Mast beam crushing

  • August 17, 2019 5:15 AM
    Reply # 7833331 on 7821436

    I don't mean to hijack Byrons thread but the reason I ask is I have some crushing myself. The bottom 'layer' of my deck beam has 'delaminated' on the longer port side leaving a 1/4" gap midway along the beam. Plus I've noticed the door to the head/v-berth has become misaligned making the door bolt hard to engage

    My main beam isn't on a straight plane. Mine is curved to match the curve of the cabin.

    I have the bronze bolts from Bud. Since the gap hasn't worsened over the years I've just never got around to installing them. Maybe I should tackle this job before it gets worse.

    In my case the problem is likely the support post under the cabin sole. For some reason the water tank 'bilge' stays wet (any ideas why?) so I could very well have dry rot there. I just am not looking forward at all to having to remove the water tanks to get to it. Gah... what a PITA

    p.s. what is the purpose of the wedge next to the support post (under the mast wiring cover)?

    Last modified: August 17, 2019 5:17 AM | Anonymous member
  • August 17, 2019 9:50 PM
    Reply # 7834151 on 7821436

    Jay,


    it it will be several weeks until I get to this. Maybe a few months.  But I will post photos of what I do.  I am talking with Dave King soon so I hope to get good insight from someone who has gone through this.


    Here is a good question though, why the beam? Couldn’t one just us a post all the way up and hang the port and starboard beams off the large post?


    thanks,

    bryon

  • August 24, 2019 12:09 PM
    Reply # 7847463 on 7833331
    Anonymous member (Administrator)
    Mike McCoy wrote:

    I don't mean to hijack Byrons thread but the reason I ask is I have some crushing myself. The bottom 'layer' of my deck beam has 'delaminated' on the longer port side leaving a 1/4" gap midway along the beam. Plus I've noticed the door to the head/v-berth has become misaligned making the door bolt hard to engage

    My main beam isn't on a straight plane. Mine is curved to match the curve of the cabin.

    I have the bronze bolts from Bud. Since the gap hasn't worsened over the years I've just never got around to installing them. Maybe I should tackle this job before it gets worse.

    In my case the problem is likely the support post under the cabin sole. For some reason the water tank 'bilge' stays wet (any ideas why?) so I could very well have dry rot there. I just am not looking forward at all to having to remove the water tanks to get to it. Gah... what a PITA

    p.s. what is the purpose of the wedge next to the support post (under the mast wiring cover)?


    Mike:  the beams are normally arched side to side -- if you sight from the cabin near the hatch -  forward - the bottom of cross beams should be on the same plain horizontally.  

    The door misalignment is a sign of something moving -- assuming that at one time / place the door worked as expected. :) 

    Checking the support block under the cabin sole is a good idea.. the water in the cabin bilge on Pygmalion dried up when the leaks from under the cap rails and other places was solved. 

    HTH

    Jay 


  • October 02, 2019 9:00 AM
    Reply # 7914493 on 7821436

    Update.


    Dave King has been generous enough to drive up and work with me on the crushed beam.  This turned out to be a great thing since he has done this a few times.  Having his experience really helped to speed up the process to this point.I removed the mast Sunday and yesterday Dave met me to take apart the beam and compression post. It took about 4 hours from both of us to get it all apart.

    Mine was an owner finished boat so some of the challenges was the none uniform way in which this part of the bot was put together.  Dave's biggest fear was that the beams might have been stuck to the bulkhead with adhesive or resin.  Fortunately that was not the case and everything actually disassembled rather smoothly.

    The beams were screwed to the bulkhead and screwed together (the forward beam screwed to the aft beam).  They were also screw to the cabin top (screws did not penetrate through the top layer of fiberglass on the cabin top).  And lastly there were two sets of screw both starboard and portside running down from the cabin top into the top of the beams.  These screws were sunk into the deck and covered with bonds and gelcoat.  Dave's experience helped there in knowing what to look for.  You search for small roundish shaped craze marks that are in line with the mast step and beam.  Again, the particular construction of this bot might not reflect the majority of bots out there.

