Mini-ARPA...Don't trust it.

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greigwill
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Joined: 3/28/10
Posts: 174
Mini-ARPA...Don't trust it.

Larry,do you need a gyro to use ARPA?A great tool if available for recreational boating...thought i would bump up your post,your course is in 2 days..only $25!

"Sailing Still" 1990 C36 M25 wing
 Sail Canada/Transport Canada training
Gibsons Harbour BC
www.landsendbc.ca

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LCBrandt
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Joined: 6/26/07
Posts: 1282

Greg, I think you have Mini-ARPA...also called MARPA...instead of ARPA. MARPA has a lot of drawbacks, but will be most helpful if you have a solid and *accurate* heading sensor. My MARPA uses simply COG, so a heading sensor is not needed for bare minimum usage; nevertheless, it is terribly inaccurate as a result.

The take-away: Never completely trust MARPA as your collision avoidance tool of choice.

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

William Miller
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Joined: 10/4/08
Posts: 294

On mt Garmin 4208 with 18 HD radar you need a gyro to make it MARPA work

Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

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LCBrandt
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Joined: 6/26/07
Posts: 1282

A gyro, Bill? Or a fluxgate compass?

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

William Miller
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Joined: 10/4/08
Posts: 294

You are right, wrong word a fluxgate compass is what it needs . I have a fluxgate for my autohelm but can not tie it to my garmin, and garmin wants 900$ so will do with out

Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

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