Few ? about building.

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  • Ljaybo41
    Member
    • Sep 2017
    • 33

    Few ? about building.

    My small catboat S+G design calls for wood cleats glued and screwed to the perimeter of the 1/4" ply frames. Is this to strengthen the ply frame or give more surface for epoxy or both? Could I increase the frame to 1/2 ply and omit the cleats? It's an older design and I followed a recent build where the builder omitted them completely.

    The centerboard calls for a metal reinforced slot for the bolt to ride in. If the hook allows me to mount the centerboard, what keeps it from being popped off while say drifting backwards and hitting an object at the right angle causing a lift? Or am I way overthinking it? Since the hook rides on the bolt, and allows for removal of the board, can I epoxy the bolt solid or keep caps accessible?

    Im planning on ripping up box store lumber for solid mast construction. Should I use epoxy or tite bond? How far apart should scarfs be spaced? For a 15' mast, should I go with two halves or four quarters glue up? I suspect the latter but will that make it too stiff?

    What type of screw head specifically do I use to hold the 1/4 ply hull to the centerboard case logs/ ? Do you countersink first or just drive it and fill then glass?

    Thanks all, I've built this boat in my head about thirty times already and should have progress other than a few notebooks soon.
  • wizbang 13
    Senior Member
    • Oct 2009
    • 24799

    #2
    Re: Few ? about building.

    I can't follow all you are asking about.
    More info and photos please.

    Comment

    • Peerie Maa
      Old Grey Inquisitive One
      • Oct 2008
      • 62422

      #3
      Re: Few ? about building.

      Originally posted by Ljaybo41
      My small catboat S+G design calls for wood cleats glued and screwed to the perimeter of the 1/4" ply frames. Is this to strengthen the ply frame or give more surface for epoxy or both? Could I increase the frame to 1/2 ply and omit the cleats? It's an older design and I followed a recent build where the builder omitted them completely.

      The centerboard calls for a metal reinforced slot for the bolt to ride in. If the hook allows me to mount the centerboard, what keeps it from being popped off while say drifting backwards and hitting an object at the right angle causing a lift? Or am I way overthinking it? Since the hook rides on the bolt, and allows for removal of the board, can I epoxy the bolt solid or keep caps accessible?
      Why buy a dog and bark yourself? Trust the designer and do as he says.
      Im planning on ripping up box store lumber for solid mast construction. Should I use epoxy or tite bond? How far apart should scarfs be spaced? For a 15' mast, should I go with two halves or four quarters glue up? I suspect the latter but will that make it too stiff?
      If you use epoxy it will not matter where the scarfs are, but in general as far apart as you economically can.
      One or 4 glue lines will not affect the stiffness of the mast. That said I would build out of two, not 4 if the wood allows.
      What type of screw head specifically do I use to hold the 1/4 ply hull to the centerboard case logs/ ? Do you countersink first or just drive it and fill then glass?

      Thanks all, I've built this boat in my head about thirty times already and should have progress other than a few notebooks soon.
      By countersink do you mean counter bore or counter sink? You are only working with 1/4 ply so counter sink as shallow as you can. Do not just drive it and hope that the wood will crush to seat the head.
      It really is quite difficult to build an ugly wooden boat.

      The power of the web: Anyone can post anything on the web
      The weakness of the web: Anyone can post anything on the web.

      Comment

      • debenriver
        Senior Member
        • Aug 2010
        • 688

        #4
        Re: Few ? about building.

        I suspect the blocks are to give more surface to bond to/fasten to. ¼" is pretty thin to get much bonding surface and pretty difficult to fasten to. If you are building with the intention of epoxy coating, then you can probably epoxy-fillet the frames to the skin instead of the blocks – depending on how the whole thing is put together - more detail would be helpful.

        Increasing to ½" could add a lot more weight - again depending on the geometry of the frames.

