Catalina sailboats have a tendency to accrue what are called "flex cracks" or smiles, in the keel. You can obviously see why they're called smiles, since they often crack in the shape of a mouth. Although they look happy, these cracks can open into major gouges in your keel, creating a catch hazard for kelp and other floatsam.
5200 creates an extremely high-strength, watertight seal above and below the waterline.Provides exceptionally strong adhesion, yet stays flexible after it cures; may be used above or below the waterline. Ideal for underwater thru-hull fittings, hull-to-deck joints, portholes and bonding wood to fiberglass. Goes on smoothly, wont sag, and remains workable up to four hours. Cures in 5–7 days with no shrinking. Key features: Ideal for bedding hull-to-deck joints or other long-term applications. Strong, flexible adhesive for virtually permanent bonding and sealing above and below waterline Adhesive bonds and seals fiberglass deck to hull, wood to fiberglass chemically reacts with moisture to deliver strong, flexible bonds. Forms watertight, weather-resistant seals on joints and boat hardware Specifications. Formulation: One-part polyurethane adhesive/sealant. Recommended Usage: Permanent bonding, above and below water. Extremely strong & flexible. Cure Time: Tack-free: 48hrs.; Complete cure: 5-7 days; moisture-activated cure. Cleanup: Mineral spirits or kerosene. Removal: Mechanical removal. Tensile strength: 700psi
Heat Gun (Any)
Gloves (A LOT)
Muriatic Acid (You can find this at Lowe's in the Garden/Pool supply section for cheap)
This crack is caused by the flexing of the keel at the joint, and should NOT be repaired by stripping and re-glassing the keel. The problem is caused by the engineering of the keel, which is MEANT TO FLEX! Stripping and re-glassing will only cause future cracks in the years to come.
The inexpensive and more beneficial way to repair these cracks is to scrape away all of the growth around the crack and acid wash (muriatic acid) if there are tube worms and other inaccessible critters inside of the crack. Once you're to a point where you think it's clean enough, simply get a spray bottle with alcohol or acetone and thoroughly soak the inside of the crack. This allows the solvent to completely dry the crack out, allowing the sealant to properly adhere to the joint.
If you have the time, once the solvent dries, you can further dry out the crack with a heat lamp or a heat gun. Obviously, be sure there is no chance of igniting the solvent with said tools!
Once completely clean and thoroughly dry, you can apply 5200 sealant to the crack with a putty knife or comparable tool. Be sure to wear gloves, as this stuff will definitely stick to your fingers for days! Completely fill the crack with the 5200, and press as much of it into the gap as possible. Allow it to dry for the entire duration, and be sure to flatten the material out with the tool or your finger to ensure a smooth leading edge.
Once this dries, you can use any type of blister repair epoxy to seal the 5200. We recommend three coats of Pettit Protect 4700 Epoxy Primer. This stuff is incredible, and we've had no issues for years.
Once those are dry and tack-free, be sure to thoroughly paint the surfaces using 3-4 coats of bottom paint! Having a thin coat here will only promote growth and your diver will end up scraping against that 4700.
WE RECOMMEND PETTIT TRINIDAD PROFESSIONAL BOTTOM PAINT, 3-4 COATS. ITS EXPENSIVE, BUT WORKS LONGER THAN ALL OTHER BOTTOM PAINTS.
That's it! Having the 5200 sealant inside of the catalina smile will allow your keel to flex, while preventing further cracks. Now, go enjoy your Catalina!