|
|
27-02-2012, 23:26
|
#31
|
Registered User
Join Date: Mar 2009
Location: Australia, Hervey Bay QLD
Boat: Boden 36 Triple chine long keel steel, named Nekeyah
Posts: 909
|
Re: How Necessary is a knot meter
We had a knot meter once, more trouble than it was worth. Just use the GPS now.
I can't get my head around why people need any meters at all. Once you know your boat she tells you through your feet when she is happy. The sound of the wind in the rigging and the look of the sea tells you how much wind is blowing. A couple of bits of cassette tape in the shrouds gives you the direction. Telltales on your sails tell you how high to point.
Regards,
Richard.
|
|
|
27-02-2012, 23:27
|
#32
|
Registered User
Join Date: Aug 2010
Location: Central California
Boat: M/V Carquinez Coot
Posts: 3,782
|
Re: How Necessary is a knot meter
Found that the paddle-driven speedometer read about 1/10ths of a knot different from one tack to another on my former cutter.
Now with a motorboat, have no speedometer but do have tachometer and GPS. Despite the significant currents around here, one can equate RPM to speed through the water after some observation. But of course, speed over ground is what's relevant for navigation. The boat's sails boost SOG for a given RPM depending on wind strength/direction.
|
|
|
28-02-2012, 03:15
|
#33
|
Registered User
Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 20,420
|
Re: How Necessary is a knot meter
BTW
How good are the propeller-less models?
I hate the fact that no matter how much I try, it seems our log gets stuck or slowed somewhere into the passage.
b.
|
|
|
28-02-2012, 05:28
|
#34
|
Moderator Emeritus
Join Date: May 2007
Location: Ohio
Boat: Now boatless :-(
Posts: 11,580
|
Quote:
Originally Posted by four winds
I agree, that would be for just long enough to clean it.
I would look for a new proper plug.
So the impeller threads into the housing? And turns out for cleaning, not pulled straight out?
I'm still looking for the paper manual, I think I have it somewhere.
|
My previous log plug was a half twist one with a steel dowel pin. The first time I pulled it I found the pin had sheared some time ago and the only thing holding it in the hull was corrosion, friction and bottom paint.
The new one plugs straight in and has a plastic threaded nut on the through hull. I lube the o-rings with vaseline.
I reckon the pin type are old design. Be prepared with a plug when you pull it...
|
|
|
28-02-2012, 06:01
|
#35
|
CF Adviser Moderator Emeritus
Join Date: Sep 2007
Location: Virginia
Boat: Island Packet 380, now sold
Posts: 8,942
|
Re: How Necessary is a knot meter
Our B&G knotmeter was pretty accurate. I used to pull it out when we were on the Chesapeake to keep it from fouling.
I'll tell you when I found it to be indispensible--offshore after crossing the Gulf Stream. You need to play the eddies, and if you get it wrong, you can lose a knot or two. Comparing the knotmeter (boat speed) to the GPS (speed over ground) tells you when you're in a fair or foul current. We would have a chart on the boat showing the eddies so we could plot a course to take advantage of the fair currents, or at least avoid the foul ones.
__________________
Hud
|
|
|
28-02-2012, 06:27
|
#36
|
Registered User
Join Date: Aug 2007
Location: Now in Central Europe
Boat: 52' Irwin Ketch
Posts: 441
|
Re: How Necessary is a knot meter
To me, it's as important as a depth sounder for a back up should the real world ever intrude on my life.
REALLY? You must have "misspoken", because unless you have never been in skinny water, this may be true, but here in the "real world", the cruising world, skinny water is a fact of life. I had to say something, because the quote above in red is, in my opinion, really really bad advise for a new sailor that is looking at what to spend his money on. While arriving later than you thought because your knot meter petered out is not nearly as important as arriving "on time" on a sandbar or other obstruction.
|
|
|
28-02-2012, 06:49
|
#37
|
Registered User
Join Date: Jun 2008
Location: Tampa, FL
Posts: 5,009
|
Re: How Necessary is a knot meter
Quote:
Originally Posted by mrohr
I'm a minimalist and do not find many instruments indispensable ,but most of us want to sail well and I find the speed log is the best instrument for any who want to get the best out of their sail trim and craft.
|
Exactly. It doesn't matter if it is accurate or not. It is the only instantaneous measure of relative boat speed.
Meaning, if I trim the main in a little, did I improve things or make them worse? With only GPS I have no way of really knowing, unless I try to calculate my average speed over several minutes. With a knot meter I know immediately. What the actual number is does not matter, but my indicated speed will go up, down, or stay the same. Whatever it does, I know the affect of my change in sail trim.
