Characteristics of Offshore Yachts

[jwcolby54]

Originally Posted by Jon Eisberg

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?

LOL, nor did the book include kayaks, canoes, aircraft carriers, or many other things.

It was written many years ago (C1987) by about 20 people, each of which knew more individually than (probably) most people on this list. The objective was simply to take the fastnet experience and learn from it. And further to publish the results so that WE could learn from it.

Now... if you don't want to learn from it, it don't make no nevermind to me.

If you want to claim that you know so much that there is no point in your reading it, well... don't make no nevermind to me.

I am reading it because I don't know the stuff discussed in the book and it is a good place to learn it. The physics involved is just as true today as it was in 1987 as it was in 1912.

I highly recommend the book to all of those of you who don't reckon you know everything. To those who do...

One of the things that the author(s) were trying to point out is that racing drives design in directions that can flat out be unsafe for cruising. Hell, they are unsafe for racing. Manufacturers all too often try to incorporate racing ideas into cruisers that shouldn't oughta be in cruisers.

The authors pointed out that the physics involved were just flat out poorly understood by the DESIGNERS THEMSELVES at the time of the FastNet race. They spent a lot of time and effort trying to understand the physics so that they could figure out how to not lose lives in the future.

Not that anyone on this forum cares about not losing lives...

So hey, read it or don't, I don't care. I'm just pointing out that for me, and maybe a fair number of other folks on this forum, it is a good read and will allow us to understand stuff that we didn't before.

[colemj]

Originally Posted by jwcolby54

The authors pointed out that the physics involved were just flat out poorly understood by the DESIGNERS THEMSELVES at the time of the FastNet race.

I'm not so sure about that. The strange boat shapes that were being designed as a result of the IOR rule were well-known to be bad physics and nothing but rule cheaters.

Olin Stephens was several years into railing against these designs as unsafe when the Fastnet happened.

BTW, when you finish that book, I highly recommend Olin Stephen's biography "All This and Sailing Too". A fantastic read with one of the best opening first lines in any book: "I was lucky, I had a goal". He was as gifted an author as he was a designer and sailor.

He describes just how well he understood the physics behind those bad designs.

Mark

[colemj]

Originally Posted by jwcolby54

I highly recommend the book to all of those of you who don't reckon you know everything.

If that is your criteria, then your order of Fossati's "Aero-hydrodynamics and the Performance of Sailing Yachts" must be on its way? Here you will find modern design and physics to round out your older knowledge.

I also recommend Marchaj's "Aero-hydrodynamics of Sailing". It was written at the same time as the book you are currently reading. It contains exquisite analyses of why some boats had trouble in a couple of disasters.

Mark

[jwcolby54]

Originally Posted by colemj

I'm not so sure about that. The strange boat shapes that were being designed as a result of the IOR rule were well-known to be bad physics and nothing but rule cheaters.

Olin Stephens was several years into railing against these designs as unsafe when the Fastnet happened.

Chapter 3 clearly describes the effort, using models and computer methodology to discover how wave shape, as well as moment of inertia and the effects of the mast itself, impacts the rollover of boats. He certainly makes it sound as if they just didn't know that stuff, or understood it only poorly. The research quoted was clearly AFTER Fastnet.

And yes, they also discuss how the racing industry will take any "rule", imposed to help even the playing field, and "design to the rule" to make boats faster. And yes, much effort has since been spent designing more safely.

Much effort has been spent in this thread exhorting how one should know the boat and not do stupid stuff. Fair enough. However it is NOT my imagination that many MANY threads on this forum have pointed to all of the boats doing circs to say that "it is really the skipper", more than the boat. I think that attitude and those posts do a disservice to those like me who come in here trying to find out "what makes the safest boat" so that before I even buy a boat I can use that knowledge to at least include than info in my planning.

This book, whose focus was analyzing the Fastnet tragedy, specifically speaks to that and says that designs aimed at making racing faster was directly responsible for many of the deaths. And it then goes on to describe what very specific things can be done to make a boat safer.

The things discussed are no less true today than 1987 when the book was published.

I don't know why, but there seems to be a whole lot of denigrating the book itself. Being only 1/2 way through the book, it sure seems to contain a whole lot of clear explanation of how and why, good and bad, and common sense.

So far I haven't seen much if anything in the book that is no longer true because of all these "new technologies, techniques and materials" that is being thrown around in this thread.

[jwcolby54]

Originally Posted by colemj

If that is your criteria, then your order of Fossati's "Aero-hydrodynamics and the Performance of Sailing Yachts" must be on its way? Here you will find modern design and physics to round out your older knowledge.
Mark

Not yet. As for "modern physics...", is this subatomic stuff? Like how quarks affect the wind hitting the sail and makes the amount of keel different than they knew about back in those olden days?

