More on stability

[Guest]

With the kerfuffle below surrounding Hunter/Legend's refusal to supply basic stability information, I looked back at the stability curve for the Island Packet 350. The boat has a reasonably respectable AVS of 140 degrees and small area below the line.

But instead of comparing it to the Contessa 32, IP's marketing department have rather cynically seen fit to compare it to a "Typical Other" yacht with an AVS of only 120 degrees and a huge area below the line. If that is typical, then I am an Irishman (I'm not). Manufacturers seem prepared to do anything to fudge the issue! In IP's case it's surprising since the IP 350's curve really isn't that bad.

On the other hand designs with AVS's not far above 120 are becoming increasingly acceptable. In your typical knockdown where the mast hits the water the angle of heel must be not far off 120 degrees. Add in-mast furling, radar, deck gear, teak decks, a bit of wind etc., and it would be interesting to know how many such boats would have positive stability to recover from a typical knockdown, let alone an inversion.

 

[Guest]

To Pacific Seacraft\'s credit

1. They were the first US based yacht builder to get a CE mark - I believe they had a significant head start before the others realised what was happening. Full marks to them for building quality boats AND going through the necessary steps to get the certification.

2. I'd never heard of Contessa's while living in the USA. To a US based boat owner (especially on the West coast) they are not relevant.

3. Contessa's, good as they certainly are, have little meaning to modern boat designs. They carry sensible beam, no aft staterooms, decent bilges, low freeboard and more. Compared to any of the major boat builders in Europe, they are an anachronism, albeit a lovely one. Why should a US based builder in 2002 try and compare its products against a design from circa 1965 - 1970?

Ideally a new "standard boat" should be chosen. I nominate the Island Packet 38 or something from the Najad range - sensible, strong, & very modern.

 

[Guest]

Re: To Pacific Seacraft\'s credit

What are the IP 380/Najad curves like?

The Contessa clearly has a "good" curve, but there must be many other designs that have similarish or better curves? I suspect that if the Contessa had a higher coachroof then its hydrostatic stability curve would appear even better, but a higher coachroof probably wouldn't in fact be an advantage in rough weather (more windage). A difference between theory and practice.

I guess that one problem is that a design like the Contessa is nowadays regarded as an unattainable paradigm, so far removed from the realities of modern accommodation-orientated yachts that owners don't really want to be reminded of what the characteristics of a good seaworthy design are.

I don't know whether the curve for say a Rival 38 looks better or worse than the Contessa's, but perhaps a design like that would be another candidate to be a standard if people have have come to think of the Contessa's characteristics as unusual?

My personal guess is that in the future there will be something of a reaction to the current extreme beamy, lightweight, high windage designs and they may be looking rather fat and outmoded in 10 years time!

 

[Twister_Ken]

anti fat movement

It may be happening already. See Hunters (UK Hunters that is) proposal for the Mystery.

check http://www.hunterboats.com/modintro.htm

 

[david_e]

Healthy discussion...

As you know this subject is of interest to me in trying to narrow down the shortlist for my next boat. Well I've been to the site and had a look at this page;

>>Hunter Boats has been building boats for 30 years. Over these years, we have won Awards for "Best Production Boat of the Year", "Yacht of the Year", "Best Sailing Boat" ... and no fewer than four separate Design Centre Selections. Two of the three directors have been with Hunters for about 25 years; the other's been there for ever! So you are dealing with an experienced team.<<

So what is the benefit to us of this experience? Experience can often be making the same mistake over and over again, Hunter need to translate this into a benefit statement. Many other boat builders can say the same about ownership including the lady who owns Ben/Jen and how long had Rival/Bowman been in ownership? Hanse have won awards and their boats are cheap (but not nasty).

>>We have pleasure in setting out a few appetising details on our current range of sailing cruisers. Rather than rely on "purple prose" from the Marketing team, we have decided to let the Magazine Testers and the actual Owners tell you what they think. This way you get a real insight into what the boats are really like. This is always better than the Builders telling you what they want you to think!<<

How does this fit with all the comments about Legend/Mags/Tests/Advertising spend etc? I wouldnt mind some definitive prose from the marketing team as long as it it is accurate, meaningful and justifies the cost difference.

