Keels and Keels Again!

I am surprised more reference was not made to the light scantlings
of the connection..
Should serve as a warning to maintenance crews of this type of
fixing to instute more rigorous inspection/repair after grounding.

The last paragraph (blanked) does not contain anything relating to scantlings.
(or relevant).
Roger Stone discharged his duty in the highest way, he has my utmost admiration.
RIP Roger.

 

Keels

There is no lack of willingness to spend huge an mounts of money on things that s don't matter, like fancy woods for interiors, electro polishing, etc ,yet skimp on critical things that the boatshow buyer doesn't see , like how well the keel is attached. In our well programed "Style over substance, consumer society " the former is what sells boats , not the latter, which boat show buyers dont see.. Thinking outside the box from our consumer programming is what will save you from disasters, like keels falling off , etc. A boat doesn't have to be expensive to be seaworthy, just have spending priorities in the right place.
Brent

 

so let me throw this in
are the lifting keels more or less likely to suffer a catastrophic failure than a solid keel
Im sure the solid keel should be safer
but is it
by the numbers
if anyone has em
how many and of what type boats are loosing keels
Im curious

 

What's relevant in this regard is the difference with solid and something that seems to be solid.. Anything done with inadequate scantlings (=lowsy engineering) will eventually fail...

 

true
all to true
but were do the screw ups tend to take place
does anyone keep stats on these failures

 

That's a huge task to keep track.. I think this thread is one of the best possible sources to track these failures internationally. Of course local authorities, and perhaps some national/federal ones have some more insight but it's mostly related to individual events. Think the participans making the new ISO standard of keels have also better insight (and orgs like DNV and Loyds)...
Anyway it's fairly easy task to calculate and check an individual boat and how well floors and bolts etc meet the requirements of some well proven set of scantlings. However if the data to make such calculations is not provided (or it's a secret) by the manufacturer there's a good reason to believe that the engineering is made in a way that ain't even close to be acceptable..

 

Lloyds insurance house would be the most probable to have the info
Ill write them and if I get a response Ill post it here
cheers folks
B

 

The full USCG report on the Cynthia Woods tragedy has been put up as files on a Yahoo group. Go to groups.yahoo.com and sign up for the group "cwsailboat"

After signing up, go to the Files section and the pdfs of the report are there.

It appears at first glance that the damage due to multiple groundings was much more severe than first thought, but I'll let the experts weigh in on that.

Earl

 

When it comes to short, deep, airplane wing like keels, my vote goes for the lifting keel being less likely to fail.

The reason I say this is because the lifting keel has to to go through a case, just like a dagger board on a dinghy. That case is relatively easy to brace well either to the surrounding bottom or to a cockpit sole or deck above. And when it is not well braced, it becomes quite obvious. The case will lean slightly from one side to the other as the boat rolls or changes tacks. And since it will most likely be in plain sight, something is more likely to be done about it.

With the fixed keel, most if not all of this flexing happens underwater, out of sight, out of mind, until the failure happens.

Also, with a fixed keel, there is the temptation to attach a huge flange to the bottom of the boat and have the keel joined to that by either welding it together or by having the keel and the flange a single casting.

The problem here is the joint were the keel connects to the flange. This is under huge, hinge like stresses that are concentrated in an almost straight line along the joint. With a more conventional fixed keel, the keel is significantly longer in proportion to its depth and, therefore, has a significant amount of fore and aft bottom curvature along its keel hull joint. This curvature puts shear and tension stresses along the joint rather than bending and tension stresses. Also, the Center of gravity, of the more conventional fixed keel is closer to the joint and, therefore puts less stress on it to start with.

I would not be surprised to hear of a way of making that joint, on a short deep, bulbed keel, strong enough. I suppose the key would be to make the joint massively thick and having it taper far down the depth of the keel, so the bending stresses would be better distributed. But this would make an ugly bulge at the top of the keel which probably would not be all that hydrodynamic. It would also, in all likelyhood, raise the C of G of the keel as well as complicate the fabrication process.

The real issue here is not so much about engineering as it is about human nature. To adequately engineer is Divine, but to skimp is human. Especially when one is not quite sure where adequate engineering starts and skimping leaves off.

 

ROLAND JOURDAIN DAMAGED KEEL
Jan. 29, 2009; Day 81 - With less than 2000 miles to go in the Vendee Globe,
http://www.sailingscuttlebutt.com:80/

"Roland Jourdain called his shore team at around 0400hrs this morning to say
that he had a problem with the keel of Veolia Environnement. After a long
night he had heard an unexpected noise which he duly investigated, stopping
the boat and checking as much as he could. Later in the day, Jourdain
confirmed that he had lost the keel bulb, but is still unsure where the damage
begins, as it may be the joint between the bulb and keel or higher on the keel
blade. It is also unknown whether this is a consequence of his collision with
a sea mammal on January 8th.

Said Jourdain, "I can't explain how I didn't capsize. I shan't be diving in
these conditions, as there is quite a swell. On the other hand, I do know that
if I hoist more sail, the boat heels over so there is definitely a problem
with the keel." Jourdain has slowed to just under seven knots as he nurses
Veolia Environnement towards the Azores, which are 600 miles ahead on his
route. Based on the weather forecast and boat performance, Jourdain will
decide if it is possible to continue past the Azores to complete the race."


From Scuttlebutt Europe:
"The boat is being kept as stable as possible with the ballast in the bow
and in the middle of with, the centre of effort of the sailplan kept as
low as possible. It is still unknown exactly where the damage begins, as it
may be the joint between the bulb and keel or higher on the keel blade.

For the moment it is out of the question to heel the boat over to see as
this would risk causing the IMOCA Open 60 to capsize. It is also impossible
for Jourdain to risk diving because of the sea state
The first reaction was to continue to Les Sables d'Olonne, but it is
understood that the skipper will not take any undue risk. For the moment he
does not need to change course as the Azores"

 

Jean Le Cam lost his keel just west of Cape Horn earlier in the Vendee Globe. He went over very rapidly. Vincent Riou (PRB) succeeded in rescuing Le Cam from inside the capsized Open 60, but damaged his port outrigger. 250 miles later, on course for Ushuaia PRB was dismasted. See 6th January reports.

http://www.vendeeglobe.org/en/news/8/

Regards,

Perry

 

dumb question
both guys
same race?

someone had a point when they said this was happening to often
B

 

More from Scuttlebutt:

SEVEN HUNDRED MILES WITH NO KEEL
.........
Arriving yesterday in the commercial port of Porto Delgado, Sao Miguel in the Azores, Roland Jourdain's keel inspection revealed only a short twisted stump of keel blade remaining. Having sailed more than 700 miles with no keel, Jourdain believes the keel fractured in two stages.

"I think the breakage happened in two stages, otherwise I would have capsized the first time. The bang I heard, I thought it was the bulb and in fact I think that when the keel broke, it twisted and a piece stayed attached to the hull, which stopped me from capsizing. Then at a later moment, when I was taking in a reef, I heard a cracking sound coming from the hull and that must have been the piece breaking off."

Cheers

 

Open 60

From Vendee Globe.

Marc Guillemot’s Safran has keel problem. He hit a sea mammal near the Kerguelen Islands last year and now the keel is loose and sliding out of the hull. Secured with ropes.

http://www.vendeeglobe.org/en/news/9127/safran-has-keel-problem.html

Perry

 

The keel has dropped off.

http://www.vendeeglobe.org/en/news/9144/safran-carries-on-with-no-keel.html