Silva SeaData Log Problem

[Calluna]

We have just replaced a Nasa Target log and Seafarer depth sounder with a combined Silva Star SeaData unit. The depth readings are spot on, but the log won't register the boat speed (probably about 4 knots).

The two makes of log paddle wheel looked similar so we ignored the Silva instructions of where to position the transducer and used the hole that the Nasa log came out of for the Silva one - assuming that if the Nasa one turned when the boat moved, so would the Silva one. The recommended position was about a foot in front of the keel and on the centre line, this isn't practical so ours is to the side of the keel, about 3/4 of the way back. The transducer registers a speed if you blow on it, so it's all wired up correctly - Any ideas??

Heather

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[StephenSails]

Strange.

If it works when you blow on it but doesnt work when water is passing it then it would seem the wheel aint turning where you have it positioned. Turbulance by the foil maybe?

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[dickh]

Have you positioned the impellor so it is rotated by the water flow? - if say 90º out - it won't rotate! Is there a locating "nib" so it is always fitted correctly?

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I'd rather be sailing... /forums/images/icons/smile.gif

 

[Calluna]

Yes - It's got locating pins so can only fit in one way and the fins are definitely pointing towards the bow.

Heather

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[Calluna]

That's the conclusion that we came to, but the old paddlewheel was in the same place and it turned so we're a little confused as to why this one doesn't. You have to turn the paddlewheel quite fast for it to register a speed, so I'm wondering if I've set it up wrongly. It can be calibrated, but I think that it needs to register something before I can do that.

I can't move the log at the moment as the boat is in the water, and even if I could it would mean putting the paddlewheel somewhere inaccessible, so I'm not sure what to do.

Heather

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