It sure sounds as if you are telling me that this book should be recalled for bad info? And if so could you please let me know which chapters I should make sure to ignore since they are so dangerous to my well being?

[hellosailor]

New car, old car...But you never heard about a 1960's 400hp supersport killing the driver when the airbag exploded into shrapnel, do you?


The devil is in the details.


The book rapidly became a classic for a reason, it makes a number of fine points that the newcomer to sailing might not have thought of.


You can give a Stradivarius to a quad amputee, that doesn't mean they are going to play great music just because they've got a great fiddle.


Some boats, like some fiddles, are simply better than others--for different purposes. How many boats will sail themselves, with no hand on the helm, for hours on end when properly trimmed? How many just won't, no matter how hard you try to trim them? But if you never intend to sail across oceans and can always duck into shelter before the weathercast calls for storms, who needs capsize resistance anyway? Great concept, but that still doesn't mean everyone needs it.


Like anti-skid brake systems, which, ooops, have actually increased skids and collissions among the general public.

[Sundae Driver]

On the matter of the suitability of one design versus another, while in transit aboard the USS Flint (AE-32) which was a Kilauea-class ammunition ship, I learned a valuable lesson from the crew on the bridge deck. The ship's numbers were:

Length: 564 ft (172 m)
Beam: 81 ft (25 m)
Draft: 29 ft (8.8 m)
Speed: 20 knots (37 km/h; 23 mph)
Complement: 28 officers and 375 enlisted

She was a big girl, as well as fast. There were seat belts in the bunks (baby crib rails too). The angled decks on each side of the passageway gave rise to the impression that she could handle the worst that open ocean sailing could throw at us.

I found out days later that it was not so. We were going around a typhoon that turned back on us. The 60 foot swells (and 100+ knot winds) meant that we had to angle the hull so as to avoid getting straddled between two separate waves (swells?) nor take them on the beam such that they rolled us. It was the skill of the Captain and his bridge offices that kept us alive.

Being a little motormouth air traffic controller (on my way to the Kitty Hawk) there was no job for me except to work the radios on the bridge. Except that we were operating in radio silence so all I could do was look, listen, and learn.

When the cooks said "Fella's it's too rough to feed yah..." the Edmund Fitzgerald came to mind. Being a kid who grew up on the shore of Lake Superior, I knew the song well.

I asked the chief if he could imagine being aboard one of those old wooden hulled sailing ships and running into something like this... Or how they could they even survive it? He said "They chopped their sails and corked"; after a pause, he added "Most didn't". Not being shy I asked what made the difference? Chief said, "The attitude of the captain and crew." I said "I can't see how that would matter in something like this?" He said "In this, it wouldn't; where it mattered was in the yard and whether they put in effort to keep their vessel sea worthy." The bottom of the ocean, said he, is littered with the hulls of those that didn't.

Kindest,

Sundae Driver

[Cap Erict3]

Originally Posted by jwcolby54

Not yet. As for "modern physics...", is this subatomic stuff? Like how quarks affect the wind hitting the sail and makes the amount of keel different than they knew about back in those olden days?

It sure sounds as if you are telling me that this book should be recalled for bad info? And if so could you please let me know which chapters I should make sure to ignore since they are so dangerous to my well being?

I have spent many years at sea and seen many storms. When aboard a vessel 500 LOA or better we went about out like it was any other day. When hurricanes were headed our way we ran.

The largest warships avoid major storms.


It has been said a few times here but here goes, Our little sailboats are toys. Some are a little tougher than others but it is like being the tallest midget in the room.


Read boat reviews, walk the docks, design your own or let your lady pick out one that matches her shoes.

http://www.boatus.com/boatreviews/sa...nnelCutter.asp

Best of luck in your search.


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Looking for another pretty place to work on the boat.

[paulanthony]

Originally Posted by jannw

New cars are probably safer than older cars, and a go-cart should never be driven down a highway ... but ...

You should try to apply the "argument" about boats and sailors to cars and drivers ... does it still make sense?

Doesn't to me ... I've driven old cars and new cars, and new cars are undoubtedly safer as a general rule ... but its a driver who is almost always the single biggest factor in a car accident ... not a car.

People crash cars.

I don't understand your logic. The reality is that new car technology and design does in fact contribute to the prevention of accidents through human error. They are not just safer to have accidents in.

[jwcolby54]

I was on the Kennedy, an aircraft carrier. The only time I ever felt the sea was once north of Ireland. We were out playing war games when we were hit by a major storm. The waves were literally breaking over the bow of the carrier. The bow is 60 feet above the waterline.

When in a storm like that we just closed all the hatches and steamed into the waves. I had a friend on a destroyer, only a few hundred feet long, out there with us. He said they were under water more than above.

