NASA Marine CLIPPER User manual

CLIPPER
MARINE
STEERING
COMPASS
STEER INC
DEC
ILLUM
CLIPPER COMPASS
243
6TRUE

INTRODUCTION
PRE-TEST OF INSTRUMENT
INSTALLATION OF SENSOR
INSTALLING THE DISPLAY
NORMAL OPERATION
CHANGING THE BACKLIGHT SETTING
CHANGING THE DAMPING
ASSISTED STEERING
SETTING THE DESIRED HEADING
SWITCHING ASSISTED STEERING OFF
HEADING ALARM
SETTING OR STOPPING THE ALARM
1
1
1
1
2
2
3
3
4
5
5
5
TABLE OF CONTENTS PAGE

ENGINEERING
ADJUSTING MAGNETIC VARIATION
MAGNETIC OR TRUE READOUT
SETTING THE STEERING SENSITIVITY
COMPASS ERROR CORRECTIONS
SETTING THE COMPASS RING
SETTING THE COMPASS COMPENSATION VALUES
HEADING ADJUSTMENT
REPEATER FACILITY
6
6
7
7
8
9
9
10
10
PAGE

1
INTRODUCTION
The Clipper Compass is supplied complete with display unit, sensor unit, and
Mounting kit. It is designed to operate from the vessel’s 12V battery supply.
PRE-TEST OF INSTRUMENT
Before mounting the units, check that the instrument is complete and undamaged.
Connect the sensor unit to the display unit and apply 12 volts. Confirm that a reading
is shown on the display.
INSTALLATION OF SENSOR
The sensor measures the direction of the Earth’s weak magnetic field, and so is
sensitive to other magnetic fields which can affect the unit’s accuracy. It should
therefore be positioned carefully. Select a sensor position as far as possible away from large
ferrous objects such as engines, and items such as DC motors or loudspeakers which
have powerful permanent magnets in them. Check also for small ferrous objects close
to the mounting location such as screws, nails, hinges etc. These can become
magnetised and cause errors. When a likely location has been found, a check for
reasonable accuracy can be made with a hand bearing compass to confirm its
suitability.
The magnetic sensor itself is gimballed within the housing. To accommodate pitch
and roll motions most effectively, mount the sensor as near to horizontal as possible.
For best performance in rough weather conditions, it is also advisable to mount the
sensor in a position (usually amidships) that minimises lateral accelerations due to
pitch and roll. Avoid mounting the sensor high above the water line because doing so
also increases pitch and roll accelerations. The sensor is waterproof to CFR-46
standard. Ensure the sensor does not become submerged.
Position the sensor unit and mark and drill pilot holes for mounting screws to allow the
sensor to be rotated to align it exactly with the vessel’s axis. Now mount the sensor
carefully in position using non-magnetic screws. The rotational position of the sensor
should be chosen to ensure that the arrow points as close as possible fore-and-aft.
INSTALLING THE DISPLAY
Select a convenient position for the display on a panel or bulk-head. The site must be
flat and the cavity behind the panel must remain dry at all times. (The cable entry is
deliberately not sealed to ensure adequate ventilation. This prevents misting of the
display).
Cut a hole in the panel 67mm high and 87mm wide. Bring the wiring through the hole
in the panel and connect as shown on Figure 1. It is wise to use a fused supply to
provide protection should a fault occur. The current consumption is very small, so any
supply with a ¼-Amp fuse is more than adequate.
Unscrew and remove the wing nut from the rear of the instrument and remove
the stainless steel clamping bracket. Fit the “O” ring seal into the groove in the panel
mounting face of the instrument. Ensure that it is correctly lying in its groove before
fitting the instrument to the panel, which provides the watertight seal for the display.

