Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 08-05-2015, 00:13   #151
Registered User
 
Muckle Flugga's Avatar

Join Date: Apr 2008
Location: Aboard the Ocean wave
Boat: 55' sloop.
Posts: 1,426
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by mstrebe View Post
From an engineering standpoint, it is trivially easy to design and install a permanent stress indicator into FRP, although I've never seen it done.

All that is needed is the inclusion of a single continuos optical fiber thread laid into the FRP during manufacture in such a way that it winds around over the entire area of concern. This would be done as part of the layup process. Optical fiber is cheap and can be included in FRP anywhere as easily as glass mat woven roving.

When stressed, the optical fiber is deformed along with the FRP. The FRP will return to shape once the flexural stress is released, but the optical fiber will suffer permanent cracking of is sheath and core layers from being stressed. This permanent deformation can be trivially read later with a simple, inexpensive device called an optical time-domain reflectometer which would be plugged into a terminal connector on one end of the fiber, which would be located inside the boat wherever is convenient. The other end of the fiber can simply be left in the FRP wherever it happens to end.

For inspection purposes, you simply plug an OTDR into the fiber will bounce light pulses into the fiber and read the attenuation of them. This results in a simple graph that shows light losses over the length of the fiber. A lack of smoothness or abrupt change in signal will indicate precisely the amount of flexural stress that the fiber has been subjected to cumulatively over its lifetime because the stress cracking of the fiber results in light loss at that point. It also indicates how far down the fiber the stress is, but that's unimportant to this problem.

By correlating stress graphs from the OTDR readings to the results of full scale inspections, it will be possible to indicate when a hull has been subjected to enough stress to warrant full inspection.

It's simple, it's cheap, it's permanent, and it can't be faked. Anyone with an inexpensive OTDR can read it, and the signal is easy to understand: smooth continuos loss=nothing to worry about; abruptions in the signal = must inspect.

OTDRs are cheap enough for owners to carry them aboard, certainly any maritime professional and yard could have them.

Fiber is currently laid into cement on bridges and building foundations where there is seismic concern and used in exactly this manner, so the engineering practice is well known and understood.
Extremely interesting post! Shout about it!
__________________

__________________
Muckle Flugga is offline   Reply With Quote
Old 08-05-2015, 00:25   #152
Registered User
 
Exile's Avatar

Join Date: Sep 2010
Location: Land of Disenchantment
Boat: Bristol 47.7
Posts: 2,419
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Muckle Flugga View Post
I truly hope this does not turn out to be another keel loss. Capsize and sinking is suspicious though, and the death of the little girl truly awful:

French girl dies from cold off Azores after boat sinks | GlobalPost
Lagoon 400 catamaran, according to Polux in post #19 of this thread:

2015 Another bad year in the Azores..?
__________________

__________________
Exile is online now   Reply With Quote
Old 08-05-2015, 00:40   #153
Registered User
 
Muckle Flugga's Avatar

Join Date: Apr 2008
Location: Aboard the Ocean wave
Boat: 55' sloop.
Posts: 1,426
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Exile View Post
Lagoon 400 catamaran, according to Polux in post #19 of this thread:

2015 Another bad year in the Azores..?
Aha. Sorry, I missed that. Very sad indeed in any case. A 40 foot cat capsize? Must've been an interesting sea. The Azores region has claimed many boats and often their loss is unheralded. About the same time as CR, Lady Domina and Grain de Soleil disappeared in the central Atlantic within a few hundred miles of Azores. The latter looks like it may have been run down at sea, and the former may have been in sore need of proper maintenance, but no one can be sure in any case. I will be sailing through those waters soon again as a navigator in the upcoming Transatlantic Race. I'll be thinking of all the disappeared. As Minaret has in her footer: "O you who turn the wheel and look to windward, Consider Phlebas, who was once handsome and tall as you."
__________________
Muckle Flugga is offline   Reply With Quote
Old 08-05-2015, 09:04   #154
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 4,978
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by a64pilot View Post
One of the issues is I believe, define "hard" grounding?

....
So if we are going to inspect a boat after a hard grounding, define "hard"?

Plus I think a very good point was made that if your really a World traveler, you will often be a long ways from lifts, and boatyards.

