Evinrude 4906B 4HP 1969, Owner'S Manual

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Check to be sure the intended compass
site is solid. Vibration will increase pivot
wear.
Now, you are ready to mount the com-
pass. To prevent an error on all courses, the
line through the lubber line and the compass
card pivot must be exactly parallel to the
keel of the boat. You can establish the
fore-and-aft line of the boat with a stout
cord or string. Use care to transfer this line
to the compass site. If necessary, shim the
base of the compass until the stile-type
lubber line (the one affixed to the case and
not glrnbaled) is vertical when the boat is on
an even keel. Drill the holes and mount the
compass.
Magnetic Items After Installation
Many times an owner will install an
expensive stereo system in the cabin of his
boat. It is not uncommon for the speakers
to be mounted on the aft bulkhead up
against the overhead (ceiling). In almost
ever y case, this position places one of the
speakers in very close proximity to the
compass, mounted above the ceiling.
As we all know, a magnet is used in the
operation of the speaker. Therefore, it is
very likely that the speaker, mounted al-
most under the compass in the cabin will
have a very pronounced affect on the com-
pass accuracy.
Consider the following test and the ac-
companying photographs as prove of the
statements made.
First, the compass was read as 190 de-
grees while the boat was secure in her slip.
Next a full can of diet coke in an alum-
inum can was placed on one side and the
compass read as 204 degrees, a good 14-
degrees off.
Next, the full can was moved to the
opposite side of the compass and again a
reading was observed. This time as 189
degrees, 11 degrees off from the original
reading.
Finally the contents of the can were
consumed, the can placed on both sides of
the compass with NO affect 'on the compass
reading.
'Two very important conclusions can be
drawn from these tests.
1- Something must have been in the con-
tents of the can to affect the compass so
drasticall
v-
NAVIGATION 1-17
2- Keep even "innocent" things clear of
the compass to avoid any possible error in
the boat's heading.
REMEMBER,
a
boat moving through the
water at 10 knots on a compass error of just
5 degrees will be almost 1.5 miles off
course in only
ONE
hour. At night, or in
thick weather, this could very possibly put
the boat on a reef, rock, or shoal, with
disastrous resul ts.
1-11 STEERING
USCG or BIA certification of a steering
system means that all materials, equipment,
and installation of the steering parts meet
or exceed specific standards for strength,
type, and maneuverability. Avoid sharp
bends when routing the cable. Check to be
sure the pulleys turn freely and all fittings
are secure.
1-12 ANCHORS
One of the most important pieces of
equipment in the boat next to the power
plan t is the ground tackle carr ied, The
engine makes the boat go and the anchor
and its line are what hold it in place when
the boat is not secured
to a dock or on the
beach.
The weight
of
the anchor MUST be adequate
to
secure the boat without dragging.