        Not quite sure what you mean about the centreboard - is it an angled slot in the centreboard that slides down over a bolt through the centrecase? If so, some reinforcing of the slot would be good - could be epoxy/glass perhaps if metal is difficult. Again a bit more info would be helpful - or a picture/drawing of the arrangement.

        Two halves is usually good for a solid spar. Conventionally you take a piece of square or rectangular timber, split it in two and reverse the halves – this balances the grain and helps stop the glued up spar from warping. If you are going to use separate pieces of unrelated lumber, try to find pieces where the grain is vertical when viewed from the end. I would use epoxy to glue it up – not a particular fan of Titebond – but plenty of spars have been built with it. A well made scarph (say 1:10) should be as strong as the parent timber. But it is usual to space the scarphs by, say, 24" or more. You can sometimes fine quite nice Douglas Fir in 16' lengths in the larger sizes (like 2" x 10" or 2" x 12") which would save you scarphing - you need to spend time sorting through the pile!

        Cheers -- George
        Last edited by debenriver; 10-24-2017, 10:37 AM.
        To be truly free to live, one must be free to think and speak.

        A C Grayling

        Comment

        • Jay Greer
          Senior Member
          • Nov 2004
          • 14425

          #5
          Re: Few ? about building.

          Nick has covered your questions pretty well. I might add that I use 1:12" scarfs for the masts I build. While many glues have been used for mast building over the years, I prefer the G/flex epoxy that West System makes. It has a flex factor built into it that works very well for gluing up spars.

          Once you have set your screws, use a mixture of micro balloons and polyester resin to fill in over the fastenings. This makes up a filler that is easier to sand flush than epoxy fillers or to remove than fillers that are epoxy based should you need to pull a fastening in the future.
          Jay

          Comment

          • Ljaybo41
            Member
            • Sep 2017
            • 33

            #6
            Re: Few ? about building.

            Ok, I'll try to clarify. I'm studying to build the Petrel 13 , a small catboat by Selway Fisher. The plans call for sitting on the floor boards. There is a builder from Estonia who changed the cockpit to add benches supported by resting on cutouts on the frames. He did not use the cleats. I like this boat and want to build the benches the same. It is an older design. Just wanted to see if it's still recommended to keep the cleats or it's been determined over time that the ply with fillets is enough. This will be a trailered boat in lakes only. I plan on coating everything in epoxy and paint everything except top sides. Hope that helps.

            The centerboard I confused on the plans. I thought there was a slot cut out so you could push it up into the case and slide it down on the bolt. I know see I have to lift the board in place and then run the bolt through. Lots to learn.


            Thanks for for all the input. This is a first build for me so interpreting the plans and learning the basics is much easier with your help.

            Comment

            • Peerie Maa
              Old Grey Inquisitive One
              • Oct 2008
              • 62422

              #7
              Re: Few ? about building.

              Originally posted by Ljaybo41
              Ok, I'll try to clarify. I'm studying to build the Petrel 13 , a small catboat by Selway Fisher. The plans call for sitting on the floor boards. There is a builder from Estonia who changed the cockpit to add benches supported by resting on cutouts on the frames. He did not use the cleats. I like this boat and want to build the benches the same. It is an older design. Just wanted to see if it's still recommended to keep the cleats or it's been determined over time that the ply with fillets is enough. This will be a trailered boat in lakes only. I plan on coating everything in epoxy and paint everything except top sides. Hope that helps.

              The centerboard I confused on the plans. I thought there was a slot cut out so you could push it up into the case and slide it down on the bolt. I know see I have to lift the board in place and then run the bolt through. Lots to learn.


              Thanks for for all the input. This is a first build for me so interpreting the plans and learning the basics is much easier with your help.
              I cannot picture what you mean by supporting the benches on cutouts on plywood frames. Does not compute.
              Can you post a sketch of what you are discussing, or photo's of the Estonian boat?
              It really is quite difficult to build an ugly wooden boat.

              The power of the web: Anyone can post anything on the web
              The weakness of the web: Anyone can post anything on the web.

