I have a Autohelm Tri Data log and depthsounder.
It has always been no trouble until this year when the log has been playing
up.
It started by being intermittent and now does not indicate at all in normal
use.
If I remove the sensor unit from the hull and spin the wheel it seems to
work. I have given it a good clean. However it still does not work in normal
use.
I suppose there could be something on the hull but as the hull is very clean
and the boat performs normally I suspect the hull is clean.

Is there a known problem with these units? Does the magnet ever wear out?
The unit is probably 15 or so years old. can a new paddle wheel help?

Alec

Alec wrote:
I have a Autohelm Tri Data log and depthsounder.
It has always been no trouble until this year when the log has been playing
up.
It started by being intermittent and now does not indicate at all in normal
use.
If I remove the sensor unit from the hull and spin the wheel it seems to
work. I have given it a good clean. However it still does not work in normal
use.
I suppose there could be something on the hull but as the hull is very clean
and the boat performs normally I suspect the hull is clean.

Is there a known problem with these units? Does the magnet ever wear out?
The unit is probably 15 or so years old. can a new paddle wheel help?

Alec


When I have a diver check my prop shaft zincs I have him direct a fresh
water hose on the knot/log paddle wheel while observing the display.
Dick

Alec,

Does the paddle wheel always stop with the same blade down?

When it sort of works does it read about half what you expect?

If yes, buy a paddle wheel and replace it before you do anything else.

To date, I have replaced the paddles wheels on no less than four
Raytheon/Autohelm/Raymarine units. All had magnets gone. the corrode
as soon as there is any breach of the plastic they are molded into.

Matt Colie
www.yachtek.com


Alec wrote:
I have a Autohelm Tri Data log and depthsounder.
It has always been no trouble until this year when the log has been playing
up.
It started by being intermittent and now does not indicate at all in normal
use.
If I remove the sensor unit from the hull and spin the wheel it seems to
work. I have given it a good clean. However it still does not work in normal
use.
I suppose there could be something on the hull but as the hull is very clean
and the boat performs normally I suspect the hull is clean.

Is there a known problem with these units? Does the magnet ever wear out?
The unit is probably 15 or so years old. can a new paddle wheel help?

Alec

"Alec" wrote in
:

Is there a known problem with these units? Does the magnet ever wear
out? The unit is probably 15 or so years old. can a new paddle wheel
help?



Ours quit and it took us a while to find the totally corroded into oblivion
stupid little terminal strip the previous owner had installed in the bilge
to keep from having to pull a whole new cable....very well hidden under
some other stuff in the bilge.....

I don't think they ever wear out. The wheel will wind up any crap that
passes by it, however.

Has your yard worked anywhere near the hull fitting it fits into? I fixed
one for another boater who was baffled. The stupid yard birds had put the
damned thing in BACKWARDS and the paddle wheel cups were pointed AFT
instead of forward when it was in place. ON another one, a Sonar
transducer had been added FORWARD of the log, creating an eddy current
behind it, disrupting the flow over the paddle wheel. Duhh....(c;

Has anyone added some new fitting ahead of it? It's also a thought.

"Oh, it was just working last weekend!", another told me. When I pulled it
out of the sea chest to have a look you couldn't even SEE the paddle wheel
buried in THAT MUCH SEA FUZZ! "I have my hull regularly cleaned.", he told
me. We had another diver go take a look. He came up pitching a fit
because the ******* that was SUPPOSED to clean it only cleaned it down to
where the hull went under where you couldn't see it.....He's FIRED.

If you can consistently blow air across the wheel and get a nice, steady
reading faster than the boat can go, I'm voting for something underwater
disrupting the flow over the tiny bit the wheel protrudes into the
slipstream of seawater.

Richard Lane wrote in :

When I have a diver check my prop shaft zincs I have him direct a fresh
water hose on the knot/log paddle wheel while observing the display.
Dick



You can test it by taking it out of its little sea chest and blowing into
the cups on the little paddle wheel. I can make ours read 99 mph without
an air compressor!

Matt Colie wrote in news:5Lmsk.15501$Is1.11590
@newsfe04.iad:

Raymarine units. All had magnets gone. the corrode
as soon as there is any breach of the plastic they are molded into.


Hey! Just like the rainstorms that happen inside Raymarine's 2KW radomes!

Thanks for the replies.

When removed and spun by hand I can get a reading of up to 3 or 4 knots. The
paddle spins freely and is clean and in the correct way round.

I will try a new paddle wheel.

It could be that when in the water the wheel spins a little further from the
sensor due to water flow and if the magnet is weak then a loss or
sensitivity has occurred. Is the sensor a coil or a reed relay?
The problem came on intermittently and over two or three months

Alec


"Matt Colie" wrote in message
...
Alec,

Does the paddle wheel always stop with the same blade down?

When it sort of works does it read about half what you expect?

If yes, buy a paddle wheel and replace it before you do anything else.

To date, I have replaced the paddles wheels on no less than four
Raytheon/Autohelm/Raymarine units. All had magnets gone. the corrode as
soon as there is any breach of the plastic they are molded into.

Matt Colie
www.yachtek.com


Alec wrote:
I have a Autohelm Tri Data log and depthsounder.
It has always been no trouble until this year when the log has been
playing up.
It started by being intermittent and now does not indicate at all in
normal use.
If I remove the sensor unit from the hull and spin the wheel it seems to
work. I have given it a good clean. However it still does not work in
normal use.
I suppose there could be something on the hull but as the hull is very
clean and the boat performs normally I suspect the hull is clean.

Is there a known problem with these units? Does the magnet ever wear out?
The unit is probably 15 or so years old. can a new paddle wheel help?

Alec