Rudder Failures

[smackdaddy]

Originally Posted by neilpride

Your glasses are fogged hummm, read again the whole post, i dont mention anything related to hurricane damage, you guys are amazing defending the indefensible.

I guess I misunderstood you when you said this:

Originally Posted by neilpride

Look ,,, im involved in the restoration of 2 beneteaus right now after hurricane Gonzalo strike St Marteen, one is a Brand new Oceanis 50 , the other is a 45 same vintage, the 50 get holed in the bow and in starboard side, stern is holed to, it take wáter, a lot, rudder is bend , if i remember a same Oceanis 50 get rudder post problems in the north atlantic this year, well trust me if i say that after inspect deeply all the interior damage and system i just reach the conclusión that beneteau want their customers to be screwed in some isolated spot in the blue ocean somewhere, Lame and sad....

Sounded very much like a Bene holed in a hurricane by the use of the word "hurricane". My bad.

Originally Posted by neilpride

In the picture you see something similar to a watertight bulkhead or crashbox at the lower bow área, there is nothing inside , the anchor chain drain at the top by drains openings in both sides of the hull, question is?? why someone at the Factory cut the bulkhead or crash box open? the boat take a lot of wáter by there..

Plexus. Anyone in the serious boatbuilding business can tell you exactly the same , Tabing Gluing vital components with a fillet of plexus is lame and denote a lack of care in what they do in the Factory, Plexus is rigid and brittle , this boats flex , we see it in the past with the funny Lagoon claims about bulkheads problems..

Im still in shock after see the whole rudder ikea table assembled with pan head screws and fillets of plexus , not a single ounce of glass anywhere.
End of the history...

As for Plexus - I'm certainly no materials expert, but if it lives up to how it's marketed, it makes perfect sense to me as being stronger overall than FRP tabbing:

Plexus "Fiberglass Fusion" Adhesives have revolutionized the way boats are designed and built. When applied to fiberglass and other composites, they dissolve a thin layer of each mating surface and actually fuse two composite surfaces into one, creating a chemically cross-linked bond so strong that the composites will delaminate before the bond fails.

In addition to unmatched bond strength, Plexus Adhesives offer:
• Flexibility to absorb vibrations and withstand stresses caused by the pounding of wind, water, and high speed on performance boats
• Excellent resistance to fuel, chemicals, UV, extreme temperatures, and repeated thermal cycling
• Design freedom to replace wood (especially below the waterline) with composites, thereby preventing rot and warranty issues

By replacing heavy, unreliable marine putties, Plexus Adhesives:

• Virtually eliminate surface preparation (no sanding, grinding, or primers required) and replace slow, labor-intensive assembly methods, reducing production times by up to 50%
• Eliminate chlorinated solvents
• Produce stronger, lighter, faster boats

By obsoleting mechanical fasteners such as bolts, rivets, and screws, Plexus Adhesives:

• Distribute loads over a much greater area
• Minimize fiberglass fatigue, wear, and failures
• Eliminate potential leak points

ITW Plexus is ISO 9001 certified. Plexus Adhesives have been tested and certified by the world's most respected marine agencies, including Lloyd's of London, Det Norsk Veritas, Icelandic, and the American Bureau of Shipping.

If anything, I'd be suspect of the bond to the plywood - not the FRP. Maybe that's why the bulkheads failed?

Anyway - you're there, I'm not.

[neilpride]

Is not, properly fiberglass tabbing is by far the stronger and better metod to fit bulkheads , partitions , stringers etc.. what Plexus and some builders try to sell you is just pure BS marketing, the builder can save a lot of money dropping a liner just in time when a single guy with a pneumatic gun is shooting plexus, haaa yes the crapy profit and cut corners,,,,

To make it properly the builder need a FG crew doing the manual FG tabing around bulkheads, but for Beneteau and others this is just a waste of time and money..

Plexus is a wonderful adhesive and when used it in the right spot is by far one of the best doing the job.

For gluing Liners and grid liners there is no other better option, Plexus all the way , problem is where the builders start to see ways to save more costs and well the rudder post in the bene is a example.

[Polux]

Originally Posted by DeepFrz

Polux, do you work for, in any way, any boat manufacturer?

Sorry about that. I did not saw your post. The answer is no.

[Polux]

Originally Posted by neilpride

..
Plexus is a wonderful adhesive ..

Really, I thought that for you it was just green snot!!!

Originally Posted by neilpride

..rudder post glued with crap to another crapy bulkhead ... is glued with something similar to a Green snot, aka Plexus....the ply panels are assembled with the Green snot again

[neilpride]

Originally Posted by Polux

Really, I thought that for you it was just green snot!!!