To me that is extremely worthwhile information.
|
|
|
28-02-2012, 06:57
|
#38
|
Registered User
Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
|
Re: How Necessary is a knot meter
waterworldly, are you sure you read that right?
Looks like the statement supports the importance of a knot meter as well as a depth sounder.
Scanned for the post to see context but didn't find it in a quick scan of the thread.
|
|
|
28-02-2012, 07:28
|
#39
|
Registered User
Join Date: Nov 2006
Location: Back in Northern California working on the Ranch
Boat: Pearson 365 Sloop and 9' Fatty Knees.
Posts: 10,466
|
Re: How Necessary is a knot meter
As far as trimming...I usually go by sail shape. Over the years I have been able to see if the air is flowing properly over the sail. It might be true that I could be off by .1 of a kt. but I doubt a kt meter could pick that up the way they fluctuate so much...well, at least mine.
Thank you everyone for the input...GPS it is then and a constant vigilant of log entries. In other words, I don't need to change any of my habits, save $300 and a little labor to plug another hole under the water-line.
Although I just splashed after a painful engine rebuild and drive-line, I am going to haul in 2 years for an epoxy bottom and rigging. I will also be changing other thru-hulls. Putting a few above the water-line and eliminating some. So this removal of the kt meter will just be an item on the long list. Thanx again.
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"
|
|
|
28-02-2012, 07:43
|
#40
|
CF Adviser
Join Date: Dec 2008
Location: sausalito
Boat: 14 meter sloop
Posts: 7,260
|
Re: How Necessary is a knot meter
Quote:
Originally Posted by Ex-Calif
I lube the o-rings with vaseline.
|
Better to use silicon grease. Vaseline is a petroleum product, and it will break down the o-rings over time.
__________________
cruising is entirely about showing up--in boat shoes.
|
|
|
28-02-2012, 07:49
|
#41
|
Registered User
Join Date: Oct 2011
Location: Moses Lake,WA
Boat: 40 Cape Dory
Posts: 17
|
Re: How Necessary is a knot meter
Both the paddlewheel and the sonic model for Ray Marine are made by Airmar. They recommend that when not in use they be pulled and stored till you go out to reduce growth, or use water based antifouling. I have both and the sonic one is very accurate, but it is around $600. Keep lots of orings around because the flapper valve eats them and I lube with vasoline too. They're a weird size and I can only get them from airmar or Ray Marine. I keep a spare flapper valve and snap ring around but never have had to replace them. I made a pvc scrub pole I keep on the dock that I can touch up the face of the transducers with if readings don't seem correct. Are they necessary for safe navigation? In my opinion, no, but you should have some method of determing distance travelled, but they are a handy tool and I am glad to have them to increase my DR data in determining position. Are they a pain? At my age anything invented later than the 19th century is, but that's the minimalist in me coming out.
|
|
|
28-02-2012, 16:24
|
#42
|
Moderator Emeritus
Join Date: May 2007
Location: Ohio
Boat: Now boatless :-(
Posts: 11,580
|
Quote:
Originally Posted by Bash
Better to use silicon grease. Vaseline is a petroleum product, and it will break down the o-rings over time.
|
Old habits die hard - 30 years of vaseline. I must have an entire ocean of failed o-rings in my wake...
Also very much depends on the material of the o-ring but I take the point...
|
|
|
28-02-2012, 16:33
|
#43
|
Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,477
|
Re: How Necessary is a knot meter
if you have a gps, totally unecessary... for a cruiser.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
|
|
|
28-02-2012, 17:02
|
#44
|
Registered User
Join Date: Mar 2003
Location: Philippines in the winters
Boat: It’s in French Polynesia now
Posts: 11,368
|
Re: How Necessary is a knot meter
Quote:
Originally Posted by Cheechako
if you have a gps, totally unecessary... for a cruiser.
|
I heard somewhere that "the one with the most toys, wins"!
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
The measure of a man is how he navigates to a proper shore in the midst of a storm!
|
|
|
28-02-2012, 17:02
|
#45
|
Registered User
Join Date: Nov 2011
Location: Montegut LA.
Boat: Now we need to get her to Louisiana !! she's ours
Posts: 3,421
|
Re: How Necessary is a knot meter
As JDS61 said I use my Taff Rail log for not only speed but distance run in 24 hrs, and still use DR everyday !! along with noon sites offshore. of course I use a GPS but don't need it LOL I to don't really like NEW Things Ive had to many of them go belly up on me over the last 50 yrs LOL so I Stick with what I know works and has worked for 1000s of sailors before me and I hope a few after me !! Just my 2 cents Bob and Connie
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|