2
ALARM
BLEEPER
Fit the instrument into the panel, fit the stainless clamp over the stud, fit and tighten
the wing nut finger tight only.
It is important that the O-ring rubber seal makes good contact with the panel to
prevent water getting behind the unit and entering the cavity behind the panel.
It is good practice to run the cables vertically downwards from the unit, even if they
later have to rise to connect to the vessel’s supplies. Doing so prevents any water
that might get onto the cables from running back along the cables and into the unit.
NORMAL OPERATION
When power is applied to the Clipper Compass, it executes a comprehensive internal
test routine. It then displays the heading. When first powered up, the displayed
heading may not be correct until the Compass alignment is done (see Engineering,
below). A typical display is shown on Figure 2.
CHANGING THE BACKLIGHT SETTING
Backlighting is provided to allow the unit to be seen at night. The backlit area is
restricted in the top corners of the display to concentrate the lighting in the areas of
interest (see Figure 2). The brightness of the backlighting is adjusted by pressing the
ILLUM button at any time during normal operation. Each press of the button increases
the brightness by one in the range 0 to 9, shown by the backlight indicator in the
bottom left of the display (see Figures).
A setting of zero switches the backlighting off, and a setting of 9 is maximum. In
common with all the other settings in the unit, the backlight setting is stored even
when the unit is off, so that it returns to the chosen setting whenever the unit is
powered up again.
Figure 1 - Wiring Installation.
Silver/Shield
STEER INC
DEC
ILLUM
NMEA OUT
White

Figure 2 - Normal operation display.
CHANGING THE DAMPING
When the vessel is affected by rapid variations of heading in rough seas, a more
heavily damped display can be selected instead of the normal lightly damped display.
Press STEER and DEC together to switch between heavily and lightly damped
modes. The display shows “L” (for Light damping), “A” (for Average damping), or “H”
(for Heavy damping) for two seconds after the keys are released to indicate which
mode has been selected. Successive presses of the two keys switches between the
three damping settings.
ASSISTED STEERING
Assisted steering means using the Clipper Compass to show errors from a chosen
heading, and the direction to steer to bring the vessel back to the chosen heading,
which is marked by the lubber line at all times.
When the vessel’s heading is within the pre-set error limits, the dead-ahead indicator
is lit to show that all is well (see Figure 3), and no steering adjustment is required.
Steering chevrons light whenever the heading error is greater than a pre-set value
(see Figures 4a and 4b). The factory default setting for the error value is 3°, but the
setting can be adjusted when in Engineering mode (see below).
As the error builds up, more steering chevrons are lit to indicate the increasing
strength of steering needed to correct the heading error. Three are shown on Figure
4a. If the error exceeds seven chevrons-worth, the central chevrons clear in sequence
to indicate how far “Off the Scale” the steering correction is needed. Ten error
chevrons-worth are shown on Figure 4b.
3
ENTER
STEER INC
DEC
ILLUM
263
MAG.
8
Heading
263 degrees
Alarm is set
Change
Backlighting
Log
heading
shown
Decrease Increase
alarm boundaries
Backlight
digit
Magnetic
heading
shown

4
If the error increases beyond 180°, the error display reverses to show that the shortest
route back to the desired heading is now using the opposite tiller.
Figure 3 - Dead-ahead indication.
Figure 4a & 4b - Three and ten-chevron Steering indications.
SETTING THE DESIRED HEADING
Bring the Vessel to the desired heading, and press STEER to log that heading. The
display changes as shown on Figure 5. The logged heading is the heading shown
when the STEER button is FIRST pressed.
The dead-ahead symbol indicates that the vessel’s heading is within the error setting.
The size of the error setting can be changed only in Engineering (page 6).
STEER INC
DEC
ILLUM
204
TRUE
3
Lubber Line
Dead-ahead,
within error setting
STEER INC
DEC
ILLUM
2 13
TRUE
3
STEER INC
DEC
ILLUM
244
TRUE
3

