knot meter reads slow - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 06-05-2008
Senior Member
 
Join Date: Sep 2007
Posts: 171
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
hertfordnc is on a distinguished road
knot meter reads slow

I finally located the speed transducer. It had been removed from the hull and plugged.

I installed it and took the boat out for a test.

It seems to read about half speed. I can't be precise because my GPS wasn't working but I know what six knots looks and feels like on this boat.

The most I got out of it was 3.4

I figured it might be in backwards or sideways.

I checked more closely. the transduced will fit snugley and not leak no matter which way you stick it in but there is a slot in which it seats a little further down and the wheel is parralel to the boat in that position.

I don't have the manual for the ST50 /ST4000 stuff.
__________________
In over my head?
First Boat, a well-equipped 1977 Camper Nicholson 31
What is all this stuff and how does it work?
Reply With Quote Share with Facebook
  #2  
Old 06-05-2008
Senior Member
 
Join Date: Nov 2002
Location: New York
Posts: 5,548
Thanks: 0
Thanked 14 Times in 14 Posts
Rep Power: 14
bubb2 has a spectacular aura about bubb2 has a spectacular aura about bubb2 has a spectacular aura about
Two things,

It may be in backwards, there is a little arrow molded in the top transducer that should point forward (front of the boat).

Lubrication, try plummer's grease.
Reply With Quote Share with Facebook
  #3  
Old 06-05-2008
Senior Member
 
Join Date: Sep 2007
Posts: 171
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
hertfordnc is on a distinguished road
I tried it in several positions, backwards and frontwards.

The wheel spins freely- i mean, you can flick it with your finger and it will spin for a few seconds.

thanks
__________________
In over my head?
First Boat, a well-equipped 1977 Camper Nicholson 31
What is all this stuff and how does it work?
Reply With Quote Share with Facebook
  #4  
Old 06-05-2008
pfatyol's Avatar
Swansea, MA
 
Join Date: Dec 2003
Location: Massachusetts
Posts: 98
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
pfatyol is on a distinguished road
You may need to calibrate the unit. see attached link

Raymarine Marine Electronics - Retired ST50 Manuals

Raymarine has the ST50 manuals on line.

I have the ST60 and had to calibrate once I installed the unit.

Best of luck,
__________________
Patrick

S/V "Fat-Kat"
C&C 32, Hull #237
Mt. Hope Bay
Reply With Quote Share with Facebook
  #5  
Old 06-05-2008
TrueBlue's Avatar
Seńor Member
 
Join Date: Oct 2004
Location: Narragansett Bay
Posts: 4,853
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 12
TrueBlue is a jewel in the rough TrueBlue is a jewel in the rough TrueBlue is a jewel in the rough
Could also be you were surfing with the current. If so then your SOG, if reported by the inopperable GPS, would be higher than your speed over water, as reported by the speed transducer.
__________________
True Blue . . .
sold the Nauticat
Reply With Quote Share with Facebook
  #6  
Old 06-05-2008
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 10 Times in 10 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
I'd recommend reading the manual and going through the calibration procedure. I think Gui has done this to make sure his knotmeter is about 30% fast.

Be aware that when checking your knotmeter against SOG on a GPS, the GPS will not be affected by any currents, where the knotmeter will be.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #7  
Old 06-05-2008
pfatyol's Avatar
Swansea, MA
 
Join Date: Dec 2003
Location: Massachusetts
Posts: 98
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
pfatyol is on a distinguished road
Heck, when my nephew comes down to sail with me, I adjust the calibration factor all the way up. Then when we get back to the mooring, I reset it back to 1.4 so it reads correctly. He always would complain we are going too slow, he is used to being 6 inches off the water and not four feet, totally Different feel of speed. It stopped the complaints, and the wife and myself get a laugh out of it.
__________________
Patrick

S/V "Fat-Kat"
C&C 32, Hull #237
Mt. Hope Bay
Reply With Quote Share with Facebook
  #8  
Old 06-05-2008
chucklesR's Avatar
Senior Member
 
Join Date: Sep 2007
Location: Pasadena Md - Magothy side
Posts: 5,978
Thanks: 10
Thanked 30 Times in 30 Posts
Rep Power: 10
chucklesR is a jewel in the rough chucklesR is a jewel in the rough chucklesR is a jewel in the rough
Have you tried the Evelyn Woods Speed Reading Course? Helps everyone/thing read faster

It's probably calibration, might be fouled already (mine fouls in less than a week), and might be needing some lube.
Reply With Quote Share with Facebook
  #9  
Old 06-05-2008
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 10 Times in 10 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
We'll have to remember this when viewing any videos you post.

One downside of owning and sailing a multihull is people often don't realize just how fast you're going... Doing 12 knots on a monohull, unless it is a really big bastage, is going to have the sails all loaded up, and the boat heeled over, and the rigging making all sorts of noise... on my boat, we can do twelve knots with just the genny up... and it doesn't heel way over... and it's actually pretty quiet relative to a monohull...so it can be very deceptive. We don't have to have rail meat hiked out over the high side...

See the video located here—click on the video link at the top of the page, or see this video to get an idea of what I'm talking about.




Quote:
Originally Posted by pfatyol View Post
Heck, when my nephew comes down to sail with me, I adjust the calibration factor all the way up. Then when we get back to the mooring, I reset it back to 1.4 so it reads correctly. He always would complain we are going too slow, he is used to being 6 inches off the water and not four feet, totally Different feel of speed. It stopped the complaints, and the wife and myself get a laugh out of it.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.

Last edited by sailingdog; 06-05-2008 at 08:24 AM.
Reply With Quote Share with Facebook
  #10  
Old 06-05-2008
Member
 
Join Date: Mar 2007
Posts: 46
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
mallo is on a distinguished road
Hi
This might help, there are different paddle wheels and some have one, two, or four magnets in them.
Is the boat new to you? Has some one fitted an incorrect paddle wheel in the past?
The calibration will only give you a certain %age of adjustment.
Check you have the correct paddle well for the transducer.
Good luck
Michael
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Standard horizon Sl-1 digital knot meter needed TJay Gear & Maintenance 5 05-05-2009 03:31 PM
Seven Knots You Can't Live Without Sue & Larry Learning to Sail Articles 0 11-14-1998 07:00 PM
Seven Knots You Can't Live Without Sue & Larry Seamanship Articles 0 11-14-1998 07:00 PM


All times are GMT -4. The time now is 03:43 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.