yachtmaster

[Gludy]

"You would actually plot the position to be within visual but not directly at the buoy as PS says "

To think that DR can be so precise that you would plot it within 30 foot or less is surely absurd??? It seems to me that theory abounds here but as soon as you examine the pracitcal nature of it, it collapses.

30 foot visibility means you have a dustance of 30 foot from where you look - you have to allow for the bit sticking out in front called a bow and you have to allow for reaction time and the ability of the boat to turn quickly.

 

[Renegade_Master]

"So I do not see how I have the time to avoid the object I am aiming at - even if I react instantly, I would still hit it".
________________________________________________________

As I said Paul you plan the course adjacent to, not straight at the Buoy. If necessary the Navigator from the DR and feedback on depths from the helmsman can, when he works out he should be getting close and the helmsman has not got eyeball, will direct the helmsman to slow down maintain course until he seees it to his port bow.

By the way PS mentioned Radar earlier, well of course the navigator can get the helmsman to turn on the radar and report back what he sees, but would be discouraged from standing up and looking at it himself, as he could get a crafty look out the front screen (side curtains closed remember), and then he could cheat.

 

[Gludy]

[ QUOTE ]
If you plan a route which takes you across commercial routes or likely to put you in path of other boats without taking necessary precautions, you'd fail.

[/ QUOTE ]

That is one of my points, I would do all i could to avoid other traffic - I have stated that already.

[ QUOTE ]
Don't you think the RYA syllabus and examiners don't know what they are about.

[/ QUOTE ]

I am asking querstions and more questions if the answers do not make sense to me - I have a right to do that. I am sure they know what they are on about but I do not think the quoted figures of 30 foot, speed of 5 knots and no radar add up to a strategy of heading for buoys and i have given my reasons. Even YM examiners have to conform to the laws of physics!!!

My interst in this is genuine, I will probably take my YM practical this year, all I am doing is trying to make sense of the fgures quoted on this thread - I am not catching anyone out. In practice I think that the quoted 10 metre visibility will have to increase a lot before the boy hopping tactic makes ssense - do you not agree Brendan?

 

[BrendanS]

go on a YM practical course before you take the exam. It will all make a lot more sense then. It's not about pedantics, it's about how well you can cope with the scenario while down below with no visibility, and relaying position and what to do next to the person 'upstairs' who is helming.

Taking the scenario apart doesn't help anyone. You are supposed to be showing you can cope with the stress and actually get the job done.

 

[Renegade_Master]

I can assure you it works in practice Paul

 

[Gludy]

Sun_Coast
Before this thread takes off into a typical one of mine where nobody seems to read what I write, which I do not want it to ....... can I please clear a few things up.

With the figures quoted we are talking about visibility of 10 metres, no radar available, - do you agree that it would be dangerous to head anywhere near the buoy with visibility that low?

Even if you head alongside the buoy how could DR methods be accurate to within 30 foot over miles of travel?

To be able to stand any chance using the metod you outline the visibility would surely have to be way over 30 foot?

I really do not understand, it is not making sense to me, so please expand the subject so that I can understand.

 

[Gludy]

[ QUOTE ]
go on a YM practical course before you take the exam.

[/ QUOTE ]

I have my DS practical and YM thoery already.


"It's not about pedantics, it's about how well you can cope with the scenario while down below with no visibility, and relaying position and what to do next to the person 'upstairs' who is helming. "

I have actually been in a xero visibility siutaion and managed it home safely without any panicv at all.

However brendan the lawas of physics apply and it is nonesense to tell me that i am being pedantic when you are simply refusing to accept that simple physics of the case.

That is you being blind to the facts and simply not wanting to deal with them and answer ins a responsible fashion.

"Taking the scenario apart doesn't help anyone. You are supposed to be showing you can cope with the stress and actually get the job done. "

So you thin that with visibility so bad that there is next to no chance of avoiding the buoy should you be unlicky enough to head for it, that you should carry on regardless is being practical???? I think that is an absurd position.

I actually think that the answer is that the wrong visibility figure has been quoted - that is the variable that has to give for this to make sense.

So please Brendan, concrentrate on the facts and deal with them and do your best to avoid handing out advise that is just based on smearing the individual rather than deal with the facts.


There we go another blinkin Gludy thread is underway when all I am trying to do is get somebody to answer for the figures quoted and learn from the excercise.

 

[BrendanS]

Paul,

It's a practical test to show you have the capability of sitting down below while blacked out, and take decisions based on what information you have to hand. Then to take feedback and take more decisions.

