Random trivia...can we make this work

[Zanshin]

The most feared catabatic winds that I've heard of are in Greenland (ostensibly the can get over 200Knots {can that be true? Perhaps Km/H?}), where the vast highland plains can generate cold, dry air that only "drains" through a few passes; the winds are called williwaws.

[eryka]

Even if it is Km/H, that's a pretty hefty speed! Around 100 mph?

[MMR]

In Tierra del Fuego in South America as well as in Alaska, a wind known as a williwaw is a particular danger to harbouring vessels. It originates in the snow and ice fields of the coastal mountains. Williwaws commonly blow as high as 100 knots, and 200 knot williwaws have been reported.

Interesting read: Rounding the Horn: Being the Story of Williwaws and Windjammers, Drake, Darwin, Murdered Missionaries and Naked Natives--a Deck's-eye View of Cape Horn by Dallas Murphy

[merlin2375]

Don't think there is an open question out there so here I go

What is the Rule of Twelfths both definition and what is the actual rule

[eryka]

The way the total tide change is distributed over the tide cycle. i.e., very little change in the hour or so before and after high tide or low tide, and most rapid change midway between high and low. (sorry, that's pretty vague, I think 1/12 in the first 2 hours, 2/12 in the second 2 hours, then 3, 3, 2, 1 and back to slack tide)?

Has anyone gotten Hartley 18's "sewed" question?

[eryka]

Originally Posted by eryka

The way the total tide change is distributed over the tide cycle. i.e., very little change in the hour or so before and after high tide or low tide, and most rapid change midway between high and low. (sorry, that's pretty vague, I think 1/12 in the first 2 hours, 2/12 in the second 2 hours, then 3, 3, 2, 1 and back to slack tide)?

Okay, now that I'm home I was able to look this up - it is 1,2,3,3,2,1, but it's six hours (approx) between high and low tide, not 12 hours. (duh!)

Anyone want to venture a guess what "kumatage" is?

[sailingdog]

Depends on whether you're in an area with diurnal or semi-diurnal tides. Some areas only have one high and low tide per day...so twelve hours between tides.

Originally Posted by eryka

Okay, now that I'm home I was able to look this up - it is 1,2,3,3,2,1, but it's six hours (approx) between high and low tide, not 12 hours. (duh!)

[Plumper]

Regardless of the time between tides, the rule of twelfths applies. Just divide the time between tides by 6 and apply the rule of twelfths. Works for Diurnal, semi diurnal and mixed tides.

[sailaway21]

Just to clean up-the mistral is a cold, dry wind from the NW in the Tyrrhenian Sea that flows down off the Alps. The Sirocco is it's counterpart from the south or SE, mostly in the summer, off the Sahara. Pardon the interruption.

[Hartley18]

Originally Posted by eryka

.....
Has anyone gotten Hartley 18's "sewed" question?

Nope - it got lost in the wind back there somewhere!

Since it's related to the current (pun intended) discussion I'll give you the answer: If you're "sewed", you've been left high and dry on a mud flat.

It's a British term - so probably not fair on you lot.