S2 6.7 Junk Rig Conversion

  • 20 Jul 2020 22:05
    Reply # 9114860 on 6872873

    I have been thinking about posting an update for a few days. I am concerned that this may read like whining and complaining. So I am going to try to focus on things that I have made me feel thankful recently.

    I feel fortunate that I was able to get one of the four mooring balls at the new marina. They are much less expensive than a slip and a good excuse to have two boats. The Sun Dolphin Water Tender is fun to row around. Unfortunately the marina has a use it or lose it sort of policy. If I don't keep a boat on the ball I lose the spot and the next person gets it -- even after I pay for a season. I think this is good rule overall but for me right now it means I have a sailboat with no rig. I took the original rig off before launching.

    I would also like to thank whoever designed my Tohatsu Sailpro engine. The shift linkage pulls up on the lower unit to shift into forward gear. Turns out the shift linkage is strong enough to hold the lower unit up and in gear. This was important when somehow I ended up in the middle of the harbor with both of the bolts that should be holding the lower unit missing. Last time those bolts were intentionally removed waswhen I had a marine service company replace the impeller two years ago.

    I am thankful that I am using slow epoxy hardener. The local West Marine was out of resin so I ordered it online. The 'can' arrived with a big dent in the side. This seemed to be only a cosmetic problem until I was pumping out the second batch of epoxy for the bi-axial cloth. The bent angle of the top of the can seemed to put some strange stress on the mini pump. The center of the pump pushed through the part that screws on the can and the pump came apart in two pieces. One part was left floating in the can and the other on the floor of the garage. So it was good that the slow hardener gave me some time to throw out the mess, fix the pump and carefully measure a new pot.

    Lastly I am thankful that I do not have to rely on my skills with fiberglass to earn a living. I need to decide if the voids left under the bi-axial cloth need to be cut out and filled back in properly and consider getting a surgeon to remove the glass fiber that is now epoxied into my thumb.

    Still sounds like complaining, I think. But I am happy to be making progress.

    Scott.



    Last modified: 21 Jul 2020 01:27 | Anonymous member
  • 08 Jun 2020 17:29
    Reply # 9022992 on 6872873

    Thank you for the suggestions. If my drawings are correct then the 24' 8" pole should still work for me. I will likely extend it from the top if that becomes necessary.

    I have the mast partners glued and screwed to the boat. I also put six coats of topside paint over the epoxy. I left a small area unpainted where I plan to install the tabernacle. Hopefully this will allow me to avoid grinding some paint back off later. I think the whole thing is now waterproof but the unpainted section is at risk of UV damage. I taped a scrap of plywood on top of it for now, to keep the sun off the epoxy.

    Now I need to finish the tabernacle and the hardware to attach it to the mast. 

    I am thinking about bending threaded stainless steel rod into a U shape such that the radius of the U matches the radius of the mast. The idea is to epoxy this U to the front of the mast with enough straight section on the U to allow a stainless steel plate to bolt on the back of the tabernacle when the mast is raised. There would be two such assemblies. One near the top of the tabernacle and one near the bottom.

    Can anyone come up with a reason why I should avoid bending SS rod this way or any other reasons why it might weaken the structure?

    Scott.

    Edit: I attached a photo. It is not pretty. Maybe I can clean it up some later.

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    Last modified: 16 Jun 2020 03:44 | Anonymous member
  • 22 Apr 2020 08:19
    Reply # 8920813 on 6872873
    Anonymous member (Administrator)

    David T: “The tops of these tapered tubes are generally parallel for a short distance, to enable the lamp-post makers to fit the light more easily, so in fact, getting a good fit for a short extension is no problem.

    That is good news and negates some (though perhaps not all) of the reasons for suggesting that a larger diameter heel plug extension might be better or easier to make than a small diameter topmast extension.

    I sure wish we could get these lamp posts in New Zealand.


    Last modified: 22 Apr 2020 08:27 | Anonymous member (Administrator)
  • 22 Apr 2020 07:33
    Reply # 8920791 on 6872873

    I was in the same position with both Tystie and Weaverbird, wanting my aluminium mast to be a bit longer.

    On Tystie, I made a wooden extension, a metre long, and that was a mistake. It failed due to fatigue (but only after sailing the Pacific from top to bottom). It was the combination of too much length, too little diameter and possibly unsuitable timber that did for it.

