Seaworthiness

The focus on loss prevention is all the rage in North America. It is driven by the insurance companies. Crash test ratings and extra airbags are selling points. It would be wonderful to see strict enforcement here.

I do not think it would boring at all, if one had to be certified before taking off to "follow your dream". How boring would it be if boats had to be Ken Barnes proof? It might mean that boats loike the Pogo 40 could not be sold, no matter what the experience of the sailor is.

I think there is an obligation for skippers to know the handling characteristics of their boats. They should also know the loading and CG limits. Every Pilot that flies a Cessna 172 has to know these things and demonstrate that knowledge. They know that if the plane is overloaded or loaded incorrectly that it may become uncontrollable. They know that there are limits to performance. If the plane is operated outside it's design envelope it might fall out of the sky.

If every skipper had that knowledge, we would not have to worry about innocents in overloaded Pogo 40's.

I can see the other side of the argument too. Despite much more stringent requirements, the primary cause of accidents in aviation is still pilot error. Just as the primary cause of auto accidents is driver error. It should come as no surprise that skipper error is to blame in boat sailing accidents.

This is a "Catch 22" My position is that the "safer" they make cars, the worse the driving skills become. It is a documented fact that in fatal crashes, the number one driver response (in the USA) is to do nothing. No evidence of brake usage, no evidence of an attempt to turn. Cars are thought of as "safe" so why bother learning to drive?

The same thing has happened in boats. No or near zero maintenance composite boats ?... Guess what, they don't get maintained. Roller furling jibs and mains ? Guess what, sailors are afraid to work on deck, they have never changed a head sail while underway, and have little idea of what to do if one of the furlers fails. GPS navigation? ... When you can have a primary GPS unit and 2 back-ups for the price of a sextant and chronometer, why learn to navigate? ... Guess what these people not only cannot navigate, they also lack basic piloting skills.

Is it any wonder that sailors with this skill set make modern boats look unseaworthy? Imagine what the skill level would be if new designs of cruising boats were advertised as being even safer? IMO there would be more accidents, more capsizes, and more deaths. More "Sailors" like Ken Barnes would be at sea, placing their faith in equipment they don't understand and lack the skills to maintain or repair. The "new" designs would not increase safety at sea, they would have the opposite effect. They would put even more unqualified people on the water.

I realize that expecting those that go to sea to be qualified to do so is folly ... but it's my folly.

I also think that condemning modern cruising boats as unseaworthy is folly, as long as a Ken Barnes can come along and make your design look like a death trap.

Since my position is that, in the right hands, boats are plenty safe enough as they are and I have a philosophical disagreement with designing for ***** operators (I think cars should have sharpened railroad spikes in the steering wheel instead of air bags), I cannot contribute to this thread.

Cheers,
Randy

 

At the risk of being berated for going off-topic, it is not practical to regulate/legislate aginst either sailors or their boats. There are no cops at sea to enforce laws, and besides, when you are offshore you do not come under normal legislation.

Who's going to check that the sailor has a license or the boat is certifed?

You can make boats more seaworthy, but all the while I can still sell better looking, faster, roomier, more luxurious, cheaper boats that are less seaworthy - and I will outsell you 10 to 1.

One solution would be to charge people the full cost of any required rescue operation. This would force the sailor to be insured and the insurance company would insist on suitable qualifications and boat design/maintenance.

Anyhow, you want an example of a seaworthy boat - how about a Global Challenge yacht? Or a Swan?

 

The EFES 56 is the kind of boat I would like to own, but with some alterations (I've posted this opinion at the STIX thread before, where I did some parametric analyzing of the boat). Probably I'd look for a somewhat higher D/L ratio, closer to 200 (this bringing SA/D also somewhat down) although probably this is less important in a boat this size, and a skegged rudder. But unluckily I have not found info on her stability curve, to have a deeper knowledge and opinion on her. Anyhow being a relatively narrow boat with a bulbed keel, probably the curve shall be nice.
I have not major objections to not extreme fin keels for cruisers, if they are properly bolted and reinforced, even recognizing hull-moulded ones are safer from the collisions point of view.

