How to Make a Fiberglass Sailboat Rudder

Rudder designs can improve the aesthetics of the sailboat.

Sailboats are a good way to cruise across large bodies of water. Much like kayaks and other boats, rudders are used to steer sailboats through water. They are generally composed of an oblong piece of wood, plexiglass or fiberglass at the back of the sailboat. With time the sailboat rudder can become damaged or cracked due to accidents. It is therefore essential to have an emergency rudder on board to replace the damaged rudder and get back to port safely. You can build your own emergency lightweight rudder from fiberglass to keep on board at all times.

Things You'll Need

• Rudder (used)
• 2-inch-thick Styrofoam
• Pencil
• Utility knife
• Measuring tape
• Medium-grit sanding file
• Fiberglass cloth
• Resin adhesive
• Weights
• Foam roller
• Fiberglass resin
• Rubber roller
• Paintbrush
• Wooden sticks (3/4-inch diameter)
• 100-grit sandpaper
• 180-grit sandpaper
• Paint (optional)

Instructions

1. Draw the shape of the rudder on a piece of 2-inch foam. Follow the shape of the existing rudder or remove the existing rudder and use it to draw the outline of the new rudder on the foam. This will ensure that the new rudder will be the right size for the sailboat.

2. Cut the outline of the rudder from the foam with a utility knife. Use the first piece as a template to outline and cut a second piece of foam in rudder shape.

3. Use your measuring tape to measure the length of the rudder blade. Add 2 feet to the measurement to obtain a final length. Cut two wooden sticks that are 3/4 inch in diameter to that length.

4. Turn over one of the foam rubber pieces and cut two grooves into the back of the piece at each end of the rudder. The grooves should be approximately 1/2 inch deep to accommodate the wooden sticks.

5. Apply resin adhesive to the grooves and insert the sticks into each groove. The sticks will be used to hang the foam pieces when you apply the fiberglass cloth.

6. Glue the two foam pieces together by applying resin adhesive to one side of each foam piece. Press the two pieces together and apply weights to the pieces while they dry. It is normal for some resin adhesive to squeeze out of the edges of the foam pieces. Allow the resin to dry.

7. Shape the rudder blades with a medium-grit sanding file. Only sand the foam in one direction and ensure that both sides of the rudder are symmetrical. Use 100-grit sandpaper for more precision.

8. Hang the rudder upright using the sticks that were placed inside the foam. Use a paintbrush to apply a coat of resin adhesive to the rudder.

9. Dampen the fiberglass cloths with a foam roller and fiberglass resin. Apply the fiberglass cloths on the rudder. Apply multiple coats of fiberglass cloths until the desired thickness has been achieved. Press the fiberglass onto the foam rudder with a rubber roller to ensure an airtight seal and remove air bubbles.

10. Allow enough time for the fiberglass cloth to set and dry. Use 180-grit sandpaper to sand down and smooth rough spots, as well as to finalize the shape of the rudder.

Tips & Warnings

• The two pieces of foam together should have a thickness that is slightly thicker than the rudder. Obtain thicker foam if 2-inch foam is not enough.

• Paint the fiberglass rudder your desired color to achieve a sleek, finished look.

References

• Blue Moment; Emergency Rudders