Characteristics of Offshore Yachts

[David_Old_Jersey]

For those who want answers that are simple and quick and easy to understand (and invariably also cheap! And require no thinking. Lol)......own boat let alone extended voyaging is not gonna work. Disneyland probably has an experience that will fit.

[Neptune's Gear]

Great post Evans. We are on the same page. :-)

[OceanSeaSpray]

I can hardly see any such thing as a boat that will take it all, independently of what the skipper does or does not: any vessel lying around in a truly huge sea can end up in the wrong place at the wrong time and get picked up and dumped in a trough, free-falling a considerable distance. In such a case, the force of the impact and resulting accelerations would make being on board a rather unadvisable proposition.
I remember of a steel yacht in the North Atlantic that returned with a metre less headroom in the saloon.


Even excluding racers, some designs are much better than others in heavy weather and design options do matter, but this debate is often too skewed towards the "design" precisely. It takes away the personal contribution. It is rather essential for a skipper to also know and understand what his/her boat/design can do. What the boat does well, and what it doesn't. This knowledge is key when it comes to making adequate heavy weather decisions and acquiring it should be a focus.


There are usually plenty of opportunities to play with the boat and start pushing the limits on rough windy days. Does it run ok in steep seas? What happens if the headsail is sheeted in the middle? And conversely will it punch? Is it possible to tack? What happens under main alone? Is it enough to keep some speed and an acceptable angle? Can we haul upwind on a headsail alone? Maybe it doesn't work, but it looks like it might with more wind. There is a lot to learn from these things. Seeing them and experiencing them is what allows feeling beyond them should it ever become necessary one day.


A parallel of this is that I don't support the "weather avoidance" principle the way it is often understood these days. Boats are seldom perfect, but skippers need to experience weather and high winds and get to know them with their strong points and their flaws. This is at the very core of offshore readiness.
And - incidentally - if some did, they might not prepare their boats in the same way and those might not look quite the same. A lot of the offshore preparation I see in fact leaves the boats much worse off, should something reasonably severe actually happen. While this is certainly boat-related, it is no fault from the designer!


Few boats/designs are almost perfect, and few are completely useless. In the middle, it is a matter of getting a grasp of what we can consider doing successfully with what we have, should conditions get threatening. Here I am talking about sailing, not trying to apply never-tested-before canned recipes.
Realistically, most of the cruising vessels that do get into trouble offshore these days do so in what I would call standard gale conditions: give or take 40 knots for a day and a half, 4-6m seas after a while with the odd break. Conditions like those should be no problem at all. They just happen now and then. They are sailing - not survival - conditions.
In the meanwhile the talk is about dealing with the Fastnet 79 or Sydney-Hobart 98 and what the boat should and shouldn't be... Honestly, what is the point of worrying about the storm of the century if a good old standard blow is going to be a problem already? Solving that problem is still the best actual way of gaining an edge should something truly huge ever materialise one day. And in the meanwhile, it is one hell of a lot more constructive and useful.


Beyond this, yes, I like lean and mean boats with a low VCG, clean lines, nothing to carry away, built like battleships with plenty of sail power. I own one. But the reality is that the average modern production cruiser - provided it is well built! - is perfectly fine in virtually all common "bad" weather conditions if handled sensibly and competently... And most of these boats only achieve an AVS of around 120 degrees through meeting ISO12217. I don't find it great, but I can't say that it is inadequate either and there are many boats that feature a higher AVS and are far worse sea boats.


Anyway, a bit of a different take on this.

[mstrebe]

Originally Posted by leftbrainstuff

The existing ocean ratings are more akin to hotel star ratings. If you have feature or equipment on the list you get a rating. Great marketing aspect but has no correlation with survivability.

Can you explain why you believe this? I did quite a bit of research into the CE and STIX ratings that they're based on, and they actually do a reasonably good job of accumulating what sparse information is available into reasonable criteria for their various categories. If you're going to dismiss them as nothing more than hotel star ratings, I think you owe casual readers an explanation of your thinking on the matter. Your following comments don't explain why you think these ratings are baseless.

Modelling and simulation is great, as is statistical analysis providing we have a clear definition of the requirements and can validate in service. The problem is we lack a clear definition of survivability and how will it be applied in practice.

In most cases we dont have statistically valid data for what is a wide ranging broadband data set We only have individual vessel data sets. The ocean and wind is highly variable, unlike road data, which requires very large test sets to deliver validation. A single stability rating will not solve this problem but may eventually lead to better boat designs. The static stability index for SUVs acts similarly.

I have 30 years of engineering analysis and testing in motorsport, automotive and defence. Unless modelling, simulation and analysis is correlated in practical, repeatable, real world tests it is very dangerous to trust those results.

In automotive, defence and motorsport there are specific and legislative tests that are mandated and for which we have good historical evidence. Until we see the same for sailboats I dont expect any improvement in survivability in the near term.

Absolutely true. Unfortunately, we are never going to accumulate statistically significance in sailboat accidents to achieve anything like the relevance of highway accidents. 30,000-odd humans die in car accidents every year in the US. About 15 die in sailing accidents. At that rate, it takes a century to reach 3-sigma evidence, which is the bare minimum level acceptable as evidence in science and engineering.

So that's never going to happen. Hence, we have to rely on models, human intuition, the experience of experts to form an evolving base of standards, which is exactly what the STIX and CE standards are attempting to do. Considering that nobody else is even making an attempt and that the alternative is marketing driven disinformation at one end and anecdotal forum groupthink on the other, I'd say it's a vastly superior methodology.

If I'm unaware of some superior methodology or effort, please advise.


Sent from my iPhone using Cruisers Sailing Forum

[Ericson38]

Chuck Paine and Nigel Calder put a lot of thought along the lines of the question of this post, and then put pencil to paper.

http://www.jordanyachts.com/wp-conte...lorer-4750.pdf

[Cap Erict3]

This fella and his boat inspired a few folks.


https://en.m.wikipedia.org/wiki/Spray_(sailing_vessel)


------------------------------
Looking for another pretty place to work on the boat.

[Terra Nova]

Originally Posted by Ericson38

Chuck Paine and Nigel Calder put a lot of thought along the lines of the question of this post, and then put pencil to paper.

http://www.jordanyachts.com/wp-conte...lorer-4750.pdf

Stylistically that is a new low for Chuck Paine, who designed one of my favorites: Annie.

[Seymore]

Another good, relevant book is "Seaworthiness--The Forgotten Factor" by C J Marchaj. I think very highly of it.

[Ericson38]

Originally Posted by Terra Nova

Stylistically that is a new low for Chuck Paine, who designed one of my favorites: Annie.

Ah, she ain't all that bad-

https://www.youtube.com/watch?v=XBcxUCa2Je4