River current catcher

Anybody ever take a piece of plywood or something and attach it to the front of a boat/homemade raft, sticking down into the water, to catch the river current so it pulls you along into a head-wind? I've done it temporarily, just C-clamped a scrap of plywood to the front of my raft so the current would pull me along. It worked good, it would take more than 5 minutes for a floating leaf on the water to pass us, even with a 15 mph headwind.

I'm thinking about making a bracket that allows the plywood to freely swing down under the bow when I fire up the engine, so it's not dragging like a brake, and also for when I hit a submerged object or enter shallow water. The bracket will stop it from extending forward when the plywood reaches vertical position.

But the bracket itself must also be allowed to pivot FORWARDS, against some tension springs or something, that are strong enough to hold the plywood vertical against a headwind, but weak enough to stretch and allow the plywood to hyper-extend forward should I hit something submerged while backing up.

I've got a computer animation done showing how it'll work. I'm just wondering if anybody's ever done this, and how well it worked?