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Re: River Rat

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  • Sam
    I have the plans for this boat and have been studying them for a while. I think the boat has what I m looking for but I want to make sure that my few intended
    Message 1 of 8 , Oct 11, 2009
      I have the plans for this boat and have been studying them for a while. I think the boat has what I'm looking for but I want to make sure that my few intended modifications don't cause problems.

      The boat was designed in 1952 and Atkin claimed it would top out at 17.5 mph with a 25 hp outboard. It is plywood on frame with one seam batten on either side of the keel and two between the chine and sheer. He calls for frames 3/4 by 2 1/4 white oak on 18 1/2 in. centers. I plan to use longleaf pine instead of white oak. Bottom planking is one layer of 3/8 and top sides are one layer of 1/4. Cabin top is one layer of 1/4. He specifies glue and screw construction.

      1. I would like to use epoxy instead of glue. Can I cut down on the fasteners for the planking?

      2. I plan to keep the boat on a trailer, though the plans mention nothing of this. Will this cause problems with such lightweight construction? I thought I might add rigidity by adding some plywood frames longitudinally between the bottom frames, secured with epoxy fillets.

      3. I was going to glass the chines with one layer of biaxal cloth and sheath the entire hull in it as well. Any problems here?

      4. I would like to make some adjustments to add three inches of headroom inside, such as increasing the camber of the rooftop and increasing the height of the cabin sides. Any trouble with this?

      5. I want to be able to store a small tender on the roof top and use it as lounge space. The cabin top beams call for 7/8 by 2 in. spruce on 10 inch centers.

      --- In AtkinBoats@yahoogroups.com, "sam.scoville" <sam321866@...> wrote:
      >
      > I'm new to the group. I am awaiting plans for Atkin's River Rat. Does anyone have any info on this design, other that what is in the Atkin webpage's description? Know if any have been built?
      >
      > Sam
      >
    • John Kohnen
      Yes, you can cut down on the number of fasteners if you use epoxy. You just need enough to hold the pieces in place and provide even clamping pressure. After
      Message 2 of 8 , Oct 16, 2009
        Yes, you can cut down on the number of fasteners if you use epoxy. You
        just need enough to hold the pieces in place and provide even clamping
        pressure. After the goo cures you can remove the fasteners and fill their
        holes. Some modern boatbuilders consider any fastener a chink in the
        boat's defenses, a place for moisture to sneak in. If the plans call for
        through bolts, drifts, or rivets you should use them, though.

        Don't beef up the construction for trailering! The boat will be strong
        enough. I was reminded of the tendency of builders to want to build boats
        "hell for stout," despite what the designer specifies, by a quote I just
        read by George Calkins, concerning the Bartenders built by others for the
        Coast Guard, and by the CG itself, which didn't perform as well as they
        should have, "The less I had to do with the builders, the heavier the
        boats got." Atkin powerboats also depend on light weight for good
        performance, so keep that in mind every step of the way. Especially be
        careful fitting out the cabin -- keep everything simple and light.

        The problem with sheathing the whole hull with fiberglass is weight. I
        wouldn't sheath it above the waterline, or maybe the chines, and I'd use
        light cloth. Plenty of plywood boats have been built without any
        fiberglass at all and lasted well.

        Three inches of added height to the cabin isn't much, and wouldn't do much
        harm, especially if most of it is in additional crown to the top, but do
        you really need it?

        The framing and plywood for the top should do fine for holding a light
        dinghy and lounging. I'd use laminated beams. Notice that John & Wm.
        specified spruce for the beams; they were concerned with weight,
        especially up high. You should be too.

        Don't overpower the boat! Keep it light and it'll perform just fine with
        25 hp.

