"Wout B." wrote in message
...

"b393capt" wrote in message
oups.com...
I am just about to buy a bunch of Raymaine instruments for my new B
393, and just found out that the ST60 is limited to using SOW, and
won't use GPS SOG & COG, to calculate true wind.

After looking thru this forum, I see some references to this issue, but
don't see either
(1) A way to get true wind on any of the Raymarine instruments, does it
work on the Tri data ??

(2) Another vendor who does not have this limitation mentioned.

Can anyone help me ?

Especially at low sailing speed and strong current, this can make all the
difference.
The Navman wind instrument can use either SOG or water speed for true wind
calculation.
You can also "fool" any NMEA wind instrument by converting the NMEA RMC
sentence from the GPS (COG) to VHW (speed thru water). A Brookhouse
multiplexer will do this for you. You can load a simple script for this
conversion. You may need a multiplexer anyway if you are building an
integrated instrument system.
Wout


Sorry, I meant GPS (SOG) in my posting above, not GPS (COG).
Using SOG instead of speed thru water is useful if the paddle wheel of the
speed instrument gives a very inaccurate reading and/or is fouled. It is of
course only accurate if the heading of the vessel is the same as the COG, as
the measured wind-angle is relative to the centre line of the vessel.
Wout