.

[jomifl]

That's why they have helmsmen