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Boat Rudder What is the best design sails for a small model boat with wind blowing in at right angles? speed and stability? Hi just conducting an experiment. what is the best design sails to put ...
Boat Rudder
How To Repair Smooth And Paint Your Boat Bottom
Typically fiberglass boat bottoms after several years of use become scratched and gouged from rocks, grounding, and flotsam. A one-inch scratch can produce turbulence for 12 to 18 in. down your hull. Turbulence interrupts smooth flow producing drag which need more power to over come.
Your boat bottom may also have a few gel coat patches where rock impact has flexed the bottom creating weak spots that were repaired. But the gel coat used may not be flush with the bottom.
The techniques discussed here will help your application and results on both displacement sailboats with keel and a canoe. The systems employed can be applied to all fiberglass boat bottoms and can be seen in video form at: (youtube address when found)
The first step is to wet sand the bottom with a 60 to 100 grit 3M type sanding sponge. Purple or green sponges work well. Wet sanding will remove any burs of fiberglass along with any marine growth or wax buildup that may be on the bottom. Next, wipe the bottom with a damp rag to remove any dust which remains.
Using glazing compound you can now squeeze filler into these gouges and scratches. Because the canoe bottom is riddled with scratches I just squeeze some premixed glazing compound out of the toothpaste type tube. I then pull a plastic bondo blade over the hull flexing it to contour the boat bottom shape. For the keel or rudder of a boat you can do the same thing but may be able to just hit each of the divots and gouges separately.
Because this glazing compound is soft it sands quickly with the same sponges which can now be used dry. Don't worry about the soft nature of this type of filler because the boat bottom paint applied towards the end of the project will seal the boat bottom and harden the surfaces.
The trick with this process is to repeat it two or three times. Each time you will get closer and closer to the "faired hull" you are looking for. Once you have completed your final sanding be sure to rinse the hull off with a hose and wipe dry to remove any remaining dust. Use blue or green tape to mask off your water line and your are ready to apply your boat bottom paint.
For the canoe we have chosen a "non-stick" anti-fouling urethane Teflon boat bottom paint made by Smooth Sailing at www.boat-bottom-paint.com. For the keel boat we are using their fast drying Copper Teflon.
We are using a 3/16-nap "mohair" 9-in. roller for application. The hardened spots are brushed in with a high quality brush to help avoid brush marks. It is important with urethanes not to introduce air into the urethane during application as it can leave bubbles in this quick drying finish. You can spray on the finish as you would car paint with an air type or airless sprayer and a rather fine tip. Now be sure to remove the masking tape while the boat bottom paint is still wet. You don't want to glue it onto the bottom making it hard to get off.
Using a rag with epoxy thinner on it we now go around the boat to wipe off any drips that made it past our masking tapes. But the job is not over yet. Once the first coat of bottom paint is dry. Which can be in just an hour or two we can check the bottom for scratches we may have missed. Once the bottom is sporting new paint those scratches we missed will show up and can be dealt with.
Using the same glazing compound we can catch those few imperfections that remain. Next a light dry sanding can remove any small bubbles, brush marks, drips and new glazing overlap. You then need to be very careful that you wipe off all of the dust particles as you are hoping this is your last coat of bottom paint.
Now, before you coat your entire bottom it is important to "strip the boat bottom". Go over all your new repair areas with a brush and fresh bottom paint to give them some coverage. When you "strip the boat bottom" you are in effect laying two coats over the repaired areas. The stripped areas will start to set up while you are coating the bottom from stem to stern. When you do your final coat you can get more concealment over areas that may have been repaired earlier. Remove your masking tape, check for drips and take steps to prevent dust from blowing on to your finish before it sets up.
A note about support points. If you are using a product like the Smooth Sailing copper Teflon product you can just touch in the support points as the boat is picked up by straps for your boat launching. This product dries in minutes. If you are using the Urethane as we did you will need to hold the boat with the straps for about an hour before launching.
For more information on Antifouling, Copper non-stick and Urethane non-stick boat bottoms paints go to www.coat-bottom-paint.com
About the Author
Durall Industial Flooring, has over 40 years of flow coated flooring experience. With over 500 specialty chemical products Durall Industial Flooring, provides 24/7 service hand help. Free cost analysis for each flooring project is available at www.concrete-floor-coatings.com