I would like to do that, certainly, but I have no stability data on the POGO 40 as I could find nothing on internet (Nor about her STIX). It seems that designers of that kind of boats are not happy publicising that kind of info....I wonder why.

On the other hand I wouldn't like to use price as a comparative. I think we should not bring that into a technical seaworthiness debate. In my opinion is more fair to compare size with size. A comparison like this has been already posted at the STIX thread, at the very first post (Eliasson analysis of RED and BLUE boats: http://boatdesign.net/forums/showpost.php?p=103475&postcount=1). I refer to all of you there.

Cheers.

 

No, we should not compare boats with the same size; we should compare boats with the same displacement.

Of course this would be as valid as basing a comparison on length, or by size do you mean the interior volume of the boat? After all, for cruisers, space is very important and the length you need (for living) depends on the interior volume of the boat.

All this different criteria are quite irrelevant, because when you are going to buy a boat, you buy the boat your money can buy, and inside a budget you can chose over different options regarding seaworthiness, but always inside a budget.

So price is the less arbitrary criteria, as CT and FcFc said:

A used boat, as FcFc had pointed out is not a good way to go. If we are talking of a used boat against a new Pogo it will be an unfair comparison. For the same price of a new Pogo we could buy a 15 year old much bigger boat, with the same kind of Pogo hull to oppose to the used Halberg-Rassy that Mike was talking about.

The only fair comparison is based on price and new boats. We can only compare what is comparable.

And after all I am not talking about a tight budget here; I am talking about $230 000 USD, that’s a lot of money.

With this kind of money can’t you find a new oceangoing boat? I can name several, not to mention the POGO, not as nice and well finished as the ones that I have been posting in my thread about cruising boats, but good and seaworthy oceangoing sailboats…but that’s your turn to choose.

Choose that boat Guillermo (a production one) and I will help in finding the data for both boats.

 

I can't agree and I would like you to continue to contribute to this thread. To be able to define seaworthiness, we first have to define the "what", what level of seamanship and experience should we consider? What is plain stupidity and irresponsibility and what is out-of-scope at the other end of the scale. There your input as a sailor is important so please give your opinion

It is easy to select suitable boats to compare once we have this nailed down

Mikey

 

I would not go so far, saying only new boats are considered.

But if you use the new market, please choose the comparison point to a 230 000$ new pogo 40.

And if you choose used market, choose comparison with a used oceanis 390, for which you have all stability data in the MAIB report, and for which you can find a average used price of 90 000 $ (Go yachtworld, and request all beneteau 39 ft, from 1985 to 1991). There are around 20 for sale. Beware you will get also some First in the list. Exclude them.
Now, you have a used boat for 90 000$ many in this thread consider UNseaworthy. What is your better proposition for increased seaworthiness, with equal or less budget ?

 

Well, I'm sorry but I refuse to analyze seaworthiness from a budget point of view. I find it unrealistic and so useless. It's something like saying: Ok, let's take a ropes and planks bridge over a 50 m wide river and compare its safety with a 'similar priced' rigid steel one. We have to do realistic and useful comparisons. Any other member here may do that comparison here if he wants so, it's OK to me (go ahead, please!), but I will not enter that debate.

I think not even comparing equal displacements is of real use, just said like that, as we could easily find ourselves comparing boats of very, very different sizes.

I think comparing boats of more or less similar size and different displacements and forms, as Eliasson did, is the most appropriate way of facing the thing, what has been also done by many other authors when studying this matters.

I may try to find out a sailing cruiser of similar size as the POGO 40 and compare them, if Paulo or any other one gets reliable data for the POGO. But if this is not interesting, then I stick back again to post number 1 at the STIX thread, and the other many posts there on boats' analysis.

Randy:
I think talking seamanship and its influence in seaworthiness is a difficult debate. I'm afraid these are 'boatdesign.net' forums and not 'sailordesign.net' ones . We can design boats to different levels of crew expertise and crew number, as well as expected weather and sea conditions, but after that better or worse applied seamanship in each circumstance, is just an arbitrary variable.

Cheers.

