Impact With Underwater Hazards - Mercury MerCruiser Owner's Manual

There is another less common hazardous result from allowing your boat to launch off of a
wave or wake. If the bow of your boat pitches down far enough while airborne, upon water
contact it may penetrate under the water surface and submarine for an instant. This will
bring the boat nearly to a stop in an instant and can send the occupants flying forward. The
boat may also veer sharply to one side.

Impact with Underwater Hazards

Reduce speed and proceed with caution whenever you're driving a boat in shallow water
or in areas where the waters are suspected of having underwater obstacles that could be
struck by the underwater drive components, rudder or the boat bottom.
IMPORTANT: The most important thing you can do to help reduce injury or impact damage
from striking a floating or underwater object is control the boat speed. Under these
conditions, boat speed should be kept to a maximum speed of 24 to 40 km/h
(15 to 25 mph).
Striking a floating/underwater object may result in an infinite number of situations. Some
of these situations could result in the following:
• The boat could move suddenly in a new direction. Such a sharp change in direction or
turn can cause occupants to be thrown out of their seats or out of the boat.
• A rapid reduction in speed. This will cause occupants to be thrown forward, even out
of the boat.
• Impact damage to the underwater drive components, rudder and/or boat.
Keep in mind, one of the most important things you can do to help reduce injury or impact
damage in these situations is control the boat speed. Boat speed should be kept to a
minimum planing speed when driving in waters known to have underwater obstacles.
After striking a submerged object, stop the engine as soon as possible and inspect the
drive system for any broken or loose parts. If damage is present or suspected, the power
package should be taken to an authorized Mercury MerCruiser dealer for a thorough
inspection and necessary repair.
The boat should be checked for hull fractures, transom fractures and water leaks.
Operating with damaged underwater drive components, rudder or boat bottom could cause
additional damage to other parts of the power package, or could affect control of the boat.
If continued operation is necessary, do so at greatly reduced speeds.
Operating a boat or engine with impact damage can result in product damage, serious
injury, or death. If the vessel experiences any form of impact, have an authorized Mercury
Marine dealer inspect and repair the vessel or power package.
90-899883295 JUNE 2008
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WARNING
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Section 3 - On the Water
Page 37