I think calling the cassette insert "small" may be jumping the gun until we know it broke. On the thought of keel threads, if they are tapped into cast iron that brings back memories of tapping cast iron. It is harder than titanium to form a thread in. As a material it is so hard and brittle and as a result the thread can be malformed. It is possible to form a quality thread in cast iron but it requires proper technique and equipment.
Farr X2
- Thread starter BP777
- Start date
Hans Genthe
Member
I have seen quite a lot of keel drawings of FARR Design, because I have done detailled calculations for their boats for production.
All keel structures I have seen were well thought and rather oversized. On the Farr 280 the two keel nuts are M16 (or bigger).
I expect the drawings will show a welded keel structure with detailled material specs and information with torque you have to use to mount the bolts. (on my FARR280 I had to use a torque wench, otherwise I would have loosen warranty. I´ve attached a screenshot out of my handbook). By using defined forged steel sheets it is easy to calculate the forces and define the thickness. Welding as to be done accordingly and is normally not a problem if you have educated welders and a quality management.
Farr Design is a very well organised design office with a huge experience and proper internal documentation. They only have to copy and paste one of their approved keel drawings. They have a huge data basis and the X2 is not a boat which is pushed to the last limit, no need to reduce material thickness. No reason for leaving the beaten track.
From my experience I don´t believe it a fault of Farr design. As I wrote before, I expect it is a welding problem. I can´t imagine that Farr will made plans for a cast steel fin. Please note, these is my personal opinion and I don´t know the final design drawings. For our AEOLOS P30 design we have chosen a different keel design to avoid the human factor, means errors in welding.
I hope they will publish the investigations. I expect you can the se problem easily if someone is publishing a closer look of the keel box.
All keel structures I have seen were well thought and rather oversized. On the Farr 280 the two keel nuts are M16 (or bigger).
I expect the drawings will show a welded keel structure with detailled material specs and information with torque you have to use to mount the bolts. (on my FARR280 I had to use a torque wench, otherwise I would have loosen warranty. I´ve attached a screenshot out of my handbook). By using defined forged steel sheets it is easy to calculate the forces and define the thickness. Welding as to be done accordingly and is normally not a problem if you have educated welders and a quality management.
Farr Design is a very well organised design office with a huge experience and proper internal documentation. They only have to copy and paste one of their approved keel drawings. They have a huge data basis and the X2 is not a boat which is pushed to the last limit, no need to reduce material thickness. No reason for leaving the beaten track.
From my experience I don´t believe it a fault of Farr design. As I wrote before, I expect it is a welding problem. I can´t imagine that Farr will made plans for a cast steel fin. Please note, these is my personal opinion and I don´t know the final design drawings. For our AEOLOS P30 design we have chosen a different keel design to avoid the human factor, means errors in welding.
I hope they will publish the investigations. I expect you can the se problem easily if someone is publishing a closer look of the keel box.
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Hans look at the photos on my post #55. They were CNC milling the tooling for the fin. i.e. it's a cast iron part not a milled steel fin. No welding involved. The fiberglass foil shaped fairing encloses the fin.
See the X2 web page: "Cast Iron T Keel with Composite Shroud and Lead T-Bulb"
https://www.farryachtsales.com/sales/boat/farr-x2
Frogman's posting that there was no problem with the hull structure does suggest the bolts failed. Either vibrated loose or failed due to fatigue. Possibly some other mechanism like the cast iron threads failing.
See the X2 web page: "Cast Iron T Keel with Composite Shroud and Lead T-Bulb"
https://www.farryachtsales.com/sales/boat/farr-x2
Frogman's posting that there was no problem with the hull structure does suggest the bolts failed. Either vibrated loose or failed due to fatigue. Possibly some other mechanism like the cast iron threads failing.
Black Jack
Super Anarchist
Human error is very likely at commissioning and launch.
In June I saw a X2 out on SF bay. She is very sexy. I was able outpoint her on my old girl for a minute keeping pace with her upwind but once she turned to a close/beam reach she was gone. I hope they sort this hanging question out.
In June I saw a X2 out on SF bay. She is very sexy. I was able outpoint her on my old girl for a minute keeping pace with her upwind but once she turned to a close/beam reach she was gone. I hope they sort this hanging question out.
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Liquid
NFLTG
I'm betting the keel failed at the hull joint, leaving the stub in the cassette. Upon recovery they removed the bolts to put the stub in a plastic bag marked "evidence".
