Here's a cool shop trick that really helped in radiusing the rub-rails of my boat. The problem with a regular plane is that they are designed to plane flat. If used to make gentle curves, you risk getting flat spots. They make actual rounding planes with spring steel soles and threaded knobs to dial in the curve radii (Dave Fleming might find a pic of one) but here's a quick homemade version that worked perfectly.
Just cut sheet metal and chamfer the edges near the throat, then double stick tape them to the sole, with the tape set away from the throat to create a taper in the metal strips. I cannot stress enough how well this worked. The concept would work well for any curved surface planing.
Then I contour sanded the edges, epoxy sealed, and finally after 3 AM this morning spraying varnish, got this drool inducer: