Sudden Wind Gusts

[franksingleton]

The most likely explanation is the downdraft from a super cell. On one occasion off the coast of France, near les Sables d’Olonne it was pretty hazy so we could not see any nearby cloud. We had a sudden, strong, very dray blast of air. I asked former colleagues in Météo France. They suggested the super cell. The only warning in a forecast might be of thundery squalls. The CAPE parameter available on zyGrib) would give some indication of vigorous convection.

In some situations, it could be a lee wave effect. In November 1965, to the lee of the Pennines, Northern England lee waves caused wind speeds of around 80 knots. Three reinforced concrete cooling towers collaosd. In part, there were design problems and the proximity of the towers to each other was a factor. Over the Irish Sea, to the lee of the Isle of Man there can be similar effects. I doubt this effect would appear in any forecast. Look out for lenticular clouds, often ahead of a warm front and watch out if you are to the lee o fhills, not necessarily very high but with smooth slopes especially on the downwind side..

[Capitain Mike]

Originally Posted by Kettlewell

Most cruising cats will be able to handle the typical strong gust, though the performance cats are closer to the edge. This used to worry me a bit on my old French 32-foot cat, so we tended to reef early and sometimes take in a reef at night as a preventative measure if we were at all in doubt as to the weather. However, there are times when you just get hit out of the blue with something, and it catches you by surprise, so your boat does need a significant margin for error. While offshore down in the SW Caribbean a good 60-70 miles from any land we were running dead before the wind with about 10-15 knots and the mainsail vanged out to one side to keep it from roll gybing. I was asleep and my wife and daughter were on watch when they were hit dead on the nose by a squall packing 20 knots or more of wind, that quickly built to 30. It had our sails completely aback and we went out of control because I had the main boom tied off and couldn't easily release it. The boat got pinned down hard to starboard and I was glad I had a heavy keel below me. Probably a cat would have just slid off to leeward, but you never know.

Try to think "what if" it is better to err on the side of caution.

"Those that can do. Those who can't teach"

"Knife on your hip or in your pocket knife in the cockpit, knife on the mast, Knife for every crew member.
Three things to have with you land or sea, knife, high pressure wind free lighter, and mobile.

Tell someone your destination, your expected arrival time.
What to do if you don't call them after a pre-set time if you have pay as you go a spare top up card on board.

Don't forget your mobile charger. VHF is ok if there is any one listening or you haven't lost your mast.

Over confidence is not a good thing at sea.

[smurphny]

Gusts like this can happen anywhere near land, especially near mountains. As mentioned above, lake sailing is particularly prone. Slocum has some great descriptions of mountain-generated wind gusts during his passage through the Magellan Straits. Also, mentioned in Weatheritt's Atlantic Crossings.

[Sonosailor]

One good thing about cruising catamarans is that they have reasonable performance even when significantly reefed - a good thing for cautious sailors.

[beauris]

there's a thing called "up side up" which can free your mainsheet automatically if your boat either heel too much or if your stays support too much tension..it's used by racers bit they are trying to set a foot in the cruiser world with a simpler offer

[Seadog54]

I agree with previous posting about not rounding up but falling off in the gusts as this will cause bait to accelerate and take the sting out of gust like this.

[zeehag]

chubascos and katabatic winds along pacific mexico and tehuanos and papagayos are preceded by a sudden gust of wind. the chubasco i was privileged to encounter was 60 plus kts, measured. we actually made 8.4 kts sog during htis time.
if ye dont pay attention, you could well have more problems later.
i noticed that tboomers in gom were also preceded by a sudden gust and a slightly larger than normal sea. there were other very noticeable yet subtle changes before being slammed, as well, with up to 4 hours between warning and bashing.
i also noticed when a ts comes your way, the first gust is a sudden gust in excess of daily norm.
bam.
most interesting going thru what mother nature sends to us, especially when ye pay attention.
it is also good to know what your boat will do when these conditions are encountered. mine wants to round up, but it doesnt fight the helm. keeps a steady course, when properly trimmed and watchman has wheel steady.

[Cheechako]

Yes, something to keep a close eye on in cats. I was once caught in 35+ knots of wind with a full main no reef between islands in the Caribe. The seas were lumpy so it was tough to tell if the boat was heeling much. That Lagoon 42 almost never heeled more than a couple inches..... trouble is... on a cat.. it's all or nothing. One minute you're flat the next your upside down! It does happen. An Abaco based Charter cat turned turtle on charter a few years back.

[pbmaise]

Are the
weather reports accurate enough to reef your sails by?
Depends what you sail by. New Zealanders claim 30-40 knot winds is a good day sailing. Hidden in there may be some nasty peak gusts. That would likely have no warning. If weather says 5 knots, then yes it will be rare to get hit by sudden 40-50 knot blow with no warning.

Tell me I won't get knocked over in a 40' cruising cat, even if I have a little too much sail up when this happens??
Rip the genoa has been my observation. That reduces sail. Brings crew on deck too.

[thinwater]

Originally Posted by Seadog54

I agree with previous posting about not rounding up but falling off in the gusts as this will cause bait to accelerate and take the sting out of gust like this.

Just try that in a real blast. You're going over. I've sailed cats for 30 years, and mostly that is bad advice. As for hoping the cat will side slip... get a better cat, cus' if it will do that it will not go to windward.

As for the notion that you cannot feel a cat heel or react to the wind, the more accurate versions is "a mono hull sailor cannot feel a cat heel." Cat sailors can feel it perfectly well, even a few inches, or a slight sail imbalance. The wind feel is very immediate, it just requires a different calibration of the sense.

If the boat is hard on the wind, gently rounding up enough to feather just a bit and easing the traveler is enough (it is easier to grind the traveler back up than the mainsheet). Blow the mainsheet if it is scary.

With the wind aft of about 120 degrees, bearing off is generally the only thing to do. Rounding up will increase the power and you will go over before you feather. This is most true on "cat rigged" boats with no back stay, since the shrouds prevent the boom from easing all the way. However, if the wind is too strong things can still get out of hand, as there is no way to drop sail.

Anywhere in between requires judgment. If the sails are stalled or the chute is up, bear off and blow the chute if needed. If above a beam reach, blow the main completely and round up. Jib depends; if it is small, sometimes it is OK to leave, and it will pinch off the slot when the main is eased.

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The main thing is that a cat sailor NEVER looses situational awareness and will see a burst coming from the look of the water. I can honestly say I have never been surprised such that I did not have time to round up or drop the chute fast. This is not about the weather forecast or electronics, this is about keeping your eyeballs on the water.

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And there are areas where a monohull will be a better choice for most people. On the US east coast it seems clear it boils down to wants and the sailor.

[Privleoplag]

Originally Posted by roverhi

Multi hulls should fall off in gusts, not round up. Heading off allows them to accelerate decreasing the relative wind and heeling moment. Just the opposite of lead mines.

Aloha
Peter O.

We have been hit once by a strong unseen gust, 38 ft cat on auto pilot, auto pilot couldn't hold it, rounded right up, I was right on the main sheet to get it back under control.