Installation Guide for Ritchie V-57 Dash Mount Compass

CAUTION

All Magnetic Compasses are vulnerable to magnetic interference, which will produce errors, called deviation. It is the Owner/Operator and/or Helmsman's responsibility to make sure the compass is properly installed and compensated. Compensation is the act of correcting for deviation. Magnets (speakers, microphones etc.), ferrous metals (steel, iron, etc.) and current carrying devices are common causes of deviation. It is important to understand that magnetic compasses point toward Magnetic North. There is a difference between Magnetic North and True North, and that difference is called variation. Variation differs depending on your geographical location and can be determined by referring to a local chart.

Please read the Instructions completely before beginning installation.

Selecting the Proper Location

The compass should be close enough to the helmsman and positioned below the helmsman's line of sight so it is easily read during normal operation. You will need a flat and level surface (when the boat is on a level keel). Many boats have a curved mounting surface and if this is the case, a fairing block should be utilized to bring the compass to a level position.

Select a location that has no more that 20 degrees deviation on any of the four cardinal points (N S E and W). Most compasses have a built in compensation system that will correct for fixed deviation up to 20 degrees. It is important to realize that proper compensation is not possible when a compass is subjected to a magnetic field that is variable. Some shipboard devices can cause varying magnetic fields. Devices such as windshield wipers, high current carrying wire and even some steering wheels must be considered when selecting a location for your compass.

Testing Your Chosen Location

Use your compass to test a location. There are two brass rods near the bottom of the compass, which rotate 360 degrees, the slotted ends may be all that is visible. These compensation rods are used to correct your compass for deviation. When testing a location, you do not want pre-set corrections in your compass, so neutralize the comp-rods by setting the slots in a horizontal position.

Begin your test by holding the compass away from any possible interference and observing the compass reading. Then move the compass into position carefully; keeping it pointed in the same direction. If the compass reading is different without a change in direction you are observing deviation. You need to find a location that has less than 20 degrees of deviation on the 4 cardinal points if you intend to adjust your compass using the compensator rods.

After finding a location you should test for intermittent changes in the magnetic field. With the compass mounted temporarily in its intended position try moving the steering wheel, throttle controls or anything else that might cause deviation. It is also advised to turn electrical devices off and on. Please be advised that a changing magnetic field cannot be corrected with compensation and you will need to find another location for your compass.

Installation-Mounting the Compass

Great care must be taken to mount the compass so that it is aligned with the keel of the boat. An alignment error is a constant error on all headings caused by the compass not being pointed in the same direction as the boat. One recommendation is to temporarily mount the compass using one fastener so if an alignment error is detected it is easily corrected. Masking tape can be used as a reference or to keep the compass steady during installation.

If you are mounting to a bulkhead or dash that is not perpendicular (90 degrees) to the centerline of the boat, a fairing block must be used.

Due to variations in bulkhead and deck materials, mounting screws are not supplied. Use hardware that is suitable for your specific installation. SELECT MOUNTING HARDWARE THAT IS NON-MAGNETIC. Most quality stainless steel and solid brass fasteners can be used. If you are unsure test them with a magnet.

Most models have built-in lights which will require routing the wire or wires to your power source. To assure a clean installation you may want to wait and drill the routing holes after you are satisfied with the compass alignment.

V-57W.2 Dash Mount 

This model requires a 3-inch diameter cutout in the dash. Install the mounting flange, with the mounting gasket, in the cutout and secure it from behind the dash using the mounting hex nut. Be sure that the light is located at the exact bottom. Next, locate the compass capsule in the mounting flange such that the bowl (the white ring around the middle of the capsule) is approximately level. Lightly secure the capsule in place using the O-ring and the screw-on bezel. Make the final adjustment so that the capsule is perfectly level and then firmly secure the capsule in place using the screw-on bezel.

Lights should be wired to an appropriately fused 12-volt circuit in your electrical system (i.e. running light circuit).
Connect one wire to ground and one to positive, observing polarity is not necessary with Explorer compasses.

Compensation
A built-in correcting magnet system consists of two sets of magnets fixed to two adjusting rods with slotted ends. The slots should be horizontal before starting the adjusting procedure. A small non-magnetic screwdriver is provided for this purpose.
Before starting compensation, make sure you have a suitable location (see Testing Your Chosen Location).

Method 1. (Preferred)

Step One. With the compass in its intended position, but not finally secured, (see Mounting the Compass) select a course on your chart using two fixed aids that are within ten degrees of the North/South line. Try to select this course so that you can maneuver your boat down range of the marks selected.

Step Two. From a position down range of the North/South marks, and keeping the marks lined up, run the boat visually along the Northerly course selected. Turn the port/starboard compensator (slot is facing starboard) until the compass reads correctly.

Step Three. Simply repeat steps 1 & 2, except this time, using an East/West course and the fore/aft compensator (slot is facing aft).

Step Four. Check compass alignment by running the boat in a Southerly direction, again keeping the marklined up. If the compass is not correct at this time, there is an alignment error. To correct, rotate the compass itself to remove one half of this error. Repeat steps 1, 2 & 4 until your North/South line is correct then repeat step 3.

Step Five. Install fasteners, taking care not to disturb alignment.

Method 2. (Requires the use of GPS or Loran)In this method, you will be using a GPS or Loran as your reference.)

1. Your GPS or Loran must be set to provide you with Magnetic, not True headings. Check your Manual.
2. GPS and Loran provide headings based on COG (course over ground). Compasses provide heading based on the direction the boat is actually pointed. Because of Tides, Currents and Winds, the boat may not always point in the same direction as COG. Pick a time and location that will minimize these effects.
3. Because the GPS and Loran calculate COG based on current and past positions you will see greater heading accuracy while traveling at higher speeds. We recommend at least 10 knots.

Step One. While at sea, with the compass in its intended position, but not finally secured, (see Mounting the Compass), obtain the Loran/GPS bearing to a fixed aid or landmark that is within 10o of a North/South line.

Step Two. Position your boat along that line and steer directly at that mark. Turn the port/starboard compensator (slot is facing starboard) until the compass heading matches the Loran/GPS bearing.

Step Three. Simply repeat steps 1 & 2, except this time, using an East/West course and the fore/aft compensator (slot is facing aft).

Step Four. Check compass alignment by running the boat 180 degrees from the heading used in step 2. If the compass is not correct at this time, there is an alignment error. To correct, rotate the compass itself to remove one half of this error. Repeat steps 1, 2 & 4 until your North/South line is correct then repeat step 3.

Step Five. Upon completing the procedure, secure the compass in its final position.

V-57W.2
These models incorporate a compensation system that work on the intercardinal heading instead of the cardinal heading. You can use methods 1 or 2 to compensate these models but you will need to use different headings than are listed.

For example in steps 1 and 2 of both methods, you are asked to select a course that is within ten degrees of the North/South line. For these models, you will select a course that is with in 10 degrees of the NorthEast/SouthWest line (a heading of 45 or 235). Use the port compensator (slot is on the left) for your adjustments.

For steps 3 and 4 of both methods select a course that is with in 10 degrees of the SouthEast/NorthWest line (a heading of 135 or 315). Use the starboard compensator (slot is on the right) for you adjustments.

Maintenance

Protect your compass from the sun when not using your boat. Strong sunlight may decrease the life of your compass.

Ritchie compasses require very little care. To remove salt spray deposits or dirt, rinse the entire compass with clean, fresh water and wipe carefully with a damp cloth. Important Note: Never Use Chemical or Abrasive Cleaners.

The information provided here has been reproduced courtesy of Ritchie Compasses. Wholesale Marine reproduced this information 08/07/2009