Seaworthiness

So if a qualified NA with no yacht design experience can "get up to speed" on yacht design by reading Larsson et al, surely the cruising yacht designers who say that their cruising experience gives them a superior insight into cruising yachts must be wrong?

After all, if experience and study are needed so little, then an qualified NA from the racing field should be able to rustle up a live-aboard cruiser pretty quickly. Yet when they have created lightweight racers and call then seaworthy, they get taken to task by some here. Surely it cannot be so easy as to need only a few evenings with Larssen by the fireside, and yet be so hard that qualified racing designers can't get it right at all (which is the regular accusation here). I used to have a NA friend who was a senior naval vessel designer; could you guys swap jobs with just a quick read of each other's manuals?

Is it really such a simple field that "any hull designer worth their salt (hmmm, I thought MAs had already mastered their subject so this disclaimer should not be needed!) would already be aware of the compromises inherent in the hull-forms adopted for sailing vessels, and the effects and compromises this has on operational characteristics."

Does it really just take a little bit of reading from a basic text to learn the right prismatic for a boat designed to excel in short-course racing in Long Island Sound? Where in Larsson et al do they give the exact details of the hull flare (forward, midships and aft) that experience has found to be best (for a given type) in Sydney, compared to the flare that works best in the Solent. Is there really all the information that one would need to be able to work out the optimum lateral area for a couple with 2 kids and 4 years' experience on a Cal 40, aiming to cruise to Tonga with "X" kg of supplies? What textbook describes the way of working out the correct waterline beam and cross-section shape for a UK Cherub, and why does an amateur designer in that class beat the engineers?

Surely this ability to obtain specialist knowledge within one's professional field so easily must be unique only to NAs. Could my GP could move into brain surgery just by reading a textbook or two? Then again, people from other disciplines are obviously inferior intellects (despite the fact that ('round here last year, at least) a NA degree was no harder to get into than social science or arts so becoming an NA is not restricted to great minds) since few claim that they have "mastered" subjects in their undergraduate degrees.

 

You know, what I think is some NA/ME around here feel much exactly like you do:
".....my job requires that I bite my tongue when a customer wants to do something clearly idiotic to their boat."
The good (or bad) thing here is this is only open discussion, so there is not such an strong needing to bite one's tongue.

I think that probably what has kept people sticked around here is not the further interest of the debate, which has clearly become circular, but the morbidity of strong discussion. I find many of us are insane or become insane when posting (or even watching!) at these boatdesign.net forums...

Cheers.

 

D Greenwood

A troll as in fishing .............for an argument. As a few people seem to be doing.

 

That is exactly what they are doing, and the trouble is this is not an argument. An argument, as any real scientist knows (and engineering is based in science), begins with proposing an idea and proposing some assumptions to work from. That proposition is defended or argued from more than one point of view to ascertain its value, if any.
This process (even if it is just for diplomacies sake) should follow the rules of argument which you should have learned in high school. As best you can, points of argument always involve clarity of position (Audiatur et altera parsand) and are best served without being smothered in ego.
As much as possible, ambiguous or vague words and phrases should be avoided, particularly considering the language, location and perspective issues that we are handicapped by to start with. A 747 is not “airworthy” because if the engines stop it will fall out of the sky, is not a proposition. It can’t even be intelligently discussed.
And arguments particularly should never involve ad Hominem arguments or attacks on the character.
So if I would be allowed I would like to reassert Guillermo’s initial argument as best I can with what he wrote initially and in following posts, and with some assumptions of my own.

As best I can tell from his statements, he is saying:
It is dangerous and irresponsible of our industry to market boats such as, and in particular, the Pogo 40 to the public as a “cruising boat” due to dangers in dynamic stability issues that could occur in storm force sea conditions.

This requires:

Establishing whether those dynamic stability dangers are real and possible.

The establishment of what acceptable levels of danger are.

What the typical end user is likely to interpret “cruising” to mean when he purchases the Pogo 40. (Assuming the seller doesn’t tell him)

Establishing whether it is possible or significant to the typical buyer that these dangers can be avoided through the application of learnable sailing skills.

