Originally Posted by Polwart
That's interesting I've never seen a version of the Beaufort Scale which cast "judgement" on what was safe for different vessels - merely a range of wind speeds and the land and sea observations you might expect.
almost certainly not. Firstly the RCD doesn't apply to vessels used commercially. Secondly where vessels are required to have "safety boats" these usually have to be Solas approved - which it is unlikely any "off-the-shelf" SIB sold to the domestic market it.
However - it would certainly be niave to say the boat is designed for F6 and 2m waves so I should go out in that! There is an article in the most recent Rib international questioning the validity of some RCD Cat C labelling for precisely this reason. However I think (according to my understanding) that both you and the author of that article have missed the point of the RCD. (1) It is about European harmonisation so goods flow freely without each country making their own local rules - don't assume it has anything really to do with the safety of boats (2) a boat which is Cat C labelled doesn't have to be fun/comfortable/sensible to use in those conditions - it simply needs to stay roughly the right way up, not sink and not fall to pieces. A SIB driven carefully in those conditions should achieve that - but the crew may be scared to death, battered, bruised, sea sick and totally exhausted by the time they get back.
In the UK these are referred to as "white horses" although I think your description is probably better!
I have a scale with intermediate specifications in Spanish, that's where I took it from.
Waves height is more related to Douglas rather than Beaufort (which is wind scale), but waves observation may give you a clue of the wind speed more than "No insects flying, no birds flying" and things like that! And what about name in Spanish for Beaufort 5,6,7 ("Fresquito, Fresco, Frescachón" which I believe stands in English for "Chilly, Fresh, Cool").
I must also point that waves become bigger later than wind arises, so you can have problems with wind, and later with waves, and do not expect the sea to be a mirror when the wind stops.
Also, waves behaviour is different in Mediterranean Sea, as Med waves are smaller but shorter so they break more easily. And we do not have tides.
I've just started my season this Sunday, tying my buoy to the mooring block (I had to dive to look for a good one). I can't wait to go boating, but always considering weather. My family and friends sometimes do not feel like going boating, but if the weather is fine, they now that is the plan. And same, if they feel like but weather is not, just forget about the boat. Weather rules.