 

Guillermo, can you take a brief look at this one by Dudley Dix?
It's 38 or 40 feet long, quite light, and quite low cost

http://www.dixdesign.com/38didi.htm

 

I have to agree. It is more than difficult, it is nearly impossible. Prudent sailors make passages in unlikely craft all the time. Less prudent sailors get into trouble in what are considered sound craft all the time.

I don't see a problem with design trends. I do see a problem with people going to sea with fewer skills and little experience.

I don't see the major manufacturers of cruising boats selling extreme designs. I don't see anything wrong, so I don't think design can fix anything.

Since this thread is "Seaworthiness" in the Stability forum, and I don't think that stability is the most important consideration when deciding if a boat is seaworthy or not; I really have no more to say.

Fair winds,

Randy

 

A bunch of advantages of the didix 38 come from its very low weigth.

That means to allow its 12 mm plywood skin to be strong enougth, it must have a "dense" framing.

This is more or less important when you do not pay labour time (homebuilt). But it is catastrophic if you have to pay normal marine carpenter wage to do it.

If you compare the price with a fully built by a shipyard (with "normal" wages european level ) didix 38 and a oceanis 40 ( http://www.beneteau.com/ressource/documents/4793/B_oceanis_40_150906_600.pdf , list price june 2006 is 136 000€, including taxes, and build with french wages) I do not think the didix would be "quite low cost".

There is an optimum price/weigth ration wich seems to be around 7T - 7T5 for a 40. See beneteau or bavaria weigth. If you build heavier than that, price increase because of more materials, more loads etc ... But if you build ligther that that, price increase too, because of more expensive materials, more engeenering, more complex work.

The pogo is a bit ligther than that optimum price weigth, so the price goes to 180 000 €. The didix 38 is really ligther. So the price would be still higher. Mainly due to labor costs of its complex structural framing.

 

Yes, that is a very interesting boat, a modern boat light boat with a deep bulbed keel, spade rudder and a large transom.

This is a 12 year old design, and a typical example of fast and seaworthy boats that derived from the ocean racing boats of their time. If he had designed it now, probably it would be a little different and it would be influenced by today modern racing developments.

And this boat was the one he chose for himself and he considered it seaworthy enough to cross the Atlantic several times.

Dudley Dix:

"This one was for me! For the first time in my professional design career I was the client.

Launched in 1995, I have crossed the South Atlantic three times on her and experienced a run of nearly 250 miles in 24 hours and a top speed of nearly 22 knots.

Her lines are thoroughly modern, with short overhangs, fine bow at the waterline and powerful stern. Sections are slightly Veed throughout the length to give a large planing surface, efficient when upright or slightly heeled. The forward underbody has been shaped to develop dynamic lift to keep the bow up at speed and promote surfing and planing."

I like it and it is a good example how modern light fast cruiser-racers can be seaworthy and ocean-going boats.

But I agree also with what FcFC said about costs.

 

All the structure can be cnc cut + the panels for most of the hull, deck, cockpit and superstructure.
Okume plywood costs more than csm+polyester, but far less than any core material and less than high quality glass and epoxy.

When ths structure and skiin is plywood, you can leave it as it is insde, no need to hide it liek most people like to do with grp.

 

Seaworthiness is a relative concept. As you know in the WWII some destroyers sunk in a big storm in the North Atlantic. If most cruising sailors had $1 million USD to buy a sailboat, seaworthiness would be greatly improved, but still would be very far away, regarding an absolute value. And the reality is that the vast majority doesn’t have that kind of money and sailors buy the boats they can afford.

Because seaworthiness is a relative concept, it makes all sense to look at the best seaworthiness for a given price. Of course, if the budget is too low, you would not have enough money for having a boat with a seaworthiness compatible with offshore use.

I would understand your position if the budget was a low one, but it isn’t. We are talking about $230 000 USD and that money is enough to buy an oceangoing sailboat, even if we consider, like Eliasson, that an oceangoing boat should have a STIX > 40.

Besides $230 000 USD is the price of a big production 40 to43ft and that is the kind of boat that most sailors are buying as an offshore cruiser. Of course, there are better choices in seaworthiness, but whatever boat you buy, there are always better choices. What seems important to me, and to the purpose of this discussion, is that this budget is the one that is more usual on the majority of offshore cruisers and therefore it is particularly important in what regards Costs/seaworthiness.

