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DR is when you only take into account direction and distance. EP is when you then allow for tidal flow.

Also avalible on Google Play - www.navionics.com/gbr/apps/navionics-boating although there are now more apps that work in a similar way on the market.

There is software that does this however more often than not, when near land there are reasons why this does not work. For example, if you a half way between a diamond in a river mouth and one in open water the tide you experience is unlikely to to half way between the two as the river effect is likely to be localised. The best approach is to simply use the closest or most appropriate diamond to where you are.

The range of the tide and the time of high water and low water is not the same each day. These are driven by the relative position of the moon (and to a lesser extent the sun). Fir example, here in Penzance tide time move forward by around an hour each day. When high water is around 06:00 and 18:00 (we have two high waters a day) we have spring tides and when high water is around 00:00 and 12:00 we have neap tides. Spring tide having a larger range than neap. The secondary port adjustment is different (generally greater) for spring tides compared to neaps. We can therefore calculate the size of the adjustment based on the time of high water.

@@pzsc thank you. I thought it was unusal to make an ajustment for time of high tide. But its just an ajustment for spring or neap nothing unusual there. I was starting to think it was to do with the position of the sun.

Firstly it is never going to the exact but if we can stay close to course it is always going to give a more accurate position. If you do go off course it is best to the helm to be honest and make the best judgement of the actual bearing followed. It is then even more important that you allow for a larger margin of error.

You can simply do all calculations using either spring or neap rates. On one hand this will save you a lot of time as you simply need to calculate whether on the day in question you are closer to heaps or spring. However, on the other hand (and very importantly), this is not as precise as calculating a more precise rate (it will never be exact) for the day in question. This second option, will take a little more time but; particularly in areas of large tidal ranges; this can make a significant difference.

@@pzsc Yeah I can’t say that in my OOW3000 Oral.

I've just signed uo for it today Alec, online version. What was the hardest part?

@@AttitudeCharter finding the time and concentration to do it

RYA Training Almanac. They are totally made up and cannot be used in the real world. They work with RYA training chart 3 and 4 (also made up).

@@pzsc what does that mean " they are totally made up and cannot be used in the real world"?

@@michaelsrowland this almanac is designed for use of RYA training courses. In the real world we would use an almanac life this www.gaelforcemarine.co.uk/Mobile/en/Reeds-Nautical-Almanac-2021/m-m-7580.aspx?PartnerID=268&gclid=CjwKCAjwlYCHBhAQEiwA4K21mxo6l4ZZxKFjcSWPj2rWkYiVPaiRc5gE-R8cUMm40-aDvsN-kjzHtxoCOB0QAvD_BwE

Many thanks for this. I have added a correction to the video description.

@@pzsc Thankyou for the correction, that had me stumped for a bit! Very much love the content though as this is an incredible help towards my Yachtmaster exam!

The table of values in the almanac are in the standard time zone for the port. If you make the change to DST and then use the table you are using a table in one time zone and a time from another. In some locations this might be a minor difference however in others (where there are big differences between the adjusted values) this error could be significant.

@@pzsc Hi thanks for getting back to me. So if the Q was in DST ( Q,,What is the tidal stream for the hour of 15.00 DST till 16.00 DST ), would you convert back to UT to agree with the Almanac, then back to DST again at the end of your workings out ?. I'm very interested in the workings out of these problems and appreciate there is usual more than one way. I hope to do YM next year so i'm a bit keen, many thanks.

@@graemebaxter9455 hi - Yes, convention should be completed in UT (or the standard time for the convention table).

Yes, this is correct. This difference could be taken as +5 for any time between 0000 and 0600 and the above calculation is not needed. It is also true that if the correction are not the same and if you at calculating for 0300 (exactly half way between 0000 and 0600) you can go half way between the corrections shortcutting the above calculations.

@@pzsc Thank you

Have a look at this page where we explain how to do this for more that one hour - pzsc.org.uk/shorebased/coursetosteer/

No, but we can approximate the surface of the earth as being flat over small distances.

@@pzsc thanks for the reply, what distances we talking about, couple of miles squared, few hundred miles?

Across the English Channel would be fine (50-100 nm), if you are going further then look into Ocean Yachtmaster.

@@pzsc 8 inches of curvature per square mile, that's almost 784 meters difference... just under a km?? just trying to debunk something here...

It will depend on the make of the radio. Some can be reset, others might need to reset by a service agent or the manufacturer.

yeah but you just have to learn to visualize everything, I know its hard in this case but I can manage. I literally have to envision turning a compass dial in my mind when adjusting true/magnetic bearings otherwise i would hit the rocks.

You need to look up the tide times (high water times) for the standard port, you will find the name of the port above the tidal diamonds table. For example if high water at the standard port is 11:30 and you are calculating for 08:30, this is 3 hours before. 14:30 would be 3 hours after.

Thank you for the comment. In theory there is a Tidal Diamond for all the water on the chart. In open water (away from land) you can simply use the closest Tidal Diamond and therefore that Diamond may cover a very large area. This is not an exact science however will be good enough for most uses and will be more provide closer to the survey points. Once you get close to land you need to apply some common sense as to which Diamond to use. For example, in an estuary entrance it may be better to use the Diamond further up the estuary rather than a diamond in more open water out to sea from the estuary. Hope this helps.

@@pzsc ok thanks your answer is highly appreciated I hope that you can demonstrate and explain more about nautical sciences so that I can use your channel for my students online class. It will bring more people in your channel.

Graeme Baxter sorry for the slow reply. On the worksheet the bottom I am happy with the label “sea bed”. The reason for this is that in this example you are not concerned with CD. You just want to know what depth of water you should anchor in such that after the tide has dropped to low tide there will still be enough water.

@@pzsc thanks a mill'

Francis Montocchio Thanks for the comment - this May help: pzsc.org.uk/shorebased/leeway/

​@@pzsc Thanks for your speedy reply! I knew about measuring the wake angle, but I was wondering if there was a guide to approximation according to wind strength, hull type and point of sail? Cheers!

Francis Montocchio No hard and fast rule other than old slower boats likely to make more leeway. The bearing allows you to build a picture with experience.

@@pzsc Thanks!