In the right aplication the Green snot work really well, for bulkheads no! peace!!!

[Cheechako]

Originally Posted by Old Snipe

I know that I am new to the sailboat arena, but I would think that the three areas that need to be over built are the keel, mast supports, and the rudder assembly. I know racers are built for a specific need, but cruisers should always be over built?

Dunno...... just makes sense to me.

I agree.. because what "overbuilt" really means is "more than the designer anticipated"... and many designers are overly optimistic about their ability to crunch numbers.... or take the numbers given them by manufacturers as "gospel". There are many examples of broken boats... even very highly engineered ones like the Americas cup boat that literally broke in half in San Diego! I'm sure Millions were spent on the engineering of that boat... There are just too many variables and unknowns to come up with a real world prediction...

[Polux]

Originally Posted by neilpride

In the right aplication the Green snot work really well, for bulkheads no! peace!!!

I would like, I am a peaceful guy but I do not agree with you, neither the facts. Take for instance the Akilaria 40, a race boat with many boats built and sailed in many Transats and other races at speeds that a cruiser never experience and sea conditions that only very rarely a cruiser meets:

http://vimeo.com/17632930

These boats use extensively "green snot" and are subject to more stress than any cruising boat and I don't have any notice of any having ever a structural problem:

"The AKILARIA 40 is manufactured in a female mould, the hull bottom is infused balsa and fibreglass sandwich construction and the upper sides are foam and fibreglass sandwich construction.
The deck is infused fibreglass and foam sandwich construction; all internal structures such as the longitudinal and transverse bulkheads are infused fibreglass and foam sandwich construction.
The floors are made of monolithic infused vinylester fibreglass from a female mould.
These are glued to the hull bottom with PLEXUS (methacrylate glue): this material guarantees a mechanical as well as a chemical bonding.
The deck is also glued to the hull with PLEXUS. Stanchions bolted through the hull deck bonding complete the connection.
All interiors are in composite material: chart table, galley."

[malbert73]

Originally Posted by Polux

I would like, I am a peaceful guy but I do not agree with you, neither the facts. Take for instance the Akilaria 40, a race boat with many boats built and sailed in many Transats and other races at speeds that a cruiser never experience and sea conditions that only very rarely a cruiser meets:

http://vimeo.com/17632930

These boats use extensively "green snot" and are subject to more stress than any cruising boat and I don't have any notice of any having ever a structural problem:

"The AKILARIA 40 is manufactured in a female mould, the hull bottom is infused balsa and fibreglass sandwich construction and the upper sides are foam and fibreglass sandwich construction.
The deck is infused fibreglass and foam sandwich construction; all internal structures such as the longitudinal and transverse bulkheads are infused fibreglass and foam sandwich construction.
The floors are made of monolithic infused vinylester fibreglass from a female mould.
These are glued to the hull bottom with PLEXUS (methacrylate glue): this material guarantees a mechanical as well as a chemical bonding.
The deck is also glued to the hull with PLEXUS. Stanchions bolted through the hull deck bonding complete the connection.
All interiors are in composite material: chart table, galley."

Just reading above- i believe it says the floors are glued with plexus. Seriously doubt bulkheads are glued with plexus in an ocean racer. Hull deck joint, and floor/liner are great with plexus. No reason not to tab bulkheads with fiberglass in any seriously built boat, unless you're trying to cut corners in my opinion


Sent from my iPad using Cruisers Sailing Forum

[robert sailor]

I agree that floors grids and hull to deck are areas that Plexus seems to be used a lot but I have never heard of real offshore race boats gluing plywood bulkheads to the hull with plexus and that's certainly not the case with this particular boat which has foam filled glass sandwich bulkheads which will be glassed (tabbed) to the hull. This is the proper way to build a boat designed for offshore racing. It will be light and very strong and certainly anything but the cheap seats.

[neilpride]

Originally Posted by Polux

I would like, I am a peaceful guy but I do not agree with you, neither the facts. Take for instance the Akilaria 40, a race boat with many boats built and sailed in many Transats and other races at speeds that a cruiser never experience and sea conditions that only very rarely a cruiser meets:

Extreme sailing! Akilaria 40 "Allianz - Adriatiq islands group" on Vimeo

These boats use extensively "green snot" and are subject to more stress than any cruising boat and I don't have any notice of any having ever a structural problem:

"The AKILARIA 40 is manufactured in a female mould, the hull bottom is infused balsa and fibreglass sandwich construction and the upper sides are foam and fibreglass sandwich construction.
The deck is infused fibreglass and foam sandwich construction; all internal structures such as the longitudinal and transverse bulkheads are infused fibreglass and foam sandwich construction.
The floors are made of monolithic infused vinylester fibreglass from a female mould.
These are glued to the hull bottom with PLEXUS (methacrylate glue): this material guarantees a mechanical as well as a chemical bonding.
The deck is also glued to the hull with PLEXUS. Stanchions bolted through the hull deck bonding complete the connection.
All interiors are in composite material: chart table, galley."

