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Old 27-06-2012, 03:51   #226
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Re: Capsize Ratio's

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Originally Posted by s/v Jedi View Post
I believe many of those, if not all nowadays, do. That is part of it, making sure the implementation of the laminate is good. But it doesn't say anything about how strong it is yet.. you have to examine the layers of glass or other fibers for that, the ribs, stringers, core etc. Even the resin; for example: TPI used vinylester instead of polyester resin. I know they built the Lagoons like that, while I'm not sure how they were built in La Rochelle.

It all comes down to the fact that everything needs to be done right to get a strong yet light boat. You also want a stiff boat for performance.

cheers,
Nick.
Yes, I agree. Robotics, and controlled temperature and humidity also come to give more precision to the manufacture process.

Regarding almost all boats using vacuum infusion, well it would be great but it is not true. The process is more expensive or to be not expensive demands hugely expensive industrial equipment. The cheaper boats don’t use that process, only the more expensive boats use it.

That should be a thing to look when you chose a boat. Using vacuum infusion, top resins (Vinylester or epoxy) and a cored hull you can have a much lighter but stronger boat than a much heavier one built with “normal” resins and “traditional” methods.

It is pretty easy to distinguish the boats that are built with traditional methods and the ones that are made using modern technologies and materials:

If a 40ft weights between 5 and 8 tons the changes are that it is a vacuum infused cored boat.

Of course you better check it out, it can also be a not very strong and cheap built mass production boat.

Nothing wrong with a boat built with traditional methods and materials, just that in that case it is expected that the boat would weight about 2 to 3 tons more, for an equivalent strength.

Of course, they will not sail as well and many times the lighter boats have a better B/D ratio and a better stability curve as well (as it was referred on this thread) a better dynamic stability.

Cheers

Manuel
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Old 27-06-2012, 13:28   #227
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Re: Capsize Ratio's

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Yes, I agree. Robotics, and controlled temperature and humidity also come to give more precision to the manufacture process.

Regarding almost all boats using vacuum infusion, well it would be great but it is not true. The process is more expensive or to be not expensive demands hugely expensive industrial equipment. The cheaper boats don’t use that process, only the more expensive boats use it.

That should be a thing to look when you chose a boat. Using vacuum infusion, top resins (Vinylester or epoxy) and a cored hull you can have a much lighter but stronger boat than a much heavier one built with “normal” resins and “traditional” methods.

It is pretty easy to distinguish the boats that are built with traditional methods and the ones that are made using modern technologies and materials:

If a 40ft weights between 5 and 8 tons the changes are that it is a vacuum infused cored boat.

Of course you better check it out, it can also be a not very strong and cheap built mass production boat.

Nothing wrong with a boat built with traditional methods and materials, just that in that case it is expected that the boat would weight about 2 to 3 tons more, for an equivalent strength.

Of course, they will not sail as well and many times the lighter boats have a better B/D ratio and a better stability curve as well (as it was referred on this thread) a better dynamic stability.

Cheers

Manuel
Cored fibreglass structures have advantages such as lighter weight and better insulation, but they also have drawbacks. The risk of delamination and rot in the core is real. Many people point out, correctly, that if well done the risk of these problems is small, but there have been many respected bulders like Halberg Rassy that have had major problems.

Many crusing sailors would reject a boat with a cored construction below the waterline.

I am a great supporter, however of better resins. Polyester resin is still used extensively even by premium boat builders when much better resins like epoxy, or at least vinester are available.
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Old 27-06-2012, 14:49   #228
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Re: Capsize Ratio's

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The risk of delamination and rot in the core is real. Many people point out, correctly, that if well done the risk of these problems is small, but there have been many respected bulders like Halberg Rassy that have had major problems..
Most often IMO these problems are related to use of female mold during the build. There's no way to control how well core attaches to outer skin..
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Old 27-06-2012, 15:03   #229
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Re: Capsize Ratio's

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Most often IMO these problems are related to use of female mold during the build. There's no way to control how well core attaches to outer skin..
Even assuming this is the core ( sorry about that ) of the problem, isn't a female mold how 98% of fibreglass boats (both solid and cored structures) are constructed? If so the warning against cored laminates is certainly justified.
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Old 27-06-2012, 23:00   #230
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Re: Capsize Ratio's

You are correct..
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Old 28-06-2012, 16:24   #231
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Re: Capsize Ratio's

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Cored fibreglass structures have advantages such as lighter weight and better insulation, but they also have drawbacks. The risk of delamination and rot in the core is real. Many people point out, correctly, that if well done the risk of these problems is small, but there have been many respected bulders like Halberg Rassy that have had major problems.

Many crusing sailors would reject a boat with a cored construction below the waterline.

....
You mean, most cruisers would reject a new Halberg Rassy if they could afford one?

How a Hallberg-Rassy hull is built

I don’t think so.

Halberg rassy had some problems with some of the first boats when they decided to built with cored hulls. Now they master the technique and I don’t know of any problem with recent boats.