Ex Machina
Super Anarchist
Where’s the fun in that though , wild speculation is so much more satisfying
shaggybaxter
Super Anarchist
In my old metal bashing days we could get a bolted structure to fail by:
Coarse threads suck because surface area is king, the torque climbs quickly with fuck all movement and there is less hysteresis between the 'right' and 'wrong' amount of torque and less resistance to coming undone or overstressing the bolt. The proper torque of a bolt is nearer to its failure than its safety margin, IIRC a good torque setting is some 80% of max load to get the right spring tension on the mated surface.
I also learnt pretty quick about the importance of dry threads (after a couple of spectacular failures), its next to impossible to get the right torque readings once you use any lubricant.
For really high load bearing applications we would put away the torque wrench and use verniers.
A bolt into a captive nut assy sucks because none of the above is easy.
With that said, the guys involved seem to have put a huge amount of effort and thought into the design and I'm not writing it off yet. There's a lot to like, I hope Farr get behind the Nexba team and help them get back on their feet. This is what will influence me in any prospective purchase, how good the vendor is at post sales support. Something that frankly a lot of production builders suck balls at from recent observations.
I watch with interest.
- over torquing;
- torquing the bolt not the nut;
- using a coarse thread pitch; and
- using grease.
Coarse threads suck because surface area is king, the torque climbs quickly with fuck all movement and there is less hysteresis between the 'right' and 'wrong' amount of torque and less resistance to coming undone or overstressing the bolt. The proper torque of a bolt is nearer to its failure than its safety margin, IIRC a good torque setting is some 80% of max load to get the right spring tension on the mated surface.
I also learnt pretty quick about the importance of dry threads (after a couple of spectacular failures), its next to impossible to get the right torque readings once you use any lubricant.
For really high load bearing applications we would put away the torque wrench and use verniers.
A bolt into a captive nut assy sucks because none of the above is easy.
With that said, the guys involved seem to have put a huge amount of effort and thought into the design and I'm not writing it off yet. There's a lot to like, I hope Farr get behind the Nexba team and help them get back on their feet. This is what will influence me in any prospective purchase, how good the vendor is at post sales support. Something that frankly a lot of production builders suck balls at from recent observations.
I watch with interest.
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DickDastardly
Super Anarchist
Overtorqued bolts is high on my list of possible causes.
Liquid
NFLTG
The Dark Knight
Super Anarchist
Too much torque and not enough facts is a major problem on SA
Ex Machina
Super Anarchist
My money is on under talked
Sailabout
Super Anarchist
dont forget the huge difference in sh*t SS and good SS
saying that if the keel was cast do you think you could smash that tang off with a sledge hammer if the keel was laying on the ground??
I would be thinking that as you get knocked down and sail off a wave to land on your gunwhale and testing that tang..
saying that if the keel was cast do you think you could smash that tang off with a sledge hammer if the keel was laying on the ground??
I would be thinking that as you get knocked down and sail off a wave to land on your gunwhale and testing that tang..
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Teaky?Too much torque and not enough facts is a major problem on SA
Recap of rescue
HMAS Brisbane rescues sailors from capsized yacht in heavy seas off Wollongong
Two yacht sailors are alive and back in the arms of their loved ones today after a dramatic rescue in extreme sea conditions by the crew of the Royal Australian Navy Destroyer HMAS Brisbane.
The two experienced mariners struck difficulty when their yacht capsized approximately 15 nautical miles off Wollongong on the NSW South Coast at around 1am yesterday.
The Joint Rescue Coordination Centre reported the vessel missing and initiated a search shortly after 1pm and HMAS Brisbane responded to the call, reaching the 60 square nautical mile search area about an hour later.
After a sighting of the upturned yacht was promptly reported by the passing merchant vessel MV Arietta Lily just after 3pm, Brisbane was able to head directly to its position for a rescue.
The two yacht sailors were found clinging to the hull of their vessel and were rescued by the destroyer’s Rigid Hulled Inflatable Boat (RHIB) in 56 kilometre per hour winds and two metre swells.
Despite spending 15 hours in the ocean, the two sailors were assessed as being in good condition as Brisbane made the journey back to Sydney to reunite the survivors with their loved ones.
Following the rescue, the Australian Maritime Safety Authority thanked the vessels involved in an official message.
“JRCC Australia and NSW Water Police would like to thank the Australian Defence Force (ADF) and the Master and crew of Arietta Lily for their assistance rescuing the crew.
“The quick response of the ADF and Arietta Lily to our distress broadcast was in the finest traditions of seafarers, and we appreciate the commendable seamanship of both Arietta Lily and HMAS Brisbane in sighting the survivors, maintaining visual contact and coordinating a response, and then recovering them in challenging conditions,” the message read.
HMAS Brisbane Commanding Officer, Commander Kingsley Scarce, said the ship’s company were pleased to play their part in the rescue, and paid tribute to their bravery in difficult conditions.