I'm thinking this will eventually end up with recommended keel removal and inspection intervals, sort of like standing rigging. You know it had to be numerous failed rigs before a generally accepted life limit was established?
I believe you are right and I believe also what you call a hard grounding it depends of the type of vessel and what it can take. Regarding a boat like a Firts 40.7, a light cruiser racer, any grounding that is more than touching the ground softly at a low speed should be treated as an hard grounding and the boat structure should be inspected conveniently.
Polux is online now   Reply With Quote
Old 08-05-2015, 09:06   #155
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 4,978
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Exile View Post
Lagoon 400 catamaran, according to Polux in post #19 of this thread:

2015 Another bad year in the Azores..?
Yes the boat was reported capsized and sunk.
Polux is online now   Reply With Quote
Old 08-05-2015, 09:24   #156
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 4,978
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by neilpride View Post
Paulo you should define cristal clear in your post, because the im saying v im not saying that is getting boring....just to point that early 40,7 dont even use methacrylate glue , like plexus or other hig tech stuff, they are bonded with a polyester putty, whatever you can imagine or dream about this isue is not going to change the fact,,, like a previous poster point it, coastal racing with the shore in sight,,,, or modifications here and there to strenght the keel área for offshore use ....is well know that even cranking the hydraulic backstay adjuster bend the boat like a banana,,,, can you imagine that aft 14 mm keel bolt???
Whatever the way the structure is bonded to the hull (including laminated) does not change the need of regular inspections and a thoroughly inspection in case of grounding.

If a 40.7 is in a seaworthy condition it is a seaworthy boat and an offshore one. If not it should be repaired. That's about the same to all the boats that are offshore boats when in good condition.

Boats regarding that are like cars: a sports car like a Ferrari needs a lot more maintenance then a Ford focus but make absolutely no sense to say that a Ferrari is an unsafe or unreliable car, when well maintained.

Regarding safety the Ferrari can brake a lot better and has a lot more grip, a bit like a 40.7 has a lot more stability then a main market cruiser racer and it is way faster reducing the days of a passage and making it safer. For that you have to be careful regarding groundings and have more maintenance as well as to be a better sailor to be able to tame the extra power.

To each one to decide if the extra maintenance, the smaller interior and the care with groundings is worth the advantages.

Regarding the backstay I think you are vastly exaggerating.
Polux is online now   Reply With Quote
Old 08-05-2015, 09:45   #157
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 4,978
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Exile View Post
...
Finally, I don't find persuasive Polux casting some doubt on the MAIB report's conclusion that mere hard sailing vs. an actual grounding could also lead to weakening of the keel attachment. If soft groundings are suspect and cause to drop the keel for inspection, then it makes some sense that hard, upwind ocean sailing could produce similar stresses, albeit over a longer period of time. This is presumably why the experts who investigated the incident and produced the reports reached this conclusion even though, as Polux points out, none of the boats they looked at apparently had a history from mere hard sailing alone.
You have understood me wrong. I did not cast doubts on the MAIB report that I find a good document. What I said is that they should have gonna a bit further and have investigated better the debonding on the forward part of the matrix as a way of being able to establish an indisputable relationship between that, hard use, time and slamming, as they have done regarding groundings and debonding of the matrix.

For that they would have to visit several boats with forward matrix debonding that had not been previously grounded the same way that they had visited several boat that have grounded and had matrix debonding.

Even so I said that collateral evidence suggest that hard use, time and a lot of slamming can lead to the debonding of the forward part of the matrix on the First 40.7...but there is a difference between a suggestion a possibility, a suspicion and an uncontroversial fact.

If they had done that they could have been able to write on the conclusions:

"On the First 40.7, given time, hard use and slamming Matrix detachment will occur on the matrix bonded to the hull, resulting in loss of structural strength. The probability of this occurring will increase with more frequent and harder yacht usage."

Instead they said:

"It is possible for matrix detachment to occur in GRP yachts manufactured with a matrix bonded to the hull, resulting in loss of structural strength. The probability of this occurring will increase with more frequent and harder yacht usage."
Polux is online now   Reply With Quote
Old 08-05-2015, 09:56   #158
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 4,978
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Muckle Flugga View Post
....

With regards to your analysis of the rock as "soft": there is zero warrant to suggest that, and indeed its smoothness and fracturing in neat layered blocks speaks to exactly the opposite conclusion: both hard and brittle. But this idea of "soft rocks" is really, really clutching at straws. ...
I have that type of rocks near home. Very old stuff in geological time. Yes that are soft, brittle, a bit oily and with erosion they result in flat platforms like the one you see on the picture. The way they broke is also consistent with the little "pebbles" you see on the left of the pictures.

