Route Optimum Departure Time

[MikeKolling]

Hi

Sorry if this has been asked before.

Is there any plugin or addon that will enable you to enter the route and calculate the best time to leave based on Tides and Winds?

I use SavvyNavvy that has this (and in the past used Neptune)

Thanks in Advance

Mike

[Dockhead]

Originally Posted by MikeKolling

Hi

Sorry if this has been asked before.

Is there any plugin or addon that will enable you to enter the route and calculate the best time to leave based on Tides and Winds?

I use SavvyNavvy that has this (and in the past used Neptune)

Thanks in Advance

Mike

I've used Neptune for this in UK waters. Very interested if this could be replicated in O.

[Be Free]

Originally Posted by MikeKolling

Hi

Sorry if this has been asked before.

Is there any plugin or addon that will enable you to enter the route and calculate the best time to leave based on Tides and Winds?

I use SavvyNavvy that has this (and in the past used Neptune)

Thanks in Advance

Mike

The weather routing plugin has a feature that will do this for you. It will take wind and current into account. I don't think is has any provisions for tide.

[Dockhead]

Originally Posted by Be Free

The weather routing plugin has a feature that will do this for you. It will take wind and current into account. I don't think is has any provisions for tide.

But tide, tidal currents, is the whole point, the main problem.

The classical problem is an English Channel crossing where you have alternating currents and can't cross efficiently without determining the right CTS, which is laborious and inaccurate when done by hand.

What Neptune does is give you two extremely valuable sets of outputs based on a point of departure and point of arrival across tidal waters:

1. Generates a CTS for any given departure time based on your assumed passage speed.

2. Gives you optimal departure time.

It's a good system, but it only works for UK waters, and it would be nice to have something which integrates with O.

https://www.neptune-navigation.com/

[Gilletarom]

Hello,
IF you post here, on the OpenCPN forum, it is because you use OpenCPN.

However, there already exists an OpenCPN plugin that does this if you know how to use it: It's Weather-Routing (WR).

- You must have a Grib file which provides the wind and current data that WR knows how to use very well
- Add the use of the OpenCPN Draw plugin to build boundaries covering areas in which you should not navigate. Boundary that WeatherRouting knows how to use very well.

- Create a start point and end point in WR
- Create a route search configuration between these two points.
- Run the calculations to do a first try.
- Start creating a batch of several searches by indicating the departure time difference between each search and the number of searches you want.
- Start the calculations.

You will get as many possible routes and you can choose the one that suits you best.

[Dockhead]

Originally Posted by Gilletarom

Hello,
IF you post here, on the OpenCPN forum, it is because you use OpenCPN.

However, there already exists an OpenCPN plugin that does this if you know how to use it: It's Weather-Routing (WR).

- You must have a Grib file which provides the wind and current data that WR knows how to use very well
- Add the use of the OpenCPN Draw plugin to build boundaries covering areas in which you should not navigate. Boundary that WeatherRouting knows how to use very well.

- Create a start point and end point in WR
- Create a route search configuration between these two points.
- Run the calculations to do a first try.
- Start creating a batch of several searches by indicating the departure time difference between each search and the number of searches you want.
- Start the calculations.

You will get as many possible routes and you can choose the one that suits you best.

A post above suggested that the OpenCPN plugin does NOT indeed consider tidal currents. Is that true, or not? If not, then this does not indeed do what people are asking for.


If it does -- what tidal current data is used? Neptune uses the high resolution commercial model with granularity I believe of 6 minutes.

[P_Dub]

Otidalplan of Mike does it.
Bye.

[Gilletarom]

Originally Posted by Dockhead

..........

If it does -- what tidal current data is used? Neptune uses the high resolution commercial model with granularity I believe of 6 minutes.

The original question is repeated here. We want a Plugin capable of proposing a route based on external data (winds and currents, among other things.) I persist and sign. In other words, my preliminary response is adapted to the problem posed. But, I will provide more precision. On the one hand, I sail in the English Channel, mainly on the French coasts, but I sometimes cross the English border; For example, I was recently in Jersey.