FIGURE 5 - Vessel heading aligned with setting.
The alarm setting can be altered at any time during Assisted Steering operation by
pressing INC to increase its value, or DEC to decrease it. The alarm boundaries are
shown by the steering chevrons, as shown on Figure 6, for two seconds when the
key is released, whereupon the display returns to the normal steering display.
SETTING OR STOPPING THE ALARM
Press INC and DEC together to switch the alarm on or off. When the alarm is on, the
bell symbol shows, as shown on Figure 5. The alarm is off when the bell symbol is off.
Whenever the alarm is on, and the heading is outside the boundaries set at the
desired heading, the alarm sounds, and the bell symbol flashes. It can be stopped
only by correcting the heading error, or by pressing INC and DEC together (to switch
it off), or by disengaging Assisted Steering by pressing STEER.
SWITCHING ASSISTED STEERING OFF
At any time, while Assisted Steering is operating, pressing STEER switches it off.
Pressing STEER again switches it back on again, but with the reference heading
updated to the heading which is displayed when STEER is pressed. This facility is
useful for resetting the desired heading when sailing on different legs of a route.
HEADING ALARM
When Assisted Steering is in operation, an alarm can be set to sound whenever the
heading exceeds a pre-set amount from a chosen heading. The chosen heading is the
heading logged when assisted steering was selected by pressing STEER. Alarm
operation is inhibited when Assisted Steering is off. The alarm, when set, sounds
whenever the heading is at or outside the alarm setting to port or starboard.
0
STEER INC
DEC
ILLUM
1 9 2
TRUE
3
5

6
FIGURE 6 - Alarm Boundaries set +/- 9°
ENGINEERING
Engineering settings means those adjustments which seldom need changing, but
which affect how the unit operates. The settings (as are all those which can be
selected in normal operation too) are stored even when the power is disconnected.
There are four operating characteristics which can be set in Engineering: Magnetic or
True heading display; Magnetic Variation; steering error chevron sensitivity; and
Compass error (deviation) compensation settings.
Engineering mode is entered by holding down the ILLUM button while turning on the
power. The Engineering mode displays “En” (for Engineering) for two seconds when
the button is released. When the two seconds are up, the Magnetic variation is shown
in degrees. The present set-up is shown as “MAG.” (for magnetic readings) or “TRUE”
(for true readings). Note that the magnetic variation affects only true readings, and
need not be corrected as described below if magnetic bearing readings are required.
Any of the following settings can be done when in Engineering. If more than one
different setting is to be done, it is necessary only return via the “En” display
between different adjustments or settings, as described below.
ADJUSTING MAGNETIC VARIATION
The Earth’s magnetic variation varies from year to year, and from place to place. The
appropriate variation value can be found by reference to Almanacs, maps, or charts.
The variation is the offset of magnetic North from true North. If the Magnetic North
(the variation) is West of true North, enter it as a positive number. Conversely, if it is
quoted as East of true North, enter a negative variation value.
If not already in Engineering (”En” displayed), hold down the ILLUM button while
turning on the power to put the unit into the Engineering mode. The display shows
“En”(for Engineering) for two seconds. The display then changes as shown in Figure
7 to show the stored magnetic variation and whether the unit is operating in Magnetic
or true modes (Figure 7 shows Magnetic operation, and an Eastward variation of 6.5°).
STEER INC
DEC
ILLUM
9
3

7
FIGURE 7 - Magnetic Variation Display
Positive numbers represent Westward variations, and negative numbers (as shown on
Figure 7) represent Eastward variations. Each press of INC or DEC alters the stored
variation in steps of 0.1°. The fractional value is always repeated in the backlight digit (as
shown on Figure 7). If the total variation is greater than ± 9.9°, the fractional part of the
angle is shown only in the backlight digit.
Press INC or DEC to change the stored variation value to the correct value. Note that
changing the magnetic variation has no effect on the accuracy of the compass’s
compensation (see below).
If it is desired to end Engineering adjustments, press ILLUM to return to normal heading
indication, using the revised magnetic value.
MAGNETIC OR TRUE READOUT
If not already in Engineering (”En” displayed), hold down the ILLUM button while turning
on the power to put the unit into the Engineering mode.
Press STEER and INC together to switch between Magnetic and True display of the
compass readings. When True is selected “TRUE” is displayed, and the variation shown is
used to correct the readings made by the sensor. When Magnetic is selected, “MAG” is
displayed as shown on Figure 7. In Magnetic indication mode the variation value is ignored.
If it is desired to end Engineering adjustments, press ILLUM to return to normal heading
indication.
SETTING THE STEERING SENSITIVITY
During assisted steering in normal operation, the steering chevrons show the size of the
heading error, and the direction to steer to remove the heading error. The sensitivity,
which is the size of the steps between each chevron, is set in Engineering. The sensitivity
step size represents the error required to light each successive chevron during assisted
steering. The higher the sensitivity step size, the larger the error required to light all the
chevrons, which fill up as the error increases.
STEER INC
DEC
ILLUM
-6.5
5MAG.

