The tacktick T221 and Nexus MRC compensation sensors are as
expensive
I'll agree that, at $808, the mast rotation sensor is not cheap.
Given the $1,112 price of the sensor and display, the cost would be
$2,224 for two sensors/displays and $$1,920 for a single
sensor/display/
If you want redundant wind systems, that's the way to go.
Here's why I'd go with the single system:
- Redundant sensors won't give you true wind speed and direction.
With a rotating mast, the system has to do vector math on three
inputs to find the true wind velocity: speed and direction of wind
relative to the mast, speed and direction of the boat relative to the
compass, angle of the mast relative to the boat. The tacktick system
does this automatically (as I assume the Nexus does too) if you have
all four sensors installed (wind, mast, speed, compass).
Of course, if you don't care about true wind, then it doesn't
matter. Many people happily sail all their lives without knowing the
true wind speed. It's a must-have, though, if you want your VMG to
windward.
- Redundant sensors won't integrate with the tacktick single system.
Tacktick allows for a single wind sensor, and then does all its
math based on that sensor. If you were to add a second sensor, you'd
have to put it on a second independent Tacktick system on the same
boat. You could do it, but you wouldn't see data from system A on
system B, and vice versa. That means either duplicating all the
sensors on the boat, or just knowing that some displays won't show some
information.
With a single integrated system, it's pretty convenient to be able
to just slap a display anywhere you want and then get any data you want
(including GPS numbers). They even have a nice wireless handheld
remote, which is handy if you don't have a high-end autopilot with all
the boat data on its wireless remote.
---
One thing to note is that you can still have two wind displays, one
at each helm, with a single wind sensor. Or, you could get fancy and
have four displays, one true and one apparent for each helm position,
along with a few other displays for things like speed, depth, and VMG
windward.
If you wanted redundancy for purposes of recovering from some sort of
mishap, it might be better to keep a spare wind sensor ($549) in a
Pelican or faraday box inside the boat. That way the spare will likely
- Mike
jjtctaylor wrote:
as buying two separate wind instruments and displays. Why not buy
two, redundant, and view diplay from whichever helm position. You
can switch which to feed chartplotters, etc.
Just choices, but going to cost ya whichever way. Same goes for nav
lights. You can have processor figure out which to use, but still
have to buy extra sets.
JT
--- In harryproa@yahoogrou
wrote:
>
> I think that Nexus MRC box should do the trick. See
http://www.nexusmar
epslanguage=
>
> The box has compass and the wireless masthead wind unit has
compass. The two readings are compared and with speed info you have
true wind. Doesn't really matter if the mast rotates or not or if the
boat changes direction as long as the compass in the MRC box points
the same way as the boat.
>
> Arto
>
> --- On Tue, 2/10/09, Mike Crawford <jmichael@..
>
> From: Mike Crawford <jmichael@..
> Subject: Re: [harryproa] Re: Niggling practical proa questions
> To: harryproa@yahoogrou
> Date: Tuesday, February 10, 2009, 9:20 PM
>
>
>
>
>
>
>
> The mini mast sounds like a decent compromise in order to get
lights off the deck level.
>
> As much as I'd like to have a masthead tricolor light, I've
given
up on the idea. Tricolors work as poorly on a rotating wing mast on
a catamaran as they would on a proa. It would be nice to have a
masthead white light, but it would not be impossible to set up wiring
for that with a brush system below deck.
>
> As for the wind sensor, TackTick makes a nice wireless wind
setup
which I've been using for a couple of years.
>
> You need a masthead wind sensor, a mast-mounted mast rotation
sensor, and any number of displays (analog with an arrow, or
digital), and a hull transmitter with a speed/depth transducer and a
magnetic fluxgate compass. With the exception of the hull
transmitter (receives speed, depth, temperature, and compass), and
the NMEA interface (hooks up to a GPS, autopilot, etc.), everything
is wireless and solar powered, so you can put it anywhere you want.
Even on top of rotating masts. It's great for a boat that gets
demounted from time to time.
>
> The system takes the true wind, subtracts out the boat's speed
and angle (speed and compass), and then adjusts for the mast rotation
(mast rotation sensor). The results are then displayed on LCD
displays that are roughly 4" wide x 3" high. There's a choice of a
larger maxi display with huge numbers, a standard display with a
single large number, a standard display with two numbers (top and
bottom) and a standard display with an analog directional arrow with
one number. Any display can show any number in the system, from
water temperature to true wind angle. As with the other equipment,
the displays are solar powered, and can work for days in total
darkness.
>
> And if you have the NMEA interface hooked up to a GPS, the
system
can even tell you were true north is.
>
> I'm clearly a TackTick convert, but that doesn't mean it's not a
good system.
>
> - Mike
>
>
> Arto Hakkarainen wrote:
>
>
>
>
>
>
>
> A couple of thoughts from my armchair:
>
> - There are different solutions for wind instruments for rotating
masts. Making it suitable for proa should only take one more
correction to processor. Solution that has compass in the masthead
unit and compares the reading to the boat compass should do it
already in the off the self unit. Can't remember which makers had
that solution but I think it was tacktick and/or selva. Those who
know please correct me.
> - Regarding compass and lights one idea is to mount them on a
small
mast dedicated for lights, flags etc. (like ones used on powerboats).
Then make that rotating mast and have it locked to point the
current bow. Need to turn that mast manually though but less
duplicating needed.
>
> Comments?
>
> Arto
>
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