yachtmaster

The answer (as stated many times before in this thread) is SLOW DOWN when you're getting close. Indeed, slow down anyway, there may well be something solid out there which you aren't aiming for. Just as close, just as solid.

The benefit of using real/ solid "targets" when in fog is that when you find them, you know exactly where you are. One bit of arbritrary sea looks much like another - not much use in confirming your position in an "oh sh*t, the GPS has failed" situation.

Surely we can trust the word of Powerskipper on this one. She lives & breathes this stuff every day...
 
Having done real blind navigation many times pre-GPS (and as part of the YM test) then I would always aim for the bouy because the chance of hitting it exactly is small and provided you go slow enough, i.e 5knots to 250yards, 3 knots to 100 yards then engine in/out of gear with somebody on the bow then you can often see, sense or hear the bouy before you reach it. You shouldn't imagine the way you'd navigate with a chartplotter - it's a lot more tentative than that.

You then have a great fix for deciding what to do next. When worrying about collisions remember that if you're out there in fog you could be hit at any t ime, so its all about getting yourself to a safer position which may involve a few slightly riskier steps along the way.
 
I would like to add this.

With my DS parctical taught by John Hart - a tough instructor that teaches instructors, I once passed within about 15 to 20 foot of a buoy and was told off for being so close.

He pointed out that buoys themselves change postion and should always be given a wider berth.

A buoy can change position by 30 foot in any direction depending on the tidal height etc, so how anyone can expect to be so accurate in what is virtually blind navigation that they can put their boat at risk by heading for them with no chance of avoiding them after seeing them in front of you, defeats me.

If I only have 5 to 10 foot visibility past my bow, no radar, no plotter, I do not go looking for massive solid objects providing me with no chance of avoiding after spotting, that could hole me if I hit them. But then maybe I also like life rafts for the same reason?
 
If you do 5 knots in 5-10 feet "useable" visibility, your enthusiasm for liferafts is entirely justified. Just hope I'm never in the same fogbank as you...
 
Powerskipper - your answers are not right because they ignore the scenerio of 10 m vis, 5 knots speed - you change the variables. Please look back at the thread.

If you are saying slow down - what do you mean slow down to 2 knots? How do you know when to slow down?

As reegards tidal graphs, I know that but the depth changes very rapidly in that case and my point is that it decrases the accuracy - do you accept that point?
 
Well - you don't want to slow down, you don't want to navigate as accuratly as possible ... just get in your liferaft now!

I really cannot see why you fail to understand a simple suggestion (and it is only a suggestion) that whilst navigating on paper you allow a degree of inaccuracy (depending on input data) and allow for that ... so, for example - if you're asked to blind nav to a buoy from a mile away (say) and assume 10m vis then you could assume a 100m inaccuracy in nav and use that as your "dangerzone". So, eta to dangerzone is (at 5knots ~10min) then after 10min you drop your speed to 1knot or so ...

but as others have suggested - if the buoy is close or on a depth contour then perhaps you'd nav to the depth contuor and follow that instead.

Personally, without radar or GPS I would buoy hop unless I had another method of locating my vessel especially in that low a vis.
 
The scenerio that was being discussed was travelling at 5 knots with 10 m vis.

To slow down, you have to know when to slow down and so accuracy of both position and timing would have to be pretty precise.

As regards just accepting the word of PowerSkipper - certainly not. Without any slight meant towards her, I would not accept the word of anyone unless they could explain it.

Nor do I accept that PowerSkipper does it every day. What is done every day is finding biouys by following contours and that there is no dispute with. What is not done every day is the real world naviagting looking for buoys, no radar etc, with only a few seconds warning of when the buoy appears.
 
The point you are missing is that with only 5 to 10 feet beyond your bow, and the accuracy you suggest there is little point in buoy hopping because you would only ever see then when dangerously close. If they had a bell, you could hope to hear them at a greater distance and still be safe but not all have bells.
 
last time..............


[ QUOTE ]
If you are saying slow down - what do you mean slow down to 2 knots? How do you know when to slow down?

[/ QUOTE ]
2 option,
do all manoeuvring at 2 to 3 knots
or
when getting close to the danger area.


[ QUOTE ]
As regards tidal graphs, I know that but the depth changes very rapidly in that case and my point is that it decreases the accuracy - do you accept that point?

