Subject: Re: [Catalina-22] [electronics] transom speed transducer

From: Steve Morgan <[email-masked]>
Date: Wed, 02 May 2007 18:47:32 -0400

Hi Glenn and everyone else in this thread,
Thanks for all the replies. 
I have never raced my boat (yet!). My feeling is that the knotmeter will help me to be a better sail trimmer. I have found in trimming the sails on the boat I crew on, that there were many times where my instinct was to trim in the sails, where the knotmeter showed me otherwise. Or when I thought the main or traveler should be let in or out, and the opposite was true. That was why I asked if the GPS was as sensitive as a paddlewheel. Since I usually sail alone, my only feedback has been my own perception of how I was doing. I am fortunate that my sails are only three seasons old ( and not overly used as well) but I know that I am not making the most of them yet. I also went down to the boat today and saw that if I slide out the water storage tank in the v berth for the sink, that I can easily access the hull at that spot with no problem if I decide to go with the thru hull. I hadn't thought of that location. I had been looking WAY forward in the bow access cover area, under the cushions. I also took an inventory of all the junk on my boat that I could really leave at home! I guess every little bit helps.

Thanks again.

Steve Morgan
#14444 wing

Good friends are like stars... you don't always see them, but you know they are there.

http://www.geocities.com/steve4643/index.html?1168914244552
  ----- Original Message ----- 
  From: Glenn Warner 
  To: [email-masked] 
  Sent: Wednesday, May 02, 2007 6:12 AM
  Subject: Re: [Catalina-22] [electronics] transom speed transducer

  Why are you installing a speed transducer?  If you are that concerned about speed, take every extra bit of weight out of your boat including extra electronics, reduce drag by making and keeping your bottom slick as owl snot and not dragging stuff in the water(transducers), and put the money you save on not buying a speedo towards brand new sails.  Just one racers point of view:-)

  Glenn Warner
  goblin#10369
  JuJu#1222
  Jacksonville Florida
  On May 1, 2007, at 9:39 PM, Steve Morgan wrote:

    Thanks Chuck
    I like the idea of not making a hole in the boat. Plus the transom mount transducer model is cheaper :-) 
    I'll probably go to west marine and visually compare the two options.

    Steve Morgan
    #14444 wing

    Good friends are like stars... you don't always see them, but you know they are there.

    http://www.geocities.com/steve4643/index.html?1168914244552

      ----- Original Message -----
      From: [email-masked]
      To: [email-masked]
      Sent: Tuesday, May 01, 2007 5:29 PM
      Subject: Re: [Catalina-22] [electronics] transom speed transducer

      Ray;

      I purchased a used Raymarine fishfinder a few years ago.  I came with a transom transducer that provided speed, depth, water temperature, depth alarm, as well as the ability to visualize fish and the bottom contour.  Rather than epoxy it to the transom or, god forbid mount it with screws which would put another hole in the boat, I found a mount that would fit on the transom coming to which the transducer was attached.  Works just fine and I can transfer it to another boat if needed.

      Chuck Meehan
      C-22 Miss Trish
      #11821

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---

From: "Robert Bemben" <[email-masked]>
Date: Fri, 04 May 2007 11:27:53 +0000

Glenn,

I think you've hit the nail on the head.

What the racer (and sail-trim-conscious cruiser) hopes to get out of a 
high-end knotmeter is feedback on small, otherwise imperceptible, 
accelerations and decelerations of the boat in response to sail trim 
changes.

When I crewed in J105 races the knotmeter reading was prominently displayed 
in big numbers on the mast just below the boom - to the hundredths place. No 
GPS readout. It occurs to me now that there was probably a good reason for 
this!

For those of us with low-end knotmeters, on the other hand, they appear to 
have little utility, except as a navigational backup (dead reckoning) to 
GPS, should the power go out, or for the very few skippers who sail in areas 
with variable and strong currents.

