Another keel falls off
- Thread starter Twister_Ken
- Start date
stevebirch2002
Well-Known Member
Cant see it happening to a Twister or a Vega!
boatmike
Well-Known Member
Having worked in the industry in contact with the designers of various vessels I have been constantly astounded how little theoretical calculation is done. I was once project manager on the build of a fairly well known (and therefore nameless) sailing vessel of substantial proportions. The well known Naval Architect who designed it pointedly stipulated to the builder that it was his (the builders) job to "design" the mechanical, electrical and hydraulic systems including the mast, rigging and keel fixing arrangements. The company in question to my certain knowledge never did any calculation on the keel at all and sub contracted it out to a design house who approved the design on the basis that they quote "had seen many less substantial designs in the past". There were never any proper calculations done. When I pointed this out the reaction was a Gallic shrug. Even Lloyds didn't seem concerned as I expected they would be..... Smaller series production boats, built down to a price, are very rarely any better than they need to be at point of sale, and almost never carry Lloyds or DNV accreditation as this one did. I am sure most innocent customers assume that the builders are experts and have checked everything properly. Sorry, call me cynical but it ain't so.
I think most designs are probably OK until the owner grounds the keel or such like, which is bound to happen sooner or later. Thereafter bolted on keels are often subject to hidden damage and fail later. Personally I think you should stick with your Twister or like me sail a cat! Neither are prone to bits falling off....
(Mentally ducks awaiting loud protests from owners of bolted on keels)
/forums/images/graemlins/frown.gif
I think most designs are probably OK until the owner grounds the keel or such like, which is bound to happen sooner or later. Thereafter bolted on keels are often subject to hidden damage and fail later. Personally I think you should stick with your Twister or like me sail a cat! Neither are prone to bits falling off....
(Mentally ducks awaiting loud protests from owners of bolted on keels)
/forums/images/graemlins/frown.gif
ChrisE
Well-Known Member
Yep, I'd agree, these new fangled yoghurt pots have to lot to answer for.
Richard10002
Well-Known Member
[ QUOTE ]
I think most designs are probably OK until the owner grounds the keel or such like, which is bound to happen sooner or later. Thereafter bolted on keels are often subject to hidden damage and fail later. Personally I think you should stick with your Twister or like me sail a cat! Neither are prone to bits falling off....
(Mentally ducks awaiting loud protests from owners of bolted on keels)
/forums/images/graemlins/frown.gif
[/ QUOTE ]
What is different about a Twister, (lifting keel, moulded bilge keels, encapsulated?)
perhaps I've answered my own question.
wonder if a fore/aft groove that the keel slides into would be more secure than a mere join?
I think most designs are probably OK until the owner grounds the keel or such like, which is bound to happen sooner or later. Thereafter bolted on keels are often subject to hidden damage and fail later. Personally I think you should stick with your Twister or like me sail a cat! Neither are prone to bits falling off....
(Mentally ducks awaiting loud protests from owners of bolted on keels)
/forums/images/graemlins/frown.gif
[/ QUOTE ]
What is different about a Twister, (lifting keel, moulded bilge keels, encapsulated?)
perhaps I've answered my own question.
wonder if a fore/aft groove that the keel slides into would be more secure than a mere join?
Poignard
Well-Known Member
[ QUOTE ]
What is different about a Twister, (lifting keel, moulded bilge keels, encapsulated?)
[/ QUOTE ]
The keel is moulded as part of the hull and the ballast [lead or steel] is encapsulated inside. The keel is long and quite wide so it is very strong.
The penalty for this long, wide keel is difficulty in manouvering in some circumstances but it can usually be got round with plenty of fenders, warps, a sense of humour and helpful advice from members of this forum!
What is different about a Twister, (lifting keel, moulded bilge keels, encapsulated?)
[/ QUOTE ]
The keel is moulded as part of the hull and the ballast [lead or steel] is encapsulated inside. The keel is long and quite wide so it is very strong.
