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Pics following are of connecting link between clevis dovetail plate at bow and roller furling gear. yacht is a Bavaria Match 42.
I received email via previous owner that Previous previous owner (PPO) had found one of these connecting links broken on sistership in his charter fleet.
I've tried to contact PPO to find out the circumstances but unsuccessful so far.
Q.1 Is anyone aware of any failures of this connecting link in the match 42 or other similar Bavaria. I'll obviously replace but I would like to know what could have lead to failure and whether this is common or not.
Q.2 What is the U-bar welded to the link for? It doesn't seem to have any purpose with my setup.
NB. yacht is stored for winter in Dubrovnik. I am in Oz and won't be going to Croatia till May.

Much appreciated if anyone can share insights.

Cheers


 

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Pics following are of connecting link between clevis dovetail plate at bow and roller furling gear. yacht is a Bavaria Match 42.
I received email via previous owner that Previous previous owner (PPO) had found one of these connecting links broken on sistership in his charter fleet.
I've tried to contact PPO to find out the circumstances but unsuccessful so far.
Q.1 Is anyone aware of any failures of this connecting link in the match 42 or other similar Bavaria. I'll obviously replace but I would like to know what could have lead to failure and whether this is common or not.
Q.2 What is the U-bar welded to the link for? It doesn't seem to have any purpose with my setup.
NB. yacht is stored for winter in Dubrovnik. I am in Oz and won't be going to Croatia till May.

Much appreciated if anyone can share insights.

Cheers


Without knowing where the link plate failed it's difficult to know what caused the fail.

I would guess that not all Bavaria Match 42 where rigged with furler, so the U could be a tack attachment point (odd with only one on a racer though).

The bottom attachment of the link does not allow sideways movement, that could be a failure point, the link plate can move sideways due to the large hole in the deck - have you seen if it is moving sideways while under sail?

Looking at the pics - is there to little "meat" at the ends?
 

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The bottom attachment of the link does not allow sideways movement, that could be a failure point, the link plate can move sideways due to the large hole in the deck - have you seen if it is moving sideways while under sail?
Yup, the absence of some sort of toggle there is a really bad arrangement, even a moderate amount of headstay sag is gonna put an eccentric load on that connection...
 

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The hole on the boat does not seem to be properly aligned ( Second picture ). The plate seems too close to the head of the boat. Increasing the width will further cause the metal to touch to the front part of the hole.
 

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make a new one and have movement on all axis with new toggle...connector

I beleive there was a thread not too long ago with a charter bavaria that had the mast come down in a gust in the adriatic and someone on here talking about it.

same comments being made
 

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That long 'toggle plate' has two very severe potential failure areas - IMO. Id make the guess that Bavaria didnt do this; but, a 'rigger' did this. 'IT DOESNT 'LOOK RIGHT'.

1. that U-bolt is probably setting up a weird inconstant elastic zone that will affect fatigue and ultimately tensile strength long term - Id call this a potential 'stress riser', a design fault/anomaly that can easily affect the long term load bearing capability. This would be the same (poor) anomaly often seen in 'traditional' chain plates that have 'multiple bore holes' ... all in a line.
If the U bolt was welded to the plate, Id surely insist that the 'plate' be re-annealed / stress relieved after that U-bolt was attached, and then an exact mirror image 'sample' be dynamically tested/evaluated to failure to prove structural efficacy of the 'design'.

2. More importantly and what my experienced 'eye' sees, those large bore holes for the pins in that plate would be VERY subject to whats known as insufficient 'projected saddle stress bearing area' (another magnificent 'stress riser'). Id expect in long term use that fatigue cracks would begin to appear from the OD of the bore (at either 3 or 9 o'clock w/r to the long axis of the plate) continually propagating from the bore to the far outside of the plate, until failure.
As a former stress analyst these bore holes 'look' too BIG in relation to the amount of cross sectional area of stainless that is adjacent at 90° from those bore holes - it simply DOESNT LOOK RIGHT based on a lot of forensic experience. I would fully expect that engineering wise - 'all the lines of stress/force' when the part is at full tensile load are severely 'concentrated' going 'around' the area of these large bores - a 'stress riser' - a design anomaly that weakens the design. Based on my experience, Id expect that these bores would soon develop 'happy face' cracks at 90° from those bore holes.
If starting from scratch, this area of the plate 'should' probably have its 'width' increased significantly and with a smooth transition to the cross section of the area without the bores ---- would probably look like a 'dog bone'. Id also want a (tensile) SAFETY FACTOR of 3 to 4 and the design based on the fatigue endurance limit of the material, not 'tensile/yield' values.

I'd bet the farm that Bavaria designers didnt do this as it (looks) very inconsistent with the usual very good 'German style' dynamic-structural engineering; but rather, a rigger did it and without full approval from Bavaria. If Bavaria did this they should increase their liability policy if several of these 'links' were not 'dynamically proven' - put into a dynamic tensile testing machine and properly evaluated and tested to failure.

Just off the top of my head this 'design' LOOKS ~half (or less) as strong as it needs to be and I would guestimate that it will prematurely fail via fatigue mode AT those bore holes (and ignoring any crevice corrosion that would vastly enhance fatigue failure).
'IT DOESNT 'LOOK RIGHT'.
 

