CLC Shearwater 14 build

Discussion in 'Boat and Accessory Building' started by KathyD, Dec 1, 2009.

  1. KathyD

    KathyD Paddler

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    Hi Roy, I've read posts on the kayakforum and CLC builder's forum of others who have tried the superglue bungee technique and report that they have no problems 4-5 years later, and Joe reports no failures either. One issue is that you would need to replace the entire shock cord when you re-varnish since you can't untie and re-tie them, but I'm hoping with the WR-LPU varnish it will be several years before I get to that point, and by then I'll probably want to replace the bungees anyway.
     
  2. KathyD

    KathyD Paddler

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    Here’s a post on making the Moby hatch hold downs. I wanted some kind of non-visible, under-deck hatch hold down, and looked at many different options (rare earth magnets – which I would have done except the hatch rims in the kit were not wide enough; under-deck bungees, and Mobies). I decided to see how the Mobies would work. They were definitely harder to construct than simple under-deck bungees with hooks. I found instructions from other builders on the following links:

    http://pawistik.blogspot.com/2009/0...6TOiR7fogpKcoNaAdhjOT5bo#c6910734348302585341

    http://www.kayakforum.com/cgi-bin/B...j/strip-night-heron-finally-on-the-water-pic/


    Here’s the basic pieces I used for each latch (4 latches per hatch):
    Wood
    1 latch (hook-shaped piece)
    2 hold downs (whale-shaped pieces)
    Hardware (I used stainless steel in the following sizes)
    1 #10 x 1 ¾” long pan head bolt
    1 #10 lock nut to fit bolt
    4 #10 washers (between all wood/bolt/nut pieces)
    1 #10 x ¾ inch aluminum spacers – these were hammered through the holes in each latch to prevent the wood from wearing at the pivot point.




    I cut out the many pieces using my Dad’s scroll saw. I used ¾ inch plywood that I had for the latches and ¼ inch plywood leftover from the bulkhead blank for the hold downs. Other builders have suggested using these thicknesses because thinner stock will break. I drilled holes for the bolt assembly through the stack of hold down-latch-hold down for each of the 8 Mobies, and another hole perpendicular to the bolt hole through the neck of each latch to thread a bungee cord. Here are all the little pieces I cut out, then sanded, stained, and with several coats of WR-LPU, including coating inside the drilled holes.



    I assembled all 8 of the Mobies, then epoxied the bottom of the hold-downs to the underside of the hatches. Also shown in the photo are the bottom of the pad-eye (used for a handle on the top of the hatch) and the drilled and cut-in-half teak plug that I epoxied on so I could thread a hatch retaining cord through it to attach the hatch to the boat (the other half of the teak plug is epoxied to the underside of the deck in front of the hatch opening).



    Then I took bungee cord, threaded it through the holes in the Moby latches, put on a washer (to spread out the force over the hole) tied a knot, and threaded the other end through the opposite Moby latch. I found that a clamp was useful for holding the second end of the bungee under tension once I had the first side tied down. Then I could easily tie a know in the second side and release the clamp.



    Here’s the hatch latched down. Note that the weather stripping supplied with the kit for the hatch seal is WAY too thick and will not allow the hatch to be flush with the deck – I could not compress it even putting all my weight on it. Today I got some neoprene and I will make thinner hatch seals.


    Hopefully this post will show up OK - there's a new way to post photos and URLs and I'm not sure I did it correctly.
     

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  3. Astoriadave

    Astoriadave Paddler

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    Looks beautiful, Kathy. Not seen those before. They look to be more fail safe than the other hidden systems I know about. For these, if the hatch gets popped, the restoring force increases as the hatch is forced open. The rare earth magnet system is the reverse -- if the hatch is ever forced slightly open, the restoring force at the compromised part rapidly goes to zero, so that the whole hatch might come free.

    Forces on a boat in surf can be horrendous.

    Those Mobies are kinda cool. Named after Moby Dick? The levers look sort of whale like in profile.
     
