HFJY34

  • 19 Apr 2021 09:48
    Reply # 10327674 on 10326788
    Deleted user
    Graeme wrote:

    I am interested in your chine runners. They look tiny to me. I put somewhat more substantial ones on my scow, horizontal fore-and-aft, at 45 degrees, so they do not follow the line of the chine, rather they run out at each end as dictated by the bottom planking - they came out looking quite different to yours. I have absolutely no idea if they will be a help or a hindrance, but keeping my fingers crossed they will do no harm at any rate. Mine are integrated with the bottom planking, so they are probably going to be permanent whatever the result! All I know is, they do work on the Paradox, I've seen it with my own eyes. I am not sure if the concept is transferable, however, so lets both keep our fingers crossed - yours at least will do little harm.


    On the subject of bilge runners, when building my little 6 m catamaran the design called for a dagger board, the case of which intruded quite considerably in the accommodation. I asked the designer for another non-intrusive option. He came back to me with a design for an inward angled bilge keel on the inside of each hull. These were very small, .9 m in length and about 95 mm depth at the forward end, and 60 mm at the aft end. I was a little bit skeptical about their effectiveness, but thought they were worth a try. They were very quick and easy to construct, and I have to say I am very pleasantly surprised at how well they work. The boat goes to windward just fine. The keels don't start working until the boat speed is at about 2 knots, but then any leeway disappears and my little catamaran goes to windward as well as any cruising boat I have owned. There is apparently a lot of science involved in the design of leeway prevention devices, and different devices are suitable for different hull shapes. Chine runners being suitable for flat bottom hulls, and the bilge keels I have fitted being suitable to single chine, v shaped hulls. I wonder whether such an unballested bilge keel which does not protrude below the bottom of the hull would be an option for the SibLim hull shape. From my perspective I have effective leeway preventers which are as simple as is possible, add almost no weight, and do not add to the draft of the hulls. After all my worrying about the construction of the dagger boards and cases, and their effect in the interior of the boat, I am now very pleased to have come up with such a simple and effective alternative. Image below


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    Last modified: 19 Apr 2021 10:10 | Deleted user
  • 19 Apr 2021 09:40
    Reply # 10327669 on 7155071

    Excellent work Frederick, I'm sure there are more people than you think here quietly watching you quietly beavering away! Please post as much as you can.

    I think the chine runners look great, possibly in a Less Is More way? Chris Morejohn and Sven Yrvind have possibly got more chine runner sea-miles experience than anyone else on the water so I suppose you have to trust their judgement. In that respect it's interesting to see Yrvind's latest Exlex canoe yawl will sport near vertical 20cm appendages which he is still calling chine runners but look more like bilge keels to me. He is also going with a bow centerboard. It might be interesting to have a separate thread to discuss Yrvind or chine runners and leave this thread to Frederick's progress. 

  • 19 Apr 2021 03:02
    Reply # 10326788 on 7155071
    Anonymous member (Administrator)

    Well done Frederick. Beavering away there quietly and making good progress. I should learn from you.

    I am interested in your chine runners. They look tiny to me. I put somewhat more substantial ones on my scow, horizontal fore-and-aft, at 45 degrees, so they do not follow the line of the chine, rather they run out at each end as dictated by the bottom planking - they came out looking quite different to yours. I have absolutely no idea if they will be a help or a hindrance, but keeping my fingers crossed they will do no harm at any rate. Mine are integrated with the bottom planking, so they are probably going to be permanent whatever the result! All I know is, they do work on the Paradox, I've seen it with my own eyes. I am not sure if the concept is transferable, however, so lets both keep our fingers crossed - yours at least will do little harm.

    Best wishes on your build, keep up the good progress and keep us all informed.

    Ignore the water line - she's currently floating in 7" (just immersing the chine runner), you can see where the coppercoat has turned muddy-blue. The draft will increase a bit later, of course, when topsides, internals, rig etc are in place. 5 or 6" more I expect - nothing like the line of the coppercoat indicates. I hope.

    The hole is for the internal off-centreboard pin, and leads only into the case. It will be bogged up later.

    The reason for the white paint is, the tops of the chine-runners were sheathed after the boat was turned over (I could not do that part upside down.) They are ferrocement sheathed, like the rest of the hull, and the white paint is water-borne epoxy resin as a water-curing membrane, and sealer. I hope I've got enough coppercoat left to do them. Its expensive stuff and I have some misgivings about using it over ferrocement, relying on a good primary layer of epoxy sealer to keep it isolated. Time will tell.

