Log Sensor mechanical Installation
32
flow direction
Boundary Layer
The Log Sensor of a sail
boat should be mounted on
the centre line. On V-shaped
hulls it may be mounted a few centimetres
away from the centre line.
It should also be easily accessible from
inside, to permit cleaning.
Location of Log Sensor
Regatta Speed Sensor
Attention: In
case of a wooden
hull, a soft rubber washer
should be placed under the
nut.
Swelling of the hull
could break the through
hull fitting, resulting in sub-
sequent flooding.
Keel (seen from the front)
In case of yachts with deep V-shaped and
long keel hull, a
second log sensor
should be added.
This second sen-
sor is connected
to any other display
unit, e.g. to a compass
display.
The display configura-
tions will then be set to SE:02 and SE:03 re-
spectively. Speed is then averaged over both
sensors. Should one sensor fail (stop) or be
disconnected, only the remaining one will be
used automatically.
10 mm min.
Note: The Sensor could pick up electro-
magnetic noise. Avoid vicinity of high currents
(battery or battery cable).
The boundary layer
Measuring boat speed is not possible in-
side the boundary layer, since flow speed is
not proportional to boat speed.
Therefore always push the sensor down as
far as it will go. The paddle wheel must be
outside the boundary layer.
Align the sensor handle with
the boat axis.
WARNING: The Log Sensor (or
alternatively the sealing plug) must
always be secured with the locking
spring, to prevent unintentional retraction by
water pressure or other force.
Never grease the O-ring seals of the sen-
sor, otherwise it might be pushed up by water
pressure towards the locking spring and the
paddle wheel will be fully or partly retracted.