Polux is online now   Reply With Quote
Old 08-05-2015, 10:26   #159
Registered User
 
Muckle Flugga's Avatar

Join Date: Apr 2008
Location: Aboard the Ocean wave
Boat: 55' sloop.
Posts: 1,426
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Polux View Post
I have that type of rocks near home. Very old stuff in geological time. Yes that are soft, brittle, a bit oily and with erosion they result in flat platforms like the one you see on the picture. The way they broke is also consistent with the little "pebbles" you see on the left of the pictures.

Dear Paolo,

Can you name the type of strata that you think you see? "Very old in time" does not bespeak "soft" strata. What makes you think it does? Whether you have them at home or not is really, honestly, not at issue. And I repeat, geology is neither your strong point nor really even in argumentation should you be holding on to the bite wound you think you inflicted with the idaa of "beaches" or "soft rocks". You didn't, and it is time to let go.

Anyhow, as a genuine offering of just intercollegial accord I would like to say that during a conversation I had tonight with the Singaporean wife of a skipper I know around here (currently in the Far East), about the nature of the insurance industry, not only did you come to mind in terms of your tenacity, but also in terms of your cogency, the latter in a very good way, and by contrast. The geological thing above notwithstanding I have found your ability, for example at the very beginnning of this thread, to sift data and have a decent adversarial discussion which is enlightening on both sides, very good. The conversation with this perticular person, also a terrier in her own fashion over a certain point, threw into stark relief in my mind how your own tenacity differs: you will not give up the point you wish to make… but at least you fully understand in your answers, even by your often skilful evasion, the ones I am making. And of course no, it has zero to do with the fact that she is a woman, at all. Just an anectodal observation.
__________________
Muckle Flugga is offline   Reply With Quote
Old 08-05-2015, 11:31   #160
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 4,978
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Muckle Flugga View Post
Dear Paolo,

Can you name the type of strata that you think you see? "Very old in time" does not bespeak "soft" strata. What makes you think it does? Whether you have them at home or not is really, honestly, not at issue. And I repeat, geology is neither your strong point nor really even in argumentation should you be holding on to the bite wound you think you inflicted with the idaa of "beaches" or "soft rocks". You didn't, and it is time to let go. ...
Jurassic time. That is the kind of stone that is made of hardened mud. Lots of fossils inside. Of course I can be wrong but not in what regards being soft. Only on soft stones erosion produces those big flat surfaces. We call it "lagido" from "lage" that means slab.
Polux is online now   Reply With Quote
Old 08-05-2015, 11:59   #161
Registered User
 
Muckle Flugga's Avatar

Join Date: Apr 2008
Location: Aboard the Ocean wave
Boat: 55' sloop.
Posts: 1,426
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Polux View Post
Jurassic time. That is the kind of stone that is made of hardened mud. Lots of fossils inside. Of course I can be wrong but not in what regards being soft. Only on soft stones erosion produces those big flat surfaces. We call it "lagido" from "lage" that means slab.
Well, no, or maybe, but what is the point? But thanks anyhow. Such surfaces are typically sedimentary or semi metamorphic and can be made in fairly wide variety of different ways and may also be igneous in the form of repeated lava flows overlaying sedimented ash deposits, and may date from a very wide variety of periods, so "Jurassic" is an odd particular to mention. Hardness varies considerably, honestly, your dogged pursuit of the idea that these rocks are "soft" is becoming beyond ridiculous. Really. Even the "softest" such rocks are so hard it makes your whole drive here beyond absurd. Geology is not your strong point so before I turn to it seriously if I were you I would get off the subject. In any case what on earth are you still beating this well dead horse for? Do you want me to address some geological issue properly (a lifelong hobby of mine as it happens), or are we talking about the possibllity of preventing future loss of life at sea?

Shame you didn't reply to the rest of my post, though. It offered a way out of this nonsense.
__________________
Muckle Flugga is offline   Reply With Quote
Old 08-05-2015, 12:13   #162
I promise to put my pants on
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 11,196
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Muckle Flugga View Post
. It offered a way out of this nonsense.
Just stop maybe
__________________
stop blowing smoke up my rear, blow it at the sails instead
sailorboy1 is offline   Reply With Quote
Old 08-05-2015, 17:45   #163
Registered User
 
neilpride's Avatar

Join Date: Jul 2009
Location: in the world
Boat: csy 44 tall rig.
Posts: 2,764
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by Polux View Post
Whatever the way the structure is bonded to the hull (including laminated) does not change the need of regular inspections and a thoroughly inspection in case of grounding.