In this area, I use the "Openskiron" grib files:

https://openskiron.org/en/openwrf

These files contain a lot of data including obviously the wind, the gusts but also the currents due to the tides in the Channel. See first screen copy

What's in the GRIBs The openWRF GRIBs include the following data: Wind at 10m (velocity & direction) Surface tastes Pressure corrected to MSL Accumulated precipitation Snow depth Total cloud coverage Relative humidity Surface temperature CAPE Simulated RADAR Reflectivity Significant wave height Swell height Swell direction Swell period Wind wave height Wind wave direction Wind wave period Sea current velocity & direction

To build a route, there are two methods:

1° the method automated by the WeatherRouting plugin (Alias WR).
2° the manual method


1° : With WR :
The WR plugin (Version 1.14.x) allows, as a first use, to create a track, a starting point, an arrival point and a departure time. We obtain a route weather report which shows the route and gives on the one hand a duration of the journey and on the other hand, obviously, an arrival time.
You must then export this track to the OpenCPN track manager. After which, you must, in the routes and tracks manager, transform this track into a route.

Ok, the method is long for those who are not used to it, but it works.

Still in WR, there is a "Batch processing" option which allows you to obtain several routes with the same starting point and the same ending point, but not the same departure time. See second screen copy.

So, not necessarily the same duration or the same arrival time.

With this option, WR offers the fastest route, but you are not required to use it. You can use any route from those built by WR.


2° If you build your route manually:

The WR plugin also offers an option allowing you to evaluate a manually constructed route and to know, for a given time, the duration of the journey and the arrival time. In fact, and if you allow me, I won't go into more detail here on this subject. You really have to know how to operate WR to use it.


BUT, DID I UNDERSTAND YOUR ORIGINAL QUESTION?

- The Otidalplan plugin from Mike (Rasbats) seems to answer your question. But, I haven't used it and I can't say anything negative or positive about it.

- In OpenCPN, there is a "Currents" option but the data it uses cannot be used with WR and apparently with Otidalplan.

- MIKE has also created a new plugin, frcurrents which uses data from SHOM to display beautiful pages on currents on the French coasts. This plugin does not allow you to evaluate the interest of a route to determine the best departure time for a manually created route.


REGARDING THE FUTURE OF WR:


I managed to show Mr Dave Register that WR:
- contained operating faults which deserved to be corrected,
- needed to be simplified.

WR fixes are currently being tested that will make WR easier to use.

In the current state of the tests, it will certainly also be necessary to modify the OpenCPN route managers.

So we will wait for the next version of OpenCPN for this.

[Gilletarom]

Originally Posted by Dockhead

........

If it does -- what tidal current data is used? Neptune uses the high resolution commercial model with granularity I believe of 6 minutes.

Please, Dockhead, what is Neptune ?

Thank by advance.


Gilletarom

[Rasbats]

Originally Posted by P_Dub

Otidalplan of Mike does it.
Bye.

This plugin only uses tidal current harmonics. It is suited to areas where many tidal current harmonics are available. Not suited to European waters imo.

OtidalRoute (not 5.8.4) was an experiment using tidal current gribs to plan a number of routes, which could be inspected for best departure time, based on the current. Wind data was not used.

Mike

[CarCode]

@Gilletarom
If you really want such a feature use qtVlm:
https://www.meltemus.com/index.php/fr/download

[P_Dub]

I agree with you Mike, for small speed (such as 6 knots) it as probably little value. But for speed such as 10 or more, it is probably fairly acceptable. I have made more current point in the English Channel and things seems to be different depending we use Dover or Brest (like the France gribs).

[Dockhead]

Originally Posted by Gilletarom

Please, Dockhead, what is Neptune ?

Thank by advance.


Gilletarom

https://www.neptunenavigation.co.uk/plotter%20plus.htm

[wholybee]

Originally Posted by CarCode

@Gilletarom
If you really want such a feature use qtVlm:
https://www.meltemus.com/index.php/fr/download

I would really like a decent tutorial/demo of qtVlm. It looks very good, but as a pretty advanced user of OpenCPN, I can't wrap my head around it at all. The terminology seems wrong, like routes and waypoints seem to mean different things and work totally differently. And there are routes and routings, and I don't understand the difference, and neither is similar to a route in OpenCPN, Navionics, or any other software I have used. And something simple like creating a route (like OCPN has) I couldn't figure out how to do and gave up after an hour of trying.

It seems to have some great racing features, and if you know how it works I'm sure it is easy enough, but it is just such a different way of working I am completely lost. And the manual was no help.

[LeaseOnLife]

this has helped me to get used to qtVlm:
https://www.starpath.com/qtVlm/