a bygone age

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Obscured by clouds
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a bygone age

Post by Obscured by clouds » Sun Jan 05, 2014 12:44 pm

Not dinghies, but worth a watch anyway. Lots of wood and 60's ear yachts....



http://www.youtube.com/watch?feature=pl ... 1LcojP-cvY
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Re: a bygone age

Post by roger » Sun Jan 05, 2014 2:06 pm

Lovely thanks for sharing that and a young Magnus Magnussen as well.
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Re: a bygone age

Post by trebor » Sun Jan 05, 2014 5:46 pm

enjoyed this, did you spot the helm using his buttocks to hold tiller? could be nasty hitting an underwater obstruction.
I have noticed most yachts heel over, does the keep it flat make it fast rule not apply?
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Max McCarthy
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Re: a bygone age

Post by Max McCarthy » Sun Jan 05, 2014 6:27 pm

Hi Rob,

I believe (with my very limited knowledge of yachts) that this is exactly why canting keels have become used more, as they do the exact same job as the crew on a dinghy. Of course you can hike on a yacht (in a very different style to in a dinghy, as I am sure you're aware, although, I can't actually remember if it is definitely called hiking on a yacht!). Although with the very limited leverage you can get on most yachts, compared to the sail area, i.e. even a 35' racer cruiser could have a main area of nearly 80 metres squared (for example, take a look at the Bavaria Match 35), or in excess of that, and of course the racers have even more. Perhaps the most extreme of this sail area to waterline length ratio is the Mini Transat, which I have once heard someone say 'My Mini Transat, has more sail area than the last 40' racer I was on'. Of course, Mini Transat's have a pretty large beam, to aid leverage. My point is this, it is a lot harder to keep a yacht flat, due to the much larger sail area to water line length, and the often narrow beam, with not much access to means of leverage, compared to that of a dinghy.

Of course there are exceptions, just take a look at Principessa http://www.youtube.com/watch?v=sshXv8UKz7M which have come up with other ways of countering this.

At least, that is my theory...

But take what I say with a pinch of salt as it is mainly a guess.

Although, there are reasons for reefing points on a yacht, and the huge different number of sails (especially foresails).

But if you want to talk about keel boats, take a look at this: http://cardifflocalguide.co.uk/wp-conte ... -web-2.jpg

Flying Fifteens have NO reef points (at least, none that I am aware of) but than again, this is very unusual for such a boat....

Hope this helps (if it is correct!).

Cheers,

Max
Last edited by Max McCarthy on Sun Jan 05, 2014 6:32 pm, edited 1 time in total.
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Re: a bygone age

Post by Max McCarthy » Sun Jan 05, 2014 6:29 pm

Hi Tony,

A very nice film you have found there, really, nice to see how yacht design of yesteryear compares to most modern yachts...

Thanks for sharing!

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Re: a bygone age

Post by trebor » Sun Jan 05, 2014 7:11 pm

Hi Max, Thanks for explanation and links, never thought I would see a Flying fifteen over. The time and trouble taken to design and fit wings, plus all the trapeze cables, appears to suggest keep it flat works on Yachts as well.
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Re: a bygone age

Post by simonf » Sun Jan 05, 2014 8:05 pm

Fabulous little film - I do the Port Bannatyne - Kyles - Tarbert run a couple of times a year and it's interesting to note how little has changed!

Thanks for sharing!

best rgds

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Re: a bygone age

Post by davidh » Sun Jan 05, 2014 8:58 pm

Oh dear Max but no - your understanding is way of the beam regarding yachts and heeling. If you go back a generation or two, when boats had overhangs fore and aft (you're looking at the boats from the era of the great George Lennox Watson onwards then the boats HAD to heel to get any speed. A simple look at the hull form show that the yachts could often increase their apparent waterline length by 40% once they'd heeled to a certain 'designed degree'.

When you race something light in keelboat terms, such as a Quarter Tonner, then the weight of the crew up on the rail does exert a significant righting force (buoyant, beamy hull, helm + 4 crew) or if you're driving for that ultimate in performance, then you line the rail but on the yachts of the era in the film, to be honest it may not have made all that much difference (try racing a Contessa 32 for the experience... you'll see what I mean and then sail on the Quarter or Half Tonner and the difference will become clear).

As for the Flying Fifteen - remember this was supposed to be the 'planning keelboat' - you'd not want to be trying to shake out reefs on every down wind leg. Some used to carry reefing points - but then so did a lot of early Wayfarer sails.

But here is a suggestion: look at the hull lines of the FF, then look at how they'd be with 30 degrees of heel!

D
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Re: a bygone age

Post by Max McCarthy » Sun Jan 05, 2014 9:39 pm

Hi David,

Thanks for the correction of information. As I said, take everything regarding what I say about yachts with a pinch of salt....

And as you wisely say...what I thought is wrong....