8
FIGURE 8 - Sensitivity Setting Display
If not already in Engineering (”En” displayed), hold down the ILLUM button while turning
on the power to put the unit into the Engineering mode. The display shows “En” (for
Engineering) when in Engineering mode.
To set the sensitivity, press STEER and DEC together. “MAG.” and “TRUE” both
disappear, and the first port and starboard error chevrons light to show that sensitivity is
being set (see Figure 8).
The step size is shown in degrees. The factory default is 3°. Press INC to increase the
setting in 1° steps, and DEC to decrease the setting in 1° steps. The minimum setting is
1°, and the maximum is 10°. If 1° is set, the maximum indication of heading error which
can be displayed is when 13° (and beyond) is reached to Port or Starboard. Likewise,
when 10° is chosen, the maximum indication of heading error which can be displayed is
when 130° (and beyond) is reached to Port or Starboard. The maximum displayable
error is always 13 times the step size shown.
Press STEER to return to engineering (”En” displayed for two seconds) again. If it is desired
to end Engineering adjustments, press ILLUM to return to normal heading indication.
COMPASS ERROR CORRECTIONS
In common with all magnetic compasses, the presence of magnetic objects in the vessel
distorts the earth’s magnetic field nearby, and can affect the accuracy of the detection of
magnetic North, and the accuracy of readings at other points of the compass.
These errors can be compensated automatically in the Clipper compass if the vessel can be
pointed accurately in particular directions by reference to known geographical features.
The first requirement is to align the North setting of the whole compass to North, known as
setting the Compass ring. It MUST always be done on first installation to ensure that North
is correctly shown. If the compass is then found to measure all points of the compass with
sufficient accuracy, the sources of external magnetic field distortion are at an acceptably low
level, and no further adjustments will be required.
STEER INC
DEC
ILLUM
3

9
If, after setting North on the compass ring correctly, it is found that there are significant errors
at other points of the compass, these errors can be compensated. This compensation is done
by logging the actual readings when the vessel is correctly aligned at the principal directions
45° (North-East), 90° (East), 135° (South-East), and so on. The logging is done automatically,
with the compensations calculated and stored in the unit’s memory. Corrections at
intermediate angles in normal operation of the compass are in proportion to the
compensation values logged at the seven principal directions. All settings are stored even
when the unit is switched off. However, compensation at these other points of the compass is
seldom necessary if a good position for the sensor head has been chosen which has no field
distortion by magnetic objects.even when the unit is switched off. However, compensation at
these other points of the compass is seldom necessary if a good position for the sensor head
has been chosen which has no field distortion by magnetic objects.
SETTING THE COMPASS RING
It is important to decide before setting the compass ring how the alignment of the vessel is to
be achieved. If a hand bearing reference compass is to be used, set the unit to display
Magnetic. If maps or chart references are to be used, set the unit to display True, and ensure
that the magnetic deviation is correctly set (see above). It is important that the correct
magnetic deviation is set before doing the compass setting, because the magnetic deviation
is always allowed for before the true heading is displayed.
Note that it is not necessary to reset the compass ring if the magnetic deviation is changed
during a voyage or from year to year - the original setting of the Compass ring remains
correct.
Accurately point the vessel to True (or Magnetic) North. Either MAG. or TRUE is displayed to
remind the user which physical alignment of the vessel is to be used.
Put the unit into Engineering mode, and then press the three keys STEER, INC and DEC
together. It is not important to release them at exactly the same moment, but all must have
been pressed at the same time to calibrate the compass ring. This three-key requirement is to
ensure that the compass ring cannot easily be recalibrated by accident, because all the other
compensation settings are also cleared when North is set. The word “clr” is displayed for two
seconds, showing that the indication accords with the vessel’s North heading, and to show
that all the compass error compensation settings have been cleared.
SETTING THE COMPASS COMPENSATION VALUES
North alignment as described above must be done before compensating for errors at other
points of the compass. If the compass errors after setting the compass ring’s North alignment
are found to be significant, the errors can be compensated as follows:
1. Put the unit into Engineering mode. Power off, press and hold the ILLUM key and then
power on. Release the ILLUM key.
2. Press INC and DEC together to get into compass compensation mode. The first display is
45°, representing North-East.
3. Bring the vessel to the displayed heading using a reference compass or charts.
4. Allow at least ten seconds to pass after aligning the vessel to allow the damping to settle at
the correct value, and then press STEER to log the compass error automatically. The display
shows “At” for two seconds to acknowledge the key press, and to show that the error at that
bearing has been logged and permanently stored.

