Raymarine SL72 Owner's Handbook Manual page 175

8-8
Figure 8-4:
Planing hull vessels, and some displacement hull vessels, adopt a higher bow
angle when the vessel is at its cruising speed. In many cases this substantially
alters and raises the radar's main radiation plane, and can cause poor detection
of nearby targets. It may be helpful to lower the radar beam back towards the
parallel, by shimming the rear of the radar, so that the beam points slightly
downwards with respect to the waterline when the vessel is at rest.
Figure 8-5:
The shims may be made from aluminium plate wedges, simple flat washers, or
an angled wooden block. For thick shims, you may need longer securing bolts
than the M8x40 bolts supplied with the radome scanner, or the M10 studding
supplied with the open array scanners.
SL72 & SL72RC PLUS Pathfinder Radar & Radar/Chartplotter
12.5˚
12.5˚
Waterline
Ideal Radiation Plane
Ideal Radiation Plane
Wedge or
washers
Forward
Using shims to lower the main beam
Adjusting the Radiation Plane
D3223-2
D3229-3