Fin Keel Strength ?

[K_V_B]

Originally Posted by neilpride

Baveria Yachts - YouTube

Just found this in youtube , min 8.48 show the asembly of a fin keel in a new Bavaria, where is the STUB?¿?¿?¿?

Hmm. My opinion of Bavaria just went up. Didn't know they were that advanced.

No keel stub. But that isn't needed. I don't see how the hull-keel attachment is made any stronger by moving the plane the keel is attached to down a few cm.

[sailorboy1]

Some real time beng spent on intiernet research by some posters in order to "win" the debate.

If you dig around long enough you can find a few boats that have had any problem you want to use to support anything. Doesn't mean that much except that there is a small chance of anything happening.

[Maine Sail]

It is funny how the same few examples of boats losing keels are reused every time the subject comes up. Cynthia Woods, Bavaria and some J Boats... If we were to look at the sheer number of sailboats built with bolt on fins over the last 40 years, perhaps 2.5 million or more, world wide (guessing at the number). These few examples equate to numbers on the 0.001 range if in fact 2.5 million bolt on keels have shipped over the last 40 years.

I even know of a few more boats, like some of the O'day's, that had sub par build, but these particular O'day's are not boats people are "cruising" on.. So even if we could find 30 examples of boats people would choose to "cruise" on, out of approx 2.5 million +/- built that way we are at 0.0012% failure rate. So far we keep coming up with only a hand full of examples of boats losing keels.. I am sure some will go back to their keyboards to dig up more and hopefully we can get to 30. Perhaps someone will even dig up hard numbers on the number of sailboats built over the last 40 years....


It would be nice if we talk about real issues like sub standard wiring where we actually do have data. In the US we know that 55% of all boat fires are electrical in nature and there are FAR MORE electrical fires on boats than keels that have fallen off.

The keels that have fallen off have mostly been poor initial construction techniques or poor repairs. Without maintenance for leaking keel/hull joints we will eventually see more, but some of these boats are pushing 40 years with bolt on keels still attached...

One could argue that far more full or encapsulated keel boats have succumbed to electrical fires than bolt on boats losing keels..

Oh look here's a full keeler gutted by an electrical fire..

Give me a well made fin with a good electrical system over a full keel with a poor one any day of the week...

[carstenb]

It is beyond my comprehension that so much time is spent discussing this. As the numbers quoted above show, a fin keel dropping off is just a non-event.

Breaking your mast is a far more common occurrence and depending on the weather, just as deadly (try cutting away your mast in 25 foot waves when it is blowing force 8/9).

The same is true for spade rudders. With 2.5 million boats built, how many have lost their rudders?

Let's get real.

[Maine Sail]

Originally Posted by neilpride

Maintenance isues is another history, a full encapsulated keel dont have any maintenance schedule, 0....

OK, I did not google for my images, they are mine, I took the actual photos... They are of one of my customers boats who has INTERNAL ENCAPSULATED BALLAST.

FACT = This is an encapsulated keel vessel. Water got into the keel section and FROZE AND SPLIT as can be seen in the bilge sump by the cracking radiating UP.

Considering this split ran the entire length under the mast step and also split the keel externally I can assure you that these keels CAN and DO have more than just a "0" maintenance schedule.. Until you hit something or you have water get into the encapsulation they can be pretty maintenance free but this is NOT always the case. I have seen this a number of times including on a Pearson 30 that was totaled due to water in the encapsulation section and a repair cost that would have exceeded the boats value... This one below was not cheap to dry out and repair.

All keels are subject to issues & maintenance, including encapsulated ballast.

Sorry for the poor image quality.... Encapsulated ballast maintenance nightmare....

[neilpride]

But Maine please, we talking about maintenance or fixing problems???

A perfect full keel with no collisions or water ingress is free of maintenace mate, when a fin keel in the same conditions have maintenace isues right? you agree in this with me at least??

Here we have certain apprehension to groundings, probably in Maine is the favorite sport , i dont know, in any case constructions details and techniques vary from boat to boat, when i have 2 inch in the bottom of my keel others have 1 , when a fin keel have 7 bolts other sport 20, and well im not going to say anymore about the full v fin , i start to posting here talking about fin keel strenght -

To k-b-v , read the articles posted by Gordon , i paste a small part ..


