[Rhodes22-list] Looking for advice

[Michael Meltzer]

I have the ST60 tridata also, great unit, Rayathon came out with st40 line last year, you should check it out, BTW have GB install
it, they are used to doing it.

MJM
----- Original Message -----
From: "Roger Pihlaja" <cen09402 at centurytel.net>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Tuesday, April 15, 2003 9:49 AM
Subject: Re: [Rhodes22-list] Looking for advice


> Hi Alice,
>
> I have the Autohelm ST-50 (Now Raytheon ST-60) tridata instrument.  The
> tridata includes a knotmeter, mileage log, water temperature, & depth
> sounder all in one display package.  I also have an Autohelm autopilot.  I
> like the Autohelm series because of their proprietary "seatalk"
> communications bus, which allows all the instruments in the system to share
> information.  You may not care about having an integrated instrument package
> now, but you might in the future.  This is good equipment.  Mine have been
> bulletproof for over 12 years & counting.
>
> In my opinion, a knotlog, depth sounder, & ship's compass are the minimum
> complement of instruments your boat needs if you are going to take out of
> sight of land.  The water temperature function  came with the tridata
> package.  I wouldn't have bought it separately; but, it has turned out to be
> surprisingly useful: for fishing, as a comfort gauge for swimming, & as an
> indicator of when you have crossed into & out of currents.
>
> What ever brand of depth sounder you get, make certain it has an adjustable
> depth alarm.  That way you don't have to stare at it all the time.  It will
> alarm when the water depth gets less than the setpoint.  This function is
> also useful as an anchor alarm to detect if the boat is dragging its anchor
> while you are sleeping.  Most digital depth sounders have at least one
> adjustable depth alarm.
>
> Another useful function on a depth sounder is an adjustable offset.  An
> adjustable offset allows you to compensate for the difference in vertical
> height between the depth sounder transducer and the deepest part of the
> boat - usually the keel.  For example, I have my depth sounder setup to
> indicate the water depth under the keel.  This function is very useful,
> because in a stressful situation, you don't have to keep remembering to
> subtract 20" from the water depth reading to know when your solid shoal
> draft keel is going to touch.  Most digital depth sounders have an
> adjustable offset function.
>
> Some depth sounders are equipped with a "forward looking" function.  This
> function is derived by keeping track of the last several depth readings and
> extrapolating the trend forward in front of the boat.  In theory, this can
> give you an early warning of a shallow area ahead.  In my opinion, this
> function is of very limited utility in real world sailing situations.  I
> certainly wouldn't pay extra in order to get it.
>
> Finally, whatever brand of depth sounder you purchase, pay very close
> attention to the installation instructions especially re the location of the
> SONAR transducer.  The transducer can only transmit & receive its SONAR
> signals in a relatively narrow cone.  If you mount the transducer on a
> sloped part of the hull - like say the sharp V up near the bow; then, it may
> lose the bottom return echo signal when the boat is heeled over on one
> sailing tack or the other.  The transducer must also be in bubble-free
> water.  I have my depth sounder transducer mounted approximately amidships
> on the starboard side in front of the ice box.  It is mounted as far inboard
> as the shoal draft keel permits.  I installed a 6" ID Beckson screw-in deck
> plate in my cabin sole to permit inspection & maintenance of the backside of
> the transducer.  The other preferred depth sounder transducer location is in
> the lazarette compartment as far forward as possible & several inches to
> starboard of the centerline.  You want to be as far forward as possible & on
> the starboard side of the lazarette compartment to keep the transducer in
> bubble-free water.  There are several sources of bubbles which may cause
> problems for the transducer in this location: the cockpit drain, the
> outboard motor exhaust when running in reverse, & waves slamming into the
> transom when running before a following sea.  You also don't want to mount
> the transducer so close to the centerline that it causes a structural
> weakness between the cockpit drain thru hull & the thru hull penetration for
> the transducer - keep them several inches apart.  If you mount the depth
> sounder transducer in the lazarette compartment; then I would also fabricate
> some sort of guard or cover to protect the backside of the transducer &
> cable from being damaged by shifting cargo.  That's another favorable point
> for the amidships mounting location - there's nothing rattling around under
> the cabin sole that might damage the backside of the transducer or the
> cable.
>
> Good luck!
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
>
> ----- Original Message -----
> From: <AMICW at aol.com>
> To: <rhodes22-list at rhodes22.org>
> Sent: Tuesday, April 15, 2003 7:14 AM
> Subject: [Rhodes22-list] Looking for advice
>
>
> > Hi folks!  Hope to get delivery on my R22 soon and I'm considering a depth
> > finder.  I know, from past emails, that many, including Stan, think this
> is
> > not needed however, I'll be sailing on the Chesapeake and would feel a bit
> > safer with it.  For those who have (or want) one, what depth finder would
> you
> > recommend (don't need fishfinder - I do that on my own with a fishing
> pole).
> > Thanks.
> > Alice
> >
> >
>
>
>
>