If you have a better choice than the one they are making, regarding cost/seaworthiness, I would like to see it.

You have said about the POGO : [COLOR="Blue[B]"]“Really dangerous when not in planning conditions … Or even in planning if you lose control, whatever the reason”, [/B]…”things are even worse” [/COLOR](comparing with the RM1200). And even worse means worse than a boat that in your opinion is: “not safe at all when at open ocean”.

You have said that the Pogo AVS was 115º and about the STIX: “but I guess is probably as low as the RM's one” and you have said about the RM1200 STIX : (100) = 32,920 …Very low figure for the size”.

Seaworthiness is a relative concept and even if you consider that the kind of boat that you can buy with $230 000 USD is not, in your opinion, a true oceangoing boat, certainly you can find a much more seaworthy boat than the POGO for that price.

Or perhaps you are very wrong and you have posted a lot of wrong numbers and after all perhaps the Pogo is really an oceangoing seaworthy boat, as I have been stating from the beginning.

You have said this about me:

It looks to me that you are the one who doesn’t support your claims with hard data and it is you who refuses a serious discussion and refuses a comparison (regarding seaworthiness) between a boat that you have slandered with any other sailboat of your choice, with a similar cost.

It seems to me that what you call “size”, changes according with your conveniences. Let me remind you what your interpretation of “bigger boat” in the STIX thread was:

http://boatdesign.net/forums/showthread.php?t=13569&page=4

What I have said in my quote is correct, and you have implied that I have misinterpreted your words and that in your quote, BIGGER means HEAVIER.

I am a little confused here. To you a bigger boat is a heavier boat. It is obvious that then (to you) a lighter boat has to be a smaller boat.

What is then the logic of comparing a smaller (lighter) boat like the Pogo, with a much bigger (heavier) boat?

How can you say that a smaller boat and a bigger boat can be of the same size?

This is very confusing; I think that cost/seaworthiness is a much less ambiguous comparison.

This can only be interesting. Lots of talk on this thread, let’s pass to facts and hard data, or do you prefer to continue to substantiate your claims on old books?

 

As I told you: You have no idea of what you're talking about, you don't understand what you read, you do not work out a single number and you do not provide interesting analytical sources on these matters. It's of no longer use discussing with you, I'm afraid.
Bye.

 

Thanks, Raggi.
I had not the curves for the DIDI 40. They are impressive. I'd like to work on them and then post at the STIX thread and here. Do you know for which displacement condition(s) are they draw?.

She's relatively narrow for the length (L/B = 3,27 for the STIX definition of L, and even higher if we take static Lwl/Bwl, which is around 3.9. And in dynamic mode with the extra stern overhang it'll be even higher) and has a high ballast/displacement ratio. It seems to be 0.42 for the DWL condition and 0.5 for the IMS, although I'm not sure for what version. The info on displacement and ballast at the site is confusing to this end. Is the ballast weight the same for all keel configurations?

Although finding the trend of bulbed, narrow and relatively light cruisers a very interesting one (probably it could be what I'd call a new paradigma of cruising sailboats over a certain size), I'd say in this case D/L is too low to my taste, although I would like to know displacements for the different versions. I'm not sure they are all the same.

Also I'm not sure about the real cruising load condition. A difference of just 750 kg between DWL and IMS ones, may imply a too low loading ability. Water alone for 6 people 30 days at 4 lt/person-day, calls for 720 lt. A more realistic cruising load for 6 people could dramatically alter numbers for the boat.

I'd like to know her real roll period. If it is as low as the estimated one of 2.49 seconds, this boat may result somewhat hard to her crew. Also I'd like to check her structural strength and calculation criteria, as it is difficult to build up by standard methods yachts with D/L under 180 (have you done somekind of an an estimative on this?).

I think we need much more information on the cruising versions of this boat, to be able to give an accurate opinion.

We can eventually cross oceans with light, deep fin keeled, spade ruddered, wide beamed, with huge sail areas, etc., etc., racing or racing-like boats, absolutely, as we can also do it in many other types of boats (even on bizarre crafts), but I have really big concerns about their overall safety and suitability as crusing boats.

Cheers.