I am not going to go further and state Guillermo’s premises here because that is his domain.
But what I will say is that the core of his initial question is a good one.
Do the damn things become dangerous in a stalled state in agitated seas? Whether it is significant to the average buyer or not I would still like to know because it applies to design in general.

One last note: I am in no way implying that I am not guilty of infractions in the rules of healthy argument.

 

I agree (from post #3):

I should have realized 600 posts ago that my definition of seaworthy is so far from Guillermo's that agreeing on what seaworthy is (much less measuring and quantifying it) had gone from difficult in post 3 to impossible by post 35.

It is my opinion that such a boat does not exist and may never exist. I don't believe small boats are "safe", they may be "safe enough" for you to feel comfortable crossing oceans, but no small boat I'm aware of would be considered "intrinsically safe". Certainly not one that could sink.

We are too far apart to ever reach a conclusion. The passion of the debate has helped pass the winter.

 

Agreed, it was used in an attempt to point out that the ability of a boat to stop at sea being a requirement for seaworthiness is equally absurd (IMO) and that seaworthiness discussion, debates, arguments that ignore the skill of the sailor and the dynamic stability of the boat cannot be intelligently discussed either.

Very well put.

Since the start of this thread I've been looking at the probability of gale conditions on several cruising routes. I am also using the polars from my C30 and real time time weather to see if a 25 foot LWL can avoid sailing into or through heavy weather using routing software and freely available weather forecasts. The Ken Barnes incident is an excellent example. IMO if he had been sailing his boat to a higher percentage of it's performance and had been using weather routing software he would still be at sea. I started running a simulation about a week before his capsize and was alarmed that he was sailing at speeds about 50% of the potential of a Catalina 30 in a 44 foot steel ketch. Even after making that adjustment, my software was still able to choose a route that avoided the conditions that rolled him.

So far my experiments lead me to think that the chance of sailing in gale conditions is very low (less than 1-2%). It follows that if the chance of gales (35+ knots) is 2% the chance of 50+ knots is even more remote.

As I gain confidence in the ability of modern methods to avoid extreme conditions (even in boats that I previously thought were too slow to do so), it makes resistance to capsize an even lower priority for me that it was when this thread started.

I think the idea of an "intrinsically safe" boat will lead to more deaths at sea. If the boat is thought to be "safe" and require a minimum amount of skill and experience to operate, we will see the level of seamanship decline even father than it has in the last 20-30 years. I see a parallel in reduced driving skills with the advent of higher crash protection in motor vehicles.

I think it is a disservice to advocate boats that cannot sail in gale or storm conditions over boats that are designed to do so. At some point, how the boat acts when stalled in agitated seas becomes an academic debate. The probability of the event is too low to make it a high priority.

Early on in this thread, the idea of a boat being seaworthy included the boat being able to handle any expected conditions and bring it's crew safely to port. I have to agree. I do not think that (given good seamanship and modern methods) that "expected conditions" include sailing in or surviving Force 9+ conditions.

 

I just felt like quoting this post.

Any way

......most of the arguments for the Pogo seem to be a cut and paste from a multihull thread.
Speed, capsize resistance, strength of modern materials, light weight.....
And yet a multi hull can go faster than a mono.

How idiotic to try and make a racy mono hull. A really 'fast' boat dragging around tonnes of lead.

That lead is for safety not performance.

Pre event blah blah...
Post event is the worst case scenario.
That is what a mono hull is built for.
Pre eventers should get a multi.
Post is inversion issues.
The area under the curve.
And its minimisation
Not justification.

edit: (cool, it looks like a haiku)

 

It depends where and when.

:?: I admire your level of confidence in the perfect functioning of the fragile computers and other electronics in a salt-water environment on the small boat offshore.

 

Yes it does. My idea of recreational cruising does not include high latitude sailing in winter (either hemisphere).

If you expect your electronics to work in salt water you might have a problem. If you keep them aboard the boat, they work much more reliably.

I can only speak for myself, but I don't work well in a salt water environment either ... that is one of the reasons that I keep the cabin and navigation area of my boat dry. Paper charts and pencils don't work well in salt water either.

Any system you rely on must be made reliable and/or must be backed up by other systems. That includes all systems, not just electronics. It has been my experience that I can rely on my systems.

