Beaufort scale

[ForeverYoung]

I thought I had understood Beaufort, I have a poster with a conversion from MPH to Beaufort and I sometimes refer to that.

However, when out on our local sea lochs, the effect of wind on us doesn't seem to match up to the effect of wind on the sea state.

When we were out the other day, the forecast stated that wind would be gusting around 25mph. It slowed us down to about 3.5 kph paddling speed, so I can believe it was somewhere in that region. But looking at the sea state, you would have said about force 2, maybe going on 3 occasionally. I presume this is because we are at the end of a narrow loch, so there is not the fetch for it to whip up anything more than this unless it's a Southerly wind.

Officially, if I am talking about Beaufort, am I talking about the sea state or the wind speed?

[Ceegee]

Beaufort is an interpretive wind speed based on observation of sea state. It dates from 1805, before accurate wind measurements were a regular thing. So yes, it is subjective, and describes a sea state. The speed is a subjective derivative from that. But then, sea state is what actually matters to us most, so if I see continuous whitecaps with spray tops, it's F6, a strong breeze, and I'm staying put regardless of the measured speed. Works for me.

[ForeverYoung]

So I guess I can ignore Beaufort in our sea loch unless it's a Southerly and just go by wind speed (as after a certain point you just don't make good progress), and in more open seas think more about Beaufort as it is likely to be more relevant there?

[mrcharly]

I always say that local knowledge trumps all for this reason.

Wind against current will be different from wind over calm water. Reflected waves off cliffs, changes in sea bed . . .

Beaufort is really only accurate for open sea.

I think that for kayakers, steepness of waves matters more than height. A steep 30cm chop might make my boat slam.

[seawolf856]

I always say that local knowledge trumps all for this reason.

Wind against current will be different from wind over calm water. Reflected waves off cliffs, changes in sea bed . . .

Beaufort is really only accurate for open sea.

I think that for kayakers, steepness of waves matters more than height. A steep 30cm chop might make my boat slam.

I would agree with mrcharly 100% regarding local knowledge trumping BF wind speed forecasts. The range of wind speed from the bottom of BF3 to the top of BF4 is already wide enough to complicate paddle planning unless you have good local knowledge of where you want to paddle and which direction the wind is coming from. I generally visualize the top of BF3 as producing continuous small white tops, which can usually be readily paddled, but the prevailing wind direction for us in North Wales is Westerly and at some locations any Northerly or Easterly component to the wind can change areas normally paddleable at BF3/4 into more unpredictable places.
No apologies given to those who regularly go out in BF5/6 - I am just a moderate water paddler who doesn't enjoy spending hours battling against wind and swell.

[Sean_soup]

Officially, if I am talking about Beaufort, am I talking about the sea state or the wind speed?

Contrary to some of the posts above, I'd say you're talking about wind speed only and that it's best just not to conflate that with sea state. They're connected of course, but the the direct 1-to-1 relationship that is sometimes hinted at does not exist.

It's true that the scale was originally based on a series of observations of sea state that mariners could use to estimate the wind speed (so it's not unreasonable to assume that it's somewhat predictive of sea state), but those mariners would have been on the open ocean. Ie: not within sight of land in a coastal environment let alone on a sheltered loch.

When you're consulting a weather forecast that uses the Beaufort scale, listening to the shipping forecast maybe, there's nothing subjective about it. It's an entirely objective (albeit slightly non-linear) scale. eg: if the Met Office mention f6 winds, they mean between 22 and 27knots and that's it. A maritime forecast will talk about sea state separately, the Shipping Forecast always does it in the same order: wind - sea state - weather - visibility.

The forecast wind alone might give you a hint as to what conditions you'll find in a given place (subject to local knowledge on how the land affects what you'll feel from different wind strengths/directions), but to get a more complete picture you may also need to look at a forecast specifically of the sea state - swell size/period/direction. (And possibly surf.)

Not so much in your part of the world perhaps, where the 'fetch' is limited in most directions, but in areas of the country that are more exposed to the open ocean this is really obvious - the size and power of the waves hitting the rocks and rolling up the beach isn't just a function of the wind here and now, especially so as the sea state gets bigger because the most powerful waves (and potentially the most dangerous) might have been generated by winds a couple of days ago and a thousand miles away!

Besides the 'sea states' associated with different wind strengths (again - on the open ocean), there is also a set of observations that apply on land. For those of us hugging the coast within sight of land, and especially those of us who can see, say, a tree from our craft that's probably the more appropriate list to refer to.
(The wikipedia article on Beaufort lists both, side by side, with conversions into more 'objective' measures btw: https://en.wikipedia.org/wiki/Beaufort_scale )

Maybe there should be an experiential scale specifically for kayakers, more or less off the top of my head I'll have a go at proposing one for starters:

F0-1: No wind, or no effects felt from the wind.

F2: Wind can be felt, perhaps as mild 'wind chill' on wet skin but doesn't affect paddling.

F3: Kayaks will drift downwind while not being paddled. (Especially a rafted-up group.) Course affected whilst padding across the wind.

F4: Paddling upwind significantly harder work than paddling downwind. Manoeuvring may become difficult for some paddlers.

F5: Skilled paddlers notice effects on manoeuvring, maintaining a straight course across the wind or turning the bow upwind requires effort. Unoccupied kayak likely to blow away faster than its former occupant can swim!

F6: Sustained progress paddling upwind impossible for all but the strongest paddler. (But a downwind run might be an absolute hoot.)

F7: Gusts may cause capsizes. Upwind progress into sustained wind effectively impossible. Loading kayaks onto roof racks rather dodgy.

F8: Get off the water!

[mrcharly]

I like the idea of a paddling scale, but maybe name it KF1, 2, 3 etc to avoid confusion with beaufort scale.

I have my own subjective scale, that affects which boat I use (K1 racer or nelo 510).

Awkward lifting and swinging boat onto shoulder = not suitable for K1
510 is blown along the shore = v rough, maybe go on the rowing machine instead.

[Mark Graham]

I haven't got my copy down here (I'm temporarily in some place called England) but there is a table that gives all factors a numerical score that you add up to produce an overall rating of conditions. So it combines things quite usefully I think - a bit like the 'Incident Pit' theory in diving or mountaineering. A minor problem on its own (such as wind) becomes more serious if combined with say distance offshore or fatigue or temperature.

[ForeverYoung]

I haven't got my copy down here (I'm temporarily in some place called England) but there is a table that gives all factors a numerical score that you add up to produce an overall rating of conditions. So it combines things quite usefully I think - a bit like the 'Incident Pit' theory in diving or mountaineering. A minor problem on its own (such as wind) becomes more serious if combined with say distance offshore or fatigue or temperature.

That sounds interesting, if you remember once you are back in the civilised lands, I would love to see it.

[MikeB]

https://www.ukseakayakguidebook.co.uk/u ... _scale.htm

[Mark Graham]

That sounds interesting, if you remember once you are back in the civilised lands, I would love to see it.

👍

[Mark Graham]

This is it - I can't bring to mind where I copied it from but it's interesting to consider. Plenty of scope for amendment and/or customisation to suit individuals. Hope it's helpful (and hope you can read my writing).

[mrcharly]

That's a great chart. Most of my paddling is 3-4.5 grade on that scale.

Heavily influenced by water temp, which I'd argue is overstated if you have the right clothing.

Interesting that they don't include air temp.

I've paddled very comfortably in 5C temps, water about 8C.

Drop that temp to -5, sea at about 5C (doesn't often get colder than that around here) it is quite demanding. Windchill has a huge effect, even if you are wearing a drysuit or similar.