“We were happy that we could come to the aid of fellow mariners in their time of need today.
“Tremendous teamwork from all of Brisbane’s crew, from those who coordinated the search effort and response, to the bridge crew and lookouts, to those who provided medical care and hospitality to the survivors once rescued, and to all others who supported. The entire crew was eager to do whatever they could in the rescue effort.
“I want to particularly acknowledge the bravery of the sea boat crew who conducted the rescue in appalling sea conditions,” Commander Scarce said.
The survivors were reunited with families at Fleet Base East at around 7pm on Saturday.
The location of the stricken yacht has been reported to the Australian Maritime Safety Authority which has notified all vessels of the navigation hazard.
HMAS Brisbane rescues sailors from capsized yacht in heavy seas off Wollongong
Two yacht sailors are alive and back in the arms of their loved ones today after a dramatic rescue in extreme sea conditions by the crew of the Royal Australian Navy Destroyer HMAS Brisbane.
The two experienced mariners struck difficulty when their yacht capsized approximately 15 nautical miles off Wollongong on the NSW South Coast at around 1am yesterday.
The Joint Rescue Coordination Centre reported the vessel missing and initiated a search shortly after 1pm and HMAS Brisbane responded to the call, reaching the 60 square nautical mile search area about an hour later.
After a sighting of the upturned yacht was promptly reported by the passing merchant vessel MV Arietta Lily just after 3pm, Brisbane was able to head directly to its position for a rescue.
The two yacht sailors were found clinging to the hull of their vessel and were rescued by the destroyer’s Rigid Hulled Inflatable Boat (RHIB) in 56 kilometre per hour winds and two metre swells.
Despite spending 15 hours in the ocean, the two sailors were assessed as being in good condition as Brisbane made the journey back to Sydney to reunite the survivors with their loved ones.
Following the rescue, the Australian Maritime Safety Authority thanked the vessels involved in an official message.
“JRCC Australia and NSW Water Police would like to thank the Australian Defence Force (ADF) and the Master and crew of Arietta Lily for their assistance rescuing the crew.
“The quick response of the ADF and Arietta Lily to our distress broadcast was in the finest traditions of seafarers, and we appreciate the commendable seamanship of both Arietta Lily and HMAS Brisbane in sighting the survivors, maintaining visual contact and coordinating a response, and then recovering them in challenging conditions,” the message read.
HMAS Brisbane Commanding Officer, Commander Kingsley Scarce, said the ship’s company were pleased to play their part in the rescue, and paid tribute to their bravery in difficult conditions.
“We were happy that we could come to the aid of fellow mariners in their time of need today.
“Tremendous teamwork from all of Brisbane’s crew, from those who coordinated the search effort and response, to the bridge crew and lookouts, to those who provided medical care and hospitality to the survivors once rescued, and to all others who supported. The entire crew was eager to do whatever they could in the rescue effort.
“I want to particularly acknowledge the bravery of the sea boat crew who conducted the rescue in appalling sea conditions,” Commander Scarce said.
The survivors were reunited with families at Fleet Base East at around 7pm on Saturday.
The location of the stricken yacht has been reported to the Australian Maritime Safety Authority which has notified all vessels of the navigation hazard.
Kududine
New member
My apologies. I carelessly followed a link to a Farr 40ft which talked about a steel keel.
So a cast iron core held in place with SS screws. Possibly with ss inserts cast-in to accept the mounting screws.
Not sure I would rely on torque pre-load to ensure anti-vibration locking in this application. Complex stack of materials with different elasticity. A mechanical bolt-head lock would work.
A tapered tang fit in the cassette is great for installation, but once the bolts are loose, there is going to be movement, and more shock loads etc.
So a cast iron core held in place with SS screws. Possibly with ss inserts cast-in to accept the mounting screws.
Not sure I would rely on torque pre-load to ensure anti-vibration locking in this application. Complex stack of materials with different elasticity. A mechanical bolt-head lock would work.
A tapered tang fit in the cassette is great for installation, but once the bolts are loose, there is going to be movement, and more shock loads etc.
Tropical Madness
Super Anarchist
better it broke close to shore than middle of bass straight.
I also just realised they went south.. crikey - that's where most of the weather was...interesting choice given they could have gone any direction 50M and turned back.
I also just realised they went south.. crikey - that's where most of the weather was...interesting choice given they could have gone any direction 50M and turned back.
pacice
Anarchist
solosailor
Super Anarchist
Covered earlier..... bleeper broke. 2nd one left below. Carry a stern ditch bag on deck.
robalex117
Super Anarchist
BP were all with you and hope the boat comes back better after this "incident." Would be great if you would give us your initial take on what happened with the understanding the complete investigation is ongoing and things may change.