    Last modified: 19 Apr 2021 03:13 | Anonymous member (Administrator)
  • 18 Apr 2021 16:29
    Reply # 10325239 on 7155071

    Almost there..

    Dead lights & chine runners done. Skeg On the way and figuring out where the rubrails are going.

    Preparing for glass by the end of April I guess  




    6 files
  • 17 Mar 2021 03:54
    Reply # 10205216 on 7155071
    It looks like you are doing a great job.  Keep up the good work!


  • 14 Mar 2021 11:01
    Reply # 10194827 on 7155071

    All planked up. On to skeg, chine runners, stem cap, ports and rounding off edges. 

    So far so good..

    3 files
  • 10 Jan 2021 16:26
    Reply # 9822657 on 9742196
    Anonymous wrote:

    Great progress Frederik, I'm also watching very closely. Are you glueing the two layers of plywood together with (lots of) epoxy? I've wondered about using a PU (D4) glue for this, it's cheaper and gap filling and it's probably what the ply is made from but it may be impossible to work with big sheets of ply fast enough and it won't seal the ply as well as epoxy. Anyone else have thoughts on this?

    Also, I'm intrigued by Chris Morejohn successfully going against all advice I've ever seen (including his friend Reuel Parker) and using polyester resin over plywood. Any thoughts on this?



    I've used Collano Semparoc 60 between the layers of ply. In case you don't already know, it's a PU expanding, waterproof adhesive categorised as C4. As I understand it, C4 is probably more suitable than D4 as the C group are thermosets and the D group are thermoplasts.There is no problem time-wise with gluing up big sheets; the working time is perfectly adequate.


    Anyhow, so far, I'm happy with the results - it certainly seems to stick well!. Unfortunately the boat isn't in the water yet, so I can't tell you anything about long-term performance...

  • 09 Jan 2021 12:42
    Reply # 9776140 on 7155071



    Yes it’s coming along nicely and most of all it’s great fun to build a boat. I decided very early in the build to go with the way Chris Morejohn builds his plywood boats and that includes his method of glassing the hull with polyester resin. 3 layers of matt plus 1 layer of cloth. The whole boat is glued and scewed together with 2:1 epoxy and stainless steel 5 mm screws. The screws stay in. His boat is in great shape after 20 odd years of heavy use. 

    Now as for doing it alone, yes, most of it is no problem. The design is doable for a first-timer like me and when it gets to gluing the large sheets I call on friends that help me out. I also have a boatbuilder friend that has helped me out with the beveling of the bottom and some other stuff that I didn’t want to tackle by myself with my limited skills. Another great help is Chris himself who takes his time to  answer all my silly questions.

    Its been great to be able to build at home in the temporary but  bulletproof shed. These cold winter days I can continue the work When glueing large areas I turn on an external heat canon and raise the temperature to what’s needed. 


    So. The second layer of ply (first inside layer 10 mm sapele marine ply, second layer 12 mm fir) on and finished beveling the chine yesterday. 

    On to the bottom..  

    4 files
    Last modified: 10 Jan 2021 14:31 | Anonymous member
  • 07 Jan 2021 23:57
    Reply # 9753043 on 9742196
    Deleted user
    Jan wrote:

    Great progress Frederik, I'm also watching very closely. Are you glueing the two layers of plywood together with (lots of) epoxy? I've wondered about using a PU (D4) glue for this, it's cheaper and gap filling and it's probably what the ply is made from but it may be impossible to work with big sheets of ply fast enough and it won't seal the ply as well as epoxy. Anyone else have thoughts on this?

    Also, I'm intrigued by Chris Morejohn successfully going against all advice I've ever seen (including his friend Reuel Parker) and using polyester resin over plywood. Any thoughts on this?

    I once owned  Searunner trimaran in which I cruised the Pacific. It was built just before the use of epoxy became a widespread. It was sheathed using polyester resin. It held up very well although I noticed that when removing fittings, such as windows for renewal, that the fiberglass sheathing would peel away from the underlying plywood very easily.  I also think it did not provide a fully waterproof barrier based on the degradation of fastenings under the sheathing. Usually the reason for using polyester resin would be for cost saving, but when building a large boat the epoxy resin would normally be purchased in bulk at a discounted price, so I think there would need to be a significant cost saving to justify using the polyester. I also personally find the fumes from polyester resin to