[Rhodes22-list] Toys for Rhodes

Fri May 14 19:19:36 EDT 2004

Doug,

OK, realizing I'm probably going to provoke an argument, here goes...

1st of all, complete disclosure.  Dynamic Equilibrium's electronic
navigation aids consist of an Autohelm ST-50 tridata instrument and a
Magellan GPS 2000 handheld GPS unit.  The ST-50 tridata combines a
knotmeter, log, depth sounder, and water temperature sensor into one
package.  The ST-50 is no longer in production.  The replacement Autohelm
unit is called the ST-60 tridata & it has essentially the same functions.
My ST-50 tridata has been in service since 1993 and my GPS 2000 since 1996.
The ST-50 has been totally bulletproof.  The GPS 2000 got dunked by a wave
in the cockpit once in 1998.  Despite the waterproof rating, water got
inside the GPS 2000's case & it failed within 10 minutes of the dunking.
Magellan repaired the unit under warranty & it has lived inside of ZIPLOC
plastic bags ever since than.  By today's standards, the GPS 2000 is
obsolete.  It's slow, with sufficient memory for only 100 waypoints.
However, it does show one's present position, average speed, plus distance,
bearing, and ETA to the next waypoint.  Dynamic Equilibrium also has a
Danforth bulkhead mount ship's compass/inclinometer and an Autohelm ST1000+
Tillerpilot.

So what do you envision doing with your Rhodes 22?  If all you plan to do is
daysail within sight of land; then, you don't need any instruments.  If you
envision being out of sight of land, sailing to unfamilier ports of call,
&/or possibly being caught out in fog or at night; then, the above
complement of functions plus a good set of compass bearing binoculars &
minus the autopilot are, in my opinion, about the minimum requirement.  You
need to be able to plot compass, GPS, and dead reckoning (DR), fixes on a
chart.  A log (total distance) is more useful for plotting a DR fix than a
knotmeter because it is difficult to maintain a consistent speed while
sailing.  Unfortunately, the low cost knotmeters like the SR Mariner models
you cited do not include a log.  You will find the knotmeter will be
marginally useful for helping you learn how to optimize your sail trimming
skills, but not for much else.

The depth sounder is very useful for following a certain bottom contour in
fog or at night in order to stay a certain distance offshore.  It will also
provide early warning when you are approaching landfall - often many miles
before you can see land.  A depth sounder with an anchor alarm is a useful
feature if you plan on spending any time on the hook.  An anchor alarm will
sound to wake you up if the depth below the keel changes from more than a
+/- threshold from a setpoint water depth, presumably because the anchor is
dragging.  This function is also useful for tacking up a narrow channel.  In
this case, the alarm will sound to warn you that it's time to come about.

The water temperature sensor has turned out to be more useful than I would
have imagined when I 1st got my ST-50 tridata instrument.  Of course it's
primary function is as a swimming comfort indicator.  But, it's also very
useful for locating warm currents such as river outflows even miles
offshore.  It's also quite useful for fishing.

The 1st instrument you should buy is a good ship's compass & a set of
compass bearing binoculars.  The 2nd instrument is a handheld GPS unit.
After that, there are lots of options.  The fishfinders provide a nice
complement of depth, water temperature, and fish sensing functions.

You will be disappointed with the SR Mariner KT-5 knotmeter.  Either get an
instrument with both a knotmeter & a log or don't bother.

By the way, do you actually know how to plot a fix on a chart using various
methods and do you understand the rule of the road and other boating safety
concepts?  If not, then you should spend your money on a basic
navigation/boating safety course before doing anything else.  The US Power
Squadron offers a pretty good course.  You should do this before you put the
boat in the water!

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message -----
From: "Bob Weber" <ruba1811 at hotmail.com>
To: <rhodes22-list at rhodes22.org>
Sent: Friday, May 14, 2004 3:47 PM
Subject: RE: [Rhodes22-list] Toys for Rhodes

> Doug, I am not sure how accruate you need to be with depth and speed.  A
> less accurate solution that works for me is a fishfinder for depth and
> handheld GPS for knot.  Only the fish finder requires power from the boat.
> The knot meter on the gps is over ground not over water (if you are
subject
> ot currents).  I find the gps display to be jumpy and not much more
usefull
> than giving me a general idea of speed.  Hope it helps.  Bob Weber
>
>
> >From: "Doug Mistler" <mistler at mindspring.com>
> >Reply-To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> >To: <rhodes22-list at rhodes22.org>
> >Subject: [Rhodes22-list] Toys for Rhodes
> >Date: Fri, 14 May 2004 15:29:38 -0400
> >
> >Being a purist, Stan pleads ignorance on the subject of instruments for
the
> >Rhodes and suggests that I query the list.
> >
> >I need a depthfinder and knotmeter.  Some of the digital combo units are
> >rather "pricey" and others seem to be out of stock. I now am considering
> >separate depthfinder and knotmeter units in proven (read old-fashioned)
> >technology.
> >
> >I am inclined toward the SR Mariner Self-powered Knotmeter (KT-5), and
> >Digital Depth Meter (DDM-1), in the Defender Marine 2004 catalog, page
295.
> >As they are in stock, Stan will not have an excuse to delay getting my
> >"almost new" Rhodes to me.
> >
> >Do any  "Rhodies" have experience with these items or can you recommend
> >others?
> >
> >Thanks and fair winds!
> >--Doug
> >
> >
> >__________________________________________________
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>
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