They are trying to test your abilities under pressure in conditions they can't simulate, so do next best thing

You can't live in a black and white world all your life

Sticking you down below and saying visibility is 10 miles so it's quite safe, won't test your ability to get you to a buoy if helmsman can say 2 miles off that he can see it

 

[theforeman]

when you are navigating in fog you should have a look out on the stem to LOOK and LISTEN. he/she will have 10 metres visibility and you can see them from the helm.
if you don`t have a look out you shouldn`t be navigating.
i think you should wait a bit more before you take the practical.

 

[Gludy]

[ QUOTE ]
I can assure you it works in practice Paul

[/ QUOTE ]

Not with 1.5 seconds to 3 seconds to react, turn and avoid the buoy it cannot - so the visibility has to be more than 10m 33 feet - agreed?

 

[BrendanS]

Paul, again, it's a test of your navigational skills, not what happens in real life. Not black and white.

If the helmsman can see buoy from 2 miles away and say OK, I'll sail to that now, not much of a blind test really?

 

[Gludy]

"when you are navigating in fog you should have a look out on the stem to LOOK and LISTEN. he/she will have 10 metres visibility and you can see them from the helm.
if you don`t have a look out you shouldn`t be navigating.
i think you should wait a bit more before you take the practical. "

I have actually been in zero visibility and had the hear outs (lookouts were impossible) ..... I have not stated anywhere that I would not do that so why you assume things just to be able to state that I need more pracitce defeats me.

If I had someone at the bow and they managed to see it at 10 m visibulity 5 knots O would have 9 seconds maximum to get the message, react, and turn the boat to avoid the buoy and that is still very risky.

So instead of trying to insult me, please read what i am saying, do not assume things you know nothing about and then form a judgement on me.

If you want to contribute, please deal with the facts and answer them.

 

[Stevie_T]

Actually Power YM does (or can) include use of radar albeit fairly basic.

 

[fireball]

Having been in a low vis (~20-30m) at night I can assure you it is very reassuring to pass close to a recognisable buoy. Even working on GPS/Chartplotter (acuracy ~10m?) I was pleased to see each buoy that we were hopping too - as we passed it.
Obviously we didn't go at silly speeds - more like around 4 knots and we could hear the major buoys so knew to be more alert when approaching.
If I was doing blind nav for real then I would be buoy hopping - as this is one extreemly good way of fixing your possition.

 

[Gludy]

Brendan
We have to use simple maths in navigation - we use it in DR to estimate position. I am using the same simple mathsm which you are avoiding.
The maths here are black and white and as a good skipper you should be aware of them just as in driving in fog on a road, you should be aware of your stopping distance.

I have made my practial points, I have provided the figures and nobody is dealing with the answers.

 

[Gludy]

"Actually Power YM does (or can) include use of radar albeit fairly basic. "

Yes but in this case its assumed that there is no radar available.

 

[Phoenix of Hamble]

Gludy,

Firstly you'd probably stick someone on the bow, so you have more time that you think to slow down/avoid....

Secondly, you can find buoys if you pick them wisely in quite poor visibility using non electronic navigation techniques by using the full range of inputs available to you, such as contour lines etc etc.... although I agree, in reality, with no electronics, aiming to find a buoy in 10m vis using DR/EP calcs when you have travelled some distance is probably optimistic...... generally though you can buoy hop, and use contour lines etc etc to be suprisingly accurate.... and often buoys are quite close together....

IMHO... if aiming for a buoy using blind nav was clearly not the right thing to do, then you'd be well advised to say so!

 

[fireball]

you would know when you're in the vicinity from your EP .... so you would take appropriate action before you get too close ... wouldn't you ??
eg - if you assume 100m error on a short buoy hop ... then as you get to the 100m radius from target you'd be more cautious - slow down and if the target has a sound signal, even stop the engine for a couple of seconds to try and hear where it is.

100m is a pure guess - but depends on your start point, distance to target, wind and assumed tidal effect ... oh and the accuracy of your helming ... (difficult to hold to specific courses by hand ...)

 

[Gludy]

Fireball
I almost agree with you.

"Having been in a low vis (~20-30m) at night I can assure you it is very reassuring to pass close to a recognisable buoy."

I have been there as well and agree its reassuring but visibility was giving me time to avoid hitting it as it was in your case.

"Even working on GPS/Chartplotter (acuracy ~10m?) I was pleased to see each buoy that we were hopping too - as we passed it."

Also understood and agreed.

"Obviously we didn't go at silly speeds - more like around 4 knots and we could hear the major buoys so knew to be more alert when approaching."

Agreed .. although not all have the bells.

"If I was doing blind nav for real then I would be buoy hopping - as this is one extreemly good way of fixing your possition. "

That is not the point here, I agree its a greatay of fixing position - the question is would you do it if you has such low visibility that it gave you insufficient time to avoid hitting the buoy?

 

[Gludy]

NAS


I agree with all you say and have stated nothing different.