        On Sun, 11 Oct 2009 09:49:22 -0700, Sam wrote:

        > I have the plans for this boat and have been studying them for a while.
        > ...
        > The boat was designed in 1952 and Atkin claimed it would top out at 17.5
        > mph with a 25 hp outboard. It is plywood on frame with one seam batten
        > on either side of the keel and two between the chine and sheer. He calls
        > for frames 3/4 by 2 1/4 white oak on 18 1/2 in. centers. I plan to use
        > longleaf pine instead of white oak. Bottom planking is one layer of 3/8
        > and top sides are one layer of 1/4. Cabin top is one layer of 1/4. He
        > specifies glue and screw construction.
        >
        > 1. I would like to use epoxy instead of glue. Can I cut down on the
        > fasteners for the planking?
        >
        > 2. I plan to keep the boat on a trailer, though the plans mention
        > nothing of this. Will this cause problems with such lightweight
        > construction? I thought I might add rigidity by adding some plywood
        > frames longitudinally between the bottom frames, secured with epoxy
        > fillets.
        >
        > 3. I was going to glass the chines with one layer of biaxal cloth and
        > sheath the entire hull in it as well. Any problems here?
        >
        > 4. I would like to make some adjustments to add three inches of headroom
        > inside, such as increasing the camber of the rooftop and increasing the
        > height of the cabin sides. Any trouble with this?
        >
        > 5. I want to be able to store a small tender on the roof top and use it
        > as lounge space. The cabin top beams call for 7/8 by 2 in. spruce on 10
        > inch centers.

        --
        John <jkohnen@...>
        Never put off until tomorrow what you can do the day after
        tomorrow. <Mark Twain>
      • huttbldr@aol.com
        Look into using CPES by Smith and Co. on all wood parts. Great stuff In a message dated 10/16/2009 3:17:32 P.M. Pacific Daylight Time, jkohnen@boat-links.com
        Message 3 of 8 , Oct 16, 2009
          Look into using CPES by Smith and Co. on all wood parts. Great stuff
           
          In a message dated 10/16/2009 3:17:32 P.M. Pacific Daylight Time, jkohnen@... writes:
          Yes, you can cut down on the number of fasteners if you use epoxy. You 
          just need enough to hold the pieces in place and provide even clamping 
          pressure. After the goo cures you can remove the fasteners and fill their 
          holes. Some modern boatbuilders consider any fastener a chink in the 
          boat's defenses, a place for moisture to sneak in. If the plans call for 
          through bolts, drifts, or rivets you should use them, though.

          Don't beef up the construction for trailering! The boat will be strong 
          enough. I was reminded of the tendency of builders to want to build boats 
          "hell for stout," despite what the designer specifies, by a quote I just 
          read by George Calkins, concerning the Bartenders built by others for the 
          Coast Guard, and by the CG itself, which didn't perform as well as they 
          should have, "The less I had to do with the builders, the heavier the 
          boats got." Atkin powerboats also depend on light weight for good 
          performance, so keep that in mind every step of the way. Especially be 
          careful fitting out the cabin -- keep everything simple and light.

          The problem with sheathing the whole hull with fiberglass is weight. I 
          wouldn't sheath it above the waterline, or maybe the chines, and I'd use 
          light cloth. Plenty of plywood boats have been built without any 
          fiberglass at all and lasted well.

          Three inches of added height to the cabin isn't much, and wouldn't do much 
          harm, especially if most of it is in additional crown to the top, but do 
          you really need it?

          The framing and plywood for the top  should do fine for holding a light 
          dinghy and lounging. I'd use laminated beams. Notice that John & Wm. 
          specified spruce for the beams; they were concerned with weight, 
          especially up high. You should be too.

          Don't overpower the boat! Keep it light and it'll perform just fine with 
          25 hp.

          On Sun, 11 Oct 2009 09:49:22 -0700, Sam wrote:

          > I have the plans for this boat and have been studying them for a while. 
          > ...
          > The boat was designed in 1952 and Atkin claimed it would top out at 17.5 
          > mph with a 25 hp outboard. It is plywood on frame with one seam batten 
          > on either side of the keel and two between the chine and sheer. He calls 
          > for frames 3/4 by 2 1/4 white oak on 18 1/2 in. centers. I plan to use 
          > longleaf pine instead of white oak. Bottom planking is one layer of 3/8 
          > and top sides are one layer of 1/4. Cabin top is one layer of 1/4. He 
          > specifies glue and screw construction.
          >
          > 1. I would like to use epoxy instead of glue. Can I cut down on the 
          > fasteners for the planking?
          >
          > 2. I plan to keep the boat on a trailer, though the plans mention 
          > nothing of this. Will this cause problems with such lightweight 
          > construction? I thought I might add rigidity by adding some plywood 
          > frames longitudinally between the bottom frames, secured with epoxy 
          > fillets.
          >
          > 3. I was going to glass the chines with one layer of biaxal cloth and 
          > sheath the entire hull in it as well. Any problems here?
          >
          > 4. I would like to make some adjustments to add three inches of headroom 
          > inside, such as increasing the camber of the rooftop and increasing the 
          > height of the cabin sides. Any trouble with this?
          >
          > 5. I want to be able to store a small tender on the roof top and use it 
          > as lounge space. The cabin top beams call for 7/8 by 2 in. spruce on 10 
          > inch centers.

