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Old 27-04-2015, 07:44   #91
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Re: Characteristics of Offshore Yachts

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Originally Posted by David_Old_Jersey View Post
I am not a scientist, but am pretty sure the laws of physics have not changed recently. Or since year dot, for boats or anything else. Lol.

For those who can prove otherwise a Nobel prize awaits - even if results still disputed on cf. Lol.
Dave,

No, the laws changed very little and most of them possibly not at all.

What did change is the body of data related to boats. We may say that even though physics remained stable, our knowledge of boats expanded rapidly and so we should see the whole set-up as a dynamic rather than static design environment.

To reject modern developments only because the old laws are still valid would be contrary to our own interests.

Cheers,
b.
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Old 27-04-2015, 08:03   #92
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Re: Characteristics of Offshore Yachts

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Originally Posted by barnakiel View Post
Dave,
To reject modern developments only because the old laws are still valid would be contrary to our own interests.

Cheers,
b.
What I am trying to figure out is how, in recommending a 25 year old book as a good read, I was labeled as rejecting modern ideas.

I am working my way through that book. Actually I am working my way through half a dozen books. I don't really see anything at all that isn't as true today as when it was written back then. They have a chapter on:

1) Trends in design 1920-1986. Probably hasn't changed in the last 25 years since it only includes designs up to 1986.
2) Thoughts on stability discusses fastnet and why they wrote this book
3) Avoiding capsizing: research done to that point
4) Avoiding capsizing: practical measures
5) Steering control: ...
6) Modern Yacht Construction: This chapter obviously can't discuss 1986 to present but it does a fine job of discussing the generalities of construction, loads, structural systems, balast and so forth

My point is that it is a book. It is easy to read. It has pictures and drawings to demonstrate what they talk about. 20 out of 22 chapters is most likely just as valuable today as it was the day it was written.

And yet, when I came in to just say I liked the book I was pretty much slammed. And it hasn't let up much.

Hmmmm.

I have been on the internet since the internet has been around. And I have observed exactly this phenomenon. Any thread starts - I like / dislike XYZ (boat, piece of equipment, book, movie star, doesn't matter what) and wham, out come the "that's crap" crowd.

Then the thread quickly meanders off to a discussion of crashing old cars on the decks of freighters bound for the south pole, complete with satellite photos of the results.
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Old 27-04-2015, 08:09   #93
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Re: Characteristics of Offshore Yachts

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Originally Posted by barnakiel View Post
To reject modern developments only because the old laws are still valid would be contrary to our own interests.
b.
And finally, the modern developments simply don't make a whole hill of beans to me because my finances have me buying a boat from the 70s. So whatever has been improved in the latest half million dollar yacht may be important to you, but not so much to me.

I can appreciate you might want to have a discussion of "modern physics" before you take your boat savings account and go buy said yacht.

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Old 27-04-2015, 08:12   #94
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Re: Characteristics of Offshore Yachts

I have the aforementioned book and several others including more modern texts as well. I also have the Marchaj book , which does more technical analyis , but is in the same stable as Rousmarine

There is no doubt that more modern opinions are somewhat different in emphassis then


Note that for people referencing the Fastnet 79 disaster, the conclusion in the official report was
Quote:
The answers received show a consensus of opinion that it was the severity of the conditions rather than any defect in the design of the boats which was the prime consideration.
So it did not specifically single out design , as an issue, even if some models got some specific criticism ( like the OXD 34, etc).


Note that while Southern Ocean storms are arguably bigger, the south west coast of Ireland is a far nor dangerous place in a really bad storm, firstly there are no ports of refuges, the whole coast is a lee shore, there are offlying hazards and most importably you are in reactively shallow water, resulting in very confused and vicious seas. Southern ocean is deep!


IN my view.more modern texts tend now to look at dynamic models, rather then static parameters. for example the classic arguments that " certain" modern boats will not re-right , often just uses static data, or may omit the effect of the cabin top ( which is excluded from the static calculations) etc.