We certainly did not intentionally sail into a major storm but a big one is just about impossible to avoid if you are "out there". And if you are going to cross the oceans, you are going to be "out there". There is no "out sailing them". We could go 35 knots but not all of our fleet could, and sometimes they just move faster than that anyway. And they may be 500 miles across.

We were taught to keep a watertight hull. Every interior bulkhead had watertight doors, and we closed them.

We don't have that on our boats so what do you do? You make the boat watertight and pray for the best. You try to not get sideways to the waves. You try to own a boat that will not easily roll if you do get sideways. If it does roll, it better roll back over (upright) again. A strong enough gust, with any sail at all can put your mast in the water. There are hulls where, at that attitude you are on the edge of going over completely. Others that will just pop back up upright. I sure prefer to pop back upright.

If you are in it, there is nothing you can do other than closing all openings, and trying to point bow or stern into the wind. But before I ever get in it I can read about what creates a good seaworthy boat and use that knowledge as best I can. And if my boat isn't seaworthy, KNOW THAT and keep it close to shore. Button it up and get off.

I will not intentionally be taking any boat I own into a big storm. But I do intend to cross oceans. So looking for the right boat is part of my strategy for staying alive.

[colemj]

Originally Posted by jwcolby54

Not yet. As for "modern physics...", is this subatomic stuff? Like how quarks affect the wind hitting the sail and makes the amount of keel different than they knew about back in those olden days?

It sure sounds as if you are telling me that this book should be recalled for bad info? And if so could you please let me know which chapters I should make sure to ignore since they are so dangerous to my well being?

Maybe I missed a comma - please make that "modern design, and physics". You seemed to like the physics and I was pointing out that this book included physics along with modern design knowledge.

And yes, there is much more understood about the physics today. Back then they did not have finite element analysis, nor the ability to actually apply much of the physics that was known because they did not have the computer or sensor technology, and had no real way of collecting large integrated data sets or doing ab initio calculations. Heck, they didn't even have the ability to form some of the shapes that can be made today.

Using your view, there really hasn't been any relevant changes in Newtonian physics since the 1800's, so everything was known about boat design and construction when they built Nelson's "Victory". Surely you don't believe that? So why not consider the same for the span of the past 30yrs?

You seem to be taking a sour turn with me and apparently missed my first post stating I owned the book and loved it. Not sure where I said the book had bad information. Saying that the information is 30yrs old is simply a fact. I did advise to keep that in mind when considering designs and technology that have happened in the past 30yrs.

My only point is that while this is a great book, someone coming new into boat design should not buy completely into the information and stop - when you finish it, the correct response should be "that was great, now I want to learn about the 1980-2015 era of design from current designers".

Hence my book suggestion.

Mark

[colemj]

BTW, if you want to know what makes a safe boat design, the over-riding single primary factor is waterline length - as Cap Eric3 eludes to. A poorly designed 500' ship is going to be much safer than a Westsail 32 in survival conditions.

Mark

[Cap Erict3]

It seems a lot of today's design of pleasure boat make speed and comfort top priorities. No surprise but it does take improved safety out of the discussion.

There have been great strides in electronics like AIS, GPS, Locator Beacons and other ways ease navigation, avoid collision, grounding or aid in rescue.

I don't hear about bullet proof hulls, multiple water tight bulkheads or rudders set up with easily replaced shear pins. Indestructible spars and flexible rigging? All things long known of but not applied in construction and design.

If there are innovations in these areas I would like to hear about them or any other design criteria that make "modern" boats more seaworthy.


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Looking for another pretty place to work on the boat.

[colemj]

Originally Posted by Cap Erict3

I don't hear about bullet proof hulls, multiple water tight bulkheads or rudders set up with easily replaced shear pins. Indestructible spars and flexible rigging? All things long known of but not applied in construction and design.

If there are innovations in these areas I would like to hear about them or any other design criteria that make "modern" boats more seaworthy.

Multiple water tight bulkheads is pretty much standard fare on catamarans. Two rudders make shear pins almost unnecessary. I don't know what would make an indestructible spar - seems like there will always be forces at sea that can break any spar usable on a sailboat. Flexible rigging? Like in stretchy? I don't understand that one. If you mean flexible in terms of not stiff, then the new fiber stuff is good for that. Seems like a steel hull would be mostly bullet-proof. Many catamarans have a layer of Kevlar in their hull layup, but mostly I want to sail where people aren't shooting at me…

Mark

[Stu Jackson]

Originally Posted by valhalla360

Still missing the point. Never said I was unaware of the book. Nor did I say it was useless.

BUT, it's one point of view and at 30yrs old, it's not particularly up to date with modern materials and design. yes, some stuff is still applicable but much of it is out of date and based on the translation of wooden hull design to fiberglass.

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.