          --
          John <jkohnen@...>
          Never put off until tomorrow what you can do the day after
          tomorrow. <Mark Twain>


          ------------------------------------

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          <http://www.atkinboatplans.com/>

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        • Sam
          Very helpful. Thank you.
          Message 4 of 8 , Oct 16, 2009
            Very helpful. Thank you.

            --- In AtkinBoats@yahoogroups.com, "John Kohnen" <jkohnen@...> wrote:
            >
            > Yes, you can cut down on the number of fasteners if you use epoxy. You
            > just need enough to hold the pieces in place and provide even clamping
            > pressure. After the goo cures you can remove the fasteners and fill their
            > holes. Some modern boatbuilders consider any fastener a chink in the
            > boat's defenses, a place for moisture to sneak in. If the plans call for
            > through bolts, drifts, or rivets you should use them, though.
            >
            > Don't beef up the construction for trailering! The boat will be strong
            > enough. I was reminded of the tendency of builders to want to build boats
            > "hell for stout," despite what the designer specifies, by a quote I just
            > read by George Calkins, concerning the Bartenders built by others for the
            > Coast Guard, and by the CG itself, which didn't perform as well as they
            > should have, "The less I had to do with the builders, the heavier the
            > boats got." Atkin powerboats also depend on light weight for good
            > performance, so keep that in mind every step of the way. Especially be
            > careful fitting out the cabin -- keep everything simple and light.
            >
            > The problem with sheathing the whole hull with fiberglass is weight. I
            > wouldn't sheath it above the waterline, or maybe the chines, and I'd use
            > light cloth. Plenty of plywood boats have been built without any
            > fiberglass at all and lasted well.
            >
            > Three inches of added height to the cabin isn't much, and wouldn't do much
            > harm, especially if most of it is in additional crown to the top, but do
            > you really need it?
            >
            > The framing and plywood for the top should do fine for holding a light
            > dinghy and lounging. I'd use laminated beams. Notice that John & Wm.
            > specified spruce for the beams; they were concerned with weight,
            > especially up high. You should be too.
            >
            > Don't overpower the boat! Keep it light and it'll perform just fine with
            > 25 hp.
            >
            > On Sun, 11 Oct 2009 09:49:22 -0700, Sam wrote:
            >
            > > I have the plans for this boat and have been studying them for a while.
            > > ...
            > > The boat was designed in 1952 and Atkin claimed it would top out at 17.5
            > > mph with a 25 hp outboard. It is plywood on frame with one seam batten
            > > on either side of the keel and two between the chine and sheer. He calls
            > > for frames 3/4 by 2 1/4 white oak on 18 1/2 in. centers. I plan to use
            > > longleaf pine instead of white oak. Bottom planking is one layer of 3/8
            > > and top sides are one layer of 1/4. Cabin top is one layer of 1/4. He
            > > specifies glue and screw construction.
            > >
            > > 1. I would like to use epoxy instead of glue. Can I cut down on the
            > > fasteners for the planking?
            > >
            > > 2. I plan to keep the boat on a trailer, though the plans mention
            > > nothing of this. Will this cause problems with such lightweight
            > > construction? I thought I might add rigidity by adding some plywood
            > > frames longitudinally between the bottom frames, secured with epoxy
            > > fillets.
            > >
            > > 3. I was going to glass the chines with one layer of biaxal cloth and
            > > sheath the entire hull in it as well. Any problems here?
            > >
            > > 4. I would like to make some adjustments to add three inches of headroom
            > > inside, such as increasing the camber of the rooftop and increasing the
            > > height of the cabin sides. Any trouble with this?
            > >
            > > 5. I want to be able to store a small tender on the roof top and use it
            > > as lounge space. The cabin top beams call for 7/8 by 2 in. spruce on 10
            > > inch centers.
            >
            > --
            > John <jkohnen@...>
            > Never put off until tomorrow what you can do the day after
            > tomorrow. <Mark Twain>
            >
          • Jon n Wanda
            The solvents in CPES help it penitrate in rotten wood just like it did in Balsa but in new woods with higher density it is realy a surface coating other then
            Message 5 of 8 , Oct 17, 2009
              The solvents in CPES help it penitrate in rotten wood just like it did in Balsa but in new woods with higher density it is realy a surface coating other then endgrain. The test and examples on CPES sight have been heavely disputed for how well they realy work in new wood and stopping rot around where they penatrate to. I have removed wood that was partly penitrared and the rot was from there on with the parts coated being weak. The reason for not thinning epoxy in glassing and coating is it makes it weaker and also alows more vaper transfer. In both cases they add weight. To prevent rot one of the cheapest products is good old non pet friendly anti-freez. Brush it on let it soak in and dry then coat with epoxy or paint.