[/ QUOTE ]

All tidal grafts are a guesimation on available information, just listen to a local VTS.
the point is you will know the speed the tidal depth is changing and have a good idea of the depth to look for.


All the information is to aid YOU in making the decisions that are right for you and your boat in that situation, you may do it differently to others , all that has been discussed here is different methods used, not exact science.


have a good day
/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
 
"SO SLOW DOWN - clear enough??????? "

No not clear at all for reasons I have already explained.

In a real life situation with the 10 foot past my bow, I would not mind too much heading for a buoy wich I knew gave a sound - but in these coinditions the sea is often as flat as a pancake and no sound could be guaranteed.
 
<span style="color:red"> <u>THEN SLOW DOWN </u> </span>

Which bit of <span style="color:red"> <u>THEN SLOW DOWN </u> </span> do you not get?

Read the colregs again ... they specificy what action you should be taking in any Vis ... if you passed YM theory you would know this....

right - off to get blood out of a stone .... I'll have more success....
 
There is pretty much always a swell ... that is enough to set off a sound signal...
They also have lights .. (well the important ones anyway)

And if you approach where you think it is ... slowly enough you will have ample time to alter course (who said you have to stop ??) especially if you approach into the tide ...

The YM prac exam is testing you on your abilities to adapt to each situation as required.
 
It doesn't matter what you are/ aren't aiming at. In 10 metres visibility, 5 knots is TOO DAMN FAST. That's what I meant by THEN SLOW DOWN.

Bells, whistles, sea state, Powerskippers competency etc etc etc are all immaterial.

YOU SHOULD NOT BE GOING THAT FAST IF YOU CAN ONLY SEE 5-10 FEET OFF YOUR BOW.

How in Gods name can anyone (even you...) find that unclear.
 
Power Skipper


You are ducking my direct questions.

I boat in the bristol Channel, I am very aware of tidal heights and constantly use them. My question on that was do you accept that with a depth change as fast as 12 foot an hour, the accuracy using depth contours would be less tahn with a smuch smaller tidal range? I fully appreciate that you can correct for it and even make guesses for atmospheric pressure but with such a rapidly varying water height, there must be a greater error introduced ....... you did not answe that question.

As regards slowing down to 2 to 3 knots, that was not the case that was being discussed - it was 5 knots and that was not my figure.

In effect, under the rgs you should slow down to 2 to 3 knots all the time because with only 10 foot max past your bow, even that would probably mean hitting something.

In practice with a speed that slow, tidal sreams corrections etc become an even bigger influence and accuracy decreases ... agreed?

Direct question - do you think that a warning of say 8 seconds is sufficient time for a boat to avoid a buoy looming up in front of it? Because even at say 2 knots, that is all the time you would have from the helm position.


I am not trying to get at you or trick you, I was trying to have a sensible discussion to learn from and that is still the situation.
 
Fireball = the scenrio set was 5 knots with 10m vsibility. I have discussed the slowing down point in answer to Power Skipper. Please read what i am awriting instead of just banging on a drum and missing the point.
 
"There is pretty much always a swell ... that is enough to set off a sound signal...
They also have lights .. (well the important ones anyway)"

I have been there and got the T shirt when I could not see the bow of my boat. I have passed buoys that were a silent because there was no swell whatsoever - you cannot invent swell just to help you point!!!

"And if you approach where you think it is ... slowly enough you will have ample time to alter course (who said you have to stop ??) especially if you approach into the tide ... "

We are now talking about say 2 knots that provides you with some 8 seconds warning from your helm postion with little agility to avoid.

"The YM prac exam is testing you on your abilities to adapt to each situation as required. "

I totally agree. In the case of only 10 foot past my bow, I would do all I could to minimise risk. This would take into account many, many factors but if possoble, i would try to use the depth contours to navigate to a safe place and see the fog out. I would not attempt buoy hopping.

If there was 30 m vsibility, then yes, I would with great caution consider the gain from position affirmation a buoy gave me, as worth while and would buoy hop.
 
You must log in or register to reply here.

Other threads that may be of interest

Canopy Locked
Transom strength
Replies
10
Views
377
Canopy Locked
Canopy Locked

Share this page

Top