  4. mick_allen

    mick_allen Paddler & Moderator

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    well maybe, but to me it looks like the actual restoring force is about 1/3 for the same bungee tension in a direct system. The lever arms are backwards. It looks like it'll work, but comparatively more tension will be needed.
     
  5. Astoriadave

    Astoriadave Paddler

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    I noticed that, also. If it were me, I'd go with a larger diameter bungie and tension it more.

    Kathy, do you have a feel for how much force each one of those levers exerts on compression? Too bad you don't have a strain gauge around. Should be some sort of clever little compressive force-sensing pucks available for stuff like that. Perfect for a piezoelectric-based sensor. I bet they have deals like that in the physics lab at the local college.
     
  6. KathyD

    KathyD Paddler

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    I think I could use a hanging fish scale to measure how much lift force it takes to pull the hatch off (hook it onto the hatch handle and pull, measure how many pounds of pull it requires just before releasing).

    I did try using thicker diameter bungee at first, but I had a hard time trying to get it through the holes in the latches. I realize that I was trying to push them through, which compressed the bungees and made them even harder to get through. Perhaps if I decide it's too easy to pull the hatches off I could rig up some way to pull the thicker bungee through the hole instead of pushing (maybe thread a wire through the end of the bungee, pull it trough the hole - like pulling elastic through a casing). I'll give it some thought and see how easy it is to pull the hatches off with the existing bungees.

    I don't plan to do any surfing (looks WAY too scary), just paddling on lakes and relatively calm seas. How many pounds of lift force do you think would be good for the hatches? Anybody have any ideas or measurements on their hatches?

    Kathy
     
  7. mick_allen

    mick_allen Paddler & Moderator

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    How does one release those hatches? Just slide the lid to the side so that the hooks come free? . . .
    Would that be a safety issue if one were sliding/scrambling over the hatch area in a self or assisted rescue situation? Would the hatch come free?

    sorry to be such a jerk about this, you really have done some beautiful work putting this mechanism together.
     
  8. KathyD

    KathyD Paddler

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    Hi Mick,

    Great questions. To open the hatches, you pull up on the handle, then reach under the hatch cover and push the two Moby latches on one side down (into the boat) enough so that you can pull that side of the hatch up (the Moby latches at this point snap back onto the hatch cover. Then pull on the hatch and the other side comes off. With the hatch closed, it does not slide back and forth at all, so I don't think it would be a safety issue from that standpoint. Here's a photo of me pulling up on the handle - and pushing the latch down (you really need 2 hands, one for each latch, but I had to hold the camera with one hand!)



    Also, I used my hanging fish scale to measure the force (pounds of pull) required to open the hatches by hooking it on the handle and pulling slowly. It was pretty interesting. On the back hatch, it started opening at 6 lbs of pull, then dropped to 5 lbs of pull when the hatch was open about an inch, then went back up to at least 20 pounds of pull as I continued to try to pull it open. I stopped at 20 because I didn't really want the latch to go slamming down on the underside of the hatch cover if it did pop off. Similar results on the front hatch, but I stopped at 15 pounds of pull - probably I could tighten the bungee more on the front. You guys are right that as you try to open the hatch it requires more and more force to pop it off.
     

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  9. Astoriadave

    Astoriadave Paddler

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    Kathy,

    Those Moby hooks look good.

    I think the critical number is the force early on -- and 5-6 pounds sounds OK to me. It is hard to imagine how you would get a sustained outward force that high without some major snagging, and I don't see that happening with the low profile of the pull you have. Just a piece of webbing, isn't it?

    Once the hatch is gaping as shown in the photo, water would be pouring in, but 15-20 lbs is way in excess of what could happen, I think.

    On stringing bungee: yeah, I have used a hooked piece of wire (once, a crochet hook!) to lead it places. Also, on short runs (less than an inch), I have reached through and grabbed it with a hemostat and pulled it through. You can also use a razor blade to cut the end on an angle after hitting it with super glue so the end does not unravel, and then it will go through more easily. Kinda perverse the way it is fatter in non-use and skinnier in use.
     
