yachtmaster

Re: Round N+1 with Gludy about the blind nav.

So you get out of the way and anchor then you become the solid object in 10m vis, no ones gonna see yer black ball so you will have to keep sounding your horn.

I'd rather make it back to the Marina which isnt far anyway cos its only a bloody excercise for gods sake
 
Re: Round N+1 with Gludy about the blind nav.

calm down eh?

think the thread went to 'what if in real life' quite some way back.


so you will have to keep sounding your horn. Oh! the bells.
 
Re: Round N+1 with Gludy about the blind nav.

"I'd rather make it back to the Marina which isnt far anyway cos its only a bloody excercise for gods sake "

But we agree that as an excercise its great - there is not dispute. I repeat that the excrecise is sensible, good - understandable etc The whole point is if it were real. So I am now really confused with your point.


There is a difference between trying to get out of the way and staying there - I have an auto horn anyway as many boats now do - and going looking for the solid object!
 
Re: Round N+1 with Gludy about the blind nav.

If it were real...... it would depend on the situation obviously.
If you could set a course to steer to a nice contour without any dangers that would take you to a safe harbour without crossing any shipping lanes when the fog is forecast to stay at 10m vis for 3 days, then it would probably be realistic in real life to do the blind nav.
It also depends on your confidence to do it. Having done it, and taught it many times then I would have the confidence to do it in that given situation in real life.
However Gludy who has so obviously never tried it would not. However if Gludy would just go on a course and learn it, then he would no when he would or would not be able to use it in a given situation.
Clearly, like everything in life, every situation is different and demands a different approach and you can go on for another 2000 posts if you like, but until you practice it you will never know.
 
Re: Round N+1 with Gludy about the blind nav.

Don't start off again ... jeeze ... or is PowerSkipper quietly paying peeps to make this a monster record breaking thread ? If so ... where is my DOSH!

Anyway ... IRL ... you'd use Radar and your GPS ... and if you had power failure .. then the battery powered HH GPS complete with frantic pencil scribblings would be in order ... and if someone turned off the GPS satelites ... we'd have other problems to worry about.
 
Re: Round N+1 with Gludy about the blind nav.

Well sure you would use radar. Not everyboat has it though!
GPS, yes but the time taken to transfer position to chart is too slow. Following a contour is safer and exact as long as you know its a safe contour.
Chart plotters, well they can be a way out, at least mine can.
 
Re: Round N+1 with Gludy about the blind nav.

I don't have Radar
every 0.5 seconds update is fine - you can't scribble on the chart quicker than that.
You need to check your chartplotter or your charts ... mine (so far) have been acurate.
There might not be a contour ... or even a safe one..
 
Re: Round N+1 with Gludy about the blind nav.

Hanabella
Why oh why can you not make a point without making a fistfull of assumptions and personal remarks. By doing this the points get lost and the discussion never gets anywhere.

For the record, I will be doing my YM practical this year. I have already practiced contour following etc. I take my boating seriously and I do not make assumptions and then make points about other people based on those assumptions.

The fact is that instead of this being a proper discussion, because it actually could have developed into a good discussion, it goes off the rails because of the inablity of you and others not to stick to their point and the inability to stop making personal remarks.

Ain a typical fog situation the water is as calm as can be – you are lucky to get any buoy bells sounding. So in this situation you are telling me that with just 5 to 10 foot visibility from your helm past your bow, or 30 foot visibility from the bow for a lookout, you are happy using just depth contours and no radar etc to navigate searching out these buoys to confirm your position. You are telling me that the practice you have had in this makes you confident you can do it – the practice – I assume is following depth contours to find buoys? If so, then as you get better at it the more chance there is you will hit one in such low visibility.

Question: How many times have you skippered a boat in such a low visibility without a radar an buoy hopped?

I am sure I can follow a depth contour and find a buoy – I agree with the exercise but that is not the point – to slow down before the buoy not only your course would have to be exact but also your ETA at each buoy.

All I am saying is that it is dangerous to be out in such a situation. It is also dangerous in that situation to head for solid objects if it can at all be avoided. …. You have a right to disagree but I do think you are wrong. Just like I think that when a abandoning a boat I prefer a life raft than having to jump in the water ( someone argued that life rafts can give hypothermia) or it is dangerous to do 40 knots up the Solent at night ( a claim from another thread).

The forum does seem to have its abnormal share of super heroes capable of doing the most incredible things.

I repeat that I have no doubt that buoys can be found by following depth contours - I have no doubt that the exercise is valuable and should be part of the course/exam so please do not try and argue with points that I have never done anything else but agree with.

Now please answer my direct question.
 
Re: Round N+1 with Gludy about the blind nav.

[ QUOTE ]
There might not be a contour ... or even a safe one..

[/ QUOTE ]
No argument with that.... then I wouldnt follow one.
Anyway IMO this thread has gone far enough and so I am bowing out now.
Goodnight
 
Re: Round N+1 with Gludy about the blind nav.

PS stopped paying ... /forums/images/graemlins/frown.gif .... where was my share?!
 