>>When reading about our boats' ability to sail in strong winds, do remember that these quotes come from tests on TWIN KEEL boats. The only tests ever done on a fin keel Hunter cruiser in the current range were the February 1998 Practical Boat Owner and Yachting World tests in the fin keel Channel 323.<<

Have they not tested the Hunter 31 fin keeler relatively recently? Seem to remeber thinking that this was an excellent boat review and cursing why it wasn't within my budget when the similar size froggies were. Havn't got the time to check through back issues but fairly sure?

Hunters might be great boats but the way they mold them together looks amatuerish and spoils the boat imho. I have yet to see one which hasn't seemed to get old very quickly and in general they appear drab, not so important to me but the other half the crew (SWMBO) always walks away quickly when I start to nose about one.

When I look at design trends, I see the new Elan 31, designed by Rob humphries no less, which replaces the 295 has gone shorter and fatter despite the model name. (I do think this boat looks superb in the ad) The new Sun Fast 32i has gone shorter and fatter as well.

What do you think?

 

[Guest]

Re: To Pacific Seacraft\'s credit

I don't know - I only offered them as examples. The Najad has a fin, the IP has a long keel, and they are but two examples of well built modern boats. Like your example of a Rival, there should be a real-world benchmark.

 

[Adrian_Morgan]

Ref CE mark

I think I am right in saying that the CE mark simply states that the manufacturer believes his product is up to the necessary standard and that there is no official European 'testing' authority to confirm that, or if there is they cannot possibly test every product.

There was an informative item on the BBC the other day to that effect, although it concentrated on games and toys (yachts being clearly under that category). It concluded that the CE mark was not worth the ink.

Further to Legend thread, all I know is that I was nearly wiped out by a big Legend off Calshot last summer. The breeze was fresh the helmsman struggling to keep the thing in a straight line, such that he was on the edge of broaching to windward into me. I retreated another 200 yards to weather and even then felt a little unsafe until he passed.

So, never mind stability (which is seldom put to the ultimate test) what about directional stabilty and heeled balance? By carting around a double bed in the back of a boat you risk making any boat's waterline wildly asymmetrical when heeled, with consequent loss of control. Putting a huge rudder on the back just disguises the problem. A rudder should only be a trim tab. Take a leaf out of the books by Harrison Butler, Robert Clark and Laurent Giles, all of whom in their own ways, using different methods, took great care to balance their waterlines and ensure good balance. Less tiring on the helmsman/autopilot and on the nerves of anyone in close proximity. And who the hell needs a double bed in the back?

 

[Guest]

Re: anti fat movement

The Mystery looks like she could be a lovely boat from the drawings. I hope that Hunter put in plenty of fibreglass etc. to give her a solid hull. Nice to see a keel-stepped mast. It'll be interesting to see what the performance characteristics will be with the combination of fin and spade underwater profile and relatively deep hull sections.

As Hunter say in their bumph:

"Perhaps it's unlikely she'll become a mass market production boat. After all, are there enough sailors around with the taste or sense to appreciate such beauty and performance - whether for comfortable cruising, corporate charter, or Couth One Design? Or all three? We believe there are!"

Anyway, good luck to them with that.

 

[Guest]

CE allows self certification

At least in the area of electronics, it is up to the importer (if foreign) or the MFR (if domestic) to assign a CE mark. It does not have to be the result of any rigourous tests. The CE Mark is a STATEMENT of conformity. For this reason it IS permissable to import US electronics, for example, and to use them on UK boats.

The above is based on my actual experience of importing US and Japanese electronics into the UK for several years without problem. My customers have included many parts of government, too.

 

[AndrewB]

A serious yachting disaster ...

... might be what it takes. UK cruising designs became notably more conservative after the 1979 Fastnet, and designs like the Contessa 32 were praised. Arguably that led to the later downfall of many UK yacht manufacturors, when the public memory faded.

 

[duke]

As a matter of interest, does anyone have information on the stability curve of a
Rival 38?
The sailing review by Yachting Monthly May 1979, although fairly detailed,
does not mention stability curve.