  10. Roy222

    Roy222 Paddler

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    An easy way to sting a bungee: secure the end in a vise, pull the bungee as hard as you can with one hand, wrap tape around the necked down cord. The release the pressure and cut the cord thru the tape. If you want to do more work use heavy duty nylon thread. A 1/4 bungee will neck down to almost 3/16. Almost any tape will work. If you are using a real rubber bungee (like CLC sells), the rubber can't be melted. Tape, cord or a knot will seal the ends.
    Roy
     
  11. Rrdstarr

    Rrdstarr Paddler

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    Wow! Kathy those hatch latches are super nice! Next boat I will try making them! You have done some real nice work in making the boat just for you!
     
  12. KathyD

    KathyD Paddler

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    Here are some photos of the knotless bungee connections that Joe at Redfish Kayaks uses. I am probably not doing it exactly the same as Joe does, but it seemed to work OK. The link to his description of the process is here:
    http://www.kayakforum.com/cgi-bin/Building/Archive50.pl/noframes/read/54933
    Note: I tried this process with the ¼ inch bungee supplied with the CLC kit and had all kinds of problems with the super glue not working on it for some reason. I thought I must be doing something wrong, so I e-mailed Joe and he nicely volunteered to send me some of the bungee cord he uses when he mailed me my custom Redfish seat (more on that later). The bungees he sent worked great, so if you try this and are having problems with the casing, get some bungee cord from Joe. I also found a bottle of super glue with a brush inside; this worked really well for painting the surfaces of the bungees. Joe says not to use the gel kind of super glue.

    The first step is to stretch the end of a bungee to decrease its diameter, and paint a few inches of the casing with super glue to keep it in the thinner diameter. Let dry. I used a scrap of plywood and clamps to hold the bungees in a stretched position while painting with the glue and while the super glue dried (see, there is another use for all those clamps you accumulate!). It takes quite a while to get really hard if you saturate the casing – this is where the clamp was handy, I could go do something else while it dried.



    Here’s a photo of the un-clamped bungee showing the thinner diameter section.



    After it is really dry, cut the bungee in the middle of the thinner, glued part. I noticed that when I did this, the rubber pulled back, leaving a bit of a hollow tube of casing on the end. Since in a later step you will be gluing this end, and a flat surface works best (super glue does not fill voids well), I trimmed the edges of the casing a little with a scissors to make it as flat as possible. Now thread the bungee through whatever places you want, pull it tight, and cut the other (un-thinned) end about one inch longer than you want the final bungee. At this point I clamped both ends of the bungee to my piece of plywood so that I could work on the ends in an un-tensioned state. Roll back the casing on the un-thinned end of the bungee cord about ¾ inch. The casing starts to unravel at the ends, but it will be OK.



    Cut the protruding elastic back so just a little bit is extending beyond the casing (do not cut the casing). Try to make this cut as flat as possible. Here’s the cut piece with the casing rolled back. Sorry it's a little hard to see because of the white paper towel.



    Now, apply a good amount of super glue to both ends of the bungee cord, put together, and hold in place until set (about 30-60 seconds). Be careful not to get the glue on the rolled-back casing.

    Bungee 5

    After the ends of the cord are set enough that they stay together, paint the outside of the thinned end of the cord with super glue and roll the casing so that it overlaps the thinned end. YOU WILL WANT TO BE WEARING DISPOSABLE GLOVES for this step because you will get superglue on your fingers. This step takes a little practice. I found that if I started pulling the fraying ends of the casing back toward the thinned end and, at the same time, smoothed the casing from the back it worked best. That’s why you get super glue on your fingers (that are fortunately inside the gloves). I then saturated the outside of the casing with super glue just in case. I did not saturate the fraying ends of the casing, but later trimmed them off and used a lighter to melt them just a little (note that you should wait until the glue is really dry to use the lighter because the super glue is pretty flammable – don’t ask me how I know this). It’s also a good idea to let this whole thing harden for a good long time because otherwise if, for example, you slide it under one of your padeyes to hide it, it can stick to the nylon strapping. Don’t ask me how I know this either! Here’s a photo of the finished attachment. I think Joe and others have described using heat-shrink plastic tubing over this for aesthetic purposes (it is a little rough), but I didn’t have any so I just worked it around so it was hidden inside one of the padeye straps.
     

