GPS/ Chartplotter

[chappy]

I was on this sight a few months ago asking if GPS allows for tides, the answer was no & i should do a vecter triangle on the paper chart to get the correct course to steer allowing for the tides ( i now know how to do through a day skipper course). But what if i had a chartplotter instead, could that work out the tides & the course to steer with them?.
Cheers
Dave.

 

[muchy_]

With GPS you dont need to know the tides. It will give you your course to steer and as you make your way along this course it will tell you your cross track error which is what the tide is doing to you and it updates the course to steer as you go along. As long as you steer to keep the cross track error at zero you will arrive at your waypoint with any tidal effect taken out.
Having said all that you should still know what the tides are doing for your trip for safety sake and for making use of them etc.

 

[TigaWave]

It'll work but it wont always be the quickest way to get where you're going, like crossing the channel in 12 hours you can let the tide push you east and west, as the end result is roughly nothing....if you followed the chart plotter GPS's advice you would be putting some of your speed into fighting the tide at different angles as you went across.
For a point to point over an hour the gps is great as the tidal stream doesn't change much, so it will give you a real time heading for you current speed and whatever the tide is doing, but it cant predict your or the tides speed and direction in the future so for longer passages with varying tide and wind its information is of limted use.
Now I hope I havn't confused you....

 

[boatmike]

You will not get tidal vector calculations from a GPS and it would take a fairly advanced chartplotter to do it for you too although the answer to your question is yes. some will. Far better though is a laptop on the boat with a programme that will do all your route planning and tidal vector calculations for you and even tell you your best time of departure. I have Winchart Nexus from Chartwork UK myself which I think is about £350 now. But there are others. You will then need a chart with the area you sail. I have C-Map NT-link which gives you tidal vectors as well and you can buy an extra wide one for say the whole english channel for about £200. Then you need a laptop of course. The good news is you can plug your GPS into the laptop and it will show you precisely where you are on the chart... But it will cost you I am afraid...... Welcome to the world of electronic navigation!

 

[boatmike]

Which is all as much use as a chocolate teapot when trying to calculate your course to steer from Portsmouth to Cherbourg at any given time.....

 

[Talbot]

I have always been a fan of winchart Nexus, but dont like the dongle - a potential source of problems.

 

[boatmike]

Theres nothing wrong with my dongle old chum. Don't be personal!
Seriously though I think dongles are very reliable solid state devices but I don't like to have them sticking out of the side of my computer where they could be damaged. I therefore have a usb hub which takes my GPS, the C-Map Dongle, and the Nexus dongle velcro'd to the bulkhead where it is out of harms way with only the one USB port used for the cable from it. No chance of snapping off your dongle that way. Which would I agree be a potentially painful experience...

 

[Swagman]

[ QUOTE ]
Which is all as much use as a chocolate teapot when trying to calculate your course to steer from Portsmouth to Cherbourg at any given time.....

[/ QUOTE ]

IMHO not really - certainly not with all kit.

The SeaPro software will allow you to plot from any two N.European ports and put in your anticipated boat speed.

It will then give you a range of start and trip times for you to choose from taking into account tidal movement.

Once you choose best start time for you and trusty crew, it advises course to steer, and plots on the screen the course the boat will take as the tide pushes you this way and that........

As it does all this in less than 10 seconds, I personally found it much more useful that my chocolate teapot......

Cheers

JOHN