<P ID="edit"><FONT SIZE=-1>Edited by duke on Sun Feb 24 19:09:01 2002 (server time).</FONT></P>

 

[Chris_Stannard]

Re: Stability and the Najad 373

I have a Najad 373, bought recently so I do not have a great deal of experience in it. The Yachting Monthly tests, September 2000 gave the following data

Angle of Vanishing Stability 136 degrees
Maximum GZ78 degrees
Displacement/waterline ratio 250 (approx)
Sail Area/Dsplacement ratio 15
Ballast ratio 37%
Length on the waterline is 32 feet which accounts for the good ratios

The comment about what happens when a gust hits you I can answer, not a lot. The boat seems to me very stable as the angle of heel increases with a slight increase in weather helm. (The main sheet is very handy, just behind the helm, if you do get a problem.) The directional stability is inspite of the width being carried well aft to give a large after cabin. I do notice when I look at my boat that , although she is a bit higher out of the water than my old Sigma 362, she is not a lot higher. She is also only 12 feet in beam, but inside feels like a 'Tardis', coming in at 15.18 tonnes grt for the Part 1 register. This seems to me to show that good design can achieve most of what we want in a boat without prejudice to the sea keeping qualities.
The only problem was my eyes are still watering from the price, even although I am the second owner.

Chris

Chris Stannard

 

[Mirelle]

Lost cause

It is universally assumed that "brawn", in the shape of wheel steering, electronic autopilots, self tailing winches, in mast reefing, roller reefing headsails and above all great big diesel engines, will compensate for the lack of "brains" in the sense of good hull forms in modern yacht design, by giving enough power to overcome the vicious tendencies of the hull and rig.

To try to explain what you are talking about, to the great majority of modern sail cruisers, who have never experienced a boat from the era of good hull design (which you and I will agree reached a pinnacle of perfection in the 1930's( is quite hopeless, I fear. They have been brainwashed.

 

[andrewhopkins]

Re: Stability and the Najad 373

You lucky thing. I am curious as to how you are the 2nd owner on a boat that was only launched....last year or 2000 ?

Great boat from the looks of the review. What do you think ?

 

[Chris_Stannard]

Re: Najad 373

It is a super boat, both to sail and under engine. The accomodation is really designed for two, occasional four, which as my wife and I want to go away for most of the summer in a year of two, is just what we want. I could nit pick, for example you can bang you head in the heads but you get used ducking. The headroom in the after cabin is a bit short for me (I am 6 feet) but I do not spend a lot of time there. The galley is well thought out and you can brace yourself at sea without a belt. Taken all in all I would recommend it as a boat to anyone who wants to spend longish periods on their boat. If you see "Norrsken" around come and say hello.
The first owner had more money than he knew what to do with, and lots of time to spare, so he bought a boat. His girl friend did not like it. He now has a large motor cruiser, she doesn't like that either. A friend of mine who is a yacht insurance broker tells me that this happens much more often than you think.

Regards

Chris




Chris Stannard

 

[Guest]

Re: Ref CE mark

Well, I like a double bed in the back, but the boat has to be big enough to take it without looking like an Edwardian lady with a bustle.

Directional stability is important, but also as important as the yacht is the prudence of the crew (there's a good thread above). One should never (except perhaps when racing when one might take a chance) carry more sail than you can cope with.

I suppose I'm knocking on now, but reef well, reef safely and reef early.

William Cooper

 

[Guest]

Re: Marina prices!

A piont about why boats have got shoter anf fatter. Given most marinas are finger berths with plenty of length the number of boats that can be accomodated in a given length of pontoon is governed by the beam. So if marinas charged per foot of beam instead of length we might rapidly be back to the plank on edge era! Of course they would still be to light as boats are sold by the pound not the foot!
The seriouse piont is that this is an argument about ecconomics not seaworthyness. If design is going down hill it is because we the customer seem to put ecconomics before such traditional values as seaworthyness, whether that is purchase price of running costs.

Roly, Voya Con Dios, Glasson, Lancaster

 

[southchinasea]

Re: Stability and the Najad 373

Chris
I am not 100% sure what is meant by
'Angle of vanishing Stability' or 'Max GZ' etc.....
Can you give me definition?
Cheers