The overall strength from monocoque, GRP in modern yachts is often overlooked in traditional texts


Really the subject of sea worthiness is complex and cannot be boiled down to fin versus long keel etc. The way the boat is managed is also a big factor.

Too many neophytes simply go looking for simple answers and a boat that can withstand their incompetence, that boat model has never been discovered or made ......

to anyone arguing that old cars were more crash resistance, oh for gods sake, take off the tin hat and wake up.

Dave
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Old 27-04-2015, 08:14   #95
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Re: Characteristics of Offshore Yachts

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Originally Posted by jwcolby54 View Post
And finally, the modern developments simply don't make a whole hill of beans to me because my finances have me buying a boat from the 70s. So whatever has been improved in the latest half million dollar yacht may be important to you, but not so much to me.

I can appreciate you might want to have a discussion of "modern physics" before you take your boat savings account and go buy said yacht.


good cheaper boats from the 80s 90s too..

70s , 80s , 90s, doesn't make any particular model better just because it was from a certain decade Im afraid
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Old 27-04-2015, 08:24   #96
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Re: Characteristics of Offshore Yachts

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Originally Posted by sesmith View Post
Concerning cars...the statistics speak for themselves, so there should be no disagreement on car safety:

http://www.saferoads.org/federal/200...s1899-2003.pdf

Some more recent years here:

Fatality Facts

Many more cars on the road today, and a fatality rate half to a quarter of what it was in the 60's and 70's.

Wouldn't it be nice if there were similar safety stats on boats...it might solve the bluewater boat discussions. On second thought...no, it wouldn't.
Most people misread the stats. The lower death count today is 99% related to people almost universally using seatbelts. Had the same percentage of people were using seatbelts back when you would have seen a similar drop in fatalities.

But that's not teh only thing what I am saying when I say that the older cars with heft are inherently safer than the modern tin/plastic toys. By the logic of pro-modern car crowd if you keep your new 2015 car in the garage and get no fatalities it is an inherently safer ride than an older MB which is on the road 24/7.

I am saying - put one person behind the wheel of a 70s gas guzzler and another behind a 2015 Corolla. Neither are to use seat belts, nor air bags (disabled) etc, etc and crash them head on. Which car would you rather be in? That's an apple and an apple comparsion.
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Old 27-04-2015, 08:26   #97
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Re: Characteristics of Offshore Yachts

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Originally Posted by Jon Eisberg View Post
Of course, I agree that it is dated in some respects, by now...



Nor, does the book include ofshore/expedition motoryachts like Nordhavns, on which many people are voyaging today... Hell, when it was written, even you hadn't yet made the switch to a multihull, correct? :-)



I have simply described this book as the single best "starting point" towards gaining an appreciation of the wide array of considerations that go into rendering some boats more suitable for offshore sailing than others... It's the first recommendation I make when responding to yet another "What's the best boat to buy for my circumnavigation/bluewater/high latitude voyaging I'm gonna begin after I complete my ASA courses?" thread, which have become a neverending staple of sailing forums today :-) I still don't know of a single better primer for those who may not have a clue what 'downflooding' is, or have not done enough offshore sailing to fully appreciate the importance of good cockpit and deck ergonomics, or a system of natural ventilation that can still be effective when underway offshore - one of the features sadly lacking in many of the modern production boats I see out there today...

Certainly, DESIRABLE & UNDESIRABLE CHARACTERISTICS is by no means comprehensive, or up to date... For a fuller understanding of design elements, I'd recommend following it up with a reading of Steve Killing's excellent YACHT DESIGN EXPLAINED (if one can find it, or afford it they do)... Then, top it off with Bob Perry's superb and fully up-to-date PERRY ON YACHT DESIGN, and one should be very well armed with the knowledge to make an informed decision for selecting the right boat for you, if planning to venture offshore...
+1....

