How hard is the day skipper theory exam

[snowleopard]

Alan T has eloquently explained why you need to specify whether to use the diamonds or the atlas for an exercise. Beats me you would not want to know how to do both just for interest even if you tend to use only one.

We are talking about someone at the start of their sailing career. What they need to go to sea is a simple way of doing things. Alternative methods can come later.

You would be amazed how many experienced sailors show their friends how to navigate, and propagate significant errors.

Are you saying only RYA certified people should pass on their knowledge?

For example, HW Dover is at 1200, what time does the page HW+1 in the atlas represent? Not a trick question, but many will get it wrong.

1400 BST

 

[Doug_Stormforce]

Are you saying only RYA certified people should pass on their knowledge?

For example, HW Dover is at 1200, what time does the page HW+1 in the atlas represent? Not a trick question, but many will get it wrong.

1400 BST

I don't think the question was trying to catch you out on summer time (as he has not specified what time of yr it is). I am guessing he was after an answer along the lines of 1230-1330 (or 1330-1430 if you want to convert to BST).

 

[Elessar]

I don't think the question was trying to catch you out on summer time (as he has not specified what time of yr it is). I am guessing he was after an answer along the lines of 1230-1330 (or 1330-1430 if you want to convert to BST).

Yep. Guessed he would be wrong.

 

[Bosun Higgs]

As an ex RN engineer officer (Dartmouth 1968-9) I think you are overgeneralising. I have also served with some seaman officers who seamanship was truly appalling!

I'm generalising from a sample of one! I was more than a bit nervous when this chap applied for the course - I had visions of my every word being monitored and corrections being issued. I need not have worried. His level of knowledge was very patchy but being an engineer ( on nukes I believe) he picked up nav in no time. Ironically, he later sank his boat.

 

[Bosun Higgs]

In view of the comments about time wasted by practical course instructors on people who don't know the theory, would they not like to be able to say "theory pass required for this course"?

Got to agree. To think that a practical instructor can teach all the boat handling plus everything that is done in a shorebased course over 40 odd hours, plus homework and do it all in a 5 day course is nonsense. But then its best to look on the RYA courses as help in gaining knowledge rather than teaching / testing to a specified standard.

Not now, but when I did DS and CS theory there certainly were exams!

Not for the last 20 years there havent been - at least not in the way that an academic would understand exams ie pass/fail with a percentage pass mark. Can't repeat often enough that you cannot get the piece of paper at the end, which is a course completion cert and nothing more without taking the course and that piece of paper is at best just a component of the real qualification which gets you the ticket ie the practical .

Both you and I might doubt the wisdom of direct entry to the practical but leave that aside. The practical course tests the candidate on all aspects of what is in the end a practical skill - sailing a boat. Look on the theory course as an easier way of learning some of the skills than trying to do it head down in a moving boat.

 

[alant]

I'm suggesting an exam on all the theory - like the one I (and it seems you) did years ago at the end of a course.

I getting more than confused.

Surely an exam on "all" the theory is what happens now.

 

[alant]

Alan T has eloquently explained why you need to specify whether to use the diamonds or the atlas for an exercise. Beats me you would not want to know how to do both just for interest even if you tend to use only one.

We are talking about someone at the start of their sailing career. What they need to go to sea is a simple way of doing things. Alternative methods can come later.

You would be amazed how many experienced sailors show their friends how to navigate, and propagate significant errors.

Are you saying only RYA certified people should pass on their knowledge?

For example, HW Dover is at 1200, what time does the page HW+1 in the atlas represent? Not a trick question, but many will get it wrong.

1400 BST

Sorry can't agree with that answer.

1) If you were using the RYA Tidal Information, Diamonds or Tidal Stream Atlas, you would find that the correct tidal hour (in this case HW+1) would be based on a different Reference Port - ie Victoria.

Using the wrong reference port, is a common error!

2) Forgetting about the RYA Course stuff, if HW Dover is 1200

HW Hour = 1130 - 1230 UT = 1230 - 1330 BST

So, HW+1 = 1230 - 1330 UT = 1330 - 1430 BST

Which is how you work it out, using a tidal hour ladder.

The tidal information, applicable for an hour of time, not simply an instant like 1400 BST.


"We are talking about someone at the start of their sailing career. What they need to go to sea is a simple way of doing things. Alternative methods can come later."

Can't entirely agree.
What they need to go to sea, is the 'correct way' of doing things.
If you can simplify that as well, go for it.


"Are you saying only RYA certified people should pass on their knowledge?"

Of course not, if that were the case, we wouldn't learn from equally capable people, who have no paper qualifications. A Master Mariner isn't RYA certified is he?
But, would you accept that teaching your children to pass a driving test, isn't necessarily the domaine of your Granny, just because she has been driving (possible without ever having passed a driving test) for 100 years?

