Knotmeter question
Moderator: Jim Walsh
Knotmeter question
Every year the impeller unit gets clogged with funk within the 1st couple of weeks after launch. Is there any kind of lube/protectorant I could use before launch to avoid this problem? it is coated with antifouling paint already...all suggestions would be appreciated.
- Warren Kaplan
- Posts: 1147
- Joined: Feb 5th, '05, 11:44
- Location: Former owner of Sine Qua Non CD27 #166 1980 Oyster Bay Harbor, NY Member # 317
I feel your pain and I haven't come up with anything that works. Then again...I don't care anymore. For my purposes reading my speed over the ground (the one that counts to me) directly from my gps solved the problem. I usually know which way the tide is going so I have a good idea what I'm up against. I really haven't needed to know my speed through the water if I know the tide flow. My knotmeter hasn't worked for about 3-4 years now and I don't miss it one bit.
"I desire no more delight, than to be under sail and gone tonight."
(W. Shakespeare, Merchant of Venice)
(W. Shakespeare, Merchant of Venice)
-
- Posts: 1483
- Joined: Jul 5th, '05, 11:23
- Location: CD 31 "Loda May"
Cheap trick
I can often free mine by motoring backwards as fast as I can. Allow plenty of room, and have fun steering that rascal!
Dean
Dean
Dean Abramson
Cape Dory 31 "Loda May"
Falmouth, Maine
Cape Dory 31 "Loda May"
Falmouth, Maine
- Ray Garcia
- Posts: 258
- Joined: Apr 27th, '05, 22:08
- Location: 1981 CD27 #212 "Spirit" Huntington, NY
- Contact:
Same here, it started towards the middle of the season though. The boat would have to be taking on some real momentum before the knotmeter would register. Towards the end it just quit. When the boat was hauled I removed the paddle (held in place with stainless steel pin) and soaked it a few days in white vinegar to clean off all the crud. Came out looking like I just bought it. This year I painted it with some transducer paint I had left over. Good thing I tried spinning the paddle, the paint, which is thick, sort of glued up the works. I pulled the pin and cleaned it up a little with a toothpick. It is spinning freely again. Let's see what happens this season. My luck a piece of seaweed will clog it.
- KVickers
- Posts: 14
- Joined: Mar 14th, '09, 10:48
- Location: 1978 Cape Dory Typhoon Weekender - Hull #1503
My Solution
I always used to just tie a length of line to the bow, hand the bitter end to my son and toss him overboard. He'd swim under and free it up! After the first few times, if he saw the know meter stop, he'd just look over at me and shrug saying, "I guess it's time to get the rope, huh?" I'd nod and it was running again in no time atall.
...at rest on ocean's brilliant dyes...an image of Elysium lies...(E.A.P 1849)
- Carter Brey
- Posts: 709
- Joined: Feb 5th, '05, 12:02
- Location: 1982 Sabre 28 Mk II #532 "Delphine"
City Island, New York - Contact:
Knotmeter
I keep a dummy plug in the knotmeter through-hull, using GPS for my SOG. I test the knotmeter impeller by hand periodically and had DMI refurbish the instrument, but I just keep it in reserve in case the GPS fails and I need to know my approximate speed for dead reckoning. In the meantime it stays dry and free of growth underneath the vee berth.
Carter
Carter
knotmeter sticking
It's a good idea to clean the knotmeter impeller before launch but I think the real culprit is the stuff in the water when you launch the boat. All the floatsum and flotsum around the launch area can get in the impeller and then take its time to work out.
Even picking up a piece of grass while sailing may stop the impeller from functioning for a while.
If it spins free before launch you've done all you can. The rest is luck.
Even picking up a piece of grass while sailing may stop the impeller from functioning for a while.
If it spins free before launch you've done all you can. The rest is luck.
- Matt Cawthorne
- Posts: 355
- Joined: Mar 2nd, '05, 17:33
- Location: CD 36, 1982
Hull # 79
Mr Bober will chastise me for this
I keept the blank plug handy and remove the knotmeter from the inside and replace it with the blank plug. A minute or two with an old tooth brush and it is all clean. I then just swap out the plug with the knotmeter and all is well. Typically only a few buckets worth of water get in during this process. Don't forget to put the pin and retaining ring back in place.
During the last 7 or 8 years I have been painting a very thin layer of bottom paint on the impeller. That seems to keep the impeller reasonably clean. I use Micron-extra.
During the last 7 or 8 years I have been painting a very thin layer of bottom paint on the impeller. That seems to keep the impeller reasonably clean. I use Micron-extra.
- M. R. Bober
- Posts: 1122
- Joined: Feb 6th, '05, 08:59
- Location: CARETAKER CD28 Flybridge Trawler
No, I won't.
I do the same thing. Although with the Raymarine thru hull/sender very little water floods into the bilge. I skip the bottom paint.Matt Cawthorne wrote:I keept the blank plug handy and remove the knotmeter from the inside and replace it with the blank plug. A minute or two with an old tooth brush and it is all clean. I then just swap out the plug with the knotmeter and all is well. Typically only a few buckets worth of water get in during this process. Don't forget to put the pin and retaining ring back in place.
During the last 7 or 8 years I have been painting a very thin layer of bottom paint on the impeller. That seems to keep the impeller reasonably clean. I use Micron-extra.
Mitchell Bober
Sunny Lancaster (where we use dummies to plug holes in the hull,) VA
CDSOA Founding Member
wheel-less knotmeter sensor
airmar makes the cs4500 ultrasonic speed transducer - no wheel, accurate to .1 knots (so I read).
http://www.airmartechnology.com/uploads ... CS4500.pdf
The only trouble is that they cost $700
matt
http://www.airmartechnology.com/uploads ... CS4500.pdf
The only trouble is that they cost $700
matt
- bottomscraper
- Posts: 1400
- Joined: Feb 5th, '05, 11:08
- Location: Previous Owner of CD36 Mahalo #163 1990
- Contact:
Maybe a better use for the hole?
Our speed transducer has a typical season working lifespan of about 2 weeks. I tried transducer paint and I think it only made it worse. This year I used Micron Extra, we will see if that does any better. The location (deep in side of bilge) is just too hard to access mid season.
Here is something else that could fill the hole and might be more interesting!
http://www.gemeco.com/PDFs/ca500_rC_lr.pdf
Here is something else that could fill the hole and might be more interesting!
![Wink :wink:](./images/smilies/icon_wink.gif)
http://www.gemeco.com/PDFs/ca500_rC_lr.pdf
Rich Abato
Nordic Tug 34 Tanuki
Previous Owner Of CD36 Mahalo #163
Southern Maine
http://www.sailmahalo.com
Nordic Tug 34 Tanuki
Previous Owner Of CD36 Mahalo #163
Southern Maine
http://www.sailmahalo.com
Keepin it simple
For some reason I find it hard to enjoy my boat when something isn't working, so I decided not to install a knotmeter.
As a matter of fact, I didn't install a lot of things!
When you own a 22 it is pretty simple.
Hardly moving, figure 1 to 1 1/2
Moving pretty good, figure 3 to 4.
Big smile, and eyes, figure 5.
Good enough for DR!
Gary
As a matter of fact, I didn't install a lot of things!
When you own a 22 it is pretty simple.
Hardly moving, figure 1 to 1 1/2
Moving pretty good, figure 3 to 4.
Big smile, and eyes, figure 5.
Good enough for DR!
Gary