Rudder Failures

[smackdaddy]

Originally Posted by robert sailor

Well built older boats by and large have few problems with tabbing, I'm not saying it can't happen but its just not as common as you are trying to suggest.

Are you saying that Neil is being misleading as well?

Originally Posted by neilpride

Handholds apart, i agree with what you say regarding tabbing on bulkheads...

[Polux]

Originally Posted by neilpride

...i agree with what you say regarding tabbing on bulkheads, except 2 points, most Fg tabbing broken i see since im sailing is not definitive to have a bad failure, since the old boats are made diferent with bulkheads glassed from the bottom to the sides and even in some boats to the deck ...

It seems that have bulkheads glassed to the deck was not that frequent. Some mass production boats have them glassed to the deck too, for example the cheapest of all mass production boats

[neilpride]

Originally Posted by smackdaddy

I think this debate is actually about exactly that. What exactly is "doing it well"?
Is is the old glassed and throughbolted method? Is it using 1-1/2" of glass?

If so, is there ANY new boat out there doing this anymore? And if not, you have to ask why.

Then, as for the newb boat buyer, he or she has to decide whose advice to go with. Buy an old boat that has these things (along with a boatload of other old-boat problems) - or buy newer trusting the ratio of successes to failures out there in these boats.

But , i think you are confused, there is still new boats doing the clasic Fg tabbing in their bulkheads and this bring me the question i made to you since 100 topics and you still dont answer, no idea if you dont know the answer or dont want to answer..

QUESTION?

Why others builders still doing Fg tabbing in structural members if Plexus bonding is so great??and cheap?

QUESTION 2? why some builders are throwing to the trash the hard spot law in bulkheads bonding? even somebuilders still using a foam core or soft material in the bulkheads edges to avoid hard spots and stress in this particular point, why others just bond the ply edge with a rigid material?

Hummm...

[smackdaddy]

Originally Posted by neilpride

Some posters and members deal each day with boat problems, they can give you excelent advice based in personal experiences , and this is for me the deal, or you have posters like Smack , it come around with a baseball stick banging your head many times trying to get a Ok based on knocking numbers...

Look Neil, I'm not knocking you over the head with a baseball bat. But here's the deal, I'm not simply going to accept what you or Minaret or anyone else (even Plexus) has to say simply because you say it. Not going to happen.

You and Minaret both have very impressive experience. There's no denying that. And I completely respect that experience and knowledge. But you both also have an obvious bias toward the "old ways" of doing things. You just mentioned that above with your admiration of 1-1/2" glass and glassing/through-bolting of bulkheads.

No one here would dispute that those techniques are not "strong". The problem is, they are not used anymore for the most part. So where does that leave your argument that this is the "right way to do it"?

My intention for this thread is that it be an educational tool for the boat-buyer. When you and Minaret say that these new technologies, materials, and techniques are crap that leaves the boat-buyer who might like to take your advice in a real corner. ALL they can do is buy an old boat.

So, no, I'm sorry - despite your and Minaret's experience and knowledge, I'm not going to just accept what you have to say if/when it flies in the face of pretty much the entire modern boatbuilding industry.

There are some very smart, very experienced, very knowledgable people in that industry.

So - just provide evidence for your viewpoint. Those pics of the failed Plexus bond are very compelling to me. There's definitely something wrong. And it's what really makes me think the newer boats indeed have a shorter lifespan that the old boats you like. Understanding that aspect of things is MUCH more informative than simply saying "older is better" over and over. Because it's not.

As for me, I promise to continue to research this stuff and only ask questions and make assertions based on the evidence I find. My questions/opinions are based on these reports/etc. that I'm finding. And, yes, if you guys (who newb boat buyers respect) want to discount something that's happening across the industry you certainly need to provide something other than your opinion. Because both things can't be right.

[smackdaddy]

Originally Posted by neilpride

But , i think you are confused, there is still new boats doing the clasic Fg tabbing in their bulkheads and this bring me the question i made to you since 100 topics and you still dont answer, no idea if you dont know the answer or dont want to answer..

QUESTION?

Why others builders still doing Fg tabbing in structural members if Plexus bonding is so great??and cheap?

