[C320-list] Speed Increase by Installing App on Smart Phone - How to calibrate knotmeter?

[Jeff Hare]

Hi,

On a lake without current, I agree you should just calibrate it so that you
can go faster and kick everyone's butt.  :)

If you sail where there are tides and currents and have a chart
plotter/depth/speed/wind instruments tied together, then properly calibrated
knot meter and wind instrument can make quite a bit of difference in showing
the strength and direction of currents you're sailing against (or with).
Without calibrated gear you miss out on some helpful data, mostly because
the chart plotter calculates current vectors based on GPS course/speed
combined with knot meter speed through the water and compass heading.

Specifically, you might opt to run with the current or tide now to make
better speed over ground even if it takes you off your line, especially if
you can plan for a reversing current to help pull you back in line later.
In our area there are times when I need to head more into a current early
knowing that it will increase or change direction later along my route.
Sailing a direct line might force me to point to close to the wind to
counter the increased tidal current and stay off the shore.  Can make the
difference between being able to sail and having to motor.  Around here if
you don't take advantage of the current, you're missing a lot.

-Jeff

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Bill Lowe
Sent: Monday, August 3, 2015 9:49 AM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Speed Increase by Installing App on Smart Phone -
How to calibrate knotmeter?

 Dean,
I have the manual and have calibrated my speed readout several times.
Recently, I have been sailing to your marina fairly frequently to help some
friends who recently bought "Sunlower" a hunter 28.5 there. I would be glad
to loan you my manual if you don't have one.


Bill
Papillon
#1146


-----Original Message-----
From: Dean Vermeire <dean at vermeire.us>
To: Catalina 320 List <C320-List at Catalina320.com>
Sent: Mon, Aug 3, 2015 8:00 am
Subject: [C320-list] Speed Increase by Installing App on Smart Phone - How
to calibrate knotmeter?

 
 
 
First of all, I should point out that after 40 years of sailing, our
Catalina 320 (which we have had for 4 years) is our first boat with speed
and wind instruments.  Electronics aren't all that necessary on a lake in
Kansas. 
 
So, when I see that I am doing about 2.2 knots in 6-10 knots of breeze on a
beam reach, or motoring at 2.5 knots with the yanmar humming along at 2500
RPM, I really don't have anything to compare to.  And then, some of you
folks talk about motoring at 6-7 knots, so I just figure that I should
switch out the 2-blade prop for a 3-blade.  But when you talk about sailing
at 6-7 knots or more, and the most I have been able to get out of her is 5
knots with the Asym flying in a good breeze, I start thinking one of two
things - either the knotmeter is lying to me, or I suck. 
 
Yesterday, I downloaded a simple GPS app, "SailDroid", to my phone. My
knotmeter says 2.2 knots.  The phone says 4.5!  This is not definitive
proof, but I'm going to say that I do not suck! 
 
It is amazing how it feels like you are going faster, just because some
widget thinks you are.  :) 
 
The paddlewheel sending unit is only 2 years old.  Is there a way to
calibrate the knotmeter (ST-60)? 
 
Thanks,
Dean Vermeire
Moonstruck II (#847)