Keels and Keels Again!

Vega:
A couple of years ago I inspected one of these brand new 12 m cruising sailing boats, having a modern but not radical bolted keel. I cannot remember whether she was Bavaria or Dufour. They hit a submerged rock when motoring at 6 knots and the keel did not broke apart, neither there was sea water entering the hull, but when ashore I could move the keel one side to the other as a pendulum, just with one hand! All the internal reinforcement broke in several places and the keel was just suspended from the hull's skin...
Some of the builders in this dangerous down-pricing boats race, claim their boats comply with ISO 12215, so they are 'not guilty'. But they forget to mention this standard is still under discussion, so not fully approved yet. And I doubt some of the reinforcements I've seen even comply with ISO 12215!
As a matter of fact I do use several ISO standards in my work, but not yet the 12215. I rather use Det Norske Veritas and other rules from Classification Societies.
My Banjer, good old MARIE, with her full length monolithic keel, standed a 'close rock encounter' when I was alone doing some trawling-lines fishing in a fair summer day with almost no waves. Being busy with the lines while sailing pretty close to a rocky coast at 4 knots, trying to get some nice fishes, I misjudged the rhumb to avoid a close to surface rock (I knew it was there!), and MARIE's 13 tonnes happily rode over it coming to an halt with her bows pointing upwards, while I was retrieving a fish.
Well, I brought all fishing lines aboard as well as the fish (No way of losing them!) and waited for a bigger swell wave to rise the canoe stern and then put full reverse throttle on MARIE´s 71 cm propeller. And luckily free we went at the first intent.
When we lifted her, there were only minor cosmetic damages in the bottom of the keel, painlessly and quickly repaired in a matter of minutes.
I bet I will never choose a bolted spade keel for a cruising boat if I can avoid it!

 

So what you guys are saying is that anything bolted together must be unsafe?

Hell that scares me.....I fly on 747s and I drive over bridges bolted together! I stand on cantilevered balconies, and underneath traffic signs that are cantilevered over highways! And all this time I've been in danger. Yikes!



I was in the hangar where they refit 747s a while ago, looking at the strut that holds the engines on. They looked fairly reliable to me, yet they are surely narrower in chord AND stronger than a fin keel. Isn't there a little bit of force on the narrow bit of metal that connects the bit that holds the plane up with the bit that pushes it along?

If Boeing can keep 747 engines attached under such loads, why can't we keep fin keels attached? Surely it is possible to engineer a medium-chord fin keel that WILL withstand reasonable collisions and groundings?

 

then again, most boat designers are not qualified structural engineers:!:

 

looking at guillermos picture;and I am no engineer, but the attachment looks pretty cheesy to me, as a fisherman ,we always said you should be able to drop a boat off a roof of a house and she should just bounce ,some of the waves Ive encounterd have flexed the hull...shooting off of 30 ft breakers and slamming into the next,,,,,,designers must realize ( these must be built stronger than airplanes) boats should be built closer to tanks

 

Designers do realize, calculate, re-calculate when the marketing folks say it can't be sold at that price, factor in safety margins and generally, what you'd expect from a committee built anything.

Production vessel markets are so tight that saving a gallon of resin per boat has to be considered. It's very difficult to look at some damage or broken fin and declare it a design flaw or an under cut from the pencil pushers. In most cases the impact was a lot more then we can imagine. Well it shouldn't have broken the keel, if it hit a coral head with every thing flying in 20 knots of wind.

I find that disturbing, because I've calculated force on impacts like that and the best of us couldn't design a similar boat with a comparable performance envelope, that would tolerate the same impact. If we could, we'd be retired on a beach with scantly clad young ladies about. At some point a line has to be drawn, typically it's the bottom line, but it forces the designer's hand in many elements of the scantlings. Could a boat be done to withstand these types of loads. Sure, they exist, but they cost more, are heavier, slower and few people will plop down big bucks for an expensive, heavy, slower boat. Working and commercial craft have been made near bullet proof for many generations and understandably so. I'm reasonably sure, the market for performance sailing craft will not accept a boat that can resist a whale, submerged container or coral head strike, if it means, more money and less performance. This isn't an issue with well burdened craft having a full length keel, just the boats that must push the edges of the performance envelope enough to generate a market or win come race day.