"I have simply described this book as the single best "starting point" towards gaining an appreciation of the wide array of considerations that go into rendering some boats more suitable for offshore sailing than others... It's the first recommendation I make when responding to yet another "What's the best boat to buy for my circumnavigation/blue water/high latitude voyaging I'm gonna begin after I complete my ASA courses?" thread, which have become a never-ending staple of sailing forums today :-) I still don't know of a single better primer for those who may not have a clue what 'down flooding' is, or have not done enough offshore sailing to fully appreciate the importance of good cockpit and deck ergonomics, or a system of natural ventilation that can still be effective when underway offshore - one of the features sadly lacking in many of the modern production boats I see out there today...

Certainly, DESIRABLE & UNDESIRABLE CHARACTERISTICS is by no means comprehensive, or up to date... For a fuller understanding of design elements, I'd recommend following it up with a reading of Steve Killing's excellent YACHT DESIGN EXPLAINED (if one can find it, or afford it they do)... Then, top it off with Bob Perry's superb and fully up-to-date PERRY ON YACHT DESIGN, and one should be very well armed with the knowledge to make an informed decision for selecting the right boat for you, if planning to venture offshore... "
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Old 27-04-2015, 08:32   #98
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Re: Characteristics of Offshore Yachts

Quote:
I am saying - put one person behind the wheel of a 70s gas guzzler and another behind a 2015 Corolla. Neither are to use seat belts, nor air bags (disabled) etc, etc and crash them head on. Which car would you rather be in? That's an apple and an apple comparsion.
You will be safer in the Corolla , I would have though the video of the chevvies a few posts above is convincing enough

you are mixing up weight with safety , modern cars have far stringer safety cells, crumple cells to soak up energy, better cabs to prevent passenger injury etc etc

nothing to do with air bags.

Sheesh. where do we get these utterly uninformed views.

Engineering progresses, by its nature as its a iterative science, the past was not better engineered then today.
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Old 27-04-2015, 08:38   #99
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Re: Characteristics of Offshore Yachts

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Originally Posted by jwcolby54 View Post
What I am trying to figure out is how, in recommending a 25 year old book as a good read, I was labeled as rejecting modern ideas.

I am working my way through that book. Actually I am working my way through half a dozen books. I don't really see anything at all that isn't as true today as when it was written back then. They have a chapter on:

1) Trends in design 1920-1986. Probably hasn't changed in the last 25 years since it only includes designs up to 1986.
2) Thoughts on stability discusses fastnet and why they wrote this book
3) Avoiding capsizing: research done to that point
4) Avoiding capsizing: practical measures
5) Steering control: ...
6) Modern Yacht Construction: This chapter obviously can't discuss 1986 to present but it does a fine job of discussing the generalities of construction, loads, structural systems, balast and so forth

My point is that it is a book. It is easy to read. It has pictures and drawings to demonstrate what they talk about. 20 out of 22 chapters is most likely just as valuable today as it was the day it was written.

And yet, when I came in to just say I liked the book I was pretty much slammed. And it hasn't let up much.

Hmmmm.

I have been on the internet since the internet has been around. And I have observed exactly this phenomenon. Any thread starts - I like / dislike XYZ (boat, piece of equipment, book, movie star, doesn't matter what) and wham, out come the "that's crap" crowd.

Then the thread quickly meanders off to a discussion of crashing old cars on the decks of freighters bound for the south pole, complete with satellite photos of the results.
You correctly observed that the book is about boats. There are other books about boatmanship, which is always part of the boat-sailor dynamic.

Our Taswell 49, being conceived in the late 80's by Dixon, is old school now.

