A ferry with speed v is crossing a river whose current is w.  Try different combinations of v and w.  Drag the red point to alter the ferry angle.  Press the Play button to see the result. Press Stop to reset the simulation.

For what values of v and w is the ferry able to cross the river without any downstream drift?

As w increases relative to v, how does the ferry angle change?

If the river current increases, the ferry eventually has to accept some downstream drift.  For such cases try to find the ferry angle which gives the least drift.

As the current increases further what happens to this "minimum drift angle"?