Re: Round N+1 with Gludy about the blind nav.

I am amazed to find myself agreeing with Fireball.

"GPS, yes but the time taken to transfer position to chart is too slow."

It can be or it cannot be. I can do that in a few seconds because I have the equipment but lets assume you do not have the skill to do it nor the equipment ...


"Following a contour is safer and exact as long as you know its a safe contour.
Chart plotters, well they can be a way out, at least mine can. "

What chart plotter do you use that can be way out and less accurate than following contours? As you know there are places you can follow contours and places you cannot. However I am dying to know which chart plotter is so poor that its worse for providing a position that the claimed better choice of following contours????

Do not forget when following that contour your time/speed calc has to be just right whilst following a very often curved path but this is so accurate with you that it is better than your chart plotter??????

We are now ending up like a typical Gludy blinkin thread )and it not my thread) where silly extreme statements get made because of a step by step path away from reality.

I await to hear which chart plotter is that bad - please tell me?
 
Re: Round N+1 with Gludy about the blind nav.

There are some poor electronic charts, although I believe in the UK we're fine ... certainly had no noticable errors on my South Coast ones from Maptech.
My old Apelco GPS was terrible at updating the laptop nav software, so I plugged in my trusty Etrex - ~0.5 sec update ... just enough time for the boat to turn too far before correcting ... /forums/images/graemlins/frown.gif mind u - it was relaying out via a compass person to the helm (light was very poor on the compass so not easily visable at the helm ... it is a sailing boat u know!)
 
Re: Round N+1 with Gludy about the blind nav.

Hannabella...

Which chartplotter and charts are you using?? I would be interested.
Theoretically the only way a chartplotter can be out is if either the Electronic geodatic reference is set wrongly for the charts or the GPS is in some way wrongly set.
Most charts are now WGS84, although a few older european charts notably Mapmedia (maxsea) and some SHOM electronic replicates (fugawi) were using the older European Datum until quite recently.
Typically a datum error will give a discrepancy of between 1 and 2 cables.

Steve.
 
Re: Round N+1 with Gludy about the blind nav.

Interesting stuff.

In following contours, the heading for a buoy is a great position confirmation. However without that position confirmation you have to be accurate in time and speed (DR) following what would normally be a curved path.

Even if there are suitable contours, you have to head into them, pick your chosen one up and then begin following - whilst following you have to allow for continous tidal height adjustment which can be large or small - given that situation, I cannot concieve of a position fix being more accurate using this technique than that from any functioning chart plotter.

If it was so accurate, and we are assuming a good set of contours to follow, - using DR and contour following there would be no need for the position confirmation from a buoy and hence no need to find a buoy in the first place.

I am sorry but to me we have now reached the point of absurdity.

In practice, as you say, the whole situation is unlikey to arise. In my case for example, I have a chartplotter, yeoman interface to charts on chart table and back up hand held battery driven plotter plus radar. If I was is such a mess as to be without these and in 10m vis, I would ask the CG for an occasional fix rather than head towards solid objects.

If there was say 100 foot vis, I would probably go for the buoy following having established a fix for my starting position, using the CG for a fix.

If plotter failed, backup plotter failed - I would use radar.

If radar failed then I would using contours and DR with CG fix confirmation, try and find a safe spot to hang out but that would depend on many factors. if I could not hang out, I would contour follow trying to avoid any buoys using the occasional CG radio fix instead of heading for buoys...... whan.if I got home, I would change my underpants and sue the electronic equipment makers.
 
Re: Round N+1 with Gludy about the blind nav.

The problem with following a contour, is that it is far from an exact science.
On quite a lot of charts the soundings were taken eons ago, some from the 1930's
very commonly 1956..etc
Surveying is an expensive business and only carried out frequently on commercial port approaches for maintained depths.

Soundings may be fine in some waters, but in areas like the Bristol Channel with frequently changing depths I dont think I would like to rely on it.

Steve.
 
Re: Round N+1 with Gludy about the blind nav.

That's part of the learning curve. Knowing when it will or won't work
Areas of quickly shifting sand would raise concerns with most. Rocky shores that don't move are quite reliable
 
Re: Round N+1 with Gludy about the blind nav.

[ QUOTE ]
or it is dangerous to do 40 knots up the Solent at night ( a claim from another thread).

[/ QUOTE ]

quite safe if the light conditions are such that you can see the water surface ahead of you. This one been done to death already.
 
Re: Round N+1 with Gludy about the blind nav.

Part of that learning curve is knowing the waters.

When i mentioned this before I was shot down but as Steve states very clearly, you cannot simply trust the chart - to be safe you also need local knowledge.

I have been in parts of the Bristol Channel which are totally different to the charted depths and other parts which are failry close.

However using depth contours with DR can never be as accurate as any chart plotter.
 
You must log in or register to reply here.

Other threads that may be of interest

PaulRainbow
Princess 45 Refit
2 3 4
Replies
68
Views
3K
Skipper Felice
Skipper Felice
J
New small boat
Replies
4
Views
411
Farmer Piles
Farmer Piles

Share this page

Top