Mercury 40 JET FOURSTROKE Operation, Maintenance & Installation Manual page 107

OUTBOARD INSTALLATION
A rough water plate may be helpful in reducing cavitation when running in
windy, rough water conditions where air is sucked into the water intake when
jumping waves. Install a 0.8 mm (1/32 in.) metal plate that extends from the hull
bottom to the top of the water intake housing. This plate tends to reduce air
intake as well as reduce spray.
a
24906
a - Rough water plate
97
eng