RYA Navigation Exercises

[MedDreamer]

Is anyone out there using the RYA Navigation Exercises Book to assist in their Day Skipper/Yachtmaster Theory?

I bought it a few weeks ago so that I could get some additional practice.
this weekend I was manfully working through section 8 - Tidal Streams and Heights. Question 8.11 is about Tidal heights ant Secondary ports and on 8.11a and 8.11b they have got the bloody answers wrong!!! - They have crossed over the times for HW and LW.

If they can't get it right what chance do we poor students have - perhaps I should stick to the Lake!!

Also can anyone explain why on the Chichester Tide thread two correspondents had differing figure for the date in question (27th December I think). Low water varied by 1/2 metre which could be critical at LW I would have thought. Do different almanacs/sources have different figures or did one of the posters get it wrong?

Martyn





<hr width=100% size=1>Do you think a Fleming 55 would look out of place on Windermere?

 

[Talbot]

Frequent that 2 different programmes get different answers for the tide times/heights, and in any case different met conditions can make a diference as well so trying to be accurate to the minute is a real waste of time - you shouldnt be cutting it that fine.

<hr width=100% size=1>

 

[MedDreamer]

I understand and agree but it strikes me that 1/2 metre is a bit more than "cutting it fine" or is that within normal range?

Martyn

<hr width=100% size=1>Do you think a Fleming 55 would look out of place on Windermere?

 

[BrendanS]

Re: Tidetables

Tides predictions are exactly that. Predictions. Hence not accurate.

As one of the posters, I can tell you I did not make a mistake, as I cut and pasted directly Source was Belfield tide plotter. A thread on scuttlebutt some time back raised same issue, and several sets of numbers were produced for same location and day from different sources.

<hr width=100% size=1> I asked an economist for her phone number....and she gave me an estimate

 

[MedDreamer]

Re: Tidetables

Brendan

All my tidal work to date has been theory so it is interesting to see how imprecise the science is - once again this forum has expanded my knowledge beyond the text book.

Much rather learn about this on here than by trying to enter Chichester half an hour too learly/late at March or September springs.





<hr width=100% size=1>Do you think a Fleming 55 would look out of place on Windermere?

 

[BrendanS]

Re: Tidetables

Too right! One of the other things that doesn't get much coverage in the text books, is the effect of pressure. OK they briefly mention it, but Tide tables usually assume a standard pressure of 1013 millibars. This means that a pressure of 1040 mb, pretty high but not abnormally so, will cause level to be 30 cms lower than expected

<hr width=100% size=1> I asked an economist for her phone number....and she gave me an estimate

 

[hlb]

it's why I got sick of doing the day skipper thingy after ten years of sailing to Ireland Scotland and Wales. Just was not dumb enough just to answer there fool questions. Mostly irelivent anyway. It would probably do you alot of good if never been on the sea. But IMHO Teaches you a dam site more about doing exams than real life.

<hr width=100% size=1> <font color=blue>No one can force me to come here.<font color=red> I'm a volunteer!!.<font color=blue>

Haydn

 

[tr7v8]

Martyn,

read the headings carefully they are in 2 different places /forums/images/icons/smile.gif

And yes I made the same mistake!!!

Tides at Chi Marina 27 Dec

AND

Chichester Harbour Entrance
Saturday, 27 December 2003





<hr width=100% size=1>Jim

Draco 2500

 

[johnwest]

Re Chichester tides.

One set of figures is for the harbour entrance.

The other set is for the lock at Chichester Marina, which was the original question.

<hr width=100% size=1>

 

[gjgm]

ah I thought they were being helpful and giving you both the entrance and the marina...
i ve just finished the chartwork part of yachtmaster, and I confess my aim was broader knowledge and so safety. The course was supposed to updated with more electronics this year, but i believe the RYA hit some snags in the coursework, so its postponed. If you havent read it, i d recommend the new updated RYA book on navigation.. about £12. It gives a much more realistic approach to the matter..as BrendanS says, the whole thing comes down only to predictions (and estimated position), and that isnt the same as fact- a good point in the book. As our tutor likes to say, the best navigators are only those who are making fewest mistakes!I ve found the value in calculating to 10cm depth and 100m distance pretty ***** pointless really with gps and depth sounders, when the whole manual process being based on assumptions. but admit I ve learned more about passage planning, and i wouldnt suggest there is no value in at least understanding the techniques.I think the course will be much better when its updated, and the traditional skills are married with the modern technical options.
Meanwhile, being based in Chichester, I d rely very closely on the depthsounder ! Judging by the number of groundings, so should a few others...

<hr width=100% size=1>

 

[jimi]

Re: Tidetables

Or the effect of different wind directions both on height and timing!

<hr width=100% size=1>.. when's that again, but ..

 

[alby50]

hi anyone i have just completed the essential navigation course and have purchased chris slade 2nd edition of navigation exercises i have got to exercise 2
what charted features are to be found at the following positions i came accross 46 degrees 20.94n 6degrees 04.57w when i plotted it i came up with anchoring prohibited but it said the answer was yacht harbour marina a bit confused as i have checked this several times and come up with the same answer chart 3 is it wrong or am i missing something i got all the other plots correct thank you

 

[alby50]

Is anyone out there using the RYA Navigation Exercises Book to assist in their Day Skipper/Yachtmaster Theory?

I bought it a few weeks ago so that I could get some additional practice.
this weekend I was manfully working through section 8 - Tidal Streams and Heights. Question 8.11 is about Tidal heights ant Secondary ports and on 8.11a and 8.11b they have got the bloody answers wrong!!! - They have crossed over the times for HW and LW.

If they can't get it right what chance do we poor students have - perhaps I should stick to the Lake!!

Also can anyone explain why on the Chichester Tide thread two correspondents had differing figure for the date in question (27th December I think). Low water varied by 1/2 metre which could be critical at LW I would have thought. Do different almanacs/sources have different figures or did one of the posters get it wrong?

Martyn





<hr width=100% size=1>Do you think a Fleming 55 would look out of place on Windermere?

yes martyn i am and have come across this
i have just completed the essential navigation course and have purchased chris slade 2nd edition of navigation exercises i have got to exercise 2
what charted features are to be found at the following positions i came accross 46 degrees 20.94n 6degrees 04.57w when i plotted it i came up with anchoring prohibited but it said the answer was yacht harbour marina a bit confused as i have checked this several times and come up with the same answer chart 3 is it wrong or am i missing something i got all the other plots correct thank you

 

[MalH]

Hi, I have the navigation Exercises and the answer in my book is Anchoring prohibited, which is correct.

 

[Alex1233]

Hello,I am using the RYA Navigation Exercise book and I am stuck on Exercise 10.2 (b) (Approximately how long will it take for the vessel to reach the buoy?). I am trying to figure how in the working out of the answer they got SOG to be 7.3Kn. They have used 6.3Nm for the distance to the buoy divided by SOG which is 7.3Kn . The working out looks like this 6.3Mx7.3Kn x 60=52 minutes.

They mention the set and drift of the tide is 150(T) at 1.6Kn which I have taken into account when plotting my course to steer.
The true course to the buoy is 110(T) with variation 7W. The magnetic course therefore being 117(M).
In part a) of the question they mention the boat is travelling at 6Kn.


The answer is probably obvious and It's probably something I am missing. .
Any help would be greatly appreciated