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SR-21 Antifouling Speed Coating is an ultra-thin, low-friction film for racing boats – power or sail.
Its super slick finish and modest antifouling capabilities make it an ideal seasonal racing finish for fresh water or cold saltwater boats.
SR-21 combines copper powder and Irgarol, a slime reducing biocide, to produce an effective, thin antifouling film that prevents the attachment of fouling organisms such as barnacles, bryozoa, toredos, zebra mussels and algae.
SR-21 also contains two slicking agents PTFE (polytetrafluoroethylene) and Molybdenum Disulfide which reduce surface friction, allowing the hull to slide through the water faster.
SR-21 is recommended for use on fiberglass, wood and properly primed steel boats. It is easy to apply and dries to a flat metallic finish in just 15 minutes.
It is the superb, low-friction racing finish SR-21 provides, rather than its antifouling properties, that makes SR-21 such a popular bottom paint – especially among sailboat racers.
Depending on the part of the country, SR-21 is equally popular with fresh water racing powerboats, as well as other high speed applications such as bass boats, vintage wooden runabouts, etc. for the performance boost it offers.
If you are looking for a similar bottom paint with more aggressive antifouling properties, consider Pettit's other two antifouling speed coatings: Black Widow or Vivid bottom paints – which come with the added benefit of being able to remain out of the water for very long periods.
SR-21 comes as a two component kit. A copper powder component must be mixed into the paint prior to application.
Its color changes to a bronze color upon immersion in water (1221 Blue takes on a bronze cast).
• Fouling protection with a super slick surface
• Copper biocide (21%) controls hard-shell fouling
• Irgarol biocide (2.0%) reduces soft fouling slime and algae
• Dual slicking agents PTFE and molybdenum disulfide reduce friction and increase boat speed
• Can be burnished to create an even slicker finish
• Ultra-thin film thickness prevents paint build-up and saves weight
• No sanding required between coats when applying
• Recommended for use on fiberglass, wood, and properly primed steel boats
• Contains copper – do not apply SR-21 to aluminum hulls, outboards or outdrives
• 100% compatibility with VC-17
• Application: short-nap (3/16" max.) foam roller, or airless spray (only)
• Thinner: isopropyl alcohol
• Theoretical coverage is 90 ft²/quart (360 ft²/gallon); 3 thin coats recommended, one or two in subsequent years; consider applying a fourth coat if you are going to burnish
• 8% solids by volume
• Sold in quart kits, only
Note – like all "hard" bottom paints, SR-21 likes to stay in the water to maintain its antifouling properties, so it's not well suited for trailered or rack-stored boats. That said, many owners of dry sailed boats use SR-21 solely for the slick, fast hull it provides and not for its antifouling properties.
If you haul the boat for more than a week or so for repairs or transport, you should plan on applying a coat of SR-21 just before launching if you want to maintain its antifouling properties.