Aquilaria RC3 , nice litle boat , but sorry Mr, bulkheads are glased to the hull...

[smackdaddy]

Originally Posted by Polux

I would like, I am a peaceful guy but I do not agree with you, neither the facts. Take for instance the Akilaria 40, a race boat with many boats built and sailed in many Transats and other races at speeds that a cruiser never experience and sea conditions that only very rarely a cruiser meets:

Extreme sailing! Akilaria 40 "Allianz - Adriatiq islands group" on Vimeo

Oh hell yeah!!



Now THAT is a sailing video - and an awesome boat!

24 knots!!!!! Wow.

[Polux]

Originally Posted by neilpride

Aquilaria RC3 , nice litle boat , but sorry Mr, bulkheads are glased to the hull...

You should not get confused just because it is not a green snot and it is a white snot



Look under all the bulkheads, see the white snot? I don't know that if they are laminated too (my boat is bonded and laminated) but certainly they are bonded. I believe that the reason the use of that stuff in many boats is not advertised is because guys like you that tend to think that all that is radically new is worse than what exists and by the way, I have verified, those products have elasticity proprieties.

Here a good site about structural adhesives with lot's of information:

Bonding Technology: Thermosetting Structural Adhesives : CompositesWorld

Again, I am not saying (and I have never said) that Beneteau makes specially strong boats. I simply reacted to what this phrase of yours imply: " beneteau want their customers to be screwed in some isolated spot in the blue ocean" and all your comments regarding how inadequately the Beneteaus, namely the Oceanis 50 is built.

They are building this way for way more than 10 years, on that period they have made at least 15000 boats and if what you say had any correspondence with reality we should be looking at hundreds or thousands of boats with big structural problems....and you talk about an Oceanis 50 that had structural problems

If they were building specially weak boats for more than 10 years (probably 20 is more correct regarding the use of adhesives) the boats would give a lot of problems to their owners and that would reflect on the brand image and on the sales but that is not what happened and Beneteau is a solid leader on the market. That should say something to you. Your slander regarding a Brand and building methods, the way you do, clearly means you don't understand them. Structural bonding is used extensively in architecture, Space industries and Auto industries and not always because it is cheap to do so, sometimes because it's the better material for the job and I mean structural bonding not bonding some bits and pieces.

[barnakiel]

This "overbuilding" theme is like flue. Every year we see new infected and some casualties.

My hand becomes heavy and gravitates towards the infamous ignore button.

From an engineering point of view, there is no need for any overbuilding. All structural elements are designed with margins. PLS refer to books, e.g. by the Dashews.

When structures fail, it is not due to lack of overbuilding. It may be due to faulty engineering, material properties or technology unknowns or building errors.

And it does not imply the designer was ignorant. They may just as well have lacked data. They may just as well have designed the design for an application different than what the user asks from the design. Nobody is perfect and horses for the courses.

Now go and do not overbuild anymore.

b.

[neilpride]

Cool Pólux, i give it up, you win the Plexus debate, Cheers...

[UNCIVILIZED]

Gents,
There's a couple of key things of note:
- As I recall, this thread was/is supposedly about rudder failures. Not green snot adhesive, bulkheads, or if you want to get technical about it, not even auto pilots.
- The resolution of that image of the bulkheads in the AC3 above, is too poor to determine anything. Including whether or not they're finished attaching the bulkheads.
Nor if that white line is whatever they're using as the "flavor of the month" to prevent hard spots from the bulkheads, or is actually a bonding agent.
- Tabbed in bulkheads can & do fail too, especially if improperly done. Though regardless of proper or improper, if done with cloth & resin, the bond strength is FAR weaker than much of what it's bonding, as it's a secondary bond. Period.
If in doubt, ask me outside of this thread, & I'll happily suggest some good reads on the subject.

I'm gonna' guess that somehow, everyone here commenting about bulkhead installation here doesn't know under what various; circumstances, design, & materials types, that X, or Y constitutes a proper installation. And even if I'm incorrect on this, can we please go back to something resembling the original topic.

As, for instance. I'm curious as to whether or not using a high pressure water jet cutter to machine slots into a rudder's shaft for various structural pieces is a viable option. Or does it rank up there with those ways of doing such, which molecularly alter most grades of stainless, which make them both weaker & less corrosion resistant?
If it's viable, who's used it, how precise is it, what's the cost like, & it's drawbacks are?