Nasa Speed Log

[Sean Carter]

Hello
One of my Instruments is a NASA target Log which never seems to work when I use my Yacht which is twice a week. When I remove the paddle wheel there is no obvious obstruction or clogging. I spin the paddle wheel a few times and spray with WD40 and put it back and then it works fine. But I have to do it every time I use the boat. Anyone got any ideas why this could be happening.
Sean

 

[Clancy Moped]

Try soaking it in white wine vinegar for 20 mins instead.

 

[Sean Carter]

Worth a try thank you

 

[Poignard]

When you get underway just rotate the transducer 180degrees in its housing (so it runs backwards). Let it run backwards for a few minutes. Then rotate it back again.

That usually clears mine

 

[neil_s]

I don't think it's a NASA problem - my Autohelm one does it too.

 

[Sean Carter]

From the suggestion "Soaking in White Wine Vinegar" and thinking about it. It is possible that there is a small build up of corrosion that is creating a little friction. So the vinegar will hopefully clean the metal axle of the paddle wheel and problem will go away.

 

[Sean Carter]

When you get underway just rotate the transducer 180degrees in its housing (so it runs backwards). Let it run backwards for a few minutes. Then rotate it back again.

That usually clears mine

I often try going in reverse and it often clears it. Never thought to turn it round in the housing great idea.

 

[ash2020]

Mine is the same. Before launch in the spring, I clean it very thoroughly and it spins very easily. In fact you can blow it gently and it spins. Then I launch and after a few days it has stopped working.

 

[LittleSister]

I used to find when re-inserting the paddlewheel it sometimes wouldn't spin until I rotated it just very slightly - only a degree or two or three - from what appeared to be exactly inline. Despite looking carefully inside and (when ashore) out, I could never see what might be catching it and preventing it spinning, but that technique always worked for me. (It helped greatly to have someone else aboard, so one could tweak the alignment of the paddlewheel while the other watched the display to see when it suddenly started registering.)

. . . But I have to do it every time I use the boat. . . .

If you're having to take it out every time you go out anyway, why not remove it and put in the blank when you are not on the boat, to stop any fouling.

 

[Dellquay13]

I replaced the paddlewheel and spindle on mine (it only cost a few pounds from the Nasa website, but I think they are available on ebay) and has been trouble free for the two years since, unlike the rest of the boat.
I think the magnets were swelling out after a while in the water, and catching slightly on the skin fitting edge

 

[Poignard]

I replaced the paddlewheel and spindle on mine (it only cost a few pounds from eBay) and has been trouble free for the two years since, unlike the rest of the boat.
I think the magnets were swelling out after a while in the water, and catching slightly on the skin fitting edge

That certainly does happen.

I have had to fit a new paddle wheel twice during the 26 years I have had my NASA log.

It's a simple job to do.

 

[Refueler]

Don't use WD40 ... that's first thing.

As another says - turn it in housing and then back again ... my Echopilot does same ... but usually it starts up after a few minutes on its own ...

 

[blackbeard]

It's possible to get a bit of calcite build-up on the spindle on which the paddlewheel turns, giving the problems mentioned above, you can push the spindle out and clean it up or else use de-scaler. Vinegar mentioned above acts as a de-scaler.