Most boats have liners; which ones do it best?

[Muckle Flugga]

Originally Posted by TeddyDiver

Then there was something done wrong becouse there are wooden cored vessels without defects too.
Steps to do things right:
-Barrier coating, also inside the core
-Epoxy only
-One-off or vacuum infusion or production process with similar quality
-Properly installed hardware

This is a non sequitur. One swallow doth not a summer make…

[Dockhead]

Originally Posted by Muckle Flugga

I like most of your posts a lot, Dockhead, but I am afraid this is just not true. I have seen rot MANY times in cored hulls, often very high quality ones. I attach an example of thoroughgoing rotten marine ply inside the core of the afterdeck of an Oyster undergoing deck replacement. I did the survey for the rot on this vessel myself and found many areas of rotten balsa (although they were fairly confined in each case as the end grain stops sideways wicking) as well as rotten ply, which had been used to core the high load areas and in several rather extensive areas had entirely rotted to mush!

Did I really write that? You are of course right, and I thank you for the correction.

Obviously it's not true that wooden cores never rot. There is always a risk even with a quality job. But what I should have said is that the risk is very, very small with the latest techniques, done by quality builders, and without someone having come in later and bodged a penetration.

I know, for example, that there were lots of problems with Hinckley and Morris cores in the 70's and 80s. But I've never heard of a single case of a rotten core on a Hinckley or Morris built with SCRIMP, not caused by someone's bodged through-hull, have you? These techniques are very, very reliable.

Dollars to doughnuts, that Oyster deck is plain, non-infused, non-encapsulated, and probably not even end-grain balsa. Older boat, am I right? And even so, I bet the rot was caused by a later retrofitted penetration, not so?

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[a64pilot]

Of course there are many cored vessels without issues, vast majority I would hope, and of course if you can investigate thoroughly you will find that something was done wrong, either in the build or during maintenance / modifications.
The point is though sort of like grids and bolted on keels, there is a possibility of failure with a core.

[minaret]

Originally Posted by Muckle Flugga

I like most of your posts a lot, Dockhead, but I am afraid this is just not true. I have seen rot MANY times in cored hulls, often very high quality ones. I attach an example of thoroughgoing rotten marine ply inside the core of the afterdeck of an Oyster undergoing deck replacement. I did the survey for the rot on this vessel myself and found many areas of rotten balsa (although they were fairly confined in each case as the end grain stops sideways wicking) as well as rotten ply, which had been used to core the high load areas and in several rather extensive areas had entirely rotted to mush!

You can bring a horse to water, but you can't make him drink.



Personally, I'm pretty done trying to convince people of what happens in the real world. They'd rather go with their book learning, that's ok with me. It's their money. Watching people shell out vast sums for boats which I know have problems has always really chapped my hide in the past, hate seeing anyone get taken. But at this point, there is plenty of info out there for anyone who takes the time to look for it. I'm sure plenty of people are misled by posts like some on this thread, but I'm done fighting it. It's clear to me that only lifelong marine pros will ever get it, and those faced with a catastrophic bill. Most of whom get right out of boating. Funny how all the pro boat builders on this forum all agree on the points of hull liners and organic cores. But all those who've never built or rebuilt a boat know better. Because they are engineers.

[TeddyDiver]

Originally Posted by minaret

You can bring a horse to water, but you can't make him drink.

Not that a horse is allways thursty or the water clean

C'mon, while you are right about the plausible faults it doesn't mean every boat is the same. Merely 'buyer be aware'

[Dockhead]

Originally Posted by minaret

You can bring a horse to water, but you can't make him drink.



Personally, I'm pretty done trying to convince people of what happens in the real world. They'd rather go with their book learning, that's ok with me. It's their money. Watching people shell out vast sums for boats which I know have problems has always really chapped my hide in the past, hate seeing anyone get taken. But at this point, there is plenty of info out there for anyone who takes the time to look for it. I'm sure plenty of people are misled by posts like some on this thread, but I'm done fighting it. It's clear to me that only lifelong marine pros will ever get it, and those faced with a catastrophic bill. Most of whom get right out of boating. Funny how all the pro boat builders on this forum all agree on the points of hull liners and organic cores. But all those who've never built or rebuilt a boat know better. Because they are engineers.

Peace, brother

Your perspective is incredibly valuable, and believe me, we all listen eagerly to everything you say.

But remember that your perspective is based on your particular experience -- boats which don't have core problems, don't get brought to you, do they? You only see the problems, not the successes.

If these problems were rampant, why in the world would all the top builders in the world, including now even Oyster, build this way? Hmmm?

Which is not to say that problems don't occur, and it's extremely valuable for us to hear about it from you.


As to the engineering part of our discussion -- that had nothing to do with the question of whether cored construction has problems or not. It was concentrated on the specific, narrow question of whether it's stronger or not. And it is objectively, indisputably stronger, pound for pound, vastly stronger, for very straightforward engineering reasons. That's all I was trying to say with that.


The Buddhists have a saying that when wise men disagree, very often their disagreement arises from the fact that are simply seeing different sides of the question. There is a parable about several blind men who all touch an elephant, and describe to some king what they have felt, and argue with each other, that the others have not felt the elephant at all. When in fact they have just felt different parts of the same thing. That's very much what is going on here. The fact that you are grabbing the ear while I'm grabbing the trunk, doesn't mean that I denigrate what you feel over there. It's a different perspective -- based on your concrete and very important experience. But it's not the whole elephant.