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  13. KathyD

    KathyD Paddler

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    Here are photos of it all finished! I ordered one of the Redfish custom seats - expensive, but really nice workmanship, and it fits great, with integrated hip braces. I installed the SeaDog foot braces (they looked super easy to adjust from the cockpit), used some neoprene to make thinner hatch seals so the hatch lids sat flush (we will see if these need further modifications to limit leaking after it gets wet), and installed a perimeter line in the back and a combination perimeter line/tow rope in the front. This front piece of rigging I copied from a friend's PWS Osprey that I used for a summer and really liked. One end of the line is tied to the front carry toggle line. Then the line runs back to loop around a small cleat on the port side of the boat in front of the cockpit, back forward and through the carry loop, and then back to hook around a small cleat on the starboard side of the boat in front of the cockpit. To use as a tow line (or when landing the boat and you want to tie it off to something), you just unhook the loop on the starboard cleat, and it becomes a tow line. I realize that the small cleats could catch on things when you're doing a wet re-entry, but I never found this to be a problem on my friend's boat. The cleats are pretty far forward of where you are actually climbing into the cockpit, so you'd have to be flailing around pretty good in the wrong place to get hooked on them.







    The weather has FINALLY improved enough that I think we'll try a test paddle tomorrow! I'm excited. It was a fun project. I might try a paddle next since I don't think my husband wants me to do another boat - although I did get 100 pieces of nice 18-foot long bead and cove cedar on Craigslist for $50 the other week. Just in case!
     

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  14. Greg

    Greg Paddler

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    Wow Kathy, that kayak is beautiful. I really like that satin finish on it. It seems to make it look more usable than a super shiny hull, even though they look beautiful too they get banged up pretty quick and I think your finish may hide more of the occasional dings that come with use.

    I’m thinking of building a Pygmy Coho in the near future and I’d really like to use that hatch securing method you used. It really makes the hatches look clean.

    Also, it may have cost a few bucks more but that Redfish seat probably saved you a lot of time carving your own or settling on a cheap substitute of some sort that you would change out eventually anyways, so good choice.

    You’re really going to get a lot of attention from that looker.
    Nice job,
    Greg
     
  15. Tootsall

    Tootsall Paddler

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    Ditto what Greg said, Kathy. I have a Coho kit "on it's way" and I think I'll try that hatch closure also...looks "beaut"! (very "sanitary").
     
  16. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    Very, very nice looking boat, Kathy. Well done!

    *****
     
  17. sushiy

    sushiy Paddler

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    KathyD, congratulations! Nice boat and looks like a fun boat!
    One Q. though.
    What is the advantage of using those cleats for the safty line? I am very curiouse.
     
  18. KathyD

    KathyD Paddler

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    Sushiy, The only reason I used the cleats is because I wanted to be able to run the forward deck line the way I did, and to do that you need to have something to hook the line around so you can release it quickly from the cockpit if needed, either to be towed or to tie off on shore. I couldn't route the line through a padeye since it wasn't a hook, so I used a small cleat since that seemed to work well on the boat I had used previously. You could use some other kind of hook, but a cleat could be useful in case I ever run into a situation where I need to attach a temporary line to the boat, or an anchor or something I suppose.

    As I was drilling the holes to bolt on the cleats, I realized that I could turn them into a padeye in the future if the cleats didn't work out by just enlarging the space between the two bolt holes, so I figured I'd give it a try.

    Thanks again for all the help from everyone on the site!
    Kathy
     
  19. Whidbey

    Whidbey Paddler

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    So you're the one who got them! I thought that was a good deal too. :)

    James
     
  20. KathyD

    KathyD Paddler

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    It floats!

    The weather finally got nice and we had a successful launch yesterday. Smiles and fun all around.
     

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