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Re: Swell sailing

PostPosted: Fri Oct 03, 2014 1:07 am
by seandwyer
The idea of 6 foot chop is common on the Great Lakes. And chop in my experience usually means having the bow in one wave and the stern in the next as they can come that closely together. It is indeed daunting to be in the DS or some such sized boat when conditions like this kick up, and they often do, quickly and with little warning.

Once off one of the Lake Erie islands my wife nearly called 911 because, as she observed from the dock, the children and I kept disapearing in troughs no more than 50 or 75 yards away and she swore we had sunk.

I'll be honest though--when that sort of thing kicks up, you are incredibly thankful for the outboard! Trying to figure standard sailing amid that battering is like, well, too much, too fast for my brain! :D The clunk of the centerboard makes you feel like the bottom is going to rip off any second.

Re: Swell sailing

PostPosted: Fri Oct 03, 2014 2:13 am
by GreenLake
Sean, like-for-like I would expect the waves in the Great Lakes to be a bit higher and/or steeper than ocean waves, because fresh water is lighter. Conversely, the salinity of the Laguna Madre where John sails in the Tx200 is higher than average, so it should take more wind and fetch than on the open ocean to get the same or similarly sized waves.

I couldn't find out whether the nomogram I found is for salt or fresh water.

Re: Swell sailing

PostPosted: Fri Oct 03, 2014 1:27 pm
by jeadstx
Greenlake,

The aerials taken during this year's Texas 200 came from somebody one of the "Duckers" knew who had a plane. One the first day, several aerial pictures were taken while some of the Ducks were losing their rudders.

John

Re: Swell sailing

PostPosted: Fri Oct 03, 2014 1:57 pm
by talbot
1. Let's move Tx 200-specific discussion over to "Events," where it usually lives, so people who don't visit the "Sailing & Seamanship" area can find it
2. I went back to the coast yesterday with a full crew, but a small craft advisory for the ocean kept us inside the bar. We had to settle for picnic on a sunny beach and fast sailing on the whitecapped river. Life is tough. After two good days in a row, I submitted Winchester Bay to Small Craft Advisor's in-progress survey, Best Place to Sail a Small Boat.
To nominate your own favorite waters, visit the SCA blog at http://smallcraftadvisor.com/our-blog/

Re: Swell sailing

PostPosted: Sat Oct 04, 2014 1:47 am
by GreenLake
John, why don't you add a post to your Tx200 thread with the link to the SCA article. That way, people can find it in that context.

Re: Swell sailing

PostPosted: Sat Oct 04, 2014 10:59 am
by K.C. Walker
Swell is different from wind waves or chop in that it travels from long-distance, often thousand miles away, especially on the Pacific. Swell that hits the West Coast can originate in the Indian Ocean. It tends to have a very long wavelength compared to more local wind waves, often a period longer than 10 seconds. There can be a tremendous amount of energy in a relatively small wave height, because of the long wavelength. However, it's relatively unnoticeable in deep water. It's when it becomes ground swell, where it starts feeling the effects of the bottom it becomes noticeable waves. A swell with a period of 11.4 seconds has a wavelength of 446 feet and starts to become groundswell in depth of 200 feet. This is the stuff surfers dream of. And… The Coast Guard knows what they're doing when they issue warnings for the sandbar or close harbors.

I've been out sailing on the Atlantic when there was a high surf warning, like 9-10 feet as I recall. The swell that produced this surf originated with a hurricane off the coast of Africa and by the time they reached New England they were organized swell and the surfers loved them. The swell was much smaller though, like 3-5 feet and relatively unnoticeable where I was in deep water. I say relatively unnoticeable but it still felt big, though not scary.