    On Weaverbird, I got a 9.2 metre tapered pole, and really wanted just a little bit more. I got my brother in law to turn me a short extension from PVC bar, and drilled and tapped it for M8 screws to fasten on stainless steel eyeplates. This has been entirely satisfactory. The tops of these tapered tubes are generally parallel for a short distance, to enable the lamp-post makers to fit the light more easily, so in fact, getting a good fit for a short extension is no problem. I would choose to do this over making a heel extension at a much greater diameter. Black nylon would be stronger than PVC, and durable hardwood such as oak would also be very good. Since the masthead needs to be capped in any case, this is as good a way as any.

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    Last modified: 22 Apr 2020 08:00 | Anonymous member
  • 22 Apr 2020 04:22
    Reply # 8920579 on 6872873
    Anonymous member (Administrator)

    Not to contradict David Th, but if you are concerned about weight and want the top to remain light, you also have the option of inserting a somewhat heavier plug into the bottom of your tube instead, and extending it a few inches. If the tube is already tapered, I would personally prefer the extended heel plug, which, by the way, would also be much easier to make. This is because the walls of the tube will be parallel at the bottom, easy to fit a plain round plug. But if the lamp pole is tapered, fitting an extension to the top is quite... well...  I don't even know you would do it.

    I agree with David Th, also from unhappy experience - it is better to have the mast too long than too short. If you need to keep your options open for retrospective changes, the bottom of the mast is easier to modify than the top, especially after you have made your masthead fittings. This, too, points to a wooden heel plug extension rather than a masthead extension.

    (The beauty of a wooden top section is when you just have a parallel-sided tube. The plug-extension is then easy to fit to the top, and you have the advantage of being able to put some taper into the top of the mast.)

    Last modified: 22 Apr 2020 08:21 | Anonymous member (Administrator)
  • 22 Apr 2020 03:48
    Reply # 8920534 on 8919967
    Deleted user
    Anonymous wrote:

    My lamp pole arrived. For some reason the 25' pole I ordered is actually only 24' 8" long. Not sure what is going on there. I need to measure all the other dimensions to see if anything else is off. I have no idea how I could verify the alloy and the temper. I suppose I have already decided to just trust the vendor on that.

    At some point I determined that 24' was the absolutely minimum length for my mast. Hopefully that was correct.

    I am able to lift it and carry it around. It is not easy but I can do it.

    I am sure that if you find that you need a little bit of extra length that it will be quite easy to add a short timber extension to the top of the mast. This could incorporate the various mast head attachment points for halyards etc. I know from experience that it is much better for the mast to be too long, rather than too short.
  • 21 Apr 2020 21:22
    Reply # 8919967 on 6872873

    My lamp pole arrived. For some reason the 25' pole I ordered is actually only 24' 8" long. Not sure what is going on there. I need to measure all the other dimensions to see if anything else is off. I have no idea how I could verify the alloy and the temper. I suppose I have already decided to just trust the vendor on that.

    At some point I determined that 24' was the absolutely minimum length for my mast. Hopefully that was correct.

    I am able to lift it and carry it around. It is not easy but I can do it.

    1 file
  • 14 Apr 2020 14:34
    Reply # 8897866 on 6872873

    Thank you David Th. and David T. I hope you are both doing well during these unprecedented times.

    Your two comments read like echos of my own thoughts. First I would convince myself that wood soaked in epoxy and filled with stainless steel might actually be stronger than it was before. Then shortly after I would remind myself that my boat is not Speedwell of Hong Kong or Oryx so I can probably use lighter hardware.

    I will look for 3/8" threaded SS rod first. If for some reason 1/2" is easier to find then I will use 1/2".

    Thanks again.

  • 14 Apr 2020 07:37
    Reply # 8897425 on 6872873

    Pete was making tabernacles for larger, heavier, stiffer, ocean-going boats. I wouldn't use more than 3/8" studding on a 22ft boat intended for lake sailing. If set in epoxy, with large washers under the nuts, there can be no doubt about the overall strength of the assembly.

    Last modified: 14 Apr 2020 07:38 | Anonymous member
  • 14 Apr 2020 06:49
    Reply # 8897394 on 8896559
    Deleted user
    Scott wrote:

    I am concerned about drilling 1/2" holes in four different places on the sides of the tabernacle. The boards I used are 2" dimensional lumber which is 1.5" actual thickness.

    I am trying to decide if drilling out a third of the thickness will significantly weaken the structure.

    Does anyone have an opinion to share?

    I think it will be just fine because you are gluing the bolts in with I imagine epoxy. So long as you get a good bond, the bolts, (threaded rod), will just become part of the timber. But this would be a good occasion to adhere to all working with epoxy rules.
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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