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That long 'toggle plate' has two very severe potential failure areas - IMO. Id make the guess that Bavaria didnt do this; but, a 'rigger' did this. 'IT DOESNT 'LOOK RIGHT'.

1. that U-bolt is probably setting up a weird inconstant elastic zone that will affect fatigue and ultimately tensile strength long term - Id call this a potential 'stress riser', a design fault/anomaly that can easily affect the long term load bearing capability. This would be the same (poor) anomaly often seen in 'traditional' chain plates that have 'multiple bore holes' ... all in a line.
If the U bolt was welded to the plate, Id surely insist that the 'plate' be re-annealed / stress relieved after that U-bolt was attached, and then an exact mirror image 'sample' be dynamically tested/evaluated to failure to prove structural efficacy of the 'design'.

2. More importantly and what my experienced 'eye' sees, those large bore holes for the pins in that plate would be VERY subject to whats known as insufficient 'projected saddle stress bearing area' (another magnificent 'stress riser'). Id expect in long term use that fatigue cracks would begin to appear from the OD of the bore (at either 3 or 9 o'clock w/r to the long axis of the plate) continually propagating from the bore to the far outside of the plate, until failure.
As a former stress analyst these bore holes 'look' too BIG in relation to the amount of cross sectional area of stainless that is adjacent at 90° from those bore holes - it simply DOESNT LOOK RIGHT based on a lot of forensic experience. I would fully expect that engineering wise - 'all the lines of stress/force' when the part is at full tensile load are severely 'concentrated' going 'around' the area of these large bores - a 'stress riser' - a design anomaly that weakens the design. Based on my experience, Id expect that these bores would soon develop 'happy face' cracks at 90° from those bore holes.
If starting from scratch, this area of the plate 'should' probably have its 'width' increased significantly and with a smooth transition to the cross section of the area without the bores ---- would probably look like a 'dog bone'. Id also want a (tensile) SAFETY FACTOR of 3 to 4 and the design based on the fatigue endurance limit of the material, not 'tensile/yield' values.

I'd bet the farm that Bavaria designers didnt do this as it (looks) very inconsistent with the usual very good 'German style' dynamic-structural engineering; but rather, a rigger did it and without full approval from Bavaria. If Bavaria did this they should increase their liability policy if several of these 'links' were not 'dynamically proven' - put into a dynamic tensile testing machine and properly evaluated and tested to failure.

Just off the top of my head this 'design' LOOKS ~half (or less) as strong as it needs to be and I would guestimate that it will prematurely fail via fatigue mode AT those bore holes (and ignoring any crevice corrosion that would vastly enhance fatigue failure).
'IT DOESNT 'LOOK RIGHT'.
I would guess that this boat came without furler, so the head stay went all the way down. The link was added to accommodate the furler.
 

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Yes.... given the current setup I see no value in the hole in the deck, if fact it's likely a contributor to any failure potential. There must have been a toggle on the underdeck mount in the original install - at least I'd hope so.

I think I'd turn that 'link' into a chainplate sort of setup to a filled in deck plate.
 

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Yes.... given the current setup I see no value in the hole in the deck, if fact it's likely a contributor to any failure potential. There must have been a toggle on the underdeck mount in the original install - at least I'd hope so.

I think I'd turn that 'link' into a chainplate sort of setup to a filled in deck plate.
I don't think that it's a good idea to fill that hole it would transfer loads to a deck that is not designed for these sideways loads.

Use a toggle between the stay attachment and the link plate and also between the furler and the link plate. This way you will avoid any bending on the link plate.
 

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I don't think that it's a good idea to fill that hole it would transfer loads to a deck that is not designed for these sideways loads.

Use a toggle between the stay attachment and the link plate and also between the furler and the link plate. This way you will avoid any bending on the link plate.
Could also be done simply with a simple aux. wire rope 'stay' with toggles already swaged to the ends. --- then you'd get 'pure' tension.

A 'traditional' chainplate in that location will require 'kinks and bends' (stress risers - bad!) and then youd be pulling a 'complex' levered cantilever load with the attached 'base' at approaching 90° to the axis of the stress, which 'mathematically' reduces the structural load capacity by about 1/4 in accordance to even common 'cookbook' beam formulas.
"Pure" straight-line tensile stress is the way to do this.
Beneteau's recent designs for chainplates (rods with trunnion attachment points, actually), etc. remarkably seem to be following this 'pure' and elegantly simple stress connection methodology.
 

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This image was sent by PPO to PO and on to me. It would seem that the part is original.
I stand corrected :)
I was assuming that the Match boats came w/o roller furler and that this was an after market mod.

Sometimes builders deviate from the designers plans also..

It would be interesting to see the failure mode on that boat.
I still think the design is strange, the underside of the furler is toggled correctly. But the long lever arm created by the link plate can still move sideways and get stressed.

Regarding the crack in gelcoat it looks more like something caused by impact on outside. But you should have it checked to see how deep it is.
 

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Hi Christian. For us less schooled sailors, could you throw up a couple of pictures of appropriate toggles.
Last year I changed the bearings on my 40 year old plus, Head Stay furler.
What an improvement!
Would the toggles do any good for this old foil type, furler?
 
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