Bethwaite

Tim:

I received it yesterday. Your point is well made. The first chapter was worth the price.

Though it was written for skiffs and mono dinghys, there is a whole lot of good info in there applicable to cats.

Enjoy!

I got this book a few years ago, but now you two talking about it makes me want to go reread it. Only i remeber getting completly lost in the weather section. maybe I am smarter now so will try agian.

For weather, I use the Stuart Walker, 3 category, method to decide which way to go:

1. Persistant shift

2. Occilating shifts

3. none of the above.

Stuart's stuff is great for strategy and tactics, while Bethwaite's stuff is great for boat speed.

It's all good reading when the wind is too light (or it's too cold up north) to sail, but today it's supposed to be blowing 10-15 so as soon as I get back from my bike ride, I'm going sailing.

Oh, and I was just made aware there is a new Viper owner up in Wisc. who will also be using sail number 777, and get this, he is also a Delta 777 Captain! Small world!

So if you see him out racing this summer, don't spit on him as you might be tempted to, thinking it's me. He's proably a very nice guy! (unlike me)

so will you chage your sail number to A380? ouch

Yeah...as soon as I check out on it, but since Delta doesn't own any and probably never will, I'll have to wait for the 787's to show up, and use that, unless I get a bid to the 747 before they park them all. (they are gas hogs so they will probably be gone before I can get a bid on it)

OR...once I get rid of a few kids and their horses, I could get on an A cat and use 777 on that.

How does JJ get to take 777?

He's not "taking" it, he asked if he could -share- it.

Since he's up in Wisconsin and I'm down in Florida, and I doubt I will ever trailer up there, or he down here, I said it would be ok with me if he also used it, as long as that's OK with the class Pres, Sec, Treasure, etc. You guys can all vote on it if you think it's necessary.

If we ever do end up at the same regatta, (Nationals or perhaps Tradewinds?) he said he would add something to his number to make it distinguishable from mine.

Does the USF16 Association allow two sail numbers to be registered and approved? Regardless whether it is a Viper/Blade/Falcon .... we're all F16's.

Ok that kind of makes sense. I'm guessing there's a good chance he will be at Nationals.

USF16 Association has no say presently. The pending ISAF F16 rule set that is about to be "balloted" to current members (pay your dues if you want a voice), designates the USF16 and other respective national associations the responsibility to manage among other things, sail numbers. However, it is only at ISAF sanctioned events like Nationals or World Championship, and when registering certified sails that we would be required to enforce uniquely numbered sails. First come, first served in that case and thus the opportunity to reserve your number now.

USF16 is here to serve its members but also wishes to Keep It Simple. I am pretty sure that 2 or 3 unique sail numbers would not be onerous. Eventually, there will be a point when reserved numbers will be expected to be documented via "certification" and on file with the USF16.

I further hope that we will be able to work with the manufacturers on granting blocks of sail numbers and starting a referral program with them. If we get enough of a membership database, I hope that the USF16 will be able to solicit group discounts for its members at relevant supply houses and other related vendors, ie: APS, Murrays, ProShop, etc.

Any input is always welcomed.

What does "..... via certification ... " mean?

Jody, I can only hope there was never a time when you were dumber than you are now!

No.

Or at least that was the way it was back in the day I was chairman.

I smell Royalty Checks!

Measured boat (or sail in this case) by approved measurer.

But it seems pretty straightforward to register 7770 and sail with an invisible last digit in home waters.

Sorry Timbo

Damn, and I was sooo looking forward to all that royalty money paying for my Gunboat 78!!

And BTW, before any of you swinging dicks think twice about it, as of Right Now, I claim sail number 787 for my Gunboat 78!!

So when you all get your Gunboat 78's you'll have to pick something else! So there!!

Why a Gunboat 78?

Because they don't make a Gunboat 120!


(if you are going to dream, dream BIG!)

I can't believe I haven't been studying Bethwaite all along.

Got any of Stuart Walker's books yet?

Lots of good stuff there too.

No. I think this will take some time.

What's the easiest way to determine cloud height? Both the base and the top.

Get in an airplane and fly up to the base, then the top. Other wise, I know of no accurate way. You could use some type of sextant type angular measuring device, I guess, if you also know the exact distance to the cloud.

I am more interested in what type of clouds they are, and which way they are moving, and what's causing it. Sea Breeze? Cold Front? Building Thunderstorm?

I like to see the big picture (on the Weather Channel) and then allow for the local geographic influences which will affect the surface wind.

Remember, Bethwaite was also a competition glider pilot, so he was very much interested in updrafts/downdrafts, etc. thus his focus on cloud heights.

What I meant was, is this information given in any of the pilot forecasts. I went to the NOAA site and it was all jargon that I didn't understand.

Cloud bases are given, that is called the "ceiling" and could be described as scattered, broken or overcast. The reports are given in shorthand, you need the key to decipher it, or call the 800 number for the airport nearest where you will be sailing.

Start by looking around here:
http://aviationweather.gov/adds/winds/

And I'll try to find the 800 numbers for you to call.

Here's one for Sebring's airport, 863-655-6424

Call this and listen to the automated report. This is the actual weather report for right now, not a forecast for the future, so it's not much use for sailboat racing.

The lower the cloud the worst the weather.

From sitting on the water that may seem often the case but from an aviation perspective that is not entirely correct. Those big cummulo nimbus ( the big vertical clouds with explosive looking tops ) are incrediably destructive due to the amount of air being sucked up ( something to fear if you are a hang glider or parascending plot )but equally at ground level they create fantastic lines of " wind " which you can run along the front of in your boat, thats how they get across the atlantic averaging 30 odd knots.

Now if you start talking about nimbo stratus and the like then you need to start thinking about " dewpoint " which is the key to forecasting height of the cloud and just how much you are going to get hosed down today.

I'm just trying to find a way to predict if an approaching cloud will affect surface wind, especially in light wind conditions.

Look at the water's surface, see what's going on in front of the approaching cloud. The bigger, darker ones usually have built up to the point where they may have a downdraft coming out of the base. Now, is that cloud moving towards you (the outflow will be stronger if it is) or away from you? If it's early in the day, chances are that cloud is being formed buy rising hot air, so it's not going to help you too much, unless it's a huge building thunderstorm, in which case it will be sucking in a lot of air, right up until it "explodes" in a big downburst.

Sturart Walker has an written entire book called "The Sailors Wind". Check it out.

What I'm getting is that a downdraft is associated with rain.

Our normal puffy white cumulus (if I'm understanding this correctly) actually has an updraft immediately in front, which causes a net REDUCTION in wind speed and a header! This is the thermal effect, and the resulting subsidence will create a lift and increased speed along the side of the cloud. This is if and only if, the cloud is low enough to interact with the boundary layer.

If you look at the cumulus and it has a wispy base, that is a sign the cloud is not interacting with the boundary layer.

But, I'm getting a little confused...

The picture I have in my head is my last trip to Wildcat.

very generally speaking, if the cloud is of reasonable size and isn't raining, you will see an increase in windspeed if you are to windward of it, and a decrease if you are to leeward..

If the cloud is raining, it's the opposite because the downdraft caused by the rain will add to the wind to leeward