Secondary Ports, Estimated Position, Course to Steer

RichardS

RichardS

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Piotaskipper's helpful recent "decision tree approach to ColRegs" aid to RYA students reminded me that I'd written a spreadsheet approach for secondary ports, estimated positon and course to steer which I used when I took the Yachtmaster exam last year.

They're designed to make sure that the corrections are done in the correct order for the northern hemisphere using the fictional RYA charts and time zones. However, they can be applied to the real world as well.

For the RYA course I used paper versions of the spreadsheets as I obviously couldn't use a PC in the exam although the spreadsheet version of the Secondary Ports spreadsheet does the calculations automatically if you enter the data onscreen.

If they help anyone understand the principles (or pass the exam!) please feel free to print them out.

If you want to edit them or if any maths-junkies out there want the self-calculating secondary ports Excel spreadsheet (if you feel it's important to get a result that is precise to as many decimal places as you like!!), please add a post and I'll sort out a zip version as I don't think I can attach xls files.


Richard

PS It turned out to be trickier than I expected to attach even pdfs as the maximum file size for pdfs is pathetically small. I've therefore had to attach zips even though they are no smaller!
 
Self calculating sec ports.

If you would be so kind as to e-mail me a copy of the self calculating secondary ports spreadsheet I would be most grateful.

My e-mail address is martin@activesail.com

Thanks for sharing your spreadsheets with the mathematically challenged.:D
 
Many thanks to those who've expressed an interest in the spreadsheets. I'll contact the PMs separately.

I've attached zip files of the excel sheets so anyone can edit them to suit their purposes.

The Secondary Ports spreadsheet will do all the time and height calculations itself. You only need to enter the data from your almanac into the red cells.

Times must be entered with a colon i.e. 18:44 rather than 1844 otherwise excel cannot distinguish between hours and minutes.

Secondary ports time differences must be entered as minutes, either +ve (no sign required) or -ve (sign required) i.e. you enter -15 rather than -0015. This is because excel does not recognise the concept of negative time! Just enter the number, the "mins" is added automatically.

Heights are entered as numbers, no sign or -ve sign. Once again, don't enter the "m" as this is automatic.

There are reminders for all this on the spreadsheet and you will soon know if you enter anything incorrectly.

You can also hide the rightmost 2 calculation columns if you wish. This looks neater and hides all the maths away from sight.

This spreadsheet worked for all the test papers on my RYA course but if you find a glitch please tell me and I'll sort it out. Also remember it's free so if you calculate that clearance to 3 decimal places (this is not the default setting!) and believe that it's really that accurate it's not my fault if you crunch your keel!

Good luck

Richard
 
RichardS said:
Times must be entered with a colon i.e. 18:44 rather than 1844 otherwise excel cannot distinguish between hours and minutes.
Click to expand...

I struggled over that one for a while but I managed to get Excel to understand times in '1844' format. I actually wrote my secondary port spreadsheet in OpenOffice but it works well enough in Excel.

The secret was to specify the format with a minimum of four digits then hide the hours & minutes in hidden columns.
 
sailorman said:
suggest you remove your email address ;)
Click to expand...

Thanks for your concern and advise sailorman.:)

The e-mail address in question is published on my website, therefore people can already see it and use it. The reality is very few actually bother, I just get the odd spam.

Thanks for the downloads Richard, I am sure they will be very useful.

Cheers Martin.:D
 
It's taken me a while to get around to it, but I took Porthandbuoy's advice. Here's an example of my secondary ports spreadsheet.


http://www.4shared.com/file/226977700/d6511935/DublinTidesMar.html

This one is for Dublin for March 2010. I used Dublin because Arklow as a secondary port was a bit of a challenge and March because it tested the GMT/BST logic.



You only need change the salmon coloured fields. The others shouldn't be changed but are not locked so can be accidentally overwritten.

You can copy and paste a secondary port sheet and create a new secondary port in minutes. Again just update the data in the salmon coloured fields.

It can be modified for other primary port/secondary port combinations. Again, the salmon coloured fields on the primary port page show what has to be changed. And of course data can be entered for a different period.

There is a documented 'feature' that you have to start with a LW as the first tide on the primary port page. I haven't got around to fixing that and quite possibly won't.

The overview sheet can work out the dates when the data changes, but can't drawn the lines in different places, so you do need to do a little format painting to tidy it up.

The "Charts" sheet is a bit of a dead end. I was trying to see if I could get it to draw tidal curves, but it's a lot of work.

If you spot any errors in the calculations please let me know, with a copy of your working of course.
 
RichardS said:
Piotaskipper's helpful recent "decision tree approach to ColRegs" aid to RYA students reminded me that I'd written a spreadsheet approach for secondary ports, estimated positon and course to steer which I used when I took the Yachtmaster exam last year.

They're designed to make sure that the corrections are done in the correct order for the northern hemisphere using the fictional RYA charts and time zones. However, they can be applied to the real world as well.

For the RYA course I used paper versions of the spreadsheets as I obviously couldn't use a PC in the exam although the spreadsheet version of the Secondary Ports spreadsheet does the calculations automatically if you enter the data onscreen.