But remember, I have very little knowledge of yachts, so everything I am saying about yachts is at best, a guess...so I apologize for passing on incorrect information.

To be honest, it is just what I thought, and I also thought it would be interesting to hear others thoughts on the same subject...

So thanks for correcting me!

And, as they say, you learn new things every day, and as you also say, you don't learn unless you make mistakes....I guess I am a very good example of that (in this instance)....

Now, that is interesting, I honestly had no idea about the heel of yachts in this instance, I just assumed, and assumed wrongly...

Thanks for the correction of information!

Cheers,

Max
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Re: a bygone age

Post by Obscured by clouds » Sun Jan 05, 2014 11:27 pm

As David/Dougal says, some yachts need to be heeled to increase their waterline lenth, which due to their displacement speeds [ie not planing] is a huge element in getting the best out of them. There's plenty of math out there to explain why but it all has to do with the sum of the square of the area of the waterline length or some such magic.

the Metre boats - 8, 6, 5, 30 sq et all and the Dragon and Soling all had long overhangs on fairly short waterline lengths, for rating purposes. lean em over somewhat and you get free speed from a competitive perspective. It's more complicated than that and a look at Uffa Foxs' books will give you some idea of the concepts.

then there's the lead mine down below, balancing the rig forces above, but that's a whole new discussion.
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Re: a bygone age

Post by Rupert » Mon Jan 06, 2014 12:43 pm

There is certainly truth in what you say, Max, concerning yachts and keelboats of very light weight, designed to plane - they will often have lines like a dinghy, and at that point, flat is fast.

Most traditionalally styled yachts will have an ortimum angle of heel, though. This can even be seen in the little K1 dinghy/keelboat, which is designed to sail heeled. The boats with huge overhangs took this to an extreme to cheat the rules - they would have been faster with longer LWL, shorter overhangs and sailed more (though not fully) upright. But then, depending upon the design rule, they would have had a worse rating than the extra speed made worth it, or would have to have a smaller sail area.
h
It is well worth finding lines plans of yachts - they must be out there somewhere with explanations of why they are the shape they are. Very often, the heeled shape will have both a longer LWL and reduced wetted surface.

However, you do lose effective sail area when heeled, the hull shape has to be designed for it, which reduced planing potential, and the balance of the boat has to be designed around it, too. More and more yachts are now designed to be sailed upright or with very little heel. This may well have to do with modern rating rules liking plumb bows, too - I've not kept up with such things, though.
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Re: a bygone age

Post by rme_01 » Mon Jan 06, 2014 11:23 pm

Nice film - it is a pity that it is indeed a bygone age. Traditionally Max displacement yachts such as in the film were restricted by wave drag to a speed in knots of around 1 - 1.4 times the square root of the waterline length in feet. It follows, as others have said, that it paid to maximise waterline length without unduly increasing wetted surface when the boat was (inevitably) heeled. Typically the result was apple round bilges with long overhangs. Under the old IYRU rules heavy displacement was pretty much a given reflecting construction methods of the time and perhaps a desire by the rule makers for sea kindly hulls. Nowadays with rule changes and more modern materials it is ultra light displacement planing hulls with the crew sitting exposed on the lee rail trying to keep it flat e.g oversized flying fifteens. Looks good but not much fun on a 20 mile beat on a cold night!

An interesting mix is where the rules still require heavy displacement but concepts such as fin keels made possible by modern construction materials result in very different shapes from those that the rule makers envisaged. The late 6 and 12 metres are a good example as you can see from the lines of this 6.

http://pkboatplans.com/files/6mR-A1_Lines.pdf

a fascinating subject - if you get hooked, put a cold towel round your head and try one of the C A Marchaj books!

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Re: a bygone age

Post by Rupert » Mon Jan 06, 2014 11:43 pm

The meter boats always look somewhat pregnant, don't they?
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Re: a bygone age

Post by neil » Tue Jan 07, 2014 12:00 am

ha! 20 mile beat, luxury. Try 200 - 600 miles sleeping on the rail, all those hours in 1980s water proofs.

IOR had an awful lot to answer for, spent hours bumping and fairing 1 tonners in the 80s. At that time I was living and working in Hamble and this huge bloke came up to me asking where he could get a cup of tea. The man was a giant about 6'8" and 20+ stone, turned out he was a professional wrestler and was rail fodder for one of the 3/4 tonners - imported to act as moving weight. They developed a manoeuvre to tack "Tiny".

If you are interested and can forgive some of the typos then have a look at Peter Johnson's 'Yacht Rating', slightly more digestible than Marchaj, and has my 2nd favourite 1/4 tonner in there: Gordon Trower's Warbird.
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Re: a bygone age

Post by Obscured by clouds » Tue Jan 07, 2014 12:04 am

Well remember all night rail sitting on long beats across the Irish sea in foul weather, with just the promise of a pot noodle at 3am to look forward to.

no wonder I've come back to dinghies!
Tony



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