Robert Bemben
Bliss Twp., Michigan
1991 C22 wing keel
Sail # 15185
"Jib Dance"

>From: <[email-masked]>
>Reply-To: [email-masked]
>Subject: RE: [Catalina-22] [electronics] transom speed transducer
>Date: Thu, 3 May 2007 15:33:25 -0700 (PDT)
>
>Maybe this will help. The value of a knotmeter in regards to sail trim is 
>the trend of speed. If a sail trim trends the speed upward or down. Small 
>gains or losses in speed can readily be determined on a good knotmeter . 
>Much better than the GPS. This increase or decrease is irrelevant to 
>current if the same course is maintained. A 0.01 knot increase or decrease 
>is just that, regardless of current.
>
>   Glenn Hedmark
>   12533 sk
>   Dizire
>   Wauconda, Il.
>
>Chip Ford <[email-masked]> wrote:
>       I'm still confused.  Glenn, if you're trying to reach a mark (and 
>assuming it's in your interest to know your speed), aren't you trying to 
>reach it as fast as possible?  To me, that's what racing's all about, but I 
>could be wrong -- it might be more esoteric.
>
>   Now if you're running against a two knot current, sailing ahead and 
>making what appears to be three knots, aren't your sails actually pushing 
>your boat forward at five knots (against that current)?  And if so, isn't 
>that what a knotmeter will tell you -- that you are "moving through the 
>water" at five knots -- forward progress against backward current pressure 
>on the paddlewheel -- when you're actually making good only 3 knots speed?
>
>   A GPS will tell you that you're making three knots headway, period.  
>Three knots over ground.  You are progressing at the rate of three knots 
>toward whatever the destination, be it Portland, Maine, or the downwind 
>racing buoy.  At three knots, your boat's forward motion will take you 
>roughly 22 minutes to reach a one NM destination.  (A GPS will do all the 
>calculating for you, adjusting on-the-go as speed over ground fluctuates.)
>
>   I still feel like I must be missing something . . .
>
>   Chip Ford --
>Marblehead, Mass.
>1974 Swing Keel "Chip Ahoy" #3282
>CTY032820374
>Chip Ahoy website:  www.chipford.com
>
>
>
>
>
>   -----Original Message-----
>From: [email-masked] [mailto:[email-masked]] On 
>Behalf Of [email-masked]
>Sent: Thursday, May 03, 2007 4:27 PM
>   No, I disagree.  I never said knowing your speed either through the 
>water or over the ground were essential for one design racing.  In fact I 
>said I had neither a GPS or knot meter on my boat.  Is a gps useful for 
>phrf racing.  Yes.  In phrf racing you are racing the clock and speed 
>towards the mark is nice to know.  In one design racing, speed is relative. 
>  If you beat the other boats, you win.  What I did say is that for tune up 
>and speed testing, a knot meter is more useful than a GPS and I stand by 
>that.  When you are trying to find out if you have the sails trimmed 
>optimally, the fact that the current is adding 2 kts to your speed is not 
>beneficial, in fact it could confuse the point.
>
>
>   Glenn Warner
>   Goblin#10369
>   JuJu#1222
>   Jacksonville Florida
>
>   -------------- Original message --------------
>From: "Jim Kuertz" <[email-masked]>
>     Glenn W.,
>
>   When referring to speed over ground means the forward movement of the 
>boat, car, airplane etc.,  in miles or knots per hour over land, water or 
>air.   You adjust  the sails and whatever to get your boat to the max speed 
>(over ground)  to get from point A to point B,  the water or air speed 
>means nothing.  The air and water direction is probably the second most 
>important things to know when sailboat racing.
>
>     Jim Kuertz
>   Cincinnati, Ohio
>   1989 Wing Keel “Almost Heaven” #14834
>   CTYH4834H889
>
>   From: [email-masked]
>   Sent: Thursday, May 03, 2007 10:45 AM
>   I am with Glenn as far as accuracy.  Chip, I thought I was pretty clear 
>in my email the reason why through the water speed was more important than 
>speed over the ground in relation to optimising boat performance but I will 
>try again.  First there is a difference between  strategy/tactics and boat 
>speed.  Boat speed is how fast a boat moves through the water.  It is best 
>measured with an instrument that measures speed through the water.  Speed 
>over the ground is irrelevant because it factors in other variables besides 
>how fast the boat is moving thru the water.  If you are trying to find out 
>how different trim effects your boat speed you do not want other factors 
>being factored in.  If you are trying to get to a certain point, a race 
>mark or chart waypoint, then speed over the ground does come into play.
>
>   I primarily race one design around the cans.  I do not have a knot meter 
>or GPS.  In fact I just filled the hole in the bottom of my new boat where 
>I took a speed transducer out. It is more important to be ahead of the 
