Lying a- hull in a storm

[coopec]

Having bluewater sailing in mind with a relatively modest sized boat, I've read everything I can on the subject. In my view, nothing comes close to the analysis and solutions offered by Attainable Adventure Cruising (Morgan's Cloud). To respect their business model (it has a paywall) I won't quote but will paraphrase. One section nails the myth of 'rogue waves' and provides data and analysis of the likelihood of a wave large enough to roll a boat lying a-hull. Spoiler alert - if you read it, you won't do it in anything over a Force 7.

The myth of rogue waves? ?

They are very, very real!!

• On 11 March 1861 at midday the lighthouse on Eagle Island,[4] off the west coast of Ireland was struck by a large wave that smashed 23 panes, washing some of the lamps down the stairs and damaging beyond repair the reflectors with broken glass. In order to damage the uppermost portion of the lighthouse, water would have had to surmount a seaside cliff measuring 40 m (133 ft) and a further 26 m (87 ft) of lighthouse structure.
• The Fastnet Lighthouse off the south coast of Ireland was struck by a 47-meter-high (154-foot-high) wave in 1985
• The Queen Elizabeth 2 (North Atlantic, September 1995), 29 metres (95 ft), during Hurricane Luis in the North Atlantic. Her master said it "came out of the darkness" and "looked like the White Cliffs of Dover."[24] Newspaper reports at the time described the ocean liner as attempting to "surf" the nearly vertical wave in order not to be sunk.

List of rogue waves - Wikipedia

 

[Poey50]

You misunderstand my point. They are very real but they are not rogue. In other words they are very infrequent but predictable - that is the Morgan's Cloud argument which they back up with data. People who get rolled tend to say "everything was fine until this huge rogue wave came out of nowhere". Their takeaway argument is to prepare the boat not for the steady sea state you are in but for the wave that will come four to six times every 24 hours which will be at least twice the height of the average wave height and, if breaking, will roll a boat lying a-hull.

 

[Laminar Flow]

You misunderstand my point. They are very real but they are not rogue. In other words they are very infrequent but predictable - that is the Morgan's Cloud argument which they back up with data. People who get rolled tend to say "everything was fine until this huge rogue wave came out of nowhere". Their takeaway argument is to prepare the boat not for the steady sea state you are in but for the wave that will come four to six times every 24 hours which will be at least twice the height of the average wave height and, if breaking, will roll a boat lying a-hull.

It does not take a "huge" wave to be rolled. Ten feet is quite sufficient for a 30 footer or 30% of boat length.
A rogue wave is a wave that is 2.2 times larger and much more frequent than many believe, up to one in 30.

 

[coopec]

You misunderstand my point. They are very real but they are not rogue. In other words they are very infrequent but predictable - that is the Morgan's Cloud argument which they back up with data. People who get rolled tend to say "everything was fine until this huge rogue wave came out of nowhere". Their takeaway argument is to prepare the boat not for the steady sea state you are in but for the wave that will come four to six times every 24 hours which will be at least twice the height of the average wave height and, if breaking, will roll a boat lying a-hull.

OK I see your point. I bet these enormous waves are normally generated in storm conditions. But my understanding is that the storm can be hundreds of kilometers away. If the wave trains from two different storms located 1000(?) km away happen to coincide an enormous wave can be generated.

Rogue wave - Wikipedia

Mar 21, 2013 - Scientists do not completely understand how rogue waves form. One explanation is that wave trains travel thousands of miles across ocean basins, encountering other wave trains as they move. When the crest and trough of two different waves meet head-on, they can cancel each other out, resulting in a flat sea. But when two crests run into each other, they form a huge wave that is the sum of both wave heights—a rogue wave that towers above other nearby waves. ..

Rogue Waves Revealed

 

[zoidberg]

'Quick, reef the geraniums....!'

 

[coopec]

I keep telling myself a ping-pong ball is not a robust structure but would easily survive a freak wave and it would be the same with our yachts . They would easily handle a freak wave wouldn't they??

 

[Laminar Flow]

I keep telling myself a ping-pong ball is not a robust structure but would easily survive a freak wave and it would be the same with our yachts . They would easily handle a freak wave wouldn't they??

It is too easy to overthink these things. What is the likelihood of something happening? Statistically speaking, you are more likely to get run over by a drunk driver. Does that stop you from going to town?

When your number is up, well, it's up. My wife still comes sailing with me. She says she'd rather go down with the boat with me on it than to be left alone and on shore. True love that.

 

[Bajansailor]

I crewed on a delivery from here to England via the Azores on an 80' Maxi eight years ago.
Half way between Horta and Plymouth we got caught by a low - we knew it was coming, and attempted to prepare for it, but it still walloped us.
We were initially running under just the double reefed mainsail, achieving frightening speeds surfing - I was at the chart table on one surf where the log and the GPS both simultaneously recorded 37 knots, and the wind speed then was only about F 7 - 8.
Later we gybed accidentally, broke the boom, all hell let loose, somehow managed to get the main down while still running downwind at 10 knots, and lost a liferaft when a big wave dumped on us because we were going so slowly, relatively.
Hoisted a little staysail on the inner forestay, and the boat was transformed - she was beautifully behaved, and we surfed the rest of the way to Plymouth with this staysail. That night the wind got up to F 10 gusting 11, the seas were about 9 metres (but very long wavelength), and we were still surfing at fantastic speeds, but under perfect control. I managed a surf of 28 knots on my watch that night, and the other lads were often getting 30, 31 knots.

 

[coopec]

It is too easy to overthink these things. What is the likelihood of something happening? Statistically speaking, you are more likely to get run over by a drunk driver. Does that stop you from going to town?

When your number is up, well, it's up. My wife still comes sailing with me. She says she'd rather go down with the boat with me on it than to be left alone and on shore. True love that.

I rarely think about it.

Just like me driving a car: I could have an accident _ just have to be careful.

I live close to the beach and can hear the waves. On a few occasions over the last 20 years I have been startled by an almighty crash until I realized it was a wave maybe X3 times the size of other waves.

But thanks anyway.