Paddle wheel transducer

dargiem · #1 (**permalink**) 01-07-2003

I have an older Standard Horizon SL-1 speed/log and the paddle wheel transducer is no longer functioning. I preformed the test as outlined by the factory and they consider it "dead". The factory also said the company that made parts for these older electronics is not longer supplying them.
Any thoughts (other than buying a new SL-45 and transducer for ~$300.00)

clayton · #2 (**permalink**) 01-07-2003

I''ve had too many problems with SH stuff. I could never get my speed to calibrate. I put the plug in the through hull and have not used it for three years. Instead, I use my gps.

joub · #3 (**permalink**) 01-07-2003

I second Clayton''s remarks. The GPS does the same job unless you are in a strong current situation. i.e. GPS will give you speed over the bottom vs speed through the water with the paddle wheel. It was always traumatic for me to have all that water gushing into the bilge while changing out the plugs anyway!

Fairwinds,

Jim

loki · #4 (**permalink**) 01-07-2003

I have had the same problem with Standard Horizon with both a depth sounder transducer and an anemometer transducer. I think it is a gimic of theirs to sell new instruments

RichardElliott · #5 (**permalink**) 01-08-2003

My paddle wheel was prolific for growing mussels! Agree that GPS for speed over the ground and an engine tach are all that you need.

Jeff_H · #6 (**permalink**) 01-09-2003

I strongly disagree about a GPS being a substitute for a knotmeter. A GPS shows completely different velocity information and with far less accuracy than a knotmeter. The knotmeter shows speed through the water. It is that speed that is necessary to evaluate sail trim and other performance items. GPS is worse than useless in that mode. Used in concert with the GPS, the knotmeter allows you to better understand the currents that you are sailing in. Used in concert with a wind instrument the knot meter can give you VMG toward or away from the wind. A GPS can give you VMG toward a waypoint.

Jeff

RookieHunter · #7 (**permalink**) 01-09-2003

I don''t understand why overall speed is not the intended purpose. I have a handheld Garmin GPS 76 (not the map version) and when I walk, it updates nearly every step with an applicable change in speed readout. As most of you know I am dangerously new, but if I trim my sails and am currently at 6 knots and it changes to 8 knots, then with or without the tide speed I''ve improved. Obviously Jeff is above my head with the comparing to a wind measurement device etc.

Please confirm again that I''m not debating I''m clarifying my novice mind as to why this wouldn''t be acceptable at my experience level.

My interest level is this. I also have a through hull transducer and will look up (under motor power) and it reads out an acceptable measurement and not change speeds or direction and it will not read anything. Look up again and it''s pegged out over 10. I haven''t had my GPS (it''s handheld) out on the water yet so I can''t see if it ever correlates.

Heres to gentle seas and steady breeze!

joub · #8 (**permalink**) 01-09-2003

With due respect to Jeff''s experience and obvious expertise in many areas, I must take exception to his statement that the GPS speed readout is not a useful indicator of boat speed.
GPS reads speed over the bottom when in a general nav mode (i.e. not navigating to a waypoint position). If you are indicating 5 knots, that is your speed from your present lat/long position. If the GPS is set up to navigate to a given waypoint, then the speed indication will only be accurate if you are heading directly to or away from that waypoint. This may lead to some confusion if that point is not understood.

I use my GPS constantly as an idicator of sail trim and it works great! How many paddle wheels will give you an accurate change of .1 knots? Plus GPS doesn''t pickup seaweed or critters to screw it up.

What GPS will not give you is speed through the water, which usually isn''t significant especially for sail trim. However, one must remember, if you have a tide or river flow against you of five knots, the GPS could be reading zero if you are making five knots through the water (the same speed as the flow against you). The result is zero speed over the ground. If you turn around and go with the flow, the GPS will show ten knots!(speed through the water + current flow = 10 knots over the ground) Hey! this boat is FAST!!

Hope this helps clarify the matter

Fairwinds,

Jim

RookieHunter · #9 (**permalink**) 01-09-2003

Hey You actually did make it make a lot of sense with the analogy of moving with the tide. If I am using GPS with the tide moving 5knot and the boat hull speed is 10knot and my GPS is showing 10 knot then I would not know I can gain a little more power from my boat( boat capable of 10 and currently going 5). With the through hull transom it would show that I''m only moving at 5 knot,correct? That way I could try to get a little more from my boat.

I know many more variables come into play, but is this what were talking about?

joub · #10 (**permalink**) 01-09-2003

Actually, in my example, the boat is moving through the water at the same speed in each case.
I was just attempting to show the difference between speed through the water and speed over the bottom. Boat performance is only related to speed through the water. The extra five knots "going with the flow" is coming from the current flow not better boat performance.

I thought the original question was if you could use the GPS speed indication to determine performance. Yes...because whatever speed you were making over the bottom (i.e. GPS indicated speed) increased/decreased from the sail adjustment or power setting you made.

Jim