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Thread: Tabernacle Operation

  1. #1
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    Tabernacle Operation

    I promised to post photos of the tabernacle rig on my Pearson Ariel, "Augustine" Hull number 330 when they were available. This thread provides the photos and some accompanying text related to tabernacle rig issues.

    Originally the tabernacle arrangement on my boat was set up to be more or less a two-person operation. This didn't work for single-handing. It was also in my opinion unsafe. The rigging on the boat when I fist purchased her in 2001, included Norseman fittings all around and beefy pelican hooks on the aft lower shrouds and backstay, and a very nice backstay adjuster located at the top of the backstay chain plate, but there was no boom vang, and the mainsheet block was ancient and was no longer functioning on a 4:1 ratio. The boom and shroud stabilization lines (boom guys and bridles) were inadequate.

    I replaced the mainsheet block with a new Garhauer 4:1 light block with steel bearings. These blocks are practically frictionless. Mine make it possible for me to lift the mast single-handed. To do so, I must stand with my back to the companionway hatch at the forward end of the cockpit and pull the mainsheet toward me. This body position maximizes leverage, while minimizing back strain.

    I initially purchased a Garhauer dual action 4:1 / 8:1 block, and that really works slick for the mast raising, but the excessive amount of line used by that block provides a mess of spaghetti on deck to clean up afterwards. That proved to be a bit of a nuisance, but was really a problem at sea when jibing down wind at sea, or even tacking off of a broad reach to the opposite broad reach. Also it is more difficult, particularly when it is dark and wet to control two lines as they lip through your cold numb fingers while the mast is going down. I switched to a straight 4:1 ratio block with a larger line size and retained the dual action block to use when lowering the mast at the dock to work on the upper mast or spreaders.


    This first photo shows the mainsheet block, which is hooked to a pad eye, and not to my rather ancient traveler. It also shows the boom end of the boom guys (black line). The boom guys clip onto a bail at the aft end of the boom. Also please note that the black boom guys seem to end at the boom, but that I have added my own innovation in a loop of that same line, which is actually a continuous section of the boom guy lines that runs down from the boom end to the pad eye. This loop functions as a safety line to ensure that the mast does not accidentally lower on its own if someone inadvertently releases the mainsheet. This would be an unlikely occurrence since it takes some pressure to get the mast started forward, but a safety loop adds to the skipper comfort level. Also shown is my handy-dandy $12.95 "Ross Dress for less" Cordura mainsheet bag into which my green mainsheet line is feeding. In this photo, the backstay is still intact, and has not been broken and reattached to the boom end.
    Last edited by Scott Galloway; 09-01-2003 at 01:09 PM.
    Scott

  2. #2
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    Sorry; here is that photo:
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    Last edited by Scott Galloway; 09-02-2003 at 11:18 AM.
    Scott

  3. #3
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    These next two photos show the backstay pelican hook and tensioning device in the sailing configuration, and broken and reattached to the boom end.
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    Scott

  4. #4
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    Here is the sailing configuration (backstay intact)
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    Scott

  5. #5
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    One thing to watch out for in a tabernacle if you want to use it to actually remove the mast from your boat, or if you want to get the mast down to a level, where you can work on the masthead from the dock without a very tall step ladder is that the mast base should be elevated so that the mast will fully lower without hitting the forward hatch.

    This is not the case on my boat, so I cannot lower the mast far enough to do work on the masthead. Indeed, the mast step is now a stainless steel plate instead of the original teak mast base, so the mast pivot point is actually lower. You might be surprised how that forward hatch interferes with lowering the mast. On my last boat, I can stand on the top step of a five stepladder on the dock and perform some work on the masthead, but it's a dangerous stretch. Also a higher mast step would better facilitate running lines back to the cockpit for the halyards, downhaul, reefing lines etc.

    For the purpose of crawling under bridges the normal height of the mast step is just fine, but you will need a new mast step, since for a tabernacle, the mast step should l be stainless steel with raised sides and a bolt run through the mast. The forward edge of the mast will have to be cut in a radius, and a block with a similar radius cut and inserted in the bottom end of the mast through which a hole will be drilled. Matching holes are drilled through both port and starboard sides of the mast. A bolt is inserted through the mast, block and both starboard and port sides of the stainless steel mast base. The mast does not rest on this bolt, but on the base itself. The radius on the leading edge of the mast permits the mast to fall forward in the lowering operation.

