Better boat performance with propeller
Turbulence eats up energy and can slow
your boat down. It has been known for a long time that a 2-in. scratch on a
smooth surface can generate turbulence for 10 or 12 inches as water flows
over the scratch. Just think how much water passes over a boat's propeller
compared to the amount of water sliding past the hull.
In fact, a study* released in 2006 at the
International Conference on Advanced Marine Materials & Coatings in London
notes that, "When the reduction in ship performance is associated with the
condition of the ship hull, the effect of the propeller surface condition
is often overlooked. Nevertheless, the effect can be significant." The
report concludes that, "The results of the calculations show that
significant losses in propulsive efficiency resulting from blade
roughening can be regained by cleaning and polishing of the blades.
Alternatively, the efficiency losses could be avoided, perhaps
indefinitely, by the application of a paint system that gives a surface
finish equivalent to that of a new or well polished propeller. A foul
release coating is such a paint system."
Now boat owners can do their own tests thanks
to a new urethane Teflon-type coating from Durall's Smooth Sailing™ line
of boat paints.
Non-stick cookware uses the largest molecule known, a molecule that has a
lower drag coefficient than ice. This type of coating was first developed
by DuPont and marketed under the name Teflon. Now Durall has made
available a clear brush-on coating, using the same molecule, for use on
your prop. The coating will never yellow and can be built up to smooth out
all those little scratches, pits, and imperfections that can plague your
Aerospace engineers are currently testing this new coating on boat props
in order to verify that reducing drag on the propellers will allow more
energy to be transmitted to forward speed and less burned up in friction.
The question for boat owners is why wait for testing data when for under
$4 you can quickly apply a non-stick coating on your prop? A new urethane
Teflon-type coating with a zinc chromate primer is now available in a prop
coating size at www.boat-bottom-paint.com. Judge for yourself if that prop
is turning better. After all, it's your tests that really matter.
For more information, contact Harvey Chichester at
or phone 612-226-5200 (24/7).
* Effect of a Foul Release Coating on Propeller Noise 2006, by R. J.
Mutton, M. Atlar, M. Downie, and C. D. Anderson. International Conference
on Advanced Marine Materials & Coatings, London, UK, February 22-23, 2006.
A copy of the full report on the
study is available at www.boat-bottom-paint.com/press/propeller_study.pdf