>other boats than to sail the fastest course to the mark.  Favored tack, 
>clear air, covering the competition these things are more important.  And 
>don't forget the old adage"keep your head out of the boat" If you are ahead 
>of boats then you sailed a better course.  If you are faster than the boat 
>next to you then you have good boat speed.  No need for instruments.  If 
>you are racing phrf (handicap) then yes, boat speed and speed to the mark 
>are important because you are essentially racing the clock not other boats 
>directly.  If you are cruising to a destination or racing a long distance 
>point to point race, yes speed towards the mark is important.  My original 
>point, many posts ago, was that TO OPTIMIZE BOA! ! T PER FO RMANCE, that is 
>speed of the boat
>  through the water, a knot meter is more valuable than a GPS.  I stand by 
>that.  I am not dicounting the utility of a GPS, just not for this 
>performance measurement.  As far as placement, if you are serious about 
>performance the transducer needs to be placed foreward of the keel as close 
>to centerline as possible.  As far as a fouled transducer, well if your  
>bottom/ transducer is fouled you already aren't doing as much to optimize 
>performance as you can.  Sails and bottom baby, thats what makes a sailboat 
>go.   I didn't make this stuff up. And yes get one that measures to 
>hundredths.  Someone else can do the math, but over a 4 mile course it 
>could be the difference.
>
>   Glenn Warner
>   Goblin#10369
>   JuJu#1222
>   Jacksonville Florida
>
>
>From: <[email-masked]>
>
>     Hi Steve,
>
>   I have a Signet digital knotmeter that reads in hundreths of a knot. 
>Definately more accurate than the averaging on the GPS. It can be a good 
>tool for learning the trim on your sails. Also a valuable tool for 
>navigation if your GPS fails. Much easier to monitor than a GPS screen.
>
>   I have the earlier model C22 and the through hole for the transducer is 
>in the forward settee locker just forward of the keel on the port side as 
>near centerline as possible. I'm not really familiar with your newer model. 
>I have never had a problem catching it on the trailer.
>
>   Glenn Hedmark
>   12533 sk
>   DiZire
>   Wauconda, Il.
>
>
>
>Steve Morgan <[email-masked]> wrote:
>   I have never raced my boat (yet!). My feeling is that the knotmeter will 
>help me to be a better sail trimmer. I have found in trimming the sails on 
>the boat I crew on, that there were many times where my instinct was to 
>trim in the sails, where the knotmeter showed me otherwise. Or when I 
>thought the main or traveler should be let in or out, and the opposite was 
>true. That was why I asked if the GPS was as sensitive as a paddlewheel. 
>Since I usually sail alone, my only feedback has been my own perception of 
>how I was doing. I am fortunate that my sails are only three seasons old ( 
>and not overly used as well) but I know that I am not making the most of 
>them yet. I also went down to the boat today and saw that if I slide out 
>the water storage tank in the v berth for the sink, that I can easily 
>access the hull at that spot with no problem if I decide to go with the 
>thru hull. I hadn't thought ! ! of th at location. I had been looking WAY 
>forward in the bow access cover
>  area, under the cushions. I also took an inventory of all the junk on my 
>boat that I could really leave at home! I guess every little bit helps.
>
>   Thanks again.
>
>   Steve Morgan
>#14444 wing
>
>Why are you installing a speed transducer?  If you are that concerned about 
>speed, take every extra bit of weight out of your boat including extra 
>electronics, reduce drag by making and keeping your bottom slick as owl 
>snot and not dragging stuff in the water(transducers), and put the money 
>you save on not buying a speedo towards brand new sails.  Just one racers 
>point of view:-)
>
>   Glenn Warner
>   goblin#10369
>   JuJu#1222
>   Jacksonville Florida       On May 1, 2007, at 9:39 PM, Steve Morgan 
>wrote:
>
>     Thanks Chuck
>   I purchased a used Raymarine fishfinder a few years ago.  I came with a 
>transom transducer that provided speed, depth, water temperature, depth 
>alarm, as well as the ability to visualize fish and the bottom contour.  
>Rather than epoxy it to the transom or, god forbid mount it with screws 
>which would put another hole in the boat, I found a mount that would fit on 
>the transom coming to which the transducer was attached.  Works just fine 
>and I can transfer it to another boat if needed.
>
>   Chuck Meehan
>   C-22 Miss Trish
>   #11821
>
>
>
>
>---------------------------------
>   Glenn Hedmark
>   DiZire
>   12533
>   1984 sk
>   Wauconda, Illinois
>Glenn Hedmark
>   DiZire
>   12533
>   1984 sk
>   Wauconda, Illinois

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