If a 40.7 is in a seaworthy condition it is a seaworthy boat and an offshore one. If not it should be repaired. That's about the same to all the boats that are offshore boats when in good condition.

Boats regarding that are like cars: a sports car like a Ferrari needs a lot more maintenance then a Ford focus but make absolutely no sense to say that a Ferrari is an unsafe or unreliable car, when well maintained.

Regarding safety the Ferrari can brake a lot better and has a lot more grip, a bit like a 40.7 has a lot more stability then a main market cruiser racer and it is way faster reducing the days of a passage and making it safer. For that you have to be careful regarding groundings and have more maintenance as well as to be a better sailor to be able to tame the extra power.

To each one to decide if the extra maintenance, the smaller interior and the care with groundings is worth the advantages.

Regarding the backstay I think you are vastly exaggerating.

Its a waste of time and brain energy to keep going with that silly argument, is pointless... What you are trying to say is sail a first 40,7 and if you run aground make expensive repairs inspections for the life of the vessel, in theory make sense, but in practique i dont see any advantage to get a first 40,7 just for the pleasure to be inspected regularly, is not a expensive Hig tech boat, is a mass production product, if they cant make a strong keel attachment then they should stop building like that .. and stop hiding in the BS argument , that boat run aground!! not my problem...

I know how the french deal with warranty claims, and BS products deficiencies,, Beneteau is a huge company and for no reason they are going to change the metods even if they have a pile of claims in the table, numbers count, but lives to...

Your silly way to see this thing Paulo remember me a old Mc Donnell Douglas DC 10 isue with the cargo doors, they design the doors to open outward instead of inward and after hundreds of deaths they are forced to ground the dc10 and redesign the doors...

I quote Don Jordan from Jordan Drogues saying something about this case..

In the design of aircraft, certain machinery and equipment is in a separate category, “safety of flight”. These items must be absolutely reliable and must be capable of enduring the worst environment that the aircraft may encounter.

And then again a keel falling off is a matter of live or death...

I would argue that the ballasted keel of a sailboat is the marine equivalent of a “safety of flight” item–an item that simply must not fall off for the expected service life of the boat. A sudden keel failure, particularly in heavy weather far from land, well, that’s the marine equivalent of the wings falling off an aircraft in flight–there is pretty much nothing that airmanship or seamanship can do to avert a tragedy.


The even more worrying aspect of this is that many boats with these intrinsically difficult to engineer keels are now aging. And while their keel attachments may have been adequately strong when the boats were new, I worry that the ravages of fatigue and/or multiple groundings may have made a large number of boats out there at risk for sudden keel loss.

And. By John Harries.

In this kind of situation it is always tempting to say “they need to do something”. The faceless “they” comprising boat builders, designers and regulators. But the bottom line is that it’s simply impractical to expect mass production boat builders to increase the price of their products, or cut their profit margins, to fix a problem like this without changing the market conditions that caused the problem in the first place.

Or to put it another way, we won’t get strong keels until we-the-market start insisting on strong keels. Just as we-the-market started insisting on more stable boats after the ‘79 Fastnet. And yes, I know that regulators and race organizers have a part to play here, but it is still up to us to support them.

You see, the source is the thousands of unseaworthy brains looking for this kind of product...

Boats run aground, is a fact, is something expected in the life of a boat, sooner or later, and the keel joint structure need to be designed to withstand the abuse , if not, they simply dont deserve to be a offshore boat with long range cruising in mind.... No idea how the new 2014 2015 First series are built, but i suspect in the same fashion as older models, why dont take the example from other builders like X Yachts or Arcona Yachts,
Profit!!! is more important to sell 2 thousands more at the base Price that earn some reputation for doing the things better at the cost to sell less,..

Cheers.
__________________
neilpride is offline   Reply With Quote
Old 08-05-2015, 18:00   #164

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 12,113
Re: Cheeki Rafiki loss report

"I would argue that the ballasted keel of a sailboat is the marine equivalent of a “safety of flight” item–an item that simply must not fall off for the expected service life of the boat."
No offense but "Nonsense!" and you'll probably agree with that once you reconsider it. Aircraft may be certified for general use, or aerobatics, or military combat. Take a perfectly good 707 or Piper Cub and put it through aerobatics, and you'll tear the wings off. And if you get a plane certified for aerobatics, odds are some heavy g high-speed combat maneuvers will pull that one apart anyhow.


