Advice on Capri

Discussion in 'Capri/Catalina 14 Talk' started by lax71vcu, Jan 6, 2015.

  1. lax71vcu

    lax71vcu New Member

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    I am considering doing just this... or an adaptation...
    I was thinking something like what is below. Simply cutting the mast step on the side rather than on top and clean through to allow the step to "twist" in a demasting. Any issues forseen by cutting the original mast step in a similar fashion to what is below? I am thinking a narrow slit not big enough to fit the mast pin through so the mast would still be pinned in its "stock" location. This is an aftermarket step being sold on catalina direct.

    [​IMG]


    I also like the nylon nut idea mentioned above... now to get a good idea are you talking about nuts made entirely from nylon or the locking nuts that have the metal outside and nylon insert to prevent back threading?

    Greg thanks for taking a peak. My mast is through bolted also but uses no backing plate. Something else to consider is swapping my stainless washers out with rubber or nylon.

    Any thoughts or feedback would be great.
     
  2. boat

    boat Member

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    Sorry if I sound negative or sound like a know-it-all because I don’t. However, I do have a couple of additional comments.


    The nylon nuts I suggested are 100% nylon. The nuts with stainless steel locking nuts you mentioned are just as strong as regular nuts and the nylon is only used to keep the nut from loosening once it is installed. There would be no advantage to using the locking nuts. The idea is for the nut to strip easily in the event of a de-masting.


    If you have a through-bolt arrangement you may want to check the fit of the bolts where they go through the fiberglass. If you can easily pull the bolts through the fiberglass by hand that is a good thing. If you must screw them in and out be aware that the fiberglass is acting like a “nut” (a threaded hole). If the mast comes down it is likely the fiberglass will rip out. The solution (in my humble opinion) is to make the holes just large enough that the bolts will slide through easily so they will only be held in place using the all nylon nuts I mentioned earlier.
     
  3. boat

    boat Member

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    I don’t see how cutting the back of the bracket (as seen in the picture above) would be of much help in protecting the deck from tearing out with a de-masting. It appears the mast would have to twist in order for it to release before damaging the fiberglass. What would cause the mast to “twist” before it has moved enough to start ripping out the deck? If the mast were to immediately twist in one direction there is perhaps some possibility for it to release but, assuming the mast is falling in the same direction and twisting in the opposite direction, it would not release. What am I missing?


    The other issue I see with the pictured base is a safety concern. When raising the mast it would be necessary to always keep forward pressure until the mast is raised. If one is as clumsy I they may miss-step allowing the mast to move back just a bit releasing the base of the mast at a very bad time. This could possibly cause an accident if the person raising the mast is not strong enough to control a free floating mast or has lost their footing!


    If the slot in the base is extended straight up but not quite 1/2” wide I believe it would likely still be strong enough to damage the deck if the mast goes down.


    A relief slot in the top would have to be narrow enough and strong enough to hold up while raising the mast yet wide enough to allow the bolt holding the mast in place to pass through before the fiberglass gives away. Based on the thickness and the shape of the base mount I believe it would be quite difficult to come up with a workable “gap” size.


    Logic seems to imply that the only way the bolt would be able to pull through the gap would be for the stainless steel to be bent in the stem-to-stern direction or it would have to twist. Neither of these options would be likely without a lot of force which leads me to believe the fiberglass would go first.


    If the gap is machined out and the bolt replaced with a ½” nylon bolt the chances of saving the deck would be greatly increased. As the mast falls the nylon bolt would be compressed to the width of the gap or would sheer off allowing the mast to fall freely. The only problem with this theory deals with raising the mast. Stepping the mast would put a fair amount of stress on a nylon bolt which could possibly be enough to cause the bolt to compress thus releasing the mast causing a real problem.


    The base I am currently building eliminates all of these issues and uses the standard ½” stainless steel bolt, the standard through bolts and a backing plate. I will test it through the summer by actually letting the mast fall a number of times to make sure it works as designed.
     
  4. lax71vcu

    lax71vcu New Member

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    Boat I don't thing your negative at all. I posted the questions and ideas up here to get guidance and opinions. I truly appreciate your feedback. I am going to Home Depot or Lowes to see about finding nylon nuts that will fit the SS bolts currently in the mast step. I wonder if aluminum fasteners would work. I am thinking something similar to rivets. Just trying to think of something with SOME strength but will easily break if demasted.
     
  5. boat

    boat Member

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    lax71vcu

    Really hard to say how aluminum would work. Just keep in mind that the mast has no upward pressure except when stepping the mast so it should take very little strength to hold the base of the mast down. Any additional strength other than that needed to step is overkill and will make the mast less likely to "free fall" if a shroud fails. It is necessary to keep the mast from shifting in the horizontal plane so be cautious about using something like a long pop rivet of something of that nature. Just keep in mind what is required to accomplish the task at hand.

    I have the mast mount very near ready to test but I am waiting to get a patent completed which seems to be an endless string of red tape and legal actions. I plan to share detailed drawings at no charge to anyone that wants to build their own but I don't want someone to take the idea to manufacture and market the device. I should be able to release the drawings in " HOPEFULLY" the near future. This is a simple but unique approach to totally eliminating fiberglass damage due to standing rigging failure. I have taken this approach on a number of "gadgets" for larger boats and no one has been able to gouge folks for "manufactured" parts. If the need arises due to someone not being able to build the device I may consider, on a very limited basis, helping out for the cost of materials plus machine time. This is not a for profit item!

    Let us know what you decide to do with your boat.
     

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