When I was a welder at Todd Houston in 1971, I slid into the back of a '68 Olds Delta 88 that was stopped on Interstate 10 in a heavy morning rain in Channelview Texas, with my almost pristine '57 Chevy 2 door HT. He got out, saw that he had a dented bumperette and cracked tail light lens, and drove off into the morning mist. My car's front fenders were pushed back to the point that on either side, I couldn't open the doors without a lot of creaking and bending.
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Old 27-04-2015, 08:40   #100
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Re: Characteristics of Offshore Yachts

Quote:
I have simply described this book as the single best "starting point" towards gaining an appreciation of the wide array of considerations that go into rendering some boats more suitable for offshore sailing than others... It's the first recommendation I make when responding to yet another "What's the best boat to buy for my circumnavigation/bluewater/high latitude voyaging I'm gonna begin after I complete my ASA courses?" thread, which have become a neverending staple of sailing forums today :-) I still don't know of a single better primer for those who may not have a clue what 'downflooding' is, or have not done enough offshore sailing to fully appreciate the importance of good cockpit and deck ergonomics, or a system of natural ventilation that can still be effective when underway offshore - one of the features sadly lacking in many of the modern production boats I see out there today..
Ive sailed an awful lot of boats, from some old " duffers" to a range of modern stuff.

there were bad boats in every decade, there were old boats with terrible ventilation, or ventilation to 1950s standards, etc etc

The trouble with looking for a boat that is seaworthy , is the whole definition of what that means TO YOU. all boats are massive compromises,

what you can say is that most modern boats are " out there" bringing their occupants across oceans, whether thats down to modern systems, weather routing, better sailors, better boats or whoever is irrelevant. They are out there , doing it.

go sailing , if you are not experienced , do not form opinions based on third party books, crew on a modern boat doing a high latitudes delivery in winter to form a good opinion of what matters for example , if you want to form an opinion , crew on some older designs etc to see what they have that you like and dislike

its certainly not down to the keel or the rudder etc
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Old 27-04-2015, 09:23   #101
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Re: Characteristics of Offshore Yachts

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Originally Posted by Stu Jackson View Post
Could you please explain how the laws of physics have changed in the past 30 years?

A few examples of the changes you imply would be helpful.
Ignoring your intentional misreading of my comment (No one ever said or implied the laws of physics change).

Sure, wood is exceedingly strong if you try to cut across the fibers but is often very week if you split it along the fibers. To securely attach a fin keel to a wood boat takes an inordinate amount of reinforcing, so they tended toward long full keels to spread out the stress.

With modern fiberglass designs, the designer can determine which way the fibers lay, so they can better align them with the direction of the forces on the keel. This allows them to securely mount a more effective keel.

Long full keels can also be built from fiberglass and they will be quite strong but massively overbuilt. Of course it's typically wasted effort and results in a less efficent slower boat which brings it's own issues.

To go back to the car analogy for a second, our roads would all be much safer if we were all limited to golf carts with a 10mph goverened speed limit. Oddly, no one is suggesting this is as a viable option. The old full keel designs largely run into the same issue. They do work but with a lot of major compromises.
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Old 27-04-2015, 09:25   #102
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Re: Characteristics of Offshore Yachts

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Originally Posted by goboatingnow View Post
I have the aforementioned book and several others including more modern texts as well. I also have the Marchaj book , which does more technical analyis , but is in the same stable as Rousmarine

There is no doubt that more modern opinions are somewhat different in emphassis then


Note that for people referencing the Fastnet 79 disaster, the conclusion in the official report was


So it did not specifically single out design , as an issue, even if some models got some specific criticism ( like the OXD 34, etc).


Note that while Southern Ocean storms are arguably bigger, the south west coast of Ireland is a far nor dangerous place in a really bad storm, firstly there are no ports of refuges, the whole coast is a lee shore, there are offlying hazards and most importably you are in reactively shallow water, resulting in very confused and vicious seas. Southern ocean is deep!


IN my view.more modern texts tend now to look at dynamic models, rather then static parameters. for example the classic arguments that " certain" modern boats will not re-right , often just uses static data, or may omit the effect of the cabin top ( which is excluded from the static calculations) etc.

The overall strength from monocoque, GRP in modern yachts is often overlooked in traditional texts


Really the subject of sea worthiness is complex and cannot be boiled down to fin versus long keel etc. The way the boat is managed is also a big factor.

Too many neophytes simply go looking for simple answers and a boat that can withstand their incompetence, that boat model has never been discovered or made ......

to anyone arguing that old cars were more crash resistance, oh for gods sake, take off the tin hat and wake up.

