One of the things that just makes me crazy is offshore sailors who claim that getting rolled upside down is just a risk of being out there, yeah I’m looking at you Don McIntyre.
The other, and related, thing than makes me nuts is that big waves, twice (or more) the size of the significant wave height, are popularly called “rogues”, with the implied assertion that they are very rare and and getting rolled by one is bad luck.
The efficacy of the Jordan Series Drogue (JSD) has been proved in countless deployments over decades, which blows both of the above out of the water, but still sailors go out there without a properly installed JSD and then whimper that they were unlucky when their boat gets rolled.
They were not unlucky, they were un-seamanlike.
We have an entire Online Book dealing with all of this, but it’s still worth publicizing the latest proofs of the JSD:
To that end, our friend Susanne Huber-Curphey has just completed her second, La Longue Route (The Long Way) voyage in her Koopmans 39-foot Aluminium cutter, Nehaj.
For those of you not familiar, La Longue Route refers to a voyage made by Bernard Moitessier starting in 1968, and the book he wrote about it.
Moitessier, while in second place behind Robin Knox-Johnston in the Golden Globe Race, decided, after rounding Cape Horn, to keep on going in the Great South rather turning north for Europe with a good chance of victory.
He then sailed across the South Indian Ocean for the second time before finally ending his voyage at Tahiti after over 37,000 miles of non-stop solo ocean sailing.
In 2018 Susanne entered a loosely organized round the world voyage to commemorate Moitessier’s 50 years before, and like him she carried on after rounding Cape Horn for a second transit of the South Indian Ocean before finally stopping in Tasmania.
After many other amazing voyages in the intervening years, Susanne set out again in 2024 on roughly the same route and just completed it in New Zealand a few weeks ago.
Add the two together and she sailed 66,575 miles over 521 days.
Both Susanne’s La Longue Routes qualify as one of the great small boat voyages of all time, never mind both together, an achievement that leaves me in open-mouthed admiration.
Anyway, here’s the Tip:
I’m also going to take issue with
“Significant wave height” is, by widely-agreed-upon definition, the mean height of the highest 1/3 of the waves. (Statisticians might also define it as four times the square root of the zeroth-moment of the variance spectrum, the distinction versus the first definition being insignificant to anyone without a Ph.D in statistics.)
If there is more than one wave train in the system, then there WILL be waves much larger than the significant wave height. Not “may.” “Will.” It’s right there in the definition of the term! These are not random or unpredictable. They are simple linear superpositions of ordinary waves.
Similarly, when an established wave system reaches a region with a contrary current, the waves will bunch up and get steeper. Again, these are not crazy unexpected out-of-control waves. This is just what water does, naturally, all the time.
Genuine rogue waves – overwhelmingly larger than the others in the system, and generally nonlinear in their tendency to draw energy from adjacent waves and concentrate it in the main one – do exist, and are dangerous. But the *vast* majority of “I got rolled by a rogue wave” stories appear to consist simply of being unprepared for the totally normal, totally expected waves that are statistically certain to occur within the weather formation in question.
Hi Matt,
Thanks for the corroboration. In the linked article on “rogue” waves I dug into a bunch of work done on wave height and found that the incidence of waves twice significant wave height was alarmingly high. Of course that does not take into account whether or not a specific wave will break, but still it’s sobering.
Thanks for the good article, John.
Hard to believe people still sail the oceans without having a JSD ready.
All the best from New Zealand, Nehaj-Susanne