[bartvdv]

The knowledge in this forum is my last resort....

I have a NASA Target log o/b.
When I start it up it shows 0.1 knots, then 0.0 knots. (so far so good)
If the boat moves through the water it always shows 0 knots.

I pulled the paddlewheel out and checked it.
It was ok, paddle moved freely like it should.
When I manually move the paddlewheel, correct readings come up the screen.

So, the system works like it should, but when the sensor is inserted, it won't work!

Also, i tired to clean the hole from the outside with a hose, a brush,....

The log is placed on a place with a normal, unobstructed, laminair flow.

Does anyone know the golden tip to help me?

 

[fud]

Hmmm. I'm just going to throw some ideas out. Here is a link to a pdf of the manual (I believe) for a "Target 2 Log, Depth + Wind" In the manual they explain the calibration procedure, could it be that it lost it's calibration and only when you spin it by hand, maybe faster than what it typically would spin at, that it picks up the speed. And at the lower spin rate it just doesn't register the speed due to the calibration being off? The only other thing that I can think of is that it seizes up when screwed into the fitting? Good luck maybe at least this will get you thinking of other things that could be causing this issue.

Dave

 

[timebandit]

Is it spinning backwards?

 

[Omatako]

Is it spinning backwards?

Somehow I don't think that makes a difference. I think it simply counts the number of time the magnet passes the senor then calculate that in time.

Of course I don't know that - I just think that. Could be wrong - often am.

 

[bartvdv]

If i turn the wheel manually, i don't turn it crazy fast. (i think)
So the calibration is probably not it, but i'll check it out.

If the sensor seizes up when in the hole, can i fix it while afloat? and how?

 

[negrini]

Make sure the transducer is correctly inserted. Has it tripped all the way down ? check manual and make a visual inspection. It might get fouled on its end near water, or entered some clogging dirt. Otherwise prepare for a dive, and soon before water gets cooler ... having someone looking to the display, dive under boat and try it by hand. Also a good mask will help you determine what's going on and a fix.

 

[bartvdv]

I already tried turning the wheel in the water, and something shows up indeed.
I didn't try looking to it under water.

Im from Belgium, the water is already to cold for a dive :-(

 

[negrini]

Was it working before ? Seems not in a good place. Underwater, did you feel the placement is correct, I mean, is it showing a good blade face to the laminar flux ? Turbulence ? Very difficult without visual inspection. I hate those paddles transducer so I use 99% of time SOG from GPS. I do install mine only when doing a long trip. OK, next life, move to southamerica ....

 

[bartvdv]

I recently read smewhere that there should never be anti fouling on the paddlewheel.
Why is that?
Mine has a coat of antifouling (from the PO).
Is that the cause of trouble perhaps?

Sorry to revivethis thread, but evryone love's his boat to be ship-shape!