 

Well, 747's aren't supposed to hit rocks! No, on my side I'm sot saying anything bolted together is unsafe. Only that for an all around cruising boat (not for a high-tech racer, absolutely!), I'd rather choose an encapsulated more or less long keel, depending on type of boat, waters to sail and performance wanted. Although a bolted keel of not a radical design can withstand pretty big hits (I've seen several of those), in the long term it gives me more peace of mind a non-bolted keel, because I've also seen some pretty badly corroded bolts.

 

Ah, okay - sounds good, Guillermo.

 

I experienced once reaching with 8 - 9 knots on a Acupper a full hit on a sandbank outside the Isle of Texel, in the dangerous Molengat.

I saw the mast making all attempts falling on me but miraculously it stayed on deck. (I was standing with a lamp in the pulpit to identify the buoys)

After swallowing a few times, we continued our way, being a little shaky........

 

To my mind Gilly and Par have the right idea (that shook you gilly!) Designers DO look at structural engineering etc when designing work boats (usually). But when we come to racing boats and even those that 'might' race it's about weight saving not life saving (partially client fault) and as long as the vessel complies with some rediculous list of numbers said to be some sort of Government approval (thought up by mathamaticians not Seamen [ability not necessary] and other posers [this can include failed marine architects - and there are a lot of these about the world, f'instance the average marine achitect believes people are three foot tall with 17 foot long arms - try using or maintaining some/most of these designs]) then everything is OK!

MMMMmmmmmm!

 

The design brief for racing craft (of any sort, air ground, water, etc.) places the primary goals on the end result, performance. If a keel will survive 90 percent of what is asked in it's expected envelope of operation, performs well against the competition, then the margin of error that could cause it's fin to be snapped off has to be lived with.

In cruising craft, the design brief is quite different, requiring a level of redundancy and heft that a racer or performance oriented craft, couldn't tolerate and remain competitive. I have no problem with well engineered bolted keels, but I error on the side of not breaking things, so my stuff generally is slightly heavier then necessary. A cruiser design will do well to use similar margins (and for the most part they do) it's the "cross over" type of design that run into trouble, lulling folks into thinking it's a cruiser, but in fact, it's built like a racer. This is the fault of the buyer, not the designer. If you want a cruiser, you can have one, but you'll get beat around the buoys. If you want a racer, then they're available, but avoid hitting things other then the marks. If you buy a "performance cruiser" then you'll looking for issues to test. It's a bit like mentioning honesty and politicians in the same sentence. As a rule, you'll get one or the other, a rare example will provide both.

 

Yes. Taking apart pure racers, designed to limits and so asuming high risks, I find the actual problem is in, as PAR states, the cruiser-racer or performance cruiser segment.
Designers take techniques bred on the race field and apply them to boats conceived for weekend regattas and some ocasional cruising around. If we put in top of this the price struggle among boat builders, we have here the recipe for problems.
Cruising around even in well known home waters has always its risks, one of them hitting submerged objects (As you can see by my own story previously posted). So I find that using this kind of cruiser-racers for cruising is calling for trouble and should not be encouraged. Even the word cruiser-racer should be banned because brings people into misconception.
In my opinion, if you want a racer, you should buy one and then do not attempt to go cruising with it.
Paradigmatic is the case of cruising flotillas. Many times the boats are by no means racers at all, having ample volumes to make them comfortable, etc., but perform rigs, keels and rudders resembling the race field, maybe because it's more 'modern', 'sexier' or whatever you like. And usually they are cheapily built. Bingo! Once again the recipe for disater, as was demonstrated in Croatia.
I firmly believe the use of that kind of boats to be hired to people should be forbidden. A flotilla boat should be conceived and built specifically for serious cruising. Not as a toy.

 

Guillermo, you and I are in basic agreement from an engineering point of view, but I do strongly disagree that some models or types of craft should be banned. The true cruisers I know (I've done a bit myself) wouldn't be caught dead, on some of the so called performance cruisers the productions lines are churning out.

