In the past 12 months I had sailed 15000 miles, coming online usually for minutes only, so I am not up to date with current
development, specifically not with with the plugins discussed here. However, most of the time I was solving some kind of weather
routing problems, often interesting ones, using OpenCPN
. Maybe my experience can be relevant to this nice work in the future... As I keep all my GRIBS and tracks I sometimes play with the idea of writing up a relaxed post-analysis, but this is still a little distant. So, for now just some cruiser's notes. For planning I was using my custom OCPN 2.5.1318 and - when I had time - QtVlm and sometimes BlueWater Racing
. Two observations here:
1. Before sailing out of the harbour (and out of the Internet
range) the question almost always was not what route
to take, but when to leave. The planned route
was invariably defined by many aspects, but never directly by local speed under sail. The local speed uder sail along the otherwise defined route was indeed a factor for deciding whether to go now or to wait.
2. I made practically no use of the polar diagram for my boat and no use at all of the isochrone-driven planning. Although these obvious capabilities are hard to drop from specifications, they should not heavily influence the user interface and overall footprint. I was quite happy with with just a daily estimate of miles sailed.
I was surprised to see how little time we had for decisions when leaving the ports
before several hundred mile passage
. Originally, I imagined that loose integration with tools like QtVlm by exporting/importing waypoints and routes would be sufficient for planning, but in reality we often were so hard pressed by various activities and timetables, practicalities of Internet
access etc. that every mouseclick and every data item to enter was a real pain. We often needed decisions in minutes after getting back to the anchorage with the newest GRIB brought from shore on a portable drive...
Today, I think the key issues are the following:
- What I use most is the GRIB-based simulation of weather
expected along a defined route, so just a couple of extra columns in the Route Properties dialog, showing the GRIB values for wind/precipitation is quite sufficient. The isochrones are a useful extra comment, but the real route seldom does follow them.
- What I miss most is the global currents model. Although my 2.5.1318 does handle sea currents in GRIB format (if included in the same GRIB with wind
data), I do not have the GRIBs for sea currents in general. Such GRIBs exist and are included as monthly files e.g. in the Raymarine
Raytech Navigator, but I do not know if similar data is available in the public domain. Also, I would not know how to combine the fixed sea currents data GRIB with the momentary wind forecast
GRIB (Bluewater Racing
can use simultaneously many separate GRIB files, a very neat feature)
- The manipulation of Departure Time for a given route plan should be as simple as viewing the next GRIB record
in most GRIB viewers. Therefore the "Now", "+1 Day" and "+3 Hours" buttons in 2.5.1318. I miss sometimes the "-1 Day" and "-3 Hours", but there was no space in the dialog panel for these.
The GRIB-based route planning (wind, currents, precipitation) is extremely useful for practical cruising. I look forward to using this.