Wee Rob - Bulkhead Hatches

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  • Songololo
    Senior Member
    • Dec 2006
    • 790

    Wee Rob - Bulkhead Hatches

    The Wee Rob build is coming along slowly. One of the things that needs deciding on fairly soon, is what type of hatch design to use.

    Options seem to include:
    • Plywood hatch
      • turnbuckle secured
      • bungie secured
      • bayonet locking
    • Plastic screw or bayonet hatch (as seen below)



    How good are the plywood hatches at creating a watertight compartment for flotation and/or dry storage?

    I like the idea of a bayonet-locking-type plywood hatch cover as there are no turnbuckles or bungie cords required. Has anyone had any experience with using or making such a cover?
    "Smooth seas do not make skillful sailors". African Proverb
  • Bill Perkins
    Senior Member
    • Mar 2002
    • 2520

    #2
    Re: Wee Rob - Bulkhead Hatches

    My old ME (whitewater canoe ) has a Perception saddle with a screw in access port of solid black plastic .This looks better to my eye than the clear piece you show of about the same size .There's no real need for a see thru hatch and it just looks more plastic to me ;more visually distracting from the rest of the boat . I think wear will only make the clear plastic look worse . The solid black,though battered like the rest of my boat ,still looks decent .

    I would look at the white water canoe catalogs . Perception may still have parts , or someone else may make something similar . You'll also find bow and stern airbags for canoes and kayaks that are light and could be contained by a bulkhead and hatch that wouldn't have to be absolutely watertight in a capsize but would still protect lunch and gear during normal operation .

    If rain and spray proof was all that was required the hatch could be a generously sized and attractivly shaped panel with a straight top edge to mount a piano hinge .This can be set to show only the pin. Any simple latch system would work .If you don't need the storage (use a dry bag) the flotation could be secured with a wooden lattice bulkhead ,which could look sharp .

    Comment

    • Ed Armstrong
      Senior Member
      • Feb 2003
      • 841

      #3
      Re: Wee Rob - Bulkhead Hatches

      Hi Lance,

      I just got my Wee Rob plans last week, and in studying the plans, figured I'd probably go with the plywood hatch with backing rubber grommet and turn-buttons, which seemed like it would be pretty water-tight. I used turn-buttons to hold down the floors in my Acorn dinghy, and they were pretty easy to make and work well.

      A bayonet mount would certainly eliminate the turn-buttons, but it seems like it would take some more advanced woodworking skills.

      I personally don't think a plastic or clear hatch would look good with the traditional design of the Wee Rob.

      Cheers,

      Ed
      --------------------------------------------------------------------------------------------------
      "
      The only man who makes no mistakes is the man who never does anything."
      Roosevelt, Theodore

      Comment

      • bob easton
        Senior Member
        • Aug 2007
        • 161

        #4
        Re: Wee Rob - Bulkhead Hatches

        I just launched a Fiddlehead canoe designed by Harry Bryan. Harry included drawings for interesting oval hatches, and I built them as designed. They are screw tightened, using a tightening bar on the inside and a foam gasket on the outside. They are likely more complex to make than some will like, but they are very watertight.





        A few more details at: http://www.bob-easton.com/blog/?p=596
        Bob
        Mill Creek 13 build log: http://www.bob-easton.com/blog/?cat=18
        Fiddlehead build log: http://www.bob-easton.com/blog/?cat=7

        Comment

        • Scot L T
          Senior Member
          • Jun 2009
          • 148

          #5
          Re: Wee Rob - Bulkhead Hatches

          Interesting. Is there a reason that the inner part of the hatch isn't more form fitting to the hole?
          "Take good care of the earth, for it was not given to you by your Grandfathers but loaned to you by your Grandchildren."

          Native American Saying.

          Comment

          • wtarzia
            Senior Member
            • Feb 2007
            • 2104

            #6
            Re: Wee Rob - Bulkhead Hatches

            Stainless steel or epoxy or polysulfide may not be appropriate to traditional wooden boats either, but many of us use them ;-) I ask myself what is important: looks, other people's opinions, or watertight safety. A good watertight and quick-acting wooden hatch must be a fine thing, but I like the utility and dependability of plastic screw-in hatches, and I never looked back. Clear covers are good to keep an eye on potential leaks. I also used these ports on waterproof gear boxes.

            Here is an idea: make a wooden cover for the plastic cover. Fashion the wooden cover to cover the plastic flange too; clever people will pay attention to the required clearances. Don't forget to install finger-holes on the wooden cover. Then screw the wooden cover to the plastic cover, and squirt some 3M5200 on too (after scratching up the plastic), and tally ho! Everybody is happy. If you market this great idea I want my 15% cut. --Wade
            Last edited by wtarzia; 09-17-2009, 03:57 PM.

            Comment

            • Dennis Rioux
              Subordinate Constituent
              • Jan 2004
              • 61

              #7
              Re: Wee Rob - Bulkhead Hatches

              I did something similar to what Bob has done on my Penobscot 14 and MacGregor canoe. I used some foam on a recessed sill -- when the handle is tightened down (rubber washer seals the bolt hole through the hatch cover) the exterior surface of the hatch is flush with the bulkhead. Haven't had any problems with water getting inside on either one so far.