    To lower the mast, I break the backstay at the tensioning device, and attach the top end of the backstay to the end of the boom. A pelican hook is provided to ease this operation. I use the top of the backstay (from mast top to boom) and mainsheet (from boom to traveler) to lower the mast. You have to physically lift the boom by hand to get it started down. Now putting a backstay-tensioning device in mid-backstay is sort of loony, because you cannot tension the upper part of the backstay without unwinding wire on the lower part. In other words, you need to have one end of the tensioning device connected to something that does not twist. However locating these things at deck level means that if you are underway with the motor running and you wish to adjust the backstay tensioning device, you have to close the lazarette hatch on the running motor, and crawl out of the cockpit, sit m lie or kneel facing aft and tighten the device. That was not something that I wanted to so, I raised my tensioning device to boom level, and devised a simple "wrench" to stabilize the lower portion of the device (and lower section of the backstay, while I tension the backstay. I made it with hardware store parts for a few bucks.

    Another feature of a well-designed tabernacle rig is that boom guys on either side running from the upper shroud turnbuckle to the aft end of the boom. These boom guys are very important. They prevent the boom from flopping to one side or the other. The tabernacle rig has good lateral stability, but very poor transverse stability. You do not want to place any pressure to port or starboard during the operation. In my photos, the boom guys are black in color. It is also wise and some consider essential to utilize a "bridle". The bridle runs from the boom guy attachment point (pivot point) on the upper shroud either to the base of the aft lower shroud (at deck level) or to another deck location aft of the lower shroud. I made my bridle a permanent section of my lifeline system. That line is white in my photos and runs from a deck fitting (eye bolt) at the forward end of my spiffy teak boarding step forward to the upper shroud turnbuckle boom guy attachment point. This bridle prevents the upper shroud from bending at deck level, and causes it to bend instead at the pivot point, which is parallel with (level with) the mast base. I did not use a bridle on my Catalina 22, but that was a much lighter boat, and mast, and I did not design that set-up. Suffice it to say that adding a bridle is wise if not essential on an Ariel.

    Note: DO NOT install a "running" bridle/boom guy. That was the way my boat was rigged when I bought it. The bridles and boom guys were one continuous line that ran through blocks. The way I saw that set-up, the ability of the bridle and boom guys to self adjust in a "running" bridle/boom guy reduced, if it did not eliminate, lateral stability of the tabernacle rig.

    Raising the mast is just the reverse of lowering it. What goes down comes up. It is important to have a boom vang, or so the theory goes. The further that you lower the mast, the heavier it is to lift. The forward hatch is the limiting factor. Of course it pays to have a long mainsheet.

    This photo shows the upper shroud turnbuckle and the shackle used as the pivot point attachment shackle for the boom guys and lower lifelines including the section of the lifeline that serves as a "bridle". It is important to seize the pin on this shackle so that it wil not work free. The forward end of the black boom guy is shown. The pelican hook on the aft lower shroud has been released and is resting on the lower life line, where it will remain during the tabernacle operation.
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    Scott

  6. #6
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    This photo shows the same area, but is less cluttered since the boom guys, etc. are not in place. The bridle running back to the deck step is clearly shown. This bridle functions as the lower lifeline in this ection of the boat. The bridles (lifelines) are three strand dacron line. At all points of attachment at deck level the lifelines are attached to through deck bolted fittings. The upper lifelines are also through bolted to the teak pin rails and around the forward lower shroud.
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    Scott

  7. #7
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    In this photo, the mast is beginning to drop after being lifted manually to the point at which gravity has taken over. This point varies based on wind direction and load.
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    Scott

  8. #8
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    In this photo the mast is low enough to permit the boat to pass beneath the bridge at the far left of the photo. Keep in mind that at some point the boom rises to level higher than the masthead. So there are limits to bridge clearance.

    Note that the pin rails fall forward slowly as the mast is lowered and come to rest at or near deck level. Pin rails are not necessary for the tabernacle operation, but the operation is possible with pin rails as the photos show. The pin rails make handy places to tie off lines like my spinnaker halyard, and flag halyard. Actually, belaying pins would also be nice. The pin rails also function as mast pulpits to provide a place to lean while working on the leeward side of the mast underway.

