MacGregor 25 Knotmeter

[troutguy]

I have a 1984 MacGregor 25 with Horizon Knot Meter. The meter does not work. The boat is out of the water. The sender unit is a through the hull unit near the keel on the starboard side. The paddle wheel of the sender unit is missing the magnets. Anyone know where I can get another sender unit or replacement magnets?

[uspirate]

forget about the entire unit trying to fix it is like beating a dead horse, they dont work that well anyway, use an inexpensive GPS for your speed needs.

[ahab211]

Amen to that. I've been using my GPS for a knotmeter for over a year and besides showing both Knots and Miles it is has the total distance for trips taken. Very handy and as stated the paddle wheel knotmeters weren't very accurate and a pain to fix. I just leave the plastic cover on mine and forget about it.

[troutguy]

Any options to fix. I'd prefer over GPS.

[SJ34]

Originally Posted by troutguy

Any options to fix. I'd prefer over GPS.

I use GPS and knotmeter. The GPS is great for speed over ground and can give you distance covered at a glance. You really need a knotmeter though to tell you how fast you're moving through the water. A knotmeter is invaluable as a sail tuning indicator. Give a tweak here, pick up a .10 knot, point a little higher, lose .5 knot etc. GPS can't do that.

If all you need is a padle wheel, try Standard Horizon tech service at 714-827-7600. They are out of the marine instrumentaion business but they still have parts.

[SEMIJim]

The "you do/don't need a knotmeter" argument comes up every time somebody asks "how do I install/repair/replace a knotmeter?" One-or-more people will inevitably claim "you don't need it, just use a GPS" and one-or-more others will inevitably counter with "but that gives you SOG, not STW, and GPS' aren't reliable, anyway."

The truth is you don't need a knotmeter. You also don't need a Windex, much-less an electronic wind direction and speed instrument. You don't really need a GPS, or even a depth meter--when it comes right down to it. The wind on your face, the feel of the helm, and the shape of the sails will tell you all you need to know about the performance of your boat. An understanding of navigation for the area and up-to-date charts are all you need for navigating. But all of these devices are handy, and can make performance-tuning and navigation easier and quicker.

So, stating unequivocally that one doesn't need a knotmeter, while correct, as far as it goes, also ignores the fact that they are useful devices. I always consult the knotmeter after making a trim change, no matter how minor. I can do without it. (And have, when it was fouled, we were only day-sailing, and I didn't care about performance enough to go to the trouble of clearing it. I've also done w/o a Windex, and it didn't kill us.) But I'd far prefer to have one.

Jim