              Dennis

              Comment

              • bob easton
                Senior Member
                • Aug 2007
                • 161

                #8
                Re: Wee Rob - Bulkhead Hatches

                Originally posted by Scot L T
                Interesting. Is there a reason that the inner part of the hatch isn't more form fitting to the hole?
                Yes there is a reason. The assembly is rotated into place, sort of like a 1/4 turn latch. The hatch is inserted about 1/3 of a turn off of evel and then rotated until the innermost clamping bar lands on those two little blocks. The, the handle is turned to pull the clamping bar and compress the felt seal against the outside of the bulkhead.

                The round piece and the stops provide accurate positioning.

                A later post by Dennis Rioux shows a similar clamping mechanism, but positioning is more positively keyed by the squared shape, something we don't have with the oval.
                Bob
                Mill Creek 13 build log: http://www.bob-easton.com/blog/?cat=18
                Fiddlehead build log: http://www.bob-easton.com/blog/?cat=7

                Comment

                • Scot L T
                  Senior Member
                  • Jun 2009
                  • 148

                  #9
                  Re: Wee Rob - Bulkhead Hatches

                  Thanks Bob. I see how that works. I didn't realize it was all glued into one piece. Makes sense...I hate it when it all makes sense!

                  You guys are sure going to/do have some pretty boats there.
                  "Take good care of the earth, for it was not given to you by your Grandfathers but loaned to you by your Grandchildren."

                  Native American Saying.

                  Comment

                  • ByronB
                    Member
                    • Feb 2002
                    • 33

                    #10
                    Re: Wee Rob - Bulkhead Hatches

                    This is what I did on "Spartina". Seems to keep the water out after a capsize. The water pressure on the hatch tends to help seal it.

                    Used a 5mm round automotive rubber seal fitted into a groove around inside of cover.

                    This shows the backing piece attached to the bulkhead to provide a lip for the cover to seal against.

                    Comment

                    • Songololo
                      Senior Member
                      • Dec 2006
                      • 790

                      #11
                      Re: Wee Rob - Bulkhead Hatches

                      Progress ...

                      I eventually decided to go with a hatch design that uses a bayonet mount, similar to what one sees in lens mounts on many SLR cameras.

                      Here is the bulkhead seen from the cockpit side of the bulkhead:




                      Seen from (which will eventually be) the inside:



                      The hatch cover seen from the outside:



                      Seen from the inside:



                      A pic showing some detail of the the 4 plywood layers:


                      Last edited by Songololo; 03-07-2013, 11:12 AM.
                      "Smooth seas do not make skillful sailors". African Proverb

                      Comment

                      • Songololo
                        Senior Member
                        • Dec 2006
                        • 790

                        #12
                        Re: Wee Rob - Bulkhead Hatches

                        How it all fits together:




                        Some details:
                        • 4mm plywood
                        • Cut out using a simple circle jig and a Bosch palm router with a 2mm bit.

                        • The hatch cover consists of 4 layers:
                          • 1x Outer cover OD 220mm
                          • 2x Spacer discs OD 190mm
                          • 1x Lock disc OD1 210mm, OD2 190mm

                        • The hole also consists of 4 layers:
                          • 1x Bulkhead hole ID 220mm
                          • 2x Spacer rings ID 220mm, OD 250mm
                          • 1x Lock ring ID1 190mm, ID2 210mm, OD 250mm

                        • Seal to be provided by 15mm wide 4mm thick adhesive neoprene seal (comes in a roll) attached to the underside of the cover.
                        Last edited by Songololo; 03-07-2013, 11:12 AM.
                        "Smooth seas do not make skillful sailors". African Proverb

                        Comment

                        • paladin
                          Senior Senior Member
                          • Dec 2000
                          • 26476

                          #13
                          Re: Wee Rob - Bulkhead Hatches

                          Make them somewhat as above and use the compressible rubber seal designed for refrigerator doors. On my 27 footer I sed that system, and the deck hatches on the tri for stowage in the ama's and they were always dry.
                          Wakan Tanka Kici Un
                          ..a bad day sailing is a heckuva lot better than the best day at work.....
                          Fighting Illegal immigration since 1492....
                          Live your life so that whenever you lose, you're ahead."
                          "If you live life right, death is a joke as far as fear is concerned."

                          Comment

                          • Typhoon
                            Senior Member
                            • Jun 2003
                            • 142

                            #14
                            Re: Wee Rob - Bulkhead Hatches

                            I had a fibreglass naval launch once, it had simple fibreglass round covers like the plywood one shown above. They were tightened with a spanner and bolt, bolt screwing into a stainless steel bar that ran across the cut out horizontally and had simple gravity keepers (like an old barn door lock timber) to hold them in place.
                            Once they have water pressure behind them, they have increased sealing pressure on them, so they don't need much pressure to seal well initially.
                            So, I really like the simple plywood ones and on a small boat, you could just substitute a piece of aluminium bar or even some nice hardwood and a captive nut to secure the hatches. They could even be cut out of clear acrylic too.

                            Regards, Andrew.

                            Comment

                            • skuthorp
                              Senior Member
                              • Jan 2002
                              • 73594

                              #15
                              Re: Wee Rob - Bulkhead Hatches

                              Been sailing a Macgreggor for nearly 10 years now and it was built with ply and bungee hatches as plan. Found them not satisfactory as I seem to get quite a lot of water aboard sailing on rough days. I lengthened the cockpit about 14" aft to more easily accomodate two and fitted plastic screw hatches then. Not as attractive as wood but far more efficient.

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