The reason Halberg Rassy are today much better sailboats than the older ones is because they are lighter (and stronger) and that has to do basically with cored hulls and modern building techniques and materials.
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Old 28-06-2012, 20:27   #232
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Re: Capsize Ratio's

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You mean, most cruisers would reject a new Halberg Rassy if they could afford one?
.
Yes that's exactly what I mean. Their new cored boats are a step backwards IMHO for a long distance crusing boat.
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Old 28-06-2012, 23:33   #233
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Re: Capsize Ratio's

popcorn! peanuts col'beer! Okay.. a bit late for cold beer..

"Off-thread!!"...

..."Hey...who said that?!!!"
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Old 29-06-2012, 12:40   #234
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Re: Capsize Ratio's

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(...) The reason Halberg Rassy are today much better sailboats than the older ones is because they are lighter (and stronger)(...)
This depends on what aspect of strength we will look at.

A new HR will not take a grounding quite as well as and older HR would - different rudder/keel design and new hulls much less resistant to puncturing, abrasion and plain bashing.

But building boats so that they are good at grounding ;-) is sort of like building gliders so that they are "safe to crash".

A sailing boat should be built so that she sails well. Then come other things. And new HRs do sail better than the old ones.

b.
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Old 29-06-2012, 15:11   #235
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Re: Capsize Ratio's

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...
But building boats so that they are good at grounding ;-) is sort of like building gliders so that they are "safe to crash".

A sailing boat should be built so that she sails well. Then come other things. And new HRs do sail better than the old ones.

b.
I agree. Well, they do not sail better, they sail much better than the old ones
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Old 29-06-2012, 15:35   #236
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Re: Capsize Ratio's

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A new HR will not take a grounding quite as well as and older HR would - different rudder/keel design and new hulls much less resistant to puncturing, abrasion and plain bashing.

But building boats so that they are good at grounding ;-) is sort of like building gliders so that they are "safe to crash".

A sailing boat should be built so that she sails well. Then come other things. And new HRs do sail better than the old ones.

b.
I agree with your assessment, but long distance crusing boats are subject to abrasion and bashing resonably often. It's not uncommon for a boat that has sailed around the world to suffer an unintentional grounding
Tie up to a commercial pier, have another boat drag down on you all common situations. Then try to get a good repair in a third world country, hoping water has not penetrated the laminate.
I am not sure I agree with your glider analogy. I flew gliders for 20 years and never put a scratch on one of them. I was involved in glider accident investigation and like cars crash survival is important and the structural engineering is important, but these sort of accidents are fortunatly very rare and should not be compared to the common mishaps that occur on crusing boats.
Their are plenty of cruser / racers or outright racers that are available. Their requirements are very different to crusing boats. Weight is critical even if if it gains an extra 0.01 K. Yes I have cut the handel off my toothbrush in my racing days

Crusing yachts, generally, want a strong laminate that is easy to repair.
Complications like delamination or rot are the core are common enough in decks, without risking the hull, particularly the underwater sections. Any slight loss of speed compared to a cored laminate is easily made up with an extra few inches of length
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Old 29-06-2012, 17:11   #237
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Re: Capsize Ratio's

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This depends on what aspect of strength we will look at.

A new HR will not take a grounding quite as well as and older HR would - different rudder/keel design and new hulls much less resistant to puncturing, abrasion and plain bashing.

But building boats so that they are good at grounding ;-) is sort of like building gliders so that they are "safe to crash".

A sailing boat should be built so that she sails well. Then come other things. And new HRs do sail better than the old ones.

b.
Well, we do build gliders so that they are safe to crash, so maybe not the best analogy. How about this: Every vehicle is a compromise. You want to design a boat that is good at sailing and adequate at grounding, not one that is adequate at sailing and good at grounding. After all, most of us sail at least ten times more hours than we spend stranded aground.
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Old 29-06-2012, 17:40   #238
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Re: Capsize Ratio's

Well. I believe we could build a well sailing, well grounding ;-) boat. But we would have to build her in technology / materials that are used in racing. Now if we did this, the price would be prohibitive.

I sometimes look at things like Cigala or Atlantic or (OMG, this IS boat porn) Bougainvillea and I think their designers and builders went the extra mile to give us boats that are light and fast and strong ... and then I look at the ticket ;-)

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Old 01-07-2012, 08:41   #239
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Re: Capsize Ratio's

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Well. I believe we could build a well sailing, well grounding ;-) boat. But we would have to build her in technology / materials that are used in racing. Now if we did this, the price would be prohibitive.

...

b.
Not always. You have the cruising range of Pogo. They are built the same way the racers are (Pogo class 40), have a bit less sail and a shorter mast for being easier to handle.

The price are about the same as any other performance cruiser of that size range, sometimes less. For managing that they don't do publicity, they don't go with their boats to boat shows and they keep an interior simple but functional.

And it seems they don't needed any of those things to be elected 2012 European performance cruiser neither to have a long waiting list of clients.

Now they have even sell some boats for doing charter
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Old 01-07-2012, 21:04   #240
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Re: Capsize Ratio's

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Yes that's exactly what I mean. Their new cored boats are a step backwards IMHO for a long distance crusing boat.
...and what facts do you base this on?...oh sorry...I see it's just your opinion.
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