As with all aspects of navigation, following ‘best practice’ is the surest way to make sure you are passage planning in a seamanlike manner, says Bruce Jacobs
Rubicon 3 Adventure Sailing’s Bruce Jacobs shares his 8 tips for confident digital navigation.
1 Check the GPS settings
Is your GPS set to WGS84? Does it show true or magnetic? Is it accounting for variation? All of these settings can be changed (and may well have been by a previous skipper) so get into those settings and get things set up as you want them to be.
2 Always zoom right in on vector charts
When using vector charts always keep in mind that the dangers are hidden until you zoom in to the appropriate layer.
Don’t become a victim of unseen hazards.
Once you have your route in place, zoom right in and check, check, check.
3 Don’t put your waypoint on a hazard!
Yes, even a buoy is a hazard if you inadvertently drive into it. This really applies if you have turned on your autopilot and it is following a route.
If you ever get to this point it suggests you were not paying anything like close enough attention anyway.
4 Put your waypoints somewhere meaningful
With GPS charting it is particularly easy to be lazy in placing your waypoints.
Will you really head two miles past a headland before turning, or should that waypoint be much closer in?
If you’re cutting corners on your route, you’re in unchecked territory.
5 Know your distances
If using your GPS as an anchor alarm, make sure you know how far you can move before you wish the alarm to sound.
0.1nm is 185m, so depending on your anchorage you should probably be setting your alarm for less than a quarter of this.
6 Remember GPS is not infallible
Especially if you are in a tight, hilly area the accuracy of GPS can be off by quite a few metres.
If you are piloting through a narrow channel, this could be the difference between staying in deep water and hitting a rock.
Nothing beats the Mark 1 eyeball and a lot of common sense.
7 What does it mean in the real world
It is easy to feel that you’re a safe distance from a hazard when looking on a zoomed-in Vector Chart.
But you can often look up, or go on deck to see that you feel much closer than you thought.
It is always worth keeping your head out of the boat and looking up from the screen to take a real-world view.
8 Keep updated
One of the most useful aspects of digital charts is the ability to keep them up to date.
A chart is only as good as its last survey, but around much of the UK, hazards do move regularly.
Keeping your charts up to date is vital whether paper or digital, but making notes is not yet an option on digital charts