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Thread: Getting Ready for SHTP 2021

  1. #311
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    Nice job on the canoe! Very nice!

    And I'm right there with Stephen....totally jealous!
    S-2 7.9: "Wildcat of Loch Awe"
    1968 Selmer Series 9 B-flat and A clarinets
    1962Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  2. #312
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    It's time to build the brackets on the main rudder, for the trim tab. The stoutest example of this construction that I could find online actually is in bronze, which might be of interest to a few of us...

    This incredibly complex document discusses in great detail, the design of a trim tab system...

    http://www.svsarana.com/selfsteering...trim%20tab.pdf

    If you want even more from them, visit here: http://www.svsarana.com/selfsteering.php

    Their blog, if I remember correctly, has photographs of their outrageously strong...and outrageously heavy trim tab system on their double-ender.

    Anyway, so I've been back and forth, what to do, what to do about the brackets. Use stainless steel straps, which can be unbolted so the whole thing can come off, or epoxy sturdy oak brackets to the rudder to hold the trim tab? Stainless steel underwater really needs zincs on it to stay in one piece. Stainless is also heavy, and the rudder and trim tab itself are already pretty heavy. In the end, I'm opting for oak and epoxy, with some starboard UHMWP bolted in with stainless at the bottom for a bearing surface and an intermediate bracket near the waterline, also with some UHMWP around the shaft for support. The upper two brackets will also be oak, with the McMaster Carr pillow bearings bolted on. If those disintigrate, I'll replace them with UHMWP.
    S-2 7.9: "Wildcat of Loch Awe"
    1968 Selmer Series 9 B-flat and A clarinets
    1962Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  3. #313
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    Two things contrbuted to me deciding to 'glass the brackets to the rudder, rather than bolt them. 1.) I could make all the brackets-strut and so on out of $14 worth of 4 inch wide, 1" oak, rather than $30 worth of stainless steel. I'm facing some pushback at home over the SHTP ongoing expense.... and 2.) Alan Steel was closed on Wednesday, when I went over to get the stainless. Instead of getting nowhere all weekend, I opted to make the stuff out of wood and epoxy, UHMWPE and glass fiber.

    First up, cutting out and gluing up the upper trim tab rod bracket, and also the strut at the bottom of the rudder that takes the weight of the trim tab.

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    While I was at it, I trimmed down the tiller for the Piper to the appropriate thickness.
    Here's the upper trim tab shaft bracket. It will get a strap of 1" glass tape all round the outside edge. That's probably overkill, but hey. It's a little clunky-looking, I might put it on the saw again and make it a touch more svelte. it will only take side-to-side loads of probably 40-60 pounds, at most.

    Name:  trim-tab-shaft-bracket-upper.JPG
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    S-2 7.9: "Wildcat of Loch Awe"
    1968 Selmer Series 9 B-flat and A clarinets
    1962Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  4. #314
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    After cutting everything out, smoothing down the epoxy/sawdust spooge with a wood rasp and a bunch of sanding, the bracket tapped nicely into place. Yet more sanding on the rudder will be needed to get a good bonding surface for the glass tape. There's a pillow bearing that goes above the hole that the trim tab shaft goes through. The shaft goes through that bearing, it's pretty low friction.

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    Here's the lower strut, the piece that actually supports the weight of the trim-tab, which is probably about 10 pounds. It's oak, it will get wrapped in fiberglass. Where the trim tab shaft goes has now been cut back and the last thing I did today was make an UHMWPE "bearing" that goes right there, screwed to the oak with four s.s. wood screws. There's been some water intrusion into the rudder from cracks in the bottom fiberglass, so when I trimmed off the bottom inch, there was some drying-out to do. The doug fir core was fine, just needs a day or two or three to dry out. Three lag bolts attach the strut into the bottom of the rudder, as well as a bunch of fiberglass holding all this in place.

    Name:  trim-tab-strut-mockup.jpg
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    S-2 7.9: "Wildcat of Loch Awe"
    1968 Selmer Series 9 B-flat and A clarinets
    1962Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  5. #315
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    After much staring and debating...where to put the middle support bracket, I finally opted for a location which might get wet, but will more properly support the trim tab shaft....it's more in the middle. We'll see how the aluminum and bronze pillow bearing does, down there. I'll keep it oiled.

    Anyway, the two upper brackets are glassed on, as of today. I sanded off the paint, down to bare glass and used epoxy/sawdust to make a fillet. 1.5-inch tape went over that. The top of the antifouling paint is well above the waterline. The waterline is actually right where the top of the trim tab is. You can still see a hint of the line, in what's left of the antifouling paint on the rudder.

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    Looks like I got it pretty straight! The red thing is our patio umbrella, fresh out of the spin cycle on the washing machine.

    Name:  trimtab-rudder-brackets2-end.JPG
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    Now there's more sanding to do, and then paint. Then I mount the shaft bearings. THEN I slather epoxy all over the endgrain at the bottom of the rudder and take the strut off and wrap it with fiberglass. Once everything kicks off, I crank down on the bolts holding the strut to the bottom of the rudder. It needs to dry out for a few days. Then I make up epoxy and sawdust spooge and shape it....put a layer of 'glass over the whole thing...wait....apply antifouling and call it good.

    Oh, I need to do some microballoons/epoxy and sanding to the trailing edge of the trimtab, itself.

    Name:  trimtab-rudder-brackets3.JPG
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    S-2 7.9: "Wildcat of Loch Awe"
    1968 Selmer Series 9 B-flat and A clarinets
    1962Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

  6. #316
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    Sep 2007
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    San Francisco Bay Area
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    The new-to-me J-70 asymmetric spinnaker has arrived, so I set up the end of the pole with some wood to distribute the load and an eye bolt. I hoisted the sail in my slip, today,as there was essentially no wind.

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    I don't know much about assy's, but it seems to me like this is a little bit long on the luff/leech.

    Views of the pole...

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    There's no way to get the outboard end of the pole on the centerline. The bow pulpit won't let it happen.

    Name:  Asymmetric-pole2.JPG
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    Pole is about 45% extended, 55% on deck.
    S-2 7.9: "Wildcat of Loch Awe"
    1968 Selmer Series 9 B-flat and A clarinets
    1962Buesher "Aristocrat" tenor saxophone
    Piper One Design 24, Hull #35; "Alpha"

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