 

Good points RAYK but it still does not address the original questions
Guillermo used the POgo as an example of a dangerous ballasted monohull.

Guillermo claims he can prove that there are situations that, as a result of the Pogo being marketed as a "cruising boat" could mislead a potential buyer and resulting in dangerous encounters with waves.
Rhough claims this does not matter given the 1) likelyhood of encountering those waves and 2) being able to keep the boat in an aspect that would not allow it to become overwhelmed by such a wave.


A pretty good question to me. One apparently that can't be discussed in a civil manner.

Seems to me this discussion woud have been a lot more fruitful if that ridiculous word "seaworthy" were left out of it, and some typical usage for such a boat were established.

 

No. Guillermo claims that YOU CANNOT prove that there are NO situations that , as a result of the Pogo being marketed as a "cruising boat" could mislead a potential buyer and NOT resulting in dangerous encounters with waves.

Guillermo is asserting something without prooving it, and is asking you to proove the contrary. And instead of giving facts on what he argues, he simply demands that your argumentation has reports on ALL boats pogo alike, anywhere, anytime to be valid. Which you cannot do. So then he claims your proove of the contrary is false, so his assertion is true.

You can see it there : http://boatdesign.net/forums/showthread.php?p=118120&#post118120

 

Well, it's not just in very high latitudes. I always try to make a sailing season as long as possible. Autumn, winter and early spring have their own attractions, but chance to be suprized by unexpected storm are quite high.

It's a difficult to guaranty "dryness" on the small boat offshore.

Yes, as reliable as possible and I would add as simple as possible. Electronic systems are just to complex to be considered reliable on the boat. There are so many things that can go wrong with them. I would put them in a nice-to-have-not-to-rely-on category. I work daily with computers at the office, in ideal conditions, they are not tossed around, environment is dry, supply of electricity is constant, proper watts and volts, and yet, otenly enough, they don't work and it takes a loads of time for the experts with all professional equipment to figure out what went wrong. Small boat, in the middle of the ocean, screens on tilt. What to do?

 

I will agree that Guillermos methods are confusing at times. You have to keep in mind he is not conversing in his native language. If he is confident enough to lecture a roomful of NAs on the topic he must have more sophistication in the topic than we are able to see. On the other hand I would like to see him defend his original statement without all the dodges and obfuscation. I have tried to center the conversation on his original assertions to give him a FAIR shot at clarification.
In my ideal world, these fora would be a casual atmosphere where one could ask a question or make a statement and expect to be vigorously supported or opposed with responses that intended to progress all of our understanding, without people becoming so invested in their own position that they are willing to break all the rules to "win".

 

I would be more than happy to participate. If someone would like to select a passage and a time of year. I would provide routing that shows the expected conditions the boat would face. From that raw data, sea state can be determined and the relative merits of the boats in those conditions discussed.

Alternately, if someone provides an average wave height that would threaten a Class40, but not some other boat (of their choice). I will see if I can route the Class40 on a passage that avoids threatening conditions. If I am successful, we can then compare passage times and debate if either boat has the ability to carry stores for a crew of 4 for that time.

 

One difference that seems obvious is that you (Randy) are talking about cruising in conditions of your choice, whereas Guillermo is talking about a boat that is fairly well permanently at sea and therefore subjject to whatever the weather happens to be that day. I think Guillermo agrees that the Pogo type design is adequate for summer cruising on voyages of a week or so. His argument is that such a design, whilst okay most of the time, will encounter conditions that it struggles in if it is permanently at sea. For a live aboard cruiser there are more suitable designs which require less skill and crew attention, fatigue the sailors less and will recover from a knockdown more quickly (at the expense of being more easily knocked down in the first place). For ultimate survival, it is important to be able to recover yourself, which catamrans can not do and the Pogo can not do so easily. In today's world we are more likely to be able to rely on outside assistance, hence perhaps the trend towards boats that are not totally self-sufficient. For many, this is an acceptable risk. However, some people (e.g. Guillermo) do not want to have to rely on others. Indeed it would be foolish to, if you chose to cruise remote parts of the world.

I think it is this difference in how you perceive cruising that is the fundamental difference in the two camps here.