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Speed: You can’t win sailboat races without
with new sailboats don’t need to think much about boat bottoms because new
boats have fair bottoms so all you need to do is keep them clean. Over
time. however, your bottom will start experiencing increasing drag meaning
your sails will need to produce more power to reach hull speed. Increased
drag will slow you in lulls or turns and you require more power to recover
back to your hull speed after the lull or turn has been completed. Class
racing is all about going the right way at the right time. If your boat's
drag is greater than your competition's, you will need greater sail power
or much better tactics.
The easiest way to make your boat faster and more efficient is by fairing
its bottom. The Royal Navy was aware of this and invested millions in
seething their wooden ships with copper bottoms. The Brits found that
marine parasites did not like copper and they did not adhere to these
copper bottoms. Bottom condition is critical. The bottom of your boat
should be smooth and the paint needs to stay on with good adhesion. Older
bottom paints in many cases have built up, because the older paints (like
Interlux Bottom kote, or Petit Uniepoxy) let cuprous oxide leach through,
leaving the paint resin behind. Excessive paint build up on the bottom can
lead to chipping which ultimately causes drag. Flaking and/or peeling
paint make the bottom less smooth which increases drag and diminishes the
anti-fouling properties of the coating.
To solve this problem re-coat the bottom with a smooth and hard
anti-fouling bottom paint. The largest molecule known is used for products
like Teflon. Teflon has a drag coefficient smoother than ice. Anti-fouling
products that use fluorourethane can add anti-adhesive qualities to hard,
smooth urethane bottoms. An even better solution is a copper Teflon bottom
which gives you the advantages of anti–adhesion plus copper which is a
proven repellant of marine organisms.
If you are now convinced that a smooth bottom is a must to remain
competitive, lets talk about preparation and coating a boat bottom. Almost
no one can do a great job of painting anything with a single try and a
single coat. Imperfections seem to surface in even the most conventional
of applications. Plan on two coats if you desire a smooth, hard
competitive finish. Most of the quality coatings can last multiple seasons
but do you really want to chance losing because you save a few hours and
the cost of some crew lunches by skipping bottom paint for a season?
Bottom painting is not a science. You start to smooth your bottom by
sanding the surface. This will remove any lingering growths or organisms
and result in leveling off the high spots which will reduce much or your
drag. However, as you sand you will see spots that remain shiny. Those are
low spots which also create drag. Fill these spots in by using an easy to
shape soft epoxy glaze to smooth and level your bottom and then seal it
with your bottom paint which produces a hard watertight seal. Performing
these tasks every year, on your bottom, keel, rudder and other surfaces
that slice through the water will result in a better, smoother, and faster
surface. You can remove spidering cracks, gouges from flotsam, skiffs from
bottom mud and sand as well. Those critical leading edges that take all
the punishment and start the smooth laminate type flow over your hull
should be the smoothest parts of your boat.
In conclusion, here are some tricks for a smooth bottom finish. Your first
coat is the thickest and can fill small irregularities. Any drips or runs
need to be sanded smooth again. The first coat alerts you to low spots.
Use your glazing compound to fill those in. Plan on two applications just
like the bottom paint. The first fills it in and the second application,
the loving application, makes it fast. Now lets talk about the last coat
which is the speed coat. The thinner it is the less surface variation it
can create and the less drag. So using the smoothest roller or finest
spray will produce the best speed for you. Thin your bottom paint as much
as you can. Thin coats are smooth and smooth coats are desirable for
speed. If not satisfied with the coat, sand off the high spots and coat
again. You have already invested in the difficult part which is the
cleaning and sanding process. If you re-coat as soon as the previous coat
is no longer tacky, then no sanding is needed for good adhesion. If you
are coating the next day, you may want to put some micro scratches for
adhesion by sanding it quickly and gently.
With bottom painting at the top of your list this year, you will be fast
and have less drag, resulting in reaching top speed with quicker
acceleration and pointing better!
For more information, contact Harvey Chichester at
or phone 612-226-5200 (24/7).