U-boats were the German submarines during both world wars. Revell sells a 1/72 scale model of a Type VIIc U-boat that needs to be built and painted. U-Boats Type VIIc were built throughout WWII, and no specific paint scheme was used. The basic paint scheme was similar for U-boats, but a camouflage and rust pattern can be adapted to your liking, or use historical records to reproduce a specific submarine.
Use a can of white acrylic spray paint and paint the boat from 6 to 12 inches away. Let the paint dry.
Use a large brush to paint the underbelly of the U-boat up to the middle of the ballasts system on each side of the boat using a medium grey paint. Let the paint dry.
Use a large brush to paint the side of the boat as well as the sail and gun using a light grey paint. Let the paint dry.
Use a dark grey paint and paint the deck of the submarine. Let the paint dry.
Apply the markings on the hull of the U-boat.
Dip a large brush in light grey paint and wipe off most of the paint with a paper towel. Brush the deck lightly to give it a rough look. This technique is called dry brushing.
Take a small brush and use the dry brush technique with deep red and browns to add rust between the steel panels of the model submarine.
Use off white paint and a small brush to paint the cord on the top of the sail.
Spray the boat using a can of clear matt finish to protect the paint.
Drying time will vary based on your climate.
Make sure not to overdo the rust effect. Avoid painting in an area that is not well ventilated.