Need help for a mate at sea. Gp-32 and how it navigates

A

Anonymous

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I got this question from my friends at sea:

Or would you have time for technical assistance?
Our GPS onboard calculates routes we believe by
Great Circle, not Rhumb Line. I have just gone thru the manual onboard and there is absolutely no ref to an option to choose.
Any chance you might be able to..check on-line to see if any forum has discovered this issue?
FURUNO Model: GP-32 / GPS Navigator

Can anyone help answer this? I don't actually know what any of this means so I'm hoping they communicated enough information. Furuno appears to be frustratingly difficult to get ahold of someone that will answer technical questions like this so I am hoping this community can.

haha it took me several attempts to register here because I couldn't figure out what the heck the answer to the the Spambot question was.
 
Good afternoon geoffsweet6,

Thank you for your inquiry. To start with, where are you located in the world and what number or email contact have you been trying to get in touch with?

Here in the states we take great care to make sure technical support and customer service questions are able to get answered efficiently. We have two locations located on the west and east coast with a support hotline. Our technical support personal are available from 8:00am EST to 5:00pm PST to provide assistance via phone and email. We hope you have not incurred any difficulty getting in touch with Furuno USA for your questions if you live in the states.

The GP32 uses Rhumb Line not Great Circle. With the GP32 there is no way to change it to Great Circle.

Please relay this information to your contact.

Kind Regards,

C-Bass
 
Thanks for the reply. I was trying to call the number listed on the site: (360) 834-9300. I would get put into a queue with no answer. It's really not that big of a deal. This forum probably works better because I am relaying all this stuff back and forth to them. So here is their response to your comments:

What I subsequently did was to take our exact latitude now and then create waypoints with same latitude but varying longitude
As the latitudes are exact same, TRUE course to steer is due EAST (090 degrees true) for all examples.

Per nav chart our variation is 27 degrees east.
Over short distance the course to steer was 063 degrees Magnetic and add east variation 027E gives 090 true = PERFECT!

However, the longer the distance to the
(further) waypoints – the higher the magnetic course goes. ie from 063 to 070 to 086?

In theory – east course does not change or variation at current location
So:

Can FURUNO explain why such magnetic bearing (BRG, aka course to steer) discrepancies exist for a consistent EASTERLY course ?
we are aware of the menu option to change from Magnetic to True on the ‘plotter’ screen.

When we do that, gives course to steer (BRG) greater than 090!

Drina 577 sent this message from: Lat -48.588002 Lon -114.570923

Thanks everyone!!
 
Are they sitting stationary? The GP32 needs you to be moving greater than ~3 knots to accurately calculate these figures.
 
The response:

We were making min. 5 probably 6kts at the time of the calcs.

Distance should not (normally) be affected by speed?! ETA yes, distance no?! Weird!

Drina 577 sent this message from: Lat -48.859559 Lon -112.083549
 
I did not see any mention of distance in their post? I was referring to the bearings they were getting.
 
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