RC435 Chartplotter Shows Incorrect Ship Position

[Doug Brown]

My friend has a RC435 Chartplotter. It seems to be working fine except the ship position is off by approx. 100-200 feet. All of the options in the menu seem to be fine. I have set the SD card and rebooted. How do I calibrate to get the correct position?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Doug,

Unfortunately, the RC435 is no longer supported and as such, our ability to assist may be limited. Please click here to view a FAQ addressing this subject. Should the RC435 be reporting that it is acquired a SD FIX and a low HDOP has been reported, then the problem would appear to be a cartography georeferencing issue which would need to be reported to Navionics. Should the RC435's antenna be located where it has an unobstructed view of the skies overhead and the RC435 not be reporting that it has acquired a SD FIX and/or has a high HDOP, then it would appear that the RC435 is not operating correctly (i.e. failing), resulting in poor accuracy. In the case of the latter, it would be recommended that the RC435 be replaced (typically with an a65 or a75 MFD), as Raymarine can no longer provide parts and service for these chartplotters.

In the early days of electronic cartography, georeferencing errors within electronic charts were not uncommon and chartplotting products often included chart offset configuration setting(s) to accommodate such errors until they could corrected by the cartography manufacturer. The RC435 has a Position Calibration feature (see page 41 of the RC435 & RC435i Chartplotters Owners Manual) which may be used to used to apply an offset, permitting the vessel icon to be properly positioned on the chart. However, please be aware that the displayed chart is associated with only one of many chartlets programmed onto the chart card. While it is possible that one of the chartlets may have a georeferencing error, the chart card's other chartlets may not. In such cases, any offset configured will be applied to the correctly georeferenced chartlets as well, resulting in the vessel's position not being correctly plotted when using one of the correctly georeferenced chartlets.