 

[alant]

I'm generalising from a sample of one! I was more than a bit nervous when this chap applied for the course - I had visions of my every word being monitored and corrections being issued. I need not have worried. His level of knowledge was very patchy but being an engineer ( on nukes I believe) he picked up nav in no time. Ironically, he later sank his boat.

Apparently Dartmouth Cadets, are taught RYA DS !

 

[snowleopard]

What they need to go to sea, is the 'correct way' of doing things.

Why is use of diamonds 'correct' and tidal stream atlases incorrect? Because the RYA says so?

There are many instances where use of the diamonds can give totally the wrong answer. Some computer based tidal programs slavishly work out tide speed and direction from the nearest diamond and end up with a current flowing across a river!

Likewise saying a single tidal figure applies from exactly half an hour before to half an hour afterwards then jumps instantaneously to the next value can get you into some very odd results. If you interpolate you avoid that problem. Why is your method 'right' and mine wrong? Because that's the way the RYA does it?

And a question for you. If a current is changing and you take a single value for the whole of a 1 hour period, is that value the Mean, Mode, Median or Root Mean Square of the range of values that actually occur over that hour?

 

[Elessar]

Why is use of diamonds 'correct' and tidal stream atlases incorrect? Because the RYA says so?

you didn't listen.

The RYA never says tidal diamonds are the correct or only way to do it, they just say "please use the diamond for the purpose of this exercise"
That way the tutor can mark things easily, and knows the trainee understands diamonds.

There are many instances where use of the diamonds can give totally the wrong answer. Some computer based tidal programs slavishly work out tide speed and direction from the nearest diamond and end up with a current flowing across a river!

The tidal diamond data and tidal atlas data are IDENTICAL, from the same source, the hydro graphic office. If it's wrong as you say it's because you've used the wrong diamond, just as it would be wrong if you used the wrong arrow in an atlas.

Likewise saying a single tidal figure applies from exactly half an hour before to half an hour afterwards then jumps instantaneously to the next value can get you into some very odd results. If you interpolate you avoid that problem. Why is your method 'right' and mine wrong? Because that's the way the RYA does it?

You're wrong, because the data is provided by the hydrographic office and you don't seem to fully understand it. The RYA and others just try and help explain it. The data on the atlas and in the diamonds is simply the average of the hour, ie half hour before and half hour after the time in question.
However you're right in saying that if interpolated, the result is the same - but only if you interpolate for the correct hour. By stating a point in time, ie 1300 the liklihood is that the assumption would be the page referred to 1300-1400. At best your answer was ambiguous, never a good thing when passing from one watch to another.

And a question for you. If a current is changing and you take a single value for the whole of a 1 hour period, is that value the Mean, Mode, Median or Root Mean Square of the range of values that actually occur over that hour?

It's the mean. If you had done dayskipper you'd know that!

 

[snowleopard]

The tidal diamond data and tidal atlas data are IDENTICAL, from the same source, the hydro graphic office. If it's wrong as you say it's because you've used the wrong diamond, just as it would be wrong if you used the wrong arrow in an atlas.

Diamonds only give streams at a single point, the atlases and other tidal charts show how it flows over an area and allow one to interpolate. Here is an example. You are at the point marked inshore of anchorage 18. B, in the main channel, is the nearest diamond. At 6 hours before HWD the current is flowing 236° i.e. directly towards the shore!

 

[timbartlett]

Why is use of diamonds 'correct' and tidal stream atlases incorrect? Because the RYA says so?

The RYA does not say so, and as far as I know it never has.

In 1975 (the oldest syllabus I can easily lay my hands on) the syllabus of the National Coastal Certificate said "use of tide tables and tidal stream atlas". Tidal diamonds were not even mentioned in the syllabus.
In the Yachtmaster syllabus at the time, the section on Tidal streams said:-
"(1) Tidal Stream Atlas
(2) Tidal Diamonds"

In RYA Publication G12 -- the textbook published in 2010 to go with the new "Essential Navigation and Seamanship" beginners course -- nearly a page is devoted to Tidal Diamonds, and nearly a page to Tidal Stream Atlasses.

Anyone is entitled to an opinion about which is "best" or at which stage the other method ought to be introduced -- but not if their opinion is based on an assumption that is so blatantly false as your repeated insistence that the RYA do not recognise TSAs.

 

[timbartlett]

At 6 hours before HWD the current is flowing 236° i.e. directly towards the shore!

Looks to me more like the last of the ebb and the fresh water from the Tamar and Plym are making their way out of Plymouth Sound, and the bit you are looking at is where they curl their way round the breakwater.

