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Re: Adapting trailer for flat bottom boats

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  • cadbury@swbell.net
    Jim Michalak s comments converning athwart-ship possitioned bunks are definetly worth reading, but there is an additional point to consider. With athwart-ship
    Message 1 of 8 , Jul 1 5:27 PM
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      Jim Michalak's comments converning athwart-ship possitioned bunks
      are definetly worth reading, but there is an additional point
      to consider. With athwart-ship bunks, and a boat larger than
      a June Bug, the trailer often must be submerged to the point
      where the boat can be floated into position- you do not have the
      option of winching the boat up onto the trailer. Again, with
      the June Bug it probably won't matter as the boat is light
      enough to "man-handle" as necessary. For this reason I prefer
      longitudinal bunks, assuming the rocker of the boat's bottom
      does not preclude them, and I prefer keel rollers. I put
      a center "keel" made from a 2" by 4" on my AF4 so that it, and
      not the bottom plywood, would bear on the keel rollers.
      Jim was supprised to see how easily my AF4 launched from
      a shallow-positioned trailer. It also retrieves easily.
      One thing to keep in mind, regardless of bunk/ roller positioning,
      is that the trailer, on the ramp, is at an angle, and the
      boat floating up to it is level. Watch for interferience
      between the stem and the trailer frame in this situation.


      Max
    • richard@spellingbusiness.com
      Hey, Max. Hub is working fine! Would add, I have only athwart-ship bunks on my trailer, and have no problem winching it up. I do have to lift the nose a bit to
      Message 2 of 8 , Jul 1 8:39 PM
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        Hey, Max. Hub is working fine!

        Would add, I have only athwart-ship bunks on my trailer, and have no
        problem winching it up. I do have to lift the nose a bit to get it on
        the forward bunk, then I winch it out of the water. I have to go
        deeper of course to launch, but I can retrieve without getting the
        tires on the truck wet.

        I have often thought I needed a board, say a 9 inch wide piece of
        3/4 ply, going from the center bunk to the forward bunk. Mounted on
        hings, it would flex and guide the nose up on the forward bunk.

        As you know, I have an AF2, no keel on the bottom. When I build the
        Chebacco LC, I will go with rollers as you suggest, but use two
        athwart-ship bunks. The trick will be evenly distribing the weight
        between the bunks and the keel...

        --- In bolger@y..., cadbury@s... wrote:
        > Jim Michalak's comments converning athwart-ship possitioned bunks
        > are definetly worth reading, but there is an additional point
        > to consider. With athwart-ship bunks, and a boat larger than
        > a June Bug, the trailer often must be submerged to the point
        > where the boat can be floated into position- you do not have the
        > option of winching the boat up onto the trailer. Again, with
        > the June Bug it probably won't matter as the boat is light
        > enough to "man-handle" as necessary. For this reason I prefer
        > longitudinal bunks, assuming the rocker of the boat's bottom
        > does not preclude them, and I prefer keel rollers. I put
        > a center "keel" made from a 2" by 4" on my AF4 so that it, and
        > not the bottom plywood, would bear on the keel rollers.
        > Jim was supprised to see how easily my AF4 launched from
        > a shallow-positioned trailer. It also retrieves easily.
        > One thing to keep in mind, regardless of bunk/ roller positioning,
        > is that the trailer, on the ramp, is at an angle, and the
        > boat floating up to it is level. Watch for interferience
        > between the stem and the trailer frame in this situation.
        >
        >
        > Max
      • cadbury@swbell.net
        ... no ... on ... Hey, Capt. Richard! How bout a Messabout on TableRock/Bull Shoals/ Beaver/ Grand Lake? My goal, not necessarily realized, when I set-up my
        Message 3 of 8 , Jul 2 7:34 AM
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          --- In bolger@y..., richard@s... wrote:
          > Hey, Max. Hub is working fine!
          >
          > Would add, I have only athwart-ship bunks on my trailer, and have
          no
          > problem winching it up. I do have to lift the nose a bit to get it
          on
          > the forward bunk, then I winch it out of the water. I have to go
          > deeper of course to launch, but I can retrieve without getting the
          > tires on the truck wet.
          >
          > I have often thought I needed a board, say a 9 inch wide piece of
          > 3/4 ply, going from the center bunk to the forward bunk. Mounted on
          > hings, it would flex and guide the nose up on the forward bunk.
          >
          > As you know, I have an AF2, no keel on the bottom. When I build the
          > Chebacco LC, I will go with rollers as you suggest, but use two
          > athwart-ship bunks. The trick will be evenly distribing the weight
          > between the bunks and the keel...
          >


          Hey, Capt. Richard!