The penalty for this long, wide keel is difficulty in manouvering in some circumstances but it can usually be got round with plenty of fenders, warps, a sense of humour and helpful advice from members of this forum!
Twister_Ken
Well-Known Member
Twister underwater (after blasting off many years of old auntie fowl) :
Poignard
Well-Known Member
As a friend of mine [also a Twister owner] is fond of saying :
"Not a bad line in 'em"
"Not a bad line in 'em"
Slow_boat
Well-Known Member
A narrow deep keel is putting incredible forces onto the few bolts there are room for where it joins the hull. Imagine the leverage between a tall modern rig and a deep narrow keel. Obviously the weak point in the lever needs extra attention.
Superstrath
Well-Known Member
Well, was it 47 or 54 feet long? And does, "performance cruiser" indicate a particular manufacturer or do we actually know who it was, even though it was not mentioned in the two articles referenced?
Sounds terrifying, anyway. I wonder what IS the best raw seabird to eat.
Oops, I see WayneS has identified the baot.
Sounds terrifying, anyway. I wonder what IS the best raw seabird to eat.
Oops, I see WayneS has identified the baot.
marksaab
Well-Known Member
Shame the link to the blog is broken, I wanted to read how bad the dinghy was!
Gerry
Well-Known Member
G
Guest
Guest
"When does a series of 'one-offs' become a trend?"
On such a critical item: On the second occurrence.
In my world, the boat would have to be ripped off the keel with more force than the hull could stand without disintegrating. As in, the keel joint would not be designed for certain theoretical wind loads, but to exceed the loads that the boat would collapse under.
But then I took 8 years to get around and they nearly made it in 2. Each to their own.
(Then there are the rudders that fall off, equally disastrous if you only have 1)
On such a critical item: On the second occurrence.
In my world, the boat would have to be ripped off the keel with more force than the hull could stand without disintegrating. As in, the keel joint would not be designed for certain theoretical wind loads, but to exceed the loads that the boat would collapse under.
But then I took 8 years to get around and they nearly made it in 2. Each to their own.
(Then there are the rudders that fall off, equally disastrous if you only have 1)
sighmoon
Well-Known Member
[ QUOTE ]
... or like me sail a cat! Neither are prone to bits falling off....
[/ QUOTE ]
Yeah, right.
... or like me sail a cat! Neither are prone to bits falling off....
[/ QUOTE ]
Yeah, right.
Swagman
Well-Known Member
It actually might not be a case of more keels falling off than ever before.
Maybe we just hear about these occurances in this day and age, as opposed to them just dissappearing without a trace?
JOHN
Maybe we just hear about these occurances in this day and age, as opposed to them just dissappearing without a trace?
JOHN
DavenHelen
Well-Known Member
[ QUOTE ]
"When does a series of 'one-offs' become a trend?"
On such a critical item: On the second occurrence.
[/ QUOTE ]
I would disagree. Yes if same model or builder, less so if same keel type and not if totally different design.
"When does a series of 'one-offs' become a trend?"
On such a critical item: On the second occurrence.
[/ QUOTE ]
I would disagree. Yes if same model or builder, less so if same keel type and not if totally different design.
wotayottie
Well-Known Member
[ QUOTE ]
Yep, I'd agree, these new fangled yoghurt pots have to lot to answer for.
[/ QUOTE ]
few weeks ago, the keel fell off a Westerly of 1980's vintage at our club, and it sank. Nothing new - several other Westerly owners commented they had experienced the same sort of problem
Yep, I'd agree, these new fangled yoghurt pots have to lot to answer for.
[/ QUOTE ]
few weeks ago, the keel fell off a Westerly of 1980's vintage at our club, and it sank. Nothing new - several other Westerly owners commented they had experienced the same sort of problem
rhumlady
Well-Known Member
Out of interest and as a Westerly owner, What type of Westerly was that then?
Twister_Ken
Well-Known Member
Well, you'd expect a keel to sink!