If the data was as wrong as you suggest, I suspect the captains and navigating officers of some of the Grey Funnel liners that go in and out past that very spot might have had something to say about it by now.

But perhaps you could show us the "correct" data from the Tidal Stream Atlas for comparison?

 

[alant]

Why is use of diamonds 'correct' and tidal stream atlases incorrect? Because the RYA says so?

There are many instances where use of the diamonds can give totally the wrong answer. Some computer based tidal programs slavishly work out tide speed and direction from the nearest diamond and end up with a current flowing across a river!

Likewise saying a single tidal figure applies from exactly half an hour before to half an hour afterwards then jumps instantaneously to the next value can get you into some very odd results. If you interpolate you avoid that problem. Why is your method 'right' and mine wrong? Because that's the way the RYA does it?

And a question for you. If a current is changing and you take a single value for the whole of a 1 hour period, is that value the Mean, Mode, Median or Root Mean Square of the range of values that actually occur over that hour?

Please show me where I stated that diamonds are correct & tidal stream atlases are incorrect. I would not have made that gross error, since they are 2 different ways of displaying the 'same' information.

"Because the RYA says so?"

When did the RYA say so?

"Because that's the way the RYA does it?"

There is no RYA specific way, just the way it should be done & is done by everyone else, who uses Admiralty Charts.

http://www.youtube.com/watch?v=DzcbloPk6uE&feature=related

http://www.youtube.com/watch?v=roAvbAJmh8Q&feature=related

Many more videos in this suite, which might be useful to anyone on or going on a DS course.

Oh dear, he's using the RYA method!

 

[alant]

Springs & Neaps v Neaps & Springs

Looks to me more like the last of the ebb and the fresh water from the Tamar and Plym are making their way out of Plymouth Sound, and the bit you are looking at is where they curl their way round the breakwater.

If the data was as wrong as you suggest, I suspect the captains and navigating officers of some of the Grey Funnel liners that go in and out past that very spot might have had something to say about it by now.

But perhaps you could show us the "correct" data from the Tidal Stream Atlas for comparison?

Here's a question for you Tim, before someone accuses the RYA.

Why is the tide rate information on the diamonds given as Sp&Np, with the same information on a tida stream arrow, given as Np&Sp?

 

[RichardS]

Diamonds only give streams at a single point, the atlases and other tidal charts show how it flows over an area and allow one to interpolate. Here is an example. You are at the point marked inshore of anchorage 18. B, in the main channel, is the nearest diamond. At 6 hours before HWD the current is flowing 236° i.e. directly towards the shore!

If I remember rightly from my Yachtmaster evening course, we compared the charted tidal diamonds with the atlas.

There will be an arrow at point B in the atlas which, for a given time relative to HW, will correspond with the data for diamond B shown on the chart.

There might be another arrow nearer to the point where the boat is which would give a better guide than diamond B, or allow extrapolation between the two. However, there might not be an arrow on the atlas anywhere near where the boat is, in which case diamond B is as good as it gets!

The course showed us how to use both diamonds and the TSA which is presumably a good thing?

Richard

 

[Searush]

I've just read the whole thread . . . and wish I hadn't!



I'm glad I've never been near an "official" course, I couldn't stand all that pedantic bickering!

 

[Elessar]

Diamonds only give streams at a single point, the atlases and other tidal charts show how it flows over an area and allow one to interpolate. Here is an example. You are at the point marked inshore of anchorage 18. B, in the main channel, is the nearest diamond. At 6 hours before HWD the current is flowing 236° i.e. directly towards the shore!

atlases give streams at a single point too! In fact the point is the dot between the neap and spring rates.

If you look at the diamonds and compare it with an atlas you will see they will have an arrow at that point, and you will see the data is identical.

What you're saying is if you have a large scale atlas and small scale diamond chart there are more arrows and therefore more data. Yup, true. Doesn't make diamonds wrong as you're saying. You're just not comparing like with like.

Actually I prefer atlases because they give a visual overview that diamonds can't, but they are as accurate as atlases and they are another tool. All good navigators know how to use all the tools in their box.

 

[Elessar]

I've just read the whole thread . . . and wish I hadn't!



I'm glad I've never been near an "official" course, I couldn't stand all that pedantic bickering!

fibber. You'd love it.

 

[jimi]

I have'nt read all the thread, unfortunately but remember diamonds are forever, whereas only little boys shoot arrows in the blue..

I'll get me coat .. exits singing

"Little arrows in your clothing
Little arrows in your hair
When you're in love you'll find
Those little arrows everywhere
Little arrows that will hit you once
And hit you once again
Little arrows will hit everyone
Every now and then
"