I don't know the answer to this. I'd have to ask those builders. My hunch is that it's either because it's a more performance-oriented boat that requires more strength, or it's a higher-end brand that sells boats to people who come in and ask whether the structure is tabbed in their boats. They likely sell far fewer boats, but, just like Island Packet with a full keel, there are still customers out there that want these things.

Also, remember that I'm not claiming Plexus bonding is so great. I've presented materials that talk about how good of a bond it provides and that it is, indeed, stronger than tabbing. That's not me talking. That's the industry and academia. If you actually take the time to read that report, the author talks about the advantage of using fibercloth with Plexus as being ideal.

On the other side of that, as I just said above, when you post photos of a failed Plexus bond - it makes one wonder. It definitely makes me wonder. (But why don't you also post photos of failed tabbing?)

But here's another angle, one that even robertsailor still doesn't seem to get. That bond didn't fail on the wood side like you guys implied it would. It failed on the glass side where it should definitely be the strongest and most stable. Why? See, there's a lot going on even in those photos of yours that bring up many questions - and challenge a lot of assumptions...if, that is, you guys are willing to learn too.

Originally Posted by neilpride

QUESTION 2? why some builders are throwing to the trash the hard spot law in bulkheads bonding? even somebuilders still using a foam core or soft material in the bulkheads edges to avoid hard spots and stress in this particular point, why others just bond the ply edge with a rigid material?

Hummm...

Again, I don't know. I'm not a boat builder. But I also haven't personally talked about any of the above, or claimed that any of it is better or worse than anything else. So, I'm not sure what point you're trying to make.

[neilpride]

Is not the point, im not a new stuff hater, in fact i deal with Cf and new stuff , some are are really good some are really bad, look, my trade área is the rigging bussines, i have a 35% participation in a rigging shop, and i still going up in the bosun chair to fit a pin and a cotter pin in a new roller furler, some new stuff its really crap and other its really better , for me, is not a old legacy building theory, im not saying that a Westsail 32 is better made than many new boats this days, what im saying is , based in personal experience and facts, some things are made wrong and old ways are better until they rectify the errors and start to face that a sailboat is something else than a consumer product to throw away in a short lifespan, not even mention the risk when some of those new sailors attempt to cross a vast part of the ocean and get caught in something horrible with a weak boat not designed for the conditions.

[Polux]

Originally Posted by neilpride

....
QUESTION?

Why others builders still doing Fg tabbing in structural members if Plexus bonding is so great??and cheap?

QUESTION 2? why some builders are throwing to the trash the hard spot law in bulkheads bonding? even somebuilders still using a foam core or soft material in the bulkheads edges to avoid hard spots and stress in this particular point, why others just bond the ply edge with a rigid material?

Hummm...

I have tried to maintain an hope mind about the Plexus/ laminated bulkhead debate.

For what i could tell the bonded of structural parts of boats are on the increase and not only for economic reasons. Bonding agents are becoming better and better and laboratory experiences show that they are not inferior in strength, if well used.

Marine world is a conservative world and sailors still have a distrust about everything that is bonded so brands don't make it a market advertise but many middle of the water good quality brands like Dehler are using bonded bulkheads to all except the main that I presume that is bonded and fiberglassed to the hull and deck.

Other quality brands that make high performance boats like Pacer, that use high specs to everything use bonded bulkheads (they are not inexpensive boats). Akilaria other not cheap top racing boat uses them too, or at least uses a lot of structural bonded parts. C&C also uses them.

https://www.youtube.com/watch?v=buFDQ6W42j4

I would prefer to have them bonded and fiberglassedbut I believe that more important than to use a bonding agent or tabing, the way it is done is far more important. I believe also that in the future we would be see a lot more boats with bonded bulkheads and that does mean that the boats, that are easily built (with cost savings), are necessarily less strong.

Have a nice sailing. Fair winds to you

[neilpride]

You bring the point back on track Pólux, why you prefer bonded and glassed?? both metods together?

