[Public-List] Mast Beam Failure on #133

[crufone at comcast.net]

Mike, 

Thanks for the heads up based on your experience.   I will try to document all my disassembly as best possible. I thought that the mast beam to bulkhead bolts might exhibit the same wea kness as the 1/4" chain plate bolts.  Though the chain place bolts tend to fail in sheer, the mast beam bolts might just bend (tension failure) because of their wood to wood fastening application. 

I have seen the 'sawing affect' that threaded bolts have when used to fasten wooden components together.  Best to keep the threaded part of the bolt for the nut and washer only. I guess that the reduced threaded cross section also substanitally reduces the load carrying capacity of  the bolt as well. 

Michael #133    
----- Original Message ----- 
From: "Mike Lehman" <sail_505 at hotmail.com> 
To: "Alberg 30 Public List -- open to all" <public-list at lists.alberg30.org> 
Sent: Monday, January 11, 2010 12:49:45 PM GMT -05:00 US/Canada Eastern 
Subject: Re: [Public-List] Mast Beam Failure on #133 


If I may add one more thing to this discussion - When you remove the bolts, check to see if they are bent. They probably will be. I don't know what they used on hull #133 but on the boats I have worked on they used 1/4" bolts that are threaded all the way, which yields less that a true 1/4". So a suggestion it to increase the bolt size to 5/16" and use bolts that are only threaded on the end and use more of them. Bent bolts are an indicator of the twisting that I referred to in an earlier email. 

  
Mike Lehman 

  
><((((º>`·.¸¸.·´¯`·.¸><((((º>`·.¸¸.·´¯`·.¸><((((º> 
                                                
_________________________________________________________________ 
Hotmail: Trusted email with Microsoft’s powerful SPAM protection. 
http://clk.atdmt.com/GBL/go/196390706/direct/01/ 
_______________________________________________ 
These businesses support your Association: 
http://www.alberg30.org/store/A30supporters.html 
Please support them. 
_______________________________________________ 
Public-List mailing list 
Public-List at lists.alberg30.org 
http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org 

 1263233457.0