    Has an aside, it turned out that the crushing above the brass plate was actually two small shims that were placed due to either replacing previously crushed wood or what was cut out of the area while trying to repair the crushing.  Either way the wood was not a solid chunk over the compression post.  No rot nor water penetration was detected anywhere neither on the post nor the bulkhead (great news)!


    Dave is fabricating the new beams and beam (we decided to upsize everything). That might affect the door to the head, but I'm certain that there is a fix for that.


    ill update when there is more.


    bryon

    5 files
  • October 03, 2019 8:26 AM
    Reply # 7916256 on 7821436

    Is it necessary to step the mast or just completely loosen all the shrouds/stays?

  • October 03, 2019 8:23 PM
    Reply # 7917195 on 7821436

    Mike,

    perhaps others can argue their points for and against stepping the mast for this.  I have been told that it must be done, and I have been told that you can just loosen the rig.  

    I would say however that unless you are 100% certain that there is no water intrusion where the cables come in from the mast, taking it down so that you can inspect there area would be a good idea.  

    Honestly, it doesn’t cost that much to rent the boom truck and take it off and then replace it. The daily rate that the yard charges will get you if you don’t move quickly through the project.



  • October 19, 2019 8:33 AM
    Reply # 8065586 on 7821436

    Hello,


    I wanted to recap on how this finished up.


    It took Dave a couple of days in his shop to make the beams and post.  He made everything from using the originals has a template, upsizing things a bit.

    the beams are laminated and bent. The apex of the arch was 2 inches, which has Dave explained was just putting a 2 inch block at the center of the bend and clamping it all down. (I was inspired and did this myself to make a second beam to go aft of the beam supporting the mast, in the salon. It turned out nice and was very straight forward to do).

    the beams consist of 1/2 mahogany, 1 inch mahogany, 1 inch white oak, 1 inch mahogany, layered from top to bottom.  Dave then scarfed in a white oak block for the compression post to set in (this is due to white oak being much better at handling the compression forces than the mahogany). I'll double check but I think that all was glued up using Titbond 3.

    The beams were set into place with a spacer piece placed above the bulkhead.  This is an owner finished boat, so there was a good amount of space between the top of the bulkhead and the cabin top. I am not sure if this is normal.  The two beams (fore and aft of the bulkhead) were bolted together sandwiching the bulkead between them.

    The beams were then bolted to the cabin top with carriage bolts.  Ideally we would have first over drilled the holes and epoxied them then redrilled for the carriage bolts, but what we did looks well sealed with sealant around the bolts. I will be applying nonskid directly over the head of the bolts this spring.  The lower portion will have bungs to cover the washer and nut that were sunk into the beam.

    The compression post was then placed. It had a 3/4 in channel cut so that it would slide onto the side of the plywood bulkhead.  The top was cut at a slight angle running aft. This matches the pitch of the cabin top and took a few cuts to get tight. The beam was slid into place using a jack (braces against the edge of the starboard bulkhead. I was concerned about damaging that edge but it was fine) with light pressure and a rubber mallet.  Once in place it was just screwed into place. 

    I have since re-stepped the mast. And everything looks great! Due to over sizing these parts. I am having to rework the door on that bulkhead since we lost about an in of width for it. Also, some trim pieces will need to be remade to compensate for the size difference.

