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Discussion Starter #1
I was talking with JRP about chain plates, and decided some of you would like to see how interesting the design of the chainplates on my boat is...it's really cool, take a look.

It's a well engineered system that transfers all mast / Shroud loadings, thru the deck, pass the hull sides, into the boat's keel structure, where the reinforcing grid bears the stress, instead if bulkheads, or the boat's sides..

This system is rather light, extremely resistent, and sperads load over an enormous area, allowing the boat to sail harder and truer...less bending effect and deformations...it allows me to sail with confidence in any winds...

The bellow drawing shows a front view of the Kevlar reinforced beams or stringers.

Attached to the Kevlar stringers, there are on each side, Satinless steel plates, that reinforce the zone



The below drawing shos how the 3 stringers are laid (not to scale), and how the SS stud goes thru the 3 pieces.



The bellow photo shows the stingers being made and some already in palce (black arrows)..



and bellow photo shows the above deck plate, that transfers the load from the shrouds to the beams under the deck



This to show you that a well engineered system, on a race boat, will in fcat rival or be stronger than the "over beefed up system" of hevaier boats, ocean goings and old shoes.....

agree??
 

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It's a beautiful design and installation Alex.

Even though I have a very simple type of boat and chainplate setup, I appreciate the elegance of a well engineered system like your.

Something like that would be pretty unnecessary on a boat like mine though.
It would be like a having a B and R rig. Not necessary, overly expensive and out of place.
 

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Discussion Starter #4
No offense, Beneteau is a good boat...

The system is different, as the BEneteau rod is long an attaches at the end to the hull.

My rod is short, and thick, and has a big nut in the end that goes thru a steel rod that is horizontal

My rod is maybe 25 inches long
 

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Alex, I do not want to compare Beneteau with your boat (Fiat to Ferrari), but the rod attachment on my B. 423 looks very similar.
There just 2 stringers and not 3, but the vertical rod is attached to the horizontal rod and the horizontal rod is webbed into some sort of stringers.
Here is a cut-paste from a Beneteau 423 review:
"Finot and Beneteau, separately and together, have engineered a great many hulls. While it’s topical, and appropriate, to boast that a boat meets European Union requirements, the best codicil to that is Beneteau USA president Wayne Burdick’s statement to me that Beneteaus have sailed many millions of miles without a hull failure.

That he can make such a claim is a credit to the way the company handles potential conflicts between the need to engineer the boat’s components for their own sake and the need to engineer them for economy in manufacturing. Behind the saloon settee is the chainplate that ties the cap and aft-lower shrouds into the hull structure. A tie rod is attached to the underside of the deck fitting and, with a toggle, to a horizontal stainless-steel bar glassed into a web structure in the manner I first saw on high-tech one-off racing boats."
 

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Looks like a simple rod tying into ribs (and the hull to which they are bonded) and nothing really new. Tying into a bulkhead that was affixed to the hull would simply be more economical--if the bulkhead was in the right location. If not, the bars and ribs make sense to replace a bulkhead.

My only question would be if anyone tried to measure the load in the three ribs, to see if it was equal. If there's no way to equalize it across all three--I'd expect the spreader rod to worry the hole in one rib more than the others, or the load to be applied unevenly. Don't know if that would be a real problem or an ignorable one, I don't have the tools or experience to figure that beyond a doubt. Did your designer consider that? three ribs trying to play "weakest link" versus just one rib?
 

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Ales, I don't want to offend you! But it looks very much like the Beneteau tie rod system.
I was thinking the same thing.
 

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Looks like a simple rod tying into ribs (and the hull to which they are bonded) and nothing really new. Tying into a bulkhead that was affixed to the hull would simply be more economical--if the bulkhead was in the right location. If not, the bars and ribs make sense to replace a bulkhead.

My only question would be if anyone tried to measure the load in the three ribs, to see if it was equal. If there's no way to equalize it across all three--I'd expect the spreader rod to worry the hole in one rib more than the others, or the load to be applied unevenly. Don't know if that would be a real problem or an ignorable one, I don't have the tools or experience to figure that beyond a doubt. Did your designer consider that? three ribs trying to play "weakest link" versus just one rib?
I don't know all about the engineering stuff but it is strong. I had a 45 ft Sea Ray Took out my back stay and a shroud and the tie rod didn't move at all. The rig stayed up also.
 