HEADING ADJUSTMENT
It may be necessary to make a minor adjustment to the sensor alignment to ensure that
the Compass correctly measures the vessel’s heading. If an adjustment is found to be
needed, accurately point the vessel to a know heading. Either MAG. or TRUE is
displayed to remind the user which physical alignment of the vessel is to be used.
If the display does not show the known heading, the sensor unit must be rotated
slightly to bring the display into alignment. Slacken the sensor unit’s mounting screws
sufficiently to allow the unit to be turned, and rotate it until the display shows the
know heading. Then re-tighten the sensor unit’s mounting screws to lock the
compass calibration at that position.
REPEATER FACILITY
The Clipper compass display unit takes in un-compensated magnetic readings from
the sensor unit, and transmits the compensated (if the compass has been swung)
heading and the magnetic variation stored in the unit in a standard NMEA 0183
$HCHDG... string.
5. Press INC to advance the display by 45°, and then continue the sequence at instruction 3
until 315° has been logged.
6. When all the errors have been logged, Press INC and DEC together to return to
Engineering.
7. Press ILLUM to return the unit to normal operation.
As a final test, the vessel can be swung to confirm that the compass is operating
satisfactorily with all errors correctly compensated.
Note that it is not necessary to do all the settings as described above at the same session,
and the fixed headings (45°, 90°, 135°, etc.) can, if desired, be checked at different times to
improve the compass’s accuracy. Likewise, if the error at a particular angle is known to be
negligible, there is no need to align the vessel and log the compensation at that position.
10

Declaration of Conformity
NASA Marine Ltd declare this product is in compliance with the essential requirements of
R&TTE directive 1995/5/EC.
The original Declaration of Conformity certificate can be requested at [e-mail]
THIS PRODUCT IS INTENDED FOR USE ONLY ON NON SOLAS VESSELS
IMPORTANT READ THIS BEFORE
UNPACKING INSTRUMENT
LIMITED WARRANTY
Prior to unpacking this instrument read and fully understand the installation instructions.
Only proceed with the installation if you are competent to do so. Nasa Marine Ltd. will
not accept any responsibility for injury or damage caused by, during or as a result of
the installation of this product. Any piece of equipment can fail due to a number of
causes. Do not install this equipment if it is the only source of information and its failure
could result in injury or death. Instead return the instrument to your retailer for full credit.
Remember this equipment is an aid to navigation and not a substitute for proper
seamanship. This instrument is used at your own risk, use it prudently and check its
operation from time to time against other data. Inspect the installation from time to time
and seek advice if any part thereof is not fully seaworthy.
Nasa Marine Ltd. warrants this instrument to be substantially free of defects in both
materials and workmanship for a period of one year from the date of purchase.
Nasa Marine Ltd. will at its discretion repair or replace any components which fail in
normal use within the warranty period. Such repairs or replacements will be made at
no charge to the customer for parts and labour. The customer is however responsible
for transport costs. This warranty excludes failures resulting from abuse, misuse,
accident or unauthorised modifications or repairs. In no event shall Nasa Marine Ltd.
be liable for incidental, special, indirect or consequential damages, whether resulting
from the use, misuse, the inability to correctly use the instrument or from defects in
the instrument. If any of the above terms are unacceptable to you then return the
instrument unopened and unused to your retailer for full credit.
Name
Address
Dealer Name
Address
Date of Purchase
Proof of purchase may be required for warranty claims.
Nasa Marine Ltd.
Boulton Road, Stevenage, Herts SG1 4QG England