[neilpride]

Hummm, let me see if I get it but if I'm right ,,Minaret is trying to say that organic cores aka Balsa, wood or whatever organic crap plus liners , when I say liners I refer to those funny massive pieces of plastic glued with a funny adhesive as the whole structural point in the boat and then I think Minaret is quite frankly correct on this 2 aspects of boat construction, just my 2 cents...

[Dockhead]

Originally Posted by neilpride

Hummm, let me see if I get it but if I'm right ,,Minaret is trying to say that organic cores aka Balsa, wood or whatever organic crap plus liners , when I say liners I refer to those funny massive pieces of plastic glued with a funny adhesive as the whole structural point in the boat and then I think Minaret is quite frankly correct on this 2 aspects of boat construction, just my 2 cents...

Yes, only -- do you know a single boat which is cored below the waterline AND has a liner?

Hmmm?

Mass produced boats with liners have solid hulls. Thin. But uncored.

Fully cored hulls are characteristic of high end boats. Hinckley, Morris, Shannon, Hallberg Rassy, Contest, Discovery, etc., etc., none of which has a liner.

[neilpride]

Originally Posted by Dockhead

Yes, only -- do you know a single boat which is cored below the waterline AND has a liner?

Hmmm?

Mass produced boats with liners have solid hulls. Thin. But uncored.

Fully cored hulls are characteristic of high end boats. Hinckley, Morris, Shannon, Hallberg Rassy, Contest, Discovery, etc., etc., none of which has a liner.

Old C&C.s have full cored hulls with full liners ..

[Dockhead]

Originally Posted by neilpride

Old C&C.s have full cored hulls with full liners ..

The operative word being "old". Not today.

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[Garrettw]

Just contributing a data point here with no comment on design:

I have a later model Jeanneau and, unlike older models, it does have a fiberglass grid/liner. It seems to be a bit of a hybrid of the two actually. It is made from molded fiberglass and they've cut out the center sections of many of the grid squares. The entire liner is glued but it is also appears to be tabbed at the perimeters of the cut out sections as well as at the hull liner joint at the sides. As you might imagine, all furniture and bulkheads are attached directly to this structure. I have seen construction photos of larger Jeanneaus and there, the major transverse bulkheads appear to be glassed directly to the hull.

[neilpride]

Originally Posted by Dockhead

The operative word being "old". Not today.

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No no Dock, no offense but cored hulls and liners together are used this days to, old and new designs, a solid weak laminate can live with a liner or without a liner, they choose the latest by profit reasons... the new C&C line is cored to the bones and they use a grid liner to, Wauquiez core the hulls and use a grid, DuFour, HR use a Hybrid in their hulls..... by far many builders are switching to integral grid liners this days...

[minaret]

Originally Posted by Dockhead

Peace, brother

Your perspective is incredibly valuable, and believe me, we all listen eagerly to everything you say.

But remember that your perspective is based on your particular experience -- boats which don't have core problems, don't get brought to you, do they? You only see the problems, not the successes.

If these problems were rampant, why in the world would all the top builders in the world, including now even Oyster, build this way? Hmmm?

Which is not to say that problems don't occur, and it's extremely valuable for us to hear about it from you.


As to the engineering part of our discussion -- that had nothing to do with the question of whether cored construction has problems or not. It was concentrated on the specific, narrow question of whether it's stronger or not. And it is objectively, indisputably stronger, pound for pound, vastly stronger, for very straightforward engineering reasons. That's all I was trying to say with that.


The Buddhists have a saying that when wise men disagree, very often their disagreement arises from the fact that are simply seeing different sides of the question. There is a parable about several blind men who all touch an elephant, and describe to some king what they have felt, and argue with each other, that the others have not felt the elephant at all. When in fact they have just felt different parts of the same thing. That's very much what is going on here. The fact that you are grabbing the ear while I'm grabbing the trunk, doesn't mean that I denigrate what you feel over there. It's a different perspective -- based on your concrete and very important experience. But it's not the whole elephant.

Yes, peace and elephants. But, I assure you, boats that don't have core problems are also brought to me. Because I don't just fix rotten core, or just fix broken boats for that matter. The majority of the work in any boatyard is always maintaining boats that are in good shape. You'd be amazed how often people with boats just like yours, which they are certain are in perfect condition, come in for bottom paint and hull polish. Then I pick it apart and find all the failures they weren't aware of, and we fix it. Extremely common.

[Scot McPherson]

Originally Posted by reed1v

Kind of like wall paper. It lines or covers the inside of a boat's hull. Usually to hide the rough fiberglass of the inside of the hull. Usually a molded plastic insert that is laid into the hull during production. Sometimes made of vinyl cloth, as in the Cal line of boats, or of wood paneling like in the Hans Christian line of boats. Makes the boat look "finished" inside. Some boats have the inside of the hull finished off in a fine fiberglass cloth so it becomes part of the hull.

Isn't that called ceiling?



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[Dockhead]

Originally Posted by neilpride

No no Dock, no offense but cored hulls and liners together are used this days to, old and new designs, a solid weak laminate can live with a liner or without a liner, they choose the latest by profit reasons... the new C&C line is cored to the bones and they use a grid liner to, Wauquiez core the hulls and use a grid, DuFour, HR use a Hybrid in their hulls..... by far many builders are switching to integral grid liners this days...

That's news to me -- never seen such a thing other than on racing boats. But if you say so. Considering the high cost of doing it right, I would certainly avoid a cored hull on an inexpensive boat.