Dave
I was at sea close to the area at the time of the Fastnet 1979 race, cruising home from a vacation but not racing, with first wife, two kids and a dog on board. Many friends from my then UK YC and even my sailmaker, in 'Pinball Wizard' were in the race itself, all fortunately made it home alive. The seas were horrendous resulting from wavetrains from different directions meeting and causing the 'hand in bath tub and stir fast' effect. I believe the enquiry established that there were micro-storms within the main storm itself, as in areas where conditions were even worse and like many we got lucky and missed those, not by superior skill or a better boat design ( I had a 1970s 30 footer, built to half ton cup race rules under IOR). THe OOD 34, AKA Contessa 34, boats that were hard hit ( designed BTW by Doug Peterson from America)I personally liked and had sailed on several times, they were mostly clustered at the worst location within the storm at the worst time I believe. I later owned a One Ton Cup boat that was also designed by Doug Peterson, the best boat I ever owned, and one we sailed in several bad gales (cruising not racing) with full confidence. One factor oft forgotten is that most of the deaths were of crews that abandoned to liferafts and that in many cases the abandoned yachts survived the storm even those that were abandoned with their main hatches left open, so in those cases the boats knew better alone than with their crews.

The BBC several years later produced a docudrama of the race, see here on U tube

The boat in the film BTW is not the real 'Grimalkin' which IIRC was a Nicholson 305 or 345, whereas the one used in the film, and called there 'Grimalkin', is actually a Westerly GK29 a stock cruiser/racer of the time. I still find it difficult to watch that video with dry eyes. Incidentally I believe(because I saw it sailing) the original Grimalkin was still in use, by different owners, many years later, even retained the same name.


I wonder how many offshore adventures were postponed or cancelled following the Fastnet 1979, maybe a few more if peeps on here watch the video re-creation.

The sea is the real master here not the boat designers or builders, even the unsinkable Titanic proved that.
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Old 27-04-2015, 09:30   #103
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Re: Characteristics of Offshore Yachts

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se-
I see one crucial piece of information missing in those motor vehicles stats. There's no attempt to correlate the number of deaths by the actual number of MILES or HOURS driven per capita. I know that in 1970 I drove 4x more miles than I did last year, so I'm not necessarily driving any safer, I'm just driving 1/4 as much, and that should make my accident rate 1/4 as much.


Or perhaps the rate should be worse, as I'm getting less practice on the road.


The statistics seem less than scientifically, or mathematically, accurate without corrections for unstated changes like that.


When Tricky Dick Nixon reduced the federal speed limit from 65 to 55, everyone said "See? The death rate went down, 55 is safer!" and then the New York Times got some numbers from the NYS Thruway Authority, showing that the actual number of vehicle miles driven [which are the direct base of the number of toll dollars collected and thus easily tracked] had plummeted even more than the death rate. The real numbers, when corrected for that rate, showed that driving at 55mph was actually more dangerous than driving at 65mph.


Perhaps because more hours on the road created more fatigue and more crashes, no one knows because it was terribly inconvenient to do any real research.
I'm in the buisness. The standard is to look at the rate and it's crashes per 100million vehicle miles and it is dropping. We do consider frequency also dropping. By any objective measure the roads are much safer.

I also do speed studies and a dirty little secret about the 55mph limit. They changed the signs not the speeds. Unless you have active and agressive patrolling, the freeway speeds were the same before, during and after the 55mph rule. And once the agressive patrolling stops, the speeds go right back up.
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Old 27-04-2015, 09:32   #104
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Re: Characteristics of Offshore Yachts

I just finished reading the account of the tragedy of the Grimalkyn from the man that was left aboard alone. Sad tale.


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Old 27-04-2015, 09:36   #105
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Re: Characteristics of Offshore Yachts

indeed, the real heroes of the night were the lifeboats, every boat from CourtMac to Dunmore East in Ireland was out that night, the crews were lucky they were sailing in one of the most rescue asset dense territory there is .
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