Click
on any of the pictures below to see a larger version.
This 7-inch color monitor controls and displays radar, chartplotter
and sonar. GPS coordinates are also displayed. The existing
components had to be reconfigured. We moved the VHF radio from
the wood-grain panel down into the gelcoat and moved the digital
remote up six inches.
The engine management, VHF radio and radar/chart control
head are linked together via NMEA and share information.
A
navigation unit was installed in a cabinet within the salon
and just outside of the forward berth. This provides a GPS
coordinate alarm to the sleeping occupants if the boat drifts
while at anchor. A dedicated GPS antenna atop the arch is
run directly to the navigation unit. The GPS data is then
transferred from this navigation unit to the chartplotter
on the helm via Sea Talk.
Atop
the arch, from starboard to port, there is a GPS antenna, XM
satellite radio antenna, 24-inch RaDome and a glomex UHF/VHF
omni-directional antenna. The RaDome is elevated on a short
powder-coated aluminum tower. The light is extended and elevated
via a custom stainless steel tube with two 45 degree bends.
This places the light 15 degrees above the RaDome from all angles
per coast guard specs.
A
brass thru-hull transducer was used for the sonar. This is
standard for exposure to salt water.
Shown is the angled hole that is drilled from the exterior
hull into the forward section of the engine compartment. The
raw interior edge of the hole gets sealed with a marine two-part
resin that first seals the layers of fiberglass. Once cured
the hole is redrilled to precisely fit the transducer's threaded
shaft.
A polymer fairing block is positioned against the hull and
is sealed with an underwater poly sealer. A concealed thru-bolt
at one end keeps the fairing block from rotating. The excess
sealer is carded smooth directly after application and while
it is still soft. This eliminates any unnecessary drag.
Shown is the finished transducer from the engine compartment
perspective. The interior of the gelcoat is first sanded smooth
and sealed before the interior side of the fairing block is
used. Each fairing block is custom cut into the two sections
(interior and exterior) at the precise dead rise angle of each
individual hull. This keeps the transducers thru-hull stem perpendicular
to the ocean's floor rather than the angled hull.
This view shows the finished transducer well forward of the
shafts and props. The transducer must also be out of the path
of the forward intakes and the resulting turbulence. Also, the
transducer must remain in the water when on plane and be accessible
from within. As a standard precaution a thru-hull transducer
must be located in a section of the bilge that is serviced by
a pump. It takes careful planning in consideration of multiple
and oftentimes conflicting requirements. Do not leave this type
of procedure to the uninitiated.