Without the “stubby,” fiberglass keels put tremendous stress on the hull and can clear break off. Or at least, he had seen on Hunters crazing all around the unsound hull where the keel was beginning to break away.


Cheers...

[barnakiel]

Originally Posted by vtcapo

(...) And like someone said in a previous post, with enough experience you WILL go aground.(...)

I believe the first, the second and the third time we went aground before we got any experience. Now the fourth time we went aground we already had enough experience.

;-)
b.

[carstenb]

I've run aground several times. Keel is still hanging with no sign of damage.

Reality check VP. Fin keel don't just fall off

[daddle]

Originally Posted by neilpride

Without the “stubby,” fiberglass keels put tremendous stress on the hull and can clear break off.

No. "Without proper design ..."

My other race boat is a Ron Holland design. Deep bulb keel bolted to the hull with 6 bolts. It will never come off. We have slammed granite boulders in lake races. Cosmetic damage to the bulb. Several good bruises on the crew. Pretty sure Ron considered the stresses.

[neilpride]

Originally Posted by daddle

No. "Without proper design ..."

My other race boat is a Ron Holland design. Deep bulb keel bolted to the hull with 6 bolts. It will never come off. We have slammed granite boulders in lake races. Cosmetic damage to the bulb. Several good bruises on the crew. Pretty sure Ron considered the stresses.

Agree, if your Ron Holland have a hell of structure inside and the bolts are bolted there no doubt is strong enough, but many production boats just have their bolts bolted to the bilge floor ....

[bob_77903]

[barnakiel]

Originally Posted by carstenb

I've run aground several times. Keel is still hanging with no sign of damage.

Reality check VP. Fin keel don't just fall off

Reality? What reality?

Some keels do. Not sure if there is any relationship to the actual type (fin, stub, long, full, etc.) though.

A Jeanneau lost her keel this summer just off Fuerteventura. It sailed in open water. No collision with anything (not at the time of the accident anyways).

b.

[sabray]

Oyyyvey. So sure enough some bolt ups do not have good backing plate or frame. That would suck if you pounded up in the hard. Really loved the way Cambria spread the load on a floor grid. Think that's the one up if a big long keel. It gets the load thrown over a larger area. Less room for a design or manufacturers screw up. Easy to distribute the load in a large full keel takes a little more thought to get it good in a bolt on fin.
Next worry my mast is held up by a single bolt. If the upper bolt fails I'm screwed. Can't we get a tang that has twelve bolts in it. Don't think it's ever the fin keel that fails its the hull or the installer/builder.

[K_V_B]

Originally Posted by neilpride

Agree, if your Ron Holland have a hell of structure inside and the bolts are bolted there no doubt is strong enough, but many production boats just have their bolts bolted to the bilge floor ....

I have not come across a boat that did not have substantial reinforcements where the keel is attached. "Just bolted to the bilge floor" will not get your boat sold.

[carstenb]

Originally Posted by barnakiel

Reality? What reality?

Some keels do. Not sure if there is any relationship to the actual type (fin, stub, long, full, etc.) though.

A Jeanneau lost her keel this summer just off Fuerteventura. It sailed in open water. No collision with anything (not at the time of the accident anyways).

b.

Well I'll beat the dead horse one last time. Barniekel, look at some of the number further up. Say 2.5 MILLION boats built with fin keels. If they were dropping off on a daily basis, these manufacturers would be out of business - ever hear of product liability laws?

So yes, sometimes a fin keel detaches. Probably greater liability of you hit something really hard going at high speed. Boats with fully encapsulated keels also have their problems.

There are many other items on a boat where the incidence of failure is much greater - I've mentioned mast breakage, which is scary for sure, if not always fatal. And lots of others.

Fin keel falling off is so rare, but if you and others want to spend sleepless nights thinking about it, hey - no sweat.

Without knowing for sure, I suspect you have a greater chance of being struck by lightning when sailing, than your fin keel falling off.

Do you spend sleepless nights worrying about lightning? What type of boat design is your preference for avoided the dreaded lightning strikes.

again

reality check here - the chances of your fin keel falling off are so small as to be nonexistent.