Secrets of Raymarine

Don't know if this affects anyone else, but on my system (C-120/GPS 125), the log function is terribly inaccurate. I verified it many times against another GPS, and against measured distances on the chart. The log function always reads less than the actual distance travelled. On average, the typical error is 15% - I saw errors as high as 17%, and as low as 10%. I had plenty of opportunity to check it during our cruise. It measures SOG correctly, but not distance. Wierd.

I haven't asked Raymarine yet - they are still working on why my MARPA software doesn't provide the true course and speed for the acquired target. Currently it gives the relative data (adding my boat's movement to the target vessel). The guy who was helping me just escalated it up the chain.

I had already tried to get them to figure out why my system thinks it is moving (a couple of feet every few seconds) even when we are tied to a dock and not rocking. I tried adjusting the dithering rate, etc. but it didn't make a difference. Raymarine just sid that's normal (but my Garmin doesn't do it)

I don't want to confuse them too much at one time....

Has anyone else checked the calibration of their log function? It sure makes a difference when calculating fuel economy.

Mac
 
My E80 log reads low by as much as 50%. I reported this problem to Raymarine over a year ago with no response. Speed over water has been calibrated (paddle wheel) and is very accurate. So is Speed over ground generated by the GPS. The log generated by the Navman fuel moniter is bang on as is the Garmin handheld unit.
 
Hank,

My paddlewheel is horribly inaccurate! Not even close. Esp. at slow speeds. I am surprised the C-80 does not match the Garmin hand held. We check ours against a Garmin and a Lowrance iFinder and they all three match.

I wonder if some setting on the C-80 is off... When you check the satellites it's tracking, do they match the satellites on the Garmin? Is something blocking the C-80 satellite gps antenna when you turn or run close to mountains and buildings?

John
 
The paddle wheel on our CD22 wasn't very accurate - except at the one speed we calibrated it at - the calibration factor is in the Fishfinder menu. Unfortuately, there is no way to adjust the curve (speed vs paddle wheel turns) and since the paddle wheel is in disturbed water, it reads different at different speeds


I cannot understand how Raymarine can correctly measure SOG, but not distance. The GPS very accurately reports our position. It must be in the algorithm/software they developed. Thanks for the validation

Mac
 
Mac,

Several factors could be at work here. Generally the SOG is very accurate. The log, however, accumulates all those tiny movements from buoyancy at the docks, etc.. Are you leaving the C-80 "on" for long periods of time while anchored, on mooring buoy or docked?

My paddle wheel is easily interfered with by seaweed and other small debris in the water. It reads like you are moving if the tide/current is moving the wheel while at anchor or dock. It is inaccurate at slow speeds and very high speeds. My paddle wheel reads out on the Honda gauge as a separate number from the log reading on my E-80. My E-80 pretty much accumulates the "log" total from the SOG readings, I think.

I have a paddlewheel log and an E-80 SOG log and they rarely come close to matching. You know currents, tides and drift throw off that paddlewheel reading too.

From my experience, the paddle wheel is less reliable than the Raymarine unit, but I do not have your setup, nor operate mostly at hull speed.

Good luck...

John
 
I don't have a paddle wheel - so all my measurements are using the GPS.

What I find really interesting...sitting at the dock, in completely calm water, you can watch the log count away - in increments of 6 ft (or is it 8?, I can't remember) - every second or two. That would have led me to believe the log would read more distance than actually traveled - but it reads ~15% low (with variations) compared to actual.


Mac
 
When crossing the Straits of Juan de Fuca, there is one ship that concerns me the most. The Victoria Clipper (actually, there are 4 of them) travels at 35 knots and does not use the traffic lanes due to it's size (75 feet). In foggy conditions, this bullet can come up in your windshield really fast.

I have adopted a technique with the E-80 just for this situation. First, since no big boats match our 21-23 knot cruising speed, I usually offset the Radar 2/3 to get more view in front of me. In this instance, I center our boat in the Radar screen since the Clipper can catch me from behind. Second, I push and hold the Active button to enlarge the Radar to full screen. My depth can be shown in the Data Bar and is not an issue in the central Straits. If Route waypoints are in use, they will show up on the radar screen along with the bearing line to the next waypoint. It is actually easier to stay on course using this bearing line than using the chart. We do not have an autopilot installed.

The E-80 works well in this mode for this unique situation.

 
dreamer, you can use the radars alarm systems to let you kow if anyone is coming up from behind. the areas can be set up as a radius from your ship or in different sectors. You can set the forward sector at 1/4 mile and the rear sector at 20 miles or any thing in between. I have not used this function often but there is a lot or ablitiy in the unit to customize the alarm and sectors.
 
You can also use the MARPA thing by backing off (widening the view) until you can see the big ships moving fast, then clicking on them to let MARPA track them. It will give you a flag with their speed and direction over 20 miles away. Of course the protected area for the emergency alarm warning just mentioned is nice too. After setting these, you can focus back down onto your smaller immediate area.

I like to search wide for potential problem craft, mark them for tracking with MARPA, and then I know what possible problems could arise far in advance of the actual warning zone.

John
 
Just in case anyone else has had the same problems I had at the outset of using my E-80 units, here is an odd problem and fix that are not in the book.

My boat icon's orientation was not representative of my boat's orientation, i.e., the icon did not point the same way as the boat was pointed.

My electronic's installer up in Edmonds repeated the circling and setup procedures many times. My unit would also just go "out" periodically, usually when the seas were the roughest. A local tech in Oklahoma finally found part of the problem - the installer had grounded the Seatalk cable lines. Seatalk, he said, is basically like speaker wires - no ground.

I still could not get the orientation squared away, so most of the E-80 options were not available. Not until I had purchased a set of binoculars with digital compass down in Galveston, TX. I took the bearing from those binoculars pointed straight ahead (against the center window frame) and MANUALLY entered the boat's orientation.

Finally, all the E-80 functions began to work properly. I could finally use all of the format options. I could use the green and red arrows showing boat heading and true progress, etc.. The long green arrow of true progress prediction is invaluable in making certain you are really travelling to the desired location, since the direction the boat is pointed is often not the direction of actual travel.

So, if problems, try manually setting the boat's position and manually setting the deviation for your area. It rounds off to a degree anyway, so those circling setup maneuvers are not necessary if you have the info on a map or binocular compass.

John
 
Hey Thomas,

For me it 's a good point and bares repeating. :idea :idea

BTW, I really enjoy your expertise on the Raymarine thread too.

Harvey
[b]Sleepy C[/b] :moon
 
Does anyone know how to change the color of either the range rings or the other data, numbers, etc. on a C-80 when in the chart screen? I like the range rings but often cannot find the actual range ring "range", i.e. 1/4nm, 1/2nm, etc. The numbers and lines are all black and the range ring data gets lost in all the other stuff. (of course it would help if the range ring ranges were always in one location, mine appear anywhere on the ring depending on the scale I'm using.

Thanks.
 
Does anyone know how to remove or radically scale back the vector arrow on the chartplotter? I know I can adjust it to 3 minutes, 6 minutes or Infinite, but all of those have the unfortunate tendency to obscure little things dead ahead like rocks and shoals and who knows what else?

Thanks,
Warren
 
Gang... Going on my first 180-200 mile 3 day river trip with my new e80 raymaring. I have done a cut-n-paste of each of these post...minus one or two that was just sweet mutterings we all do... and put them on a microsoft word file.

I have not cleaned it up at all...just needed to print it fast to take with me and Jeff Brigner from C-Pearl on our Cumberland River Run..

Thanks..I know I will need some of this stuff from REAL USERS...

Byrdman.... on da rivva..
 
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