              Jon

              --- In AtkinBoats@yahoogroups.com, huttbldr@... wrote:
              >
              > Look into using CPES by Smith and Co. on all wood parts. Great stuff
              >
            • Sam
              What about just coating all wood with a couple coats of regular epoxy? And what about the frame gussets? 1/4 in ply? 3/4?
              Message 6 of 8 , Oct 18, 2009
                What about just coating all wood with a couple coats of regular epoxy? And what about the frame gussets? 1/4 in ply? 3/4?

                --- In AtkinBoats@yahoogroups.com, "Jon n Wanda" <windyjon@...> wrote:
                >
                > The solvents in CPES help it penitrate in rotten wood just like it did in Balsa but in new woods with higher density it is realy a surface coating other then endgrain. The test and examples on CPES sight have been heavely disputed for how well they realy work in new wood and stopping rot around where they penatrate to. I have removed wood that was partly penitrared and the rot was from there on with the parts coated being weak. The reason for not thinning epoxy in glassing and coating is it makes it weaker and also alows more vaper transfer. In both cases they add weight. To prevent rot one of the cheapest products is good old non pet friendly anti-freez. Brush it on let it soak in and dry then coat with epoxy or paint.
                >
                > Jon
                >
                > --- In AtkinBoats@yahoogroups.com, huttbldr@ wrote:
                > >
                > > Look into using CPES by Smith and Co. on all wood parts. Great stuff
                > >
                >
              • Jon n Wanda
                All epoxy products allow some vaper through but less then polyester or vinalester products. Plywood is not all the same so first it depends on the plywood
                Message 7 of 8 , Oct 18, 2009
                  All epoxy products allow some vaper through but less then polyester or vinalester products. Plywood is not all the same so first it depends on the plywood knowing you may not seal out 100% of the water if some sits in the boat for a extended period. Fir plywod is knowen to check if it is coated only on the outside of a boat but it helps stop some checking. Glassing coating primeing and painting all work to some degree depending on use and matinace if it gets scrached. Encapsolating is a system where frames are sealed with three thin not thinned coats of epoxy the first soaka in the second seals the third getting what ever may have been to thin. The ply is sealed with a coat of epoxy on the outside and then glassed and sealed like the frames on the inside. A good way to do it is coat the first coat on the inside before applying so it seals the plywood where the frames are. This is a joint that may get a small crack so water can get into plywood. Two more coats of epoxy later. All epoxy surfaces that have been coated need to be lightly sanded to get a good primer and paint bond. Useing anty-freez on the wood can be a problem with some cheaper plywoods that don't have enough glue even if they are exterior grade because anty-freez is water base and the outside venear can get buckels in it. Glen-L boats has a good section onencapsolation and it will work with all brands of epoxy for laminating and coating many that will blush and that is explaned too.

                  Jon

                  --- In AtkinBoats@yahoogroups.com, "Sam" <sam321866@...> wrote:
                  >
                  > What about just coating all wood with a couple coats of regular epoxy? And what about the frame gussets? 1/4 in ply? 3/4?
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