[robert sailor]

Years ago there were really good builders, OK builders and not the best builders and they all used FG tabbing on bulkheads. Pretty much all of them were added well after the hull was molded and they used polyester resin which on a secondary bond is no where near as strong as epoxy. Some builders tabbed into the sides, some into the sides and decks and others all the way around. Some builders used just a couple of layers of roving and others many layers. There are a variety of these boats out there and they will all have different experiences depending how they are being used. Our boat, is glassed all around and is also thru bolted at 8" centers, this is indicative of how traditional builder built boats at that time and its a detail that many other good builders used so in boats built like this a tabbing failure is very rare and as NeilPride says pretty bullet proof.
The debate about using Plexus is pretty much run its course, we know its used on all the entry level boats gluing bulkheads and it has a reasonable history of working however there are many examples of catastrophic failures or lesser ones where furniture simply detaches itself from the hull.
From my knowledge base I know that boats are constantly bending and flexing, especially when sailed 24 hours a day for weeks offshore and FG tabbing is much more flexible than Plexus. Many people think that these boats don't move around and that the bulkheads are solid, that is not the way it works as in tougher conditions the boat is constantly flexing and the bulkheads are moving as well. It is this flexibility day in and day out that makes it much more suitable for using FG tabbed bulkheads. It is not about absolute strength because maybe Plexus is just as strong for awhile(I really don't know) but it is also much more brittle than FG and that's the downside of this product when exposed to continued wracking of the hull and rigging loads it does not appear to have the same resistance to failure that a well tabbed bulkhead does. We have learned from our experienced posters that Plexus is a hell of an adhesive and when used to bond like materials together particularly when both surfaces are flat there is none better but it has a variety of less than stellar qualities when you introduce different materials. Better boats are still built with tabbed bulkheads but at a real premium. Polux tells us that Bavaria is going back to glassed in bulkheads and that is probably a good thing as they are trying to say to their customers, look we may have built a lot of boats very cheaply in the past but we want to position our brand as more capable offshore and an improved structure is one way to do it, good on them, buyers should give their new boats a second look. Maybe others will follow and stop the race to the bottom.

[neilpride]

Swichting off the laptop and going to sail a melges 24 with a friend in the bay, after all is sunday and my only day to enjoy few tacks in the wáter.. see you later.....

[smackdaddy]

Originally Posted by neilpride

what im saying is , based in personal experience and facts, some things are made wrong and old ways are better until they rectify the errors and start to face that a sailboat is something else than a consumer product to throw away in a short lifespan, not even mention the risk when some of those new sailors attempt to cross a vast part of the ocean and get caught in something horrible with a weak boat not designed for the conditions.

I totally agree with you there. I'm probably more okay with the "disposable boat" thing than you are - but I'm definitely not okay with undue risk for new sailors.

[minaret]

Originally Posted by smackdaddy

Look Neil, I'm not knocking you over the head with a baseball bat. But here's the deal, I'm not simply going to accept what you or Minaret or anyone else (even Plexus) has to say simply because you say it. Not going to happen.

You and Minaret both have very impressive experience. There's no denying that. And I completely respect that experience and knowledge. But you both also have an obvious bias toward the "old ways" of doing things. You just mentioned that above with your admiration of 1-1/2" glass and glassing/through-bolting of bulkheads.


No bias here, I have built & repaired a number of very modern, very high end yachts, with much carbon fiber and other exotic materials, including designs by Carl Schumacher. I'm very much clued into the latest methods, and as you've seen from pics I've posted manufacturers from companies like 3M send me experimental not for sale equipment as a test bed.




No one here would dispute that those techniques are not "strong". The problem is, they are not used anymore for the most part. So where does that leave your argument that this is the "right way to do it"?

As has been repeatedly noted on this thread, they are indeed still used. And used in all of the high end options. You are once again simply trying to be obtuse, as you know this.



My intention for this thread is that it be an educational tool for the boat-buyer. When you and Minaret say that these new technologies, materials, and techniques are crap that leaves the boat-buyer who might like to take your advice in a real corner. ALL they can do is buy an old boat.


No, they can buy a new boat that doesn't use the corner cutting methods we dislike. There are quite a few, as you know.