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Discussion Starter #10
That system was overcalculated, the difference between it and the rest is the loading starts at he keel box, or the boat's structre, and not the boat's sides, as in the Beneteau and similar designs.

The load is "under" the boat.

The 3 ribs are different sizes to compensate the load shares and surfaces of adhesion...
 

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Sweet boat Gui.

You all talk so well about these load bearing system. Does anyone know if Beneteau will give you a tour of hulls under contruction? I'd love to see what's underneath all the woodwork.
 

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Discussion Starter #13
Alex, are your bulkheads therefore tightly bonded to the deck and hull, or do they "float" slightly to allow for flex?
Val,

My bulkhead (froward) is bonded (attached) on the bottom to that famous multiple legged "H" piece that constitutes the structure of my boat.

It's base is supported by a transversal beam that also supports the mast and it's jack, and that load is passed onto the "H" structure, and then spread onto the hull.

Remember the hull is cored with Divinycell, so you can't really attach the bulkhead sides, otherwise the loads would tear thru the core..However, yes, the sides are floating, they do have a gap, that is filled with sikaflex or similar.

Also, if you bond the bulkhead, it causes it to be vivible from the outside of the hull as it makes a protrusion, as the hull shrinks.

So the bulkhead is only attached on the botom, and maybe first foot of the hull from the "H" up, maybe to the water line. then it's floating, and the top, where the cabin attaches is again fixed to the cabing ceiling with bonding in key areas and gaps filled with sikaflex or other bonding paste i can't remeber.

Do you remember I showed you inside the kitchen cabinets the floating anchoring points between the bulkhead and hull?? Or maybe was Tom...

Alex
 

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I think they do, when we first bought our boat we were invited down there even though we ended up buying a boat that at the time was 4 years old.
 

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Alex, I know you've said it before; but this really reinforces the value of being able to build new from scratch.

Very elegant.
 

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Do you remember I showed you inside the kitchen cabinets the floating anchoring points between the bulkhead and hull?? Or maybe was Tom...

Alex
It was Tom, but I assumed the bulkheads were loosely attached in places necessary to allow movement. On older FRP boats, such as my 33 footer, many of the necessary repairs are due to "detabbing" of furniture and bulkheads that have been bonded too strongly to the hull, or with inadequate "spread" or surface area over which the stresses of a lightly flexing hull can be transferred.

By contrast, of course, is my steel hull, which is a form of monocoque construction in which the bulkheads are strongly welded to the frames and stringers and to the deck and hull itself, making a nearly watertight seal, except for the limber holes.

My steel cutter's chainplates are 1/2" steel bar stock welded in place on deck and presumably welded further down to the frames. They aren't going anywhere soon.

On the 1973 plastic sloop are 3/8" steel bar chainplates passing through thick (four inches or so) glassed in, underdeck "knees" that look just like old wooden boat knees, as some "wooden boat" ideas were still alive in fibreglass boat construction even at that late date. I service these every year by tightening the bolts and occasionally putting sealant on deck. I had to replace a couple of the bolts one year as they had deformed, probably due to my sailing the boat hard in heavy air. I will consider rebuilding these "knees" when I rerig the boat standing rigging in the next couple of years...all the shrouds and stays are original...thank you, fresh water!
 

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Just because I've sailed on his boat and he's probably sleeping, Giulietta is I would say a "semi-custom" yacht in that it is a modified racing hull with a cruiser interior and more "amenities" than a typical racer.



Alex himself made a lot of the decisions on customization, and it shows: Giulietta has the most orderly deck I think I've ever seen, and a number of logical and good looking touches in the cabinetry and the saloon.

While the boat is very much light displacement and easily driven, I nor my wife (who sailed separately with Alex as crew in better wind) noticed any "vices" with her handling. It is a very well-mannered sailboat and is, as you may suspect, ridiculously fast when conditions allow.
 

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Discussion Starter #20
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