Mary,
In my real job I supervise submarine design and research for the Navy. There was quite a bit of experimintation in the 60s and 70s related to torpedos skin friction. I know of at least three approaches that were looked into for reducing skin friction:
1. Long chain polymer injection into the boundary layer.
2. Compliant hull surface. This emulates how "spongy" dolphin skin complies to the little turbulent eddies in the boundary layer - delays seperation of the layer from the hull.
3. Using a ring of small holes in the bow to either blow or suck air into the boundary layer and alter the flow mechanics.

It is interesting to note that the polymer injection actually takes a very small voulme of fluid. The stuff is so slimey, a little goes a long way.

Kevin