Modern coastal route planning

[prv]

I remember a well respected yacht designer and contributor to Yachting magazines telling of a gentle trip down west and back describing the nav as being of the "Keep the land on the right going and the land on the left coming home"

Thats pretty much how it can be in familiar waters.

Or even in unfamiliar waters if offlying rocks and shoals are rare.

I plan things a bit more closely amongst the Channel Islands

Pete

 

[dilly]

How often would you place a waypoint

 

[dilly]

Say on a straight passage say from Dale to Lundy how meny waypoint s would you put

 

[prv]

Say on a straight passage say from Dale to Lundy how meny waypoint s would you put

I don't know the area at all, but I imagine probably just the one, at Lundy itself. And that mostly just to have a handy "are we nearly there yet?" figure rather than to base all my navigation off.

It's across the mouth of the Bristol Channel, so I assume the tides are quite strong and I'd work out a proper course to steer just as I do for crossing the English Channel. So this is an occasion when I would have drawn some lines on the chart, and early in the passage I'd be plotting fixes and checking they were roughly where I expected (which might not be on a straight ground track, depending on what the tide was doing). Towards the end of the crossing I'd shift more to using the plotter, putting the green track line over my destination and steering to keep it there. If using the autopilot I might put the plotter cursor over my destination and tell the pilot to steer there - essentially doing the same as the previous sentence but automatically. This is a waypoint of sorts, but only a temporary one. The non-electronic equivalent of course is a transit, using whatever handy features the island might have, but the plotter's green line works from further out when the land is just a grey silhouette

Pete

 

[laika]

I should probably elaborate a little more.

I define a "route" as a series of courses to steer between "pilotage" at each end (and possibly in the middle too in tricky places).

I'm unaware of an official distinction between "pilotage" and "route planning" but I regard the former as the latter in miniature, where points in the "pilotage plan" are no more than a few hundred metres apart, each probably visible from the previous, and where the tide doesn't change appreciably in the time it takes to go from one point to the next.

If there are no hazards between the start and end points you don't need a "route", it's just a single course to steer.

I used the term "waypoint" to describe the points at which you change from one course to steer to the next. Vertices for those who enjoy directed graphs . This doesn't necessarily mean a datapoint in a chart plotter: it could be a point marked on a paper chart. Those saying they don't put waypoints on top of buoys in case they hit them are probably equating "waypoints" with data points in a chart plotter rather than my more abstract notion.

There is an implicit assumption here of passage planning "The RYA way". If you don't do that but instead just "Keep the land on the left/right and watch for hazards on the plotter" this doesn't apply (Missing option: "I don't plan routes"?).

More often than not, as previously pointed out, your points of changing course will be associated with a physical feature. Between Gosport and Brighton your waypoints are probably the gap in the submarine barrier off southsea and the Looe channel, both marked. In other cases there may be overfalls between A and B which aren't marked but you'd like to avoid. The quickest way may be to mark a GPS between A and B which takes you round the overfalls. If you didn't have GPS you'd need to find a physically identifiable point C which had a safe straight line from both A and C. Going via C will be longer. You may chose to use a waypoint at C even if you do have GPS: that's pretty much what this question is about.

Using physically identifiable waypoints in route planning doesn't preclude using GPS as a navigational tool. You might plan waypoints according to physical marks and then use GPS to navigate to them. If I want to get someone quickly I may well use GPS to see how well my leeway/tide estimations matched reality and modify CTS accordingly (NOT the same as making SOG equal to BTW).

So the "route planning" question does make assumptions (more than I thought) but it isn't simply a "do you use GPS to navigate" question.

 

[prv]

More often than not, as previously pointed out, your points of changing course will be associated with a physical feature. Between Gosport and Brighton your waypoints are probably the gap in the submarine barrier off southsea and the Looe channel, both marked. In other cases there may be overfalls between A and B which aren't marked but you'd like to avoid. The quickest way may be to mark a GPS between A and B which takes you round the overfalls. If you didn't have GPS you'd need to find a physically identifiable point C which had a safe straight line from both A and C. Going via C will be longer. You may chose to use a waypoint at C even if you do have GPS: that's pretty much what this question is about.

My answer to just about everything in this thread is "it depends" . Mostly on the geography, but also the tides, my familiarity with the area, the weather, the time of day, the crew, and my mood. I don't have one specific way of planning (or not planning) a passage which I use in all circumstances. Not even a binary choice of "plan" / "don't plan", it's a continuum, and it may vary over a passage too. Boats move slowly enough that I don't need every last detail worked out in advance, even if I'm intending to work out a formal CTS I'll often leave it until we're under way and I've got a feel for the actual conditions and hence our likely speed. For a Channel crossing we typically start cooking the bacon in the Needles channel, get the butties on deck somewhere round the Bridge buoy, then once we've eaten and cleared away we're a little way south of Fairway and I'll go below and work out the course

On the specific question above, it depends on how far out of the way C will take us. I like to tie my navigation to the real world when possible, so if there's a buoy or something we can conveniently head for with perhaps a small detour then I'll do so. But I won't go a long distance out of the way just to prove the point.

Pete

 

[johnalison]

For my sailing the purpose of using a route is purely to make my life easier and the sailing more enjoyable. Sailing through the Swedish archipelagos, I would as soon have a chart in my hand, but for most sailng the route is largely to relieve me of the effort of trying to remember things, such as the name of that buoy I was supposed to be heading for, or the course I was supposed to be following. Because the route is integrated with instruments, I don't even have to look at the plotter to keep myself up to date with the data, for the most part. I enjoyed sailing before p]otters had been thought of, and I enjoy my sailing now, but I have more time to sit and dream.