Originally Posted by conachair
Has anyone actually put this to any kind of do cemented test offshore? I find offshore the weather does whatever it wants, usually trades are good, elsewhere who knows. Personally I've gone towards making no passage plan at all for long offshore passages, point in the general direction, keep an eye on the weatherfaxes and keep the boat happy rather than trying to keep to some predefined route. Even subconsciously if that line is drawn on the chart you'll try to stick to it.
All seems too much like trying to make the world behave as you think it should rather than as it really is day by day.
But, Mate, this is statistics. It is not what is blowing, it is: how often, how strong and from where(s) it had been blowing in a specific period when the data got collected.
Offshore, you want a wefax, a grib download and a wx routing software. VPP is good for the planning stage (like say, do not sail from Martinique
to Cabo Verde, unless via the Azores).
Otherwise, the data is bang on and much as the conditions in any specific year may actually fall outside of the range, in any 10 years you are likely to encounter pretty much what the software says you should. Unless there is a climate change, but I noticed none.
So to say, I am not clear why anybody would like to stick to a VPP calculated route, much as I understand why most sailors will try not to sail over routes that the VPP says should not be sailed.
Actually, even when our grib analysis says sail South, I will, in a puff, bear off, then head
up in the lulls. I will use the calculations to position my ship where we believe conditions are, or will be, best; but in doing so we will sail just as if it was a daysail in a fine swift cruiser - listening to the wind and using its energy, not fighting it.
So to say, make a voyage plan with the VPP, then use fax, gribs and routening software to plan today and tomorrow's tactics, then sail the boat as per the conditions dictate.
Otherwise, sailing any sensible route is just as good. Finding out which one is sensible is what VPP helps you out with.