Older RADAR RL70RC MARPA, CMAP NT

[evm]

I've been putting together a Raymarine Radar/chartplotter system out of bits and pieces over the last few years. I'm starting to tie it all together and needed a few bits of information and your experience.

I've asked for a few parts in this thread: http://www.ericsonyachts.org/infoexchange/showthread.php?t=4359

So on to the questions.....

I've no direct experience with CMAP and I see that they come in a number of sizes/formats. It appears that the RL70 series could handle cmap NT wide but not super wide. Is that true?

At some point I may want to try out MARPA. My fluxgate compass by its'self does not update quickly enough. It appears that one would need a smart heading system or an autopilot with a gyro stabalizer (6000, 7000 series). I'm using a 4000 pilot.

How useful is MARPA?

Given the cost of gyros I expect that this will wait till the 4000 pilot breaks and I get a new pilot.

I've been using a 4000+ pilot, Garman 76 GPS and Maptech Offshore Navigator for my navigational needs. The Radar is a new addition and I can see that having a GPS and charts on it would be very useful.

I have a fixed mount Garman 35 that I am thinking about mounting and wiring into the Radar's NMEA input. THe pilot can talk to the Radar through Seatalk and I'll install a switch to allow the PC and OSN to read either GPS (35 or 76). The 76 site at the helm and lets you see your path.

In general I'd rather not let the GPS direct the pilot. I would rather that each course change be a human commanded function, plotted and logged.

So much for rambeling....

Thanks, Ethan

 

[Peregrine]

Radar and MARPA questions

Ethan,

I installed the RL70C at the helm several years ago. Originally I had just the monocrome radar there, but when they discontinued the RL series the price for the color chartplotter/radar display was just too low for me to pass on.

The nicest feature is the overlay of the radar image on the chart. You can easily identify contacts as either fixed charted items or other vessels. You can also do that by splitting the image of the chart and the radar on the screen and then syncronizing the curser. Run the curser out to the contact on the radar and see if it is a charted item on the lower chart screen.

I also have the 4000 autopilot and find that the MARPA function, although useable, does vary quite a bit. One technique that I use to determine the potential danger of a contact is to run the curser out to it and leave it there. If the contact travels down the cursor line, you have a constant bearing, decreasing range situtation.

I am using the NT+ charts and like them.

Hope this helps,
Tony
Peregrine Spirit
E380