              Comment

              • debenriver
                Senior Member
                • Aug 2010
                • 688

                #8
                Re: Few ? about building.

                Why not just ask the designer?

                Cheers -- George
                To be truly free to live, one must be free to think and speak.

                A C Grayling

                Comment

                • Ljaybo41
                  Member
                  • Sep 2017
                  • 33

                  #9
                  Re: Few ? about building.

                  My apologies, I know it's my not knowing the correct terms yet, trying to load pictures to help.
                  image.jpgimage.jpg
                  This builder changed the plans which call for a slat floor similar to what you see with no bench.
                  He changed the shape of the frames at the centerboard and before the transom to support the bench. The original plans call for a similar opening with the addition of wooden cleats going around the outside edge of the frames next to the hull.

                  The designer Paul, has been very helpful in several questions I've had. But he certainly doesn't want 15 emails a day from me I'm sure. This forum is a great resource as well.

                  So, did this builder push the envelope by not using the cleats? Would you do anything different? I would like to strengthen this area. Can I increase to 1/2" and not use cleats?

                  Thanks for all the feedback.
                  Attached Files

                  Comment

                  • Peerie Maa
                    Old Grey Inquisitive One
                    • Oct 2008
                    • 62422

                    #10
                    Re: Few ? about building.

                    I would stick with the cleats and screw the benches to them. That way you can take the benches out again for refinishing and it will be easier to sand/repaint the hull/frames under them come refit time.
                    It really is quite difficult to build an ugly wooden boat.

                    The power of the web: Anyone can post anything on the web
                    The weakness of the web: Anyone can post anything on the web.

                    Comment

                    • Tom Lathrop
                      Senior Member
                      • Dec 1999
                      • 5305

                      #11
                      Re: Few ? about building.

                      Very nice work and should be a nice boat. There are several interpretations of cleats and I don't know what you mean by cleat or where they are meant to be used by the designer. Many builders, me included, use an epoxy bearing in the centerboard and one in each side of the trunk wall. The pin is covered on the outside of the trunk wall and floats with wood caps on each end that are caulked and screwed over the pin. This arrangement cannot leak and is robust enough to survive impacts.
                      Tom L

                      Comment

                      • debenriver
                        Senior Member
                        • Aug 2010
                        • 688

                        #12
                        Re: Few ? about building.

                        Those look to be excellent epoxy fillets from the frames to the hull skin. I would think that they are equally as good as cleats, if not better because they provide a nice easy transition from frame to hull rather than a sudden one.

                        I think I might have run a filet, or a cleat, up the centrecase/frame connection aft.

                        As Nick says - stick with cleats to screw the benches to - It'll stiffen the top edges of the frames as well.

                        Looks like a really nice job – I assume this is the one built in Estonia?

                        Cheers -- George
                        To be truly free to live, one must be free to think and speak.

                        A C Grayling

                        Comment

                        • Ljaybo41
                          Member
                          • Sep 2017
                          • 33

                          #13
                          Re: Few ? about building.

                          Yes it is. This boat fits my needs and I'm looking forward to making it. Thanks for the help everyone. Some things you can't find in a book. Tom? Would you explain how you build the epoxy core as a bearing and keep everything lined up? I've heard of it being done but not how.

                          Comment

                          • skaraborgcraft
                            Banned
                            • Jan 2010
                            • 12824

                            #14
                            Re: Few ? about building.

                            Im a bit late to the party. Many Michalk designs will use cleats around a bulkhead, it serves both functions of stiffening up a ply frame, spreading load and glue surface area. It will be in most cases cheaper than an epoxy fillet that has to be done on both sides, but as mentioned, it is a cleaner finish with no point loading. I would agree with Nick that the cleats on the seat frame will make removing the benches for service far easier. Half inch frames for this boat would be overkill in terms of weight.
                            Im looking at building an old Schock design catboat, ply on frame, much of which could be modified into a stitch and glue with fillets.

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