If they help anyone understand the principles (or pass the exam!) please feel free to print them out.

If you want to edit them or if any maths-junkies out there want the self-calculating secondary ports Excel spreadsheet (if you feel it's important to get a result that is precise to as many decimal places as you like!!), please add a post and I'll sort out a zip version as I don't think I can attach xls files.


Richard

PS It turned out to be trickier than I expected to attach even pdfs as the maximum file size for pdfs is pathetically small. I've therefore had to attach zips even though they are no smaller!
Click to expand...

While they obviously work for you, can't help but think your over-egging fairly simple navigation tasks.

Whilst secondary port calcs, require use of a tidal height curve, both CTS & EP's are best by simply drawing them on your chart as generations of seamen have done. All you need to consider, is the tidal hour(s) in order to determine set/drift. Just constructing a tidal hour ladder on a convenient section of the chart, will allow easy reference, without looking for 'spreadsheets'.
Jotting the times from HW +/- into the relevant tidal atlas, is even easier.

Secondary ports, only need 3 bits of information, which are HW ht/LW ht/HW time, at secondary port, then enter into standard port tidal curve. What could be easier?
 
alant said:
While they obviously work for you, can't help but think your over-egging fairly simple navigation tasks.
Click to expand...

Agreed - it was more of an academic exercise because I use spreadsheets at work and at the time I did my Yachtmaster shorebased I thought "I bet loads of people have automated these calculations" but when I searched the web I couldn't find a single example. I wondered if it was more difficult than I had assumed so I had a go. Although there were some issues regarding "negative times" in Excel, it wasn't that complicated.

Since my actual sailing is in the Med, the results are even more academic! ;)

Richard
 
RichardS said:
Agreed - it was more of an academic exercise because I use spreadsheets at work and at the time I did my Yachtmaster shorebased I thought "I bet loads of people have automated these calculations" but when I searched the web I couldn't find a single example. I wondered if it was more difficult than I had assumed so I had a go. Although there were some issues regarding "negative times" in Excel, it wasn't that complicated.

Since my actual sailing is in the Med, the results are even more academic! ;)

Richard
Click to expand...

Ahh!

Unfortunates are now however, being lead down that dead end street, on the assumption that this is 'the way' to now do it! :rolleyes:

Very emporers new clothes.
 
HI

tried to download your spredsheet about sec ports but it is no longer there. Would you mind sending me the file via email

thx
MArcus
 
newbee

Richard i am new to this site and was wondering if you would be so kind and send me the excel version on secondary ports, my email is s.gowen@sky.com
I am shortly taking my coastal skipper theory and this would help greatly
Stephen


RichardS said:
Piotaskipper's helpful recent "decision tree approach to ColRegs" aid to RYA students reminded me that I'd written a spreadsheet approach for secondary ports, estimated positon and course to steer which I used when I took the Yachtmaster exam last year.

They're designed to make sure that the corrections are done in the correct order for the northern hemisphere using the fictional RYA charts and time zones. However, they can be applied to the real world as well.

For the RYA course I used paper versions of the spreadsheets as I obviously couldn't use a PC in the exam although the spreadsheet version of the Secondary Ports spreadsheet does the calculations automatically if you enter the data onscreen.

If they help anyone understand the principles (or pass the exam!) please feel free to print them out.

If you want to edit them or if any maths-junkies out there want the self-calculating secondary ports Excel spreadsheet (if you feel it's important to get a result that is precise to as many decimal places as you like!!), please add a post and I'll sort out a zip version as I don't think I can attach xls files.


Richard

PS It turned out to be trickier than I expected to attach even pdfs as the maximum file size for pdfs is pathetically small. I've therefore had to attach zips even though they are no smaller!
Click to expand...
 
Spreadsheets etc should be banned from RYA lessons and exams. Just do it on paper,when you can do it properly,run away and fiddle with your gadgets.
 
steve gowen said:
Richard i am new to this site and was wondering if you would be so kind and send me the excel version on secondary ports, my email is [COLOR="Red"]SPAM sky.com[[/COLOR]/email]
I am shortly taking my coastal skipper theory and this would help greatly
Stephen[/QUOTE]

i hope you calculations are better than your internet savvy :rolleyes:
Click to expand...
 
alant said:
While they obviously work for you, can't help but think your over-egging fairly simple navigation tasks.

Whilst secondary port calcs, require use of a tidal height curve, both CTS & EP's are best by simply drawing them on your chart as generations of seamen have done. All you need to consider, is the tidal hour(s) in order to determine set/drift. Just constructing a tidal hour ladder on a convenient section of the chart, will allow easy reference, without looking for 'spreadsheets'.
Jotting the times from HW +/- into the relevant tidal atlas, is even easier.

Secondary ports, only need 3 bits of information, which are HW ht/LW ht/HW time, at secondary port, then enter into standard port tidal curve. What could be easier?
Click to expand...

+1

PS,
Don't forget the LW curves around the Solent area.
 
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