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 Myths
and Practicalities
by
Mark King
True or false: Planing hulls
on plane create less wash and less damage. True or false: Displacement
hulls do not create wash that is damaging.
Sometimes when we are learning about
specific ideas, we forget that there are practical applications
that led to the rules and regulations in the first place. A case
in point is the work undertaken this year by Rideau Canal officials
in their efforts to educate boaters about the effects of wake and
wash along the scenic waterway.
While canal authorities are specifically
concerned about shoreline damage and damage to other boats and boaters,
the lessons they offer can be effective everywhere.
As boats become beamier and more
powerful, the wake/wash issue becomes more important. Some waterways
in the United States are under pressure from boat traffic that causes
damage and personal injury. Several areas, especially along the
southeastern coast, have developed laws and regulations to help
solve the problem. These include speed zones and no-wash zones.
Two definitions and an explanation must be understood.
A wake is a disturbed column of water
around and behind a pleasure craft while cruising. The wake defines
the path of the boat. The loose and broken water left behind, the
water thrown aft by the prop and the waves that roll to the side
of the boat are called the wash. This water crashes into shore and
causes other boats to rock. (Top)
As of two years ago, boaters must
be aware of Careless Operation. This is a relatively new offence
under the Small Vessel Regulations. It reads: 'No person shall operate
a small vessel in a careless manner without due care or without
reasonable consideration for other persons.' This means that the
skipper is responsible for any discomfort or damage his boat causes
to others. In the Rideau case, the shoreline and users are both
prime issues. The shoreline is subject to natural damage from weather.
It is realistic to assume that a certain amount of damage will be
caused each year by boats, but they wish to keep that to a minimum.
Wildlife habitat and fragile ecosystems
can be damaged and destroyed in seconds by careless boaters. Plus,
reproductive cycles of fish and amphibians can be severely altered
by unexpected manmade events.
The second concern is for other users
of the canal. The Rideau attracts a lot of different types of users
and, because of its smaller size, they are typically in close proximity
to each other. You will frequently see swimmers, fishermen, divers,
cruisers, sailors, canoeists and shore-side users within a very
short distance. They all have an equal right to be there and a right
to enjoy themselves.
Studies completed on some of the
busy waterways in the United States revealed that boat wash is responsible
for shoreline damage, as well as injury and destruction to other
boats and boaters. Boaters have suffered broken backs or other serious
injuries as their boats rise over large wash and slam down on the
other side.
Other boats have been pushed out
of narrow channels from large wash and forced aground, while small
boats have been swamped and capsized. This occurs on all busy waterways,
as well as those in Canada. (Top)
A procedure as simple as docking
a boat can turn into a catastrophe. A wash can slam a boat against
the dock, or even lift it up as someone is either stepping out or
tying a line. Wash is to be expected as part of the boating experience,
but it's up to us to keep it to a minimum.
Here are a couple of myths about
boating and the answers to the questions posed at the beginning
of this column.
Myth number one: Planing hulls on
plane create less wash and less damage. The truth is quite the opposite.
Wash on the surface may have less height when the boat is on plane,
but the wave created is longer, deeper and contains more energy.
Simple physics, tested and studied. It's potentially more damaging,
especially as it enters shallower water and rises above the surface.
Myth number two: Displacement hulls
do not create wash that is damaging. A displacement hull at low
speed causes less wash. However, displacement hulls do create a
wave by pushing the water while cruising. In narrow channels, the
return flow between the boat and the shore, combined with propeller-induced
water velocities, can create a venturi effect, much like a carburetor,
that scours the bottom and reverberates off the shoreline, causing
extreme damage. All hulls, from deep-V to displacement hulls can
cause damage, depending on speed and circumstances. Unlike the legislative
approach taken in many U.S. waterways, the Canadian approach so
far is education. Something to think about.
(Top)
Lifeline
is produced through the Safe Boater Training Program, a certification
program for recreational boaters.
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