So, no, I'm sorry - despite your and Minaret's experience and knowledge, I'm not going to just accept what you have to say if/when it flies in the face of pretty much the entire modern boatbuilding industry.

There are some very smart, very experienced, very knowledgable people in that industry.

So - just provide evidence for your viewpoint. Those pics of the failed Plexus bond are very compelling to me. There's definitely something wrong. And it's what really makes me think the newer boats indeed have a shorter lifespan that the old boats you like. Understanding that aspect of things is MUCH more informative than simply saying "older is better" over and over. Because it's not.

As for me, I promise to continue to research this stuff and only ask questions and make assertions based on the evidence I find. My questions/opinions are based on these reports/etc. that I'm finding. And, yes, if you guys (who newb boat buyers respect) want to discount something that's happening across the industry you certainly need to provide something other than your opinion.

Frankly, I seriously doubt your intentions here. But, I will keep posting evidentiary pics when I have the time. Believe me, I have many.



I think you should also try to remember that the vast majority of the info you are linking to and finding was written by somebodies marketing team. This is why even basic construction terminology is often misused.

[smackdaddy]

Not a bad summary, but a few things aren't quite right:

Originally Posted by robert sailor

It is not about absolute strength because maybe Plexus is just as strong for awhile(I really don't know) but it is also much more brittle than FG....

That's a bit of a stretch. Look at the numbers in the report.

Originally Posted by robert sailor

We have learned from our experienced posters that Plexus is a hell of an adhesive and when used to bond like materials together particularly when both surfaces are flat there is none better but it has a variety of less than stellar qualities when you introduce different materials.

Not correct. Look at the report. Plexus is very, very good at joining dissimilar materials. Remember, the bond in Neil's photos failed on the FG side - not the wood side where you would have expected it.

[smackdaddy]

Originally Posted by minaret

Frankly, I seriously doubt your intentions here. But, I will keep posting evidentiary pics when I have the time. Believe me, I have many.

I think you should also try to remember that the vast majority of the info you are linking to and finding was written by somebodies marketing team. This is why even basic construction terminology is often misused.

The last document I posted which shows the "T" joint testing is a graduate thesis from a university in NZ. So, again, I'm absolutely willing to listen to you and respect your input...but you really need to keep the facts straight to maintain a credible argument.

Originally Posted by minaret

No one here would dispute that those techniques are not "strong". The problem is, they are not used anymore for the most part. So where does that leave your argument that this is the "right way to do it"?

As has been repeatedly noted on this thread, they are indeed still used. And used in all of the high end options. You are once again simply trying to be obtuse, as you know this.

My intention for this thread is that it be an educational tool for the boat-buyer. When you and Minaret say that these new technologies, materials, and techniques are crap that leaves the boat-buyer who might like to take your advice in a real corner. ALL they can do is buy an old boat.

No, they can buy a new boat that doesn't use the corner cutting methods we dislike. There are quite a few, as you know.

Okay, cool. I honestly didn't know cruising boats were still being made with through-bolted bulkheads and 1-1/2" glass. Who's doing that? I want to keep my facts straight too.

[Polux]

Originally Posted by neilpride

You bring the point back on track Pólux, why you prefer bonded and glassed?? both metods together?

I have on my boat both methods together and till the bonded method has more positive feedback I prefer it that way, but maybe I am a being too conservative or just don't have enough information...and in doubt, two methods are better then one.

But when a top NA, like Mark Mills designs a top boat, a very expensive one, with top specs everywhere, like the Redline 41 ans specifies bonded bulkheads to the deck and hull, I am quite sure he knows what he is doing, quite sure that he did apply that on other boats he designed, mostly racers and very fast cruiser racers, that are among the best and fastest anywhere. I am also sure that the choice of the bonding agent and the way it is done the job is fundamental to the strength a cruiser racer, that will be used more for racing in top events, then to cruise boat, has to have.

https://www.youtube.com/watch?v=WEwFhR-Qa2w

Beautiful boat isn't it? who said that I don't like American/Canadian boat? Put on that boat a cruising interior as nice as I have on my boat and I will change mine by that one on a heartbit, with bonded bulkheads and all

Redline 41 - C&C Yachts