    It amazes me how workable these boats are. If you have little to no rot then things are straight forward.  It was nice that things were not epoxied together, that would have made this project much more time consuming.  Dave Kings hep in this was key.  It's not that it was overly complex, but his confidence in knowing how to do it made the process much faster and less frustrating.  So a big thank you to him.

    i am waiting for better weather to change out the chain plates (which I purchased from Bud) and then Dave will come back up to help tune the rig with me.


    bryon

    #120 Apollonia 

    5 files
  • October 19, 2019 11:07 AM
    Reply # 8065748 on 7821436

    Nice summary Bryon.  Thanks.   Just a couple of comments:   Mike,  it is not necessary to unstep the mast.  In this case there was significant damage and I wanted to properly inspect everything for water intrusion.  I also wanted to see the “natural lie” of the cabin top.  I have seen a lot of moisture damage and cabin top deformation.  There was neither in this case.     Also:  all the laminating was done with West system 105/205 epoxy with a little microfiber in it.  The bungs and plugs will be installed with Titebond 3.   The area between the beams, in the passage way,  will be finished when convenient.       Dave

  • October 20, 2019 10:00 AM
    Reply # 8067280 on 7821436
    Anonymous member (Administrator)

    Bryon / Dave: 

    Great write up - thanks for the extra effort to report and photograph... 

    Jay 

  • January 15, 2020 10:13 AM
    Reply # 8582670 on 8065586
    Anonymous wrote:

    Hello,


    I wanted to recap on how this finished up.


    It took Dave a couple of days in his shop to make the beams and post.  He made everything from using the originals has a template, upsizing things a bit.

    the beams are laminated and bent. The apex of the arch was 2 inches, which has Dave explained was just putting a 2 inch block at the center of the bend and clamping it all down. (I was inspired and did this myself to make a second beam to go aft of the beam supporting the mast, in the salon. It turned out nice and was very straight forward to do).

    the beams consist of 1/2 mahogany, 1 inch mahogany, 1 inch white oak, 1 inch mahogany, layered from top to bottom.  Dave then scarfed in a white oak block for the compression post to set in (this is due to white oak being much better at handling the compression forces than the mahogany). I'll double check but I think that all was glued up using Titbond 3.

    The beams were set into place with a spacer piece placed above the bulkhead.  This is an owner finished boat, so there was a good amount of space between the top of the bulkhead and the cabin top. I am not sure if this is normal.  The two beams (fore and aft of the bulkhead) were bolted together sandwiching the bulkead between them.

    The beams were then bolted to the cabin top with carriage bolts.  Ideally we would have first over drilled the holes and epoxied them then redrilled for the carriage bolts, but what we did looks well sealed with sealant around the bolts. I will be applying nonskid directly over the head of the bolts this spring.  The lower portion will have bungs to cover the washer and nut that were sunk into the beam.

    The compression post was then placed. It had a 3/4 in channel cut so that it would slide onto the side of the plywood bulkhead.  The top was cut at a slight angle running aft. This matches the pitch of the cabin top and took a few cuts to get tight. The beam was slid into place using a jack (braces against the edge of the starboard bulkhead. I was concerned about damaging that edge but it was fine) with light pressure and a rubber mallet.  Once in place it was just screwed into place. 

    I have since re-stepped the mast. And everything looks great! Due to over sizing these parts. I am having to rework the door on that bulkhead since we lost about an in of width for it. Also, some trim pieces will need to be remade to compensate for the size difference.

    It amazes me how workable these boats are. If you have little to no rot then things are straight forward.  It was nice that things were not epoxied together, that would have made this project much more time consuming.  Dave Kings hep in this was key.  It's not that it was overly complex, but his confidence in knowing how to do it made the process much faster and less frustrating.  So a big thank you to him.

    i am waiting for better weather to change out the chain plates (which I purchased from Bud) and then Dave will come back up to help tune the rig with me.


    bryon

    #120 Apollonia 

    Bryon,

    I want to thank both you and Dave for this detailed write-up. You have given me the confidence to tackle this project myself. Do you happen to have the dimensions of the compression post and the width of the beams?  Obviously based on the info provided the beams are 3.5inchs high but how wide are they?  Were the beams next to the bulkhead laminated as one piece and then ripped in half to get 2 beams or done individually?

    Zach

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