Ritchie - Navigator Compass - Bulkhead Mount - Black - BN-202. When mounting this Compass to a bulkhead that is NOT perpendicular (90 angle) to the center-line of the boat and/or NOT vertical (90? angle) to the waterline of the boat (boat on level keel), a fairing block MUST be used to make the compass so.. Navigator Compass Features:. 4-1/2" Ritchie CombiDial and Built-in Clinometer. Easily Installed, Fits 5.75" (14.61cm) Mounting Hole. Internal Gimbal Systems for Maximum Stability During Adverse Pitch and Roll Conditions. Scientifically Matched Sapphire Jewel and Hardened Steel Pivot Dial Movement. Fiberglass Reinforced Bowl. 45 degree Lubber Lines. Exclusive Built-in 12V Amber LED Lighting. Built-in Compensators to Easily Adjust for Deviation. 100% Repairable. Exclusive 5-Year Ritchie Warranty. Approx. Shipping Weight: 2 lbs 5 oz (1.05 kg). Notes:. 12 volt lighting standard - 24 & 32V lighting options are available.