          How 'bout a Messabout on TableRock/Bull Shoals/ Beaver/ Grand
          Lake?

          My goal, not necessarily realized, when I set-up my trailer
          was to be able to launch and retrieve without getting the trailer
          hubs wet. So I have 4 keel rollers and a pair of 8-ft longitudinal
          bunks. On very steep ramps, i will have a problem with the straight
          stem trying to hit the next roller in line, on the vertical surface
          of the stem. I may need to add one more roller to close-up the
          distance between them. Another concern with the bunks is one has
          to watch for a tendency for the chines to try to get stuck between
          them rather than to climb them. The keel roller at the rear of the
          frame will usually prevent this unless the trailer is submerged too
          deep.

          Since my bunks pass under the companionway bulkhead, motor well
          forward bulkhead, and the transom, I am not much concerned about the
          bottom flexxing that Jim addresses in his newsletter concerning
          trailers. Since the bottom is usually the thickest, and heaviest,
          part of the boat, I would argue that bottom flex is probably not
          a concern on any open boat with little structure bearing down on the
          sides.

          A bigger concern of mine, primarily with powerboats, is that
          the transom should have support directly underneath it to support
          the weight of the outboard, or in my case, two outboards. This is why
          I have my bunks extend about 4 inches aft of the transom, which also
          provides a handy place to fasten transom tie-downs. A sailboat with
          a small auxiliary outboard doesn't worry me as much.

          Personally, I believe that it is harder to "set-up" a trailer to
          handle a "pointy-bow" flat-bottom boat, than a vee-bottom boat,
          primarily due to that deep, straight stem. A raked stem with rounded
          fore foot will not try to snag every cross member of the frame or
          drag on the tongue.


          Later

          Max
        • richard@spellingbusiness.com
          ... Actualy, I m planing on setting one up at Lake Keystone, my local stomping grounds, in the fall. They have a pretty decent state park. I ll do some recon,
          Message 4 of 8 , Jul 2 8:29 AM
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            --- In bolger@y..., cadbury@s... wrote:
            >
            > Hey, Capt. Richard!
            >
            > How 'bout a Messabout on TableRock/Bull Shoals/ Beaver/ Grand
            > Lake?
            >
            Actualy, I'm planing on setting one up at Lake Keystone, my local
            stomping grounds, in the fall. They have a pretty decent state park.
            I'll do some recon, pick a nice sandy beach for boats, away from
            yucky boat traffic, etc. I'll post to the list when I figure it out.

            > Since my bunks pass under the companionway bulkhead, motor well
            > forward bulkhead, and the transom, I am not much concerned about
            the
            > bottom flexxing that Jim addresses in his newsletter concerning
            > trailers. Since the bottom is usually the thickest, and heaviest,
            > part of the boat, I would argue that bottom flex is probably not
            > a concern on any open boat with little structure bearing down on the
            > sides.
            >
            I like the idea of launching without getting the trailer wet. An
            extention, as long as you had enough water to float the boat, you
            could have a fold out ramp with rollers on it for your keel. You
            could launch in VERY shallow water. Say, 4 inches...

            I would be concerned with the point loads the rollers put on keel. I
            suppose, with relativly light boats like ours, it's not really a big
            deal. Are your rollers located under bulkheads?

            I was thinking with Chebacco I would go with a roller every 6 inches
            or so. To much?
          • cadbury@swbell.net
            -- Good morning Capt. Richard! I am not too familiar with the Chebacco so I really don t have an opinion as to trailer needs. I would not want to use rollers
            Message 5 of 8 , Jul 4 9:06 AM
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              --

              Good morning Capt. Richard!

