Buck Turgidson
Well-Known Member
You need to write to all the major marine electronics companies and ask them to change the way their products calculate it. And all the designers and builders and ask them to rename their Polar charts mate!
What is more accurate for speed, navionics or nasa log?
- Thread starter Crinan12
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Chiara’s slave
Well-Known Member
Very true
The bottom line is that you cannot afford to overlook either if you want to get to the windward mark, or the pub, first.
Refueler
Well-Known Member
Vectors ....
Buck Turgidson
Well-Known Member
oldharry
Well-Known Member
Very simple rule of thumb:: GPs speed for navigation, Log speed for sail trim etc. Mechanical paddle wheel systems will need regualr cleaining if left in position between trips, and most of us have a strong and instinctive aversion to seeing water pouring in where it should not. The sea belongs outside, not inside and the sight of water pouring through a hole in the hull triggers all kinds of unexpected and sometimes irrational responses.
Train your mind to seeing it and it no lomger becomes a worry.
Train your mind to seeing it and it no lomger becomes a worry.
johnalison
Well-Known Member
As in #60, 'True wind angle' is not actually related to what we now know as TWS. TWA was around well before GPS or even Decca were on yachts or common. My memory is that it was something that B&G offered in the '70s that most of us could only dream of. It is true only in the sense of being true in relation to the water mass, and my unit will show TWA with GPS switched off (but not with the impeller withdrawn!) unlike AWA or what we learned from Windex. It would be possible to present the wind true to GPS but it wouldn't be of much practical use. It is just unfortunate that 'true' is also used in other contexts.
Refueler
Well-Known Member
Just to explain my position - considering the comments already made by others in particular.
Having come from sailing since a child and racing various from dinghys to keel boats ... then getting serious !!
As senior Deck Officer for many years ... I followed the Met Office and Official terminology of True Wind - that being the calculation of True Wind for the purposes of reporting weather. As against the apparent over deck wind.
Unfortunately the term 'True Wind' has been used in the context of racing Vectors ... as you and others have been used to. Another example of how words get into misuse. I am not interested in any form of correcting many years of misused word ... far from it ...
As I said already - I still have my Calculator for use in racing (before and during) for planning such vectors and later correction calculations. I fully accept that the angle of wind and its speed 'across deck' as boat makes its leeway etc. is far more valuable for getting to the mark ...
I just prefer the correct use of the English Language. No disrespect intended.
Buck Turgidson
Well-Known Member
Having come to sailing after a long career in aviation I too was mystified by what I considered a misuse of a well defined term. But after initially banging my head against the wall I grew to accept that context was important and accepted the specific sailing definition.
Of course one has to question whether one is really talking about "True wind" or "Magnetic wind" given the magnetic north reference used in sailing.
I've got a button to change from True to Mag reference in my mobile office but we fly Mag almost everywhere even though it is derived from True and corrected from a database based on vessel position.
Reported winds are given in True for en-route information but magnetic at airfields
Best not to get too worked up about things I guess.
Of course one has to question whether one is really talking about "True wind" or "Magnetic wind" given the magnetic north reference used in sailing.
I've got a button to change from True to Mag reference in my mobile office but we fly Mag almost everywhere even though it is derived from True and corrected from a database based on vessel position.
Reported winds are given in True for en-route information but magnetic at airfields
Best not to get too worked up about things I guess.
johnalison
Well-Known Member
I’m afraid that we simple sailor-folk are going to find it hard to change our ways, when our wind instruments are labelled true/apparent to refer to wind in relation to water/boat. For me 50 years of use will take precedence over whatever the Merchant Navy calls it or the Met Office does. Ground wind, as some of us call it, has next to no importance to me when sailing or motoring and unfortunately there is no alternative term available to avoid confusion. All that matters is that we should make clear what we mean when we use these terms, especially when relative newcomers are involved.
flaming
Well-Known Member
Installing the log at the start of the day, and removing it at the end are simply standard practice for us. I use a large sponge that i place on the slightly downhill side of the hull. Takes me about 10 seconds to mop out any of the small amount of water that comes in that the sponge doesn't immediately catch.
Helps that the access is easy. You can see when boats have been designed for this...
Helps that the access is easy. You can see when boats have been designed for this...
greeny
Well-Known Member
Just as an extra. Take it or leave it. I installed one of the apps off google play on an old phone that reads out speed, course, and lat long. Very accurate compared to my other equipment. Always good as a back up or comparison if your thinking things are not quite right and may need calibrating.
[70521]
Well-Known Member
Sadly, it is a practice that most skippers have a morbid fear of!
flaming
Well-Known Member
We're dry sailed, and the lifting straps go across the log..... Quite apart from the accuracy arguments, we'd be replacing the impeller several times a season!
Snowgoose-1
Well-Known Member
Yes. Commonly known as fountain of death. As mentioned , good access helps . I think once you have done it a few times confidence is gained and it's not a problem.
johnalison
Well-Known Member
It's one of the awkward jobs I used to get my then teenage daughter to do on our Sadler 29. We used to use a sponge, but the transducers were in a box which contained the water. With some care very little water comes in. I now have a boat with valves on the tranducer, which only lets in a trickle.
john_morris_uk
Well-Known Member
People calling it ‘The Fountain of Death’ feeds the irrational paranoia of many people to cleaning their log impeller…. It’s a ridiculously easy and trivial task in reality.
PS. I question how commonly the term is used. In 50 years of sailing I’ve never heard it.
flaming
Well-Known Member
Our log has 2 parts. Inner and outer. When you (correctly) unscrew the inner you get a little trickle.
When you make a mistake and undo the outer you get hit in the face by a jet of water. I would like to say you only make that mistake once, but sadly that hasn't proved to be true in my case!
greeny
Well-Known Member
I don't have a choice with mine. Impeller is always in. It's only removed for cleaning. Its a dual unit. Incorporates the speed and depth in one unit. Removing and replacing becomes second nature when you do it as often as I do. Practice makes perfect. Very little water ingress. Have I just jinxed myself lol.
vyv_cox
Well-Known Member
The hinges on the heads door in a Sadler 34 are chromium plated carbon steel cafe hinges. The log impeller is immediately adjacent to the lower hinge, which inevitably gets soaked in seawater. Which explains why so many Sadler owners are looking for replacement suppliers!
Daydream believer
Well-Known Member
The "jet of water" that some talk of, will go no higher than the water level outside the boat, so can we stop the exagerations please. 
You are making it sound like the fountain of youth from long lost past. It may go off at an angle in some deep bilges, but it is just a bit of water through a 32mm diameter hole, that one can hold back with the palm of one's hand. The hard bit is trying to clean the impeller with the other hand whilst it slips further into the bilge on the end of the wire.
Teach you not to keep losing the blinking blanking cap.
You are making it sound like the fountain of youth from long lost past. It may go off at an angle in some deep bilges, but it is just a bit of water through a 32mm diameter hole, that one can hold back with the palm of one's hand. The hard bit is trying to clean the impeller with the other hand whilst it slips further into the bilge on the end of the wire.
Teach you not to keep losing the blinking blanking cap.