    In this photo and in the prevous photo you can see the black boom guys doing their thing.
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    Last edited by Scott Galloway; 09-01-2003 at 01:13 PM.
    Scott

  9. #9
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    This photo is a close-up of the upper shroud turnbuckle and pivot point shackle to which the lifelines and boom guys are attached. Note that the pin in this shackle is integral to the rig. Without it the upper shround would disconnect from its lower part. Therefore, seize the pin.
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    Last edited by Scott Galloway; 09-01-2003 at 01:33 PM.
    Scott

  10. #10
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    This photo is a close-up of the lower shroud pelican hook in place for sailing. The pin on that lower shackle is a bit wide for the application. However, the shackle has functioned for years without apparent pin distortion; perhaps partly because the aft lowers tend to be less tight than your forward lowers as a result of the tabernacle rig. Those shackles were on the boat when I bought it. However, I did revise the design of the securemt device for the top (the jaw)of the hook.

    The top of the hook is now secured by two shackles. One shackle quickly slips over the jaw of the hook, and the other is attached by a pin through a hole in the end of the jaw. Two shackle provide better security, however, some people merely use a single ring that slips over the jaw, or a single shackle. My Catalina was rigged that way, but again, by someone else.
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    Last edited by Scott Galloway; 09-01-2003 at 01:32 PM.
    Scott

  11. #11
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    Wink

    I bet you scare the living crap out of some folks with that rig if they get in your way.

  12. #12
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    Mike,

    There is a kayak rental place on the other side of the bridge. The place rents kayaks that are stored on a dock on my side. It is interesting to emerge from under the bridge with the mast sticking out thrty feet into a school of kayakers...or perhaps they come in flocks.
    Scott

  13. #13
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    Thanks Scott!

    Will study and no doubt design 338s mast raising/lowering system after yours.

    Old eyes and old computer......
    Is there any way we can have full page photos?
    I really cannot examine the rig at all, most distressing!
    Perhaps the central office can make them larger -
    anybody concur with this?


    Very quick scan of your posts, so I may have missed some things.....

    I can't make out what kind of Tabernacle you have. Is it a hinged double plate? Like the Ballenger?

    What are your mast wires up to when you lower? Perhaps a loop in the wires at the heel inside the mast is all you need? Or do the mast wires go thru a gland on deck? If one was going to set it up for tansport or storage and have to disconnect - how is this done, especially with the VHF?
    Last edited by ebb; 09-02-2003 at 08:33 AM.

  14. #14
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    Dear Ebb,

    Since I was including a mess of photos in my posts, I deliberately reduced the file sizes. If you wish copies of the originals I can e-mail them to you, but I don't live in DSL land, so I like to keep my e-mail attachments down to a manageable size. Let me know if you are interested in a couple of enlargements, and I will e-mail them to you. However, keep in mind that most of the photos in this thread are cropped from larger photos, so the detail will be only so good in the photos that I send. I am not working with a digital camera. The images are on a floppy. They aren't 1 MB files to begin with. So a few of those posted, if not most of them, are already as good as it gets.

    Regarding mast electric wires, they emerge from the deck a few inches in front of the mast, and join the mast above the wood block in the mast base. I don't think I would do it any other way.

    The deck below the mast was strengthened with epoxy when the mast step was replaced, so that area is more or less solid...or so I was told.

    This photo shows the mast base from the stern. You can see the mast wires coming from the deck and entering the mast. The brighter stainless steel and teak flange unit is one of my design. The device provides attachment points for up to six blocks, and does not interfere with the operation of the tabernacle. It is attached to the mast step by three bolts and lock nuts, which are inserted through matching holes in the original mast base flange and the flange on the device whish is welded on at the same angle. The through bolted teak backing plate adds additional support.The bolts that run into the teak backing plate runn all the way through it with a securing nut on the outside of the opposite flange.

    My objective was to get the blocks high enough that they would not beat on the deck, and so that the halyards and downhaul and other lines could be run back to the cockpit without rubbing on the edge of the higher part of the trunk cabin. I looked at a few other Ariels and never saw a solution that I liked that didn't required more holes in deck, so I designed my own.

    The less bright SS vertical plate and the lower original flange are evident in the photo. The bolt on which the mast base rotates runs through this plate.
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    Last edited by Scott Galloway; 09-02-2003 at 11:21 AM.
    Scott

  15. #15
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    This is an early shot of the same system from the forward starboard quarter, showing the starboard mast electric wire again, and if you use your imagination a portion of the similar port side electrical wire, and this time a block that runs the downhaul back to the cockpit through a deck organizer block. Here you can clearly see the forward radiused edge of the mast base block. Slick looking Garhauer light block isn't it?

    There is only a single mast base plate here. There is not double plate. The mast rests directly on the permanently mounted SS plate. Again my brightly polished SS flange device has no relationship to the tabernacle.
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    Scott

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