              I am not too familiar with the Chebacco so I really don't
              have an opinion as to trailer needs. I would not want to
              use rollers on a planked hull, for fear of starting seams,
              or on a plywood hull with a relatively thin skin supported
              by frames and stringers. For the "instant" style boat, where
              it appears the lack of frames and stringers are compensated for
              by a relatively thick bottom, I don't think rollers are a problem.

              I did not want the rollers bearing on the bottom ply
              of my AF4, so I have them bearing against the 2 by 4 (laying flat,
              not on edge) keel and there doesn't seem to be any problems, even
              when I am in the boat while it is on the trailer. Roller spacing is
              about 2 feet or so in the front half of the boat, but much wider
              back by the bunks. I did not even check to see if the rollers
              were under bulkheads. My main concern was placing the rollers so
              that the boat, when winched up the trailer, would not drag on
              the trailer frame.

              The Chebacco is a nice-looking boat, but probably beyound my
              skill-level at this time. One of the designs that I am considering
              is the AF2. Have you ever had yours capsize, and if so, how difficult
              was the recovery?

              Something like a Chebacco may be further down the road for me,
              but not for the next project.

              Later

              Max
            • richard@spellingbusiness.com
              Chebacco uses 1/2 ply for the entire hull. It would of course be be sheethed in glass. (probably both sides...) It has a short keel that holds about half the
              Message 6 of 8 , Jul 4 10:06 AM
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                Chebacco uses 1/2" ply for the entire hull. It would of course be be
                sheethed in glass. (probably both sides...)

                It has a short keel that holds about half the centerboard. This would
                be what is sitting on the rollers. Would probably cover the bottom of
                the keel with aluminum rock armour. That would spread the point loads
                from the rollers. The bunks would be there to guide the boat durring
                launch and retrieval, and keep it from tipping and whatnot on the
                trailer.

                I've never had my AF2 capsize. I've seen it up to 35 degrees, and
                I've gotten the back deck wet... Most interesting manuever is the
                flying jibe in high winds. Be sure to move your ballast BEFORE the
                boom comes across!

                I don't think it would be that hard to right, even if it did capsize.
                The flare on the sides, the thick bottom. Worst comes to worst, you
                could crawl on top an parbuckle out with one of the ropes.

                Will have to test sometime. Maybe at the fall messabout at Keystone?
                Load the boat up with normal compliment, tie a rope to the top of the
                mast, and one underwater to the bottom of the leeboard. Use a spring
                scale and measure force vs angle... Think that would get people to
                come to the messabout?!

                We could try the righting experiment too!

                --- In bolger@y..., cadbury@s... wrote:
                > --
                >
                > Good morning Capt. Richard!
                >
                > I am not too familiar with the Chebacco so I really don't
                > have an opinion as to trailer needs. I would not want to
                > use rollers on a planked hull, for fear of starting seams,
                > or on a plywood hull with a relatively thin skin supported
                > by frames and stringers. For the "instant" style boat, where
                > it appears the lack of frames and stringers are compensated for
                > by a relatively thick bottom, I don't think rollers are a problem.
                >
                > I did not want the rollers bearing on the bottom ply
                > of my AF4, so I have them bearing against the 2 by 4 (laying flat,
                > not on edge) keel and there doesn't seem to be any problems, even
                > when I am in the boat while it is on the trailer. Roller spacing is
                > about 2 feet or so in the front half of the boat, but much wider
                > back by the bunks. I did not even check to see if the rollers
                > were under bulkheads. My main concern was placing the rollers so
                > that the boat, when winched up the trailer, would not drag on
                > the trailer frame.
                >
                > The Chebacco is a nice-looking boat, but probably beyound my
                > skill-level at this time. One of the designs that I am considering
                > is the AF2. Have you ever had yours capsize, and if so, how
                difficult
                > was the recovery?
                >
                > Something like a Chebacco may be further down the road for me,
                > but not for the next project.
                >
                > Later
                >
                > Max
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