Around 1990 I had the pleasure to stumble on the recent NZ entry to the America's Cup making a tour in NYC. I asked if they'd sailed it up and which way, and the guys rolled over laughing, explaining that the boat was built for something like 20 knots, and that if they'd tried to come across the Pacific, they'd have broken the spreaders off the mast, and then snapped every dotted line you could draw on the boat.


Even in the world's top racing circuits, air, sea, or land, everything is built "to a price". If you build any part to be indestructible, it will be too expensive, too heavy, and absolutely useless for racing. To paraphrase the guys at NASCAR, if you didn't break anything, you were too heavy and that makes you too slow.


Even the engines on Indy cars were built this way. The race is 500 miles long, so the engines were built for 100 miles of practice, 500 miles of race, 100 more miles "just in case" and then they were routinely expected to blow apart if they weren't torn down and rebuilt from scratch by 700 miles. TOTAL engine lifetime. That's one reason they got 10x more horsepower out of them, compared to passenger mass-market engines using all the same technologies.


Profit rules! And very few buyers are willing or able to appreciate the differences.
__________________
hellosailor is offline   Reply With Quote
Old 08-05-2015, 18:19   #165
Registered User
 
neilpride's Avatar

Join Date: Jul 2009
Location: in the world
Boat: csy 44 tall rig.
Posts: 2,764
Re: Cheeki Rafiki loss report

Quote:
Originally Posted by hellosailor View Post
"I would argue that the ballasted keel of a sailboat is the marine equivalent of a “safety of flight” item–an item that simply must not fall off for the expected service life of the boat."
No offense but "Nonsense!" and you'll probably agree with that once you reconsider it. Aircraft may be certified for general use, or aerobatics, or military combat. Take a perfectly good 707 or Piper Cub and put it through aerobatics, and you'll tear the wings off. And if you get a plane certified for aerobatics, odds are some heavy g high-speed combat maneuvers will pull that one apart anyhow.


Around 1990 I had the pleasure to stumble on the recent NZ entry to the America's Cup making a tour in NYC. I asked if they'd sailed it up and which way, and the guys rolled over laughing, explaining that the boat was built for something like 20 knots, and that if they'd tried to come across the Pacific, they'd have broken the spreaders off the mast, and then snapped every dotted line you could draw on the boat.


Even in the world's top racing circuits, air, sea, or land, everything is built "to a price". If you build any part to be indestructible, it will be too expensive, too heavy, and absolutely useless for racing. To paraphrase the guys at NASCAR, if you didn't break anything, you were too heavy and that makes you too slow.


Even the engines on Indy cars were built this way. The race is 500 miles long, so the engines were built for 100 miles of practice, 500 miles of race, 100 more miles "just in case" and then they were routinely expected to blow apart if they weren't torn down and rebuilt from scratch by 700 miles. TOTAL engine lifetime. That's one reason they got 10x more horsepower out of them, compared to passenger mass-market engines using all the same technologies.


Profit rules! And very few buyers are willing or able to appreciate the differences.
Good point but a Boeing 707 make in the past a roll over in a test flight,,
http://www.google.com/url?sa=t&rct=j...92885102,d.eXY

And in one piece, i never see a 747 or a 380 Airbus doing a roll over but me think they dont try yet.... and then we dont know if they can or not with the wings in place,, lets say CR at the time of the incident is not doing aerobatics, just sailing in some kind of nasty weather, perfect conditions for the purpose design, sure a reef can tear a keel in pieces but those conditions are extreme, for no reason a keel falling off or by previous normal groundings is a poor example of design and building practiques,,, i agree with Jonh on that... you dont need to add much weight or increase to much the cost to the keel área in question, Arcona Yachts probe that and other builders to, we are talking about a cruiser racer not a pure racer boat in any sense, then i can uderstand if they design some parts to break in favor off speed or perfomance ,but you dont choose a AC to cross the pond right?

My point stand for me...
__________________

__________________
neilpride is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
UK yacht Cheeki Rafiki missing in mid-Atlantic 1000 islands General Sailing Forum 517 11-06-2014 16:32
Cheeki Rafiki gmthompson99 Monohull Sailboats 107 30-05-2014 13:37
Restart the search for the missing Cheeki Rafiki crew members. mikethedane General Sailing Forum 0 20-05-2014 08:47


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 04:51.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.