The cruiser crowd is the most difficult client to please, as the design has to incorporate so many differing elements into the package. True cruising vessels can be had, but they cost more, are better equipped for their role and can take much more abuse or neglect. It takes many years and thousands of miles under the keel, to establish the criteria, in the cruiser's head, of their perfect yacht. This will be quite different from client to client, though many similar features could be incorporated into sister yachts. The net result of banning some types, would force only those who can afford a true cruising craft to own, leaving others to venture out in vessels even less suited then the production racer/cruiser variants, now offered.

Ultimately, the owner is responsible for the selection of the yacht. If they are influenced by the advertising hype and don't pay attention to the other cruisers or knowledgeable friends, then who's to blame? It's sad that marketing has played this nasty game for this industry, but it's little different in other industries, because it produces sales. Would BMW put a spoiler on the back of one of it's cars if it wasn't used on a race car first? It's okay when anti lock brakes trickle down from the racers to the street cars though, right? Maybe they should be used only on the race cars? How about composites, bred for the racers, finding it's way into production vessels, to lighten weight and make them go faster. I guess this type of thing should be discontinued too? The problem with banning things is like a crack in a dam, once it's started, it's likely not to stop. For this reason I don't want any vessel types "forbidden" because we'll just be opening the gates to a very ugly process that has been repeated many times in history, without success. Bone heads will always try to cross the pond in a O'Day 19, then try to sue the manufacture for the drowning of one crew member. They fail in court for the same reason they failed as a boat owner. You can't stop this, some folks are destined to make asses of them selves, possibly with injuries to others.

The bottom line is, the true cruiser is a state of mind, not so much a type of yacht.

 

I agree with you but I don’t think that what you say is what it is really happening. I mean, as Guillermo has pointed out correctly “Some of the builders in this dangerous down-pricing boats race, claim their boats comply with ISO 12215, so they are 'not guilty'. But they forget to mention this standard is still under discussion, so not fully approved yet. And I doubt some of the reinforcements I've seen even complies with ISO 12215!”

I believe that if we pick a boat from the same builder (the ones that now only comply with ISO 12215) and compare it with another, built 15 years ago, we are going to find that the older boat is a stronger boat, a boat that will vastly exceed Iso 12215, a boat that is slower but also safer than the new boat.
I find this unacceptable. If you compare with the car industry, all cars are a lot safer now if you compare them with 15 year old models.

I don’t agree with you here. Fact is that most of the builders – all the big ones (with special incidence in Europe) are selling inexpensive boats with big and attractive interiors, calling them cruiser boats. Those boats are certified as Class A boats, that means unrestricted oceangoing boats…and obviously they are not.
When you go to a boat show (that’s the place most people go when they want to buy a new boat), the boats you see are these, and consumers don’t have any reason to suspect that those are not really strong oceangoing boats. After all, the shiny catalog does not provide any real information about stability or structural integrity, nor about the way the keel is bolted, but it says that that boat is a certified oceangoing boat (from 33ft up, from all the major builders) and that should be enough.

Fact is that most people don’t understand why there are in the show some small stands with some boats that look the same and cost a lot more and even if they have the money to buy one of those, why should they do it? They look the same, apparently they are the same and after all by the same price of one of those expensive 40ft they can buy a 45ft or a 49ft with a lot more inside space…

I don’t think that sufficient information is provided to the buyer, I even believe that the provided information is misleading and I think that that is unacceptable and criminally dangerous.

 

Neither do I, PAR. Maybe I was somewhat exagerated in the use of words.
What I'm trying to say is I don't like how some marketing concepts like the 'cruiser/racer' one sometimes push people to make unwise decissions (Although every owner has its own responsibility here, for sure) and, on the other hand, what I really think it shoud be forbidden (disfavoured?) is the use of not proper cruising boats for cruising flotillas, or, more generally speaking, boats for rent with cruising in mind. Users may be people without enough navigation skills and seamanship, being many times families with small children, etc., and having very little time to know the boat and its weaknesses. I'd rather enforce the renting companies to give them sound, strong and forgiving boats to sail with. Although here we have again a responsibility of the skipper who is renting the boat, I find there is a bigger responsibilty of the renting company. If you rent boats in the very rocky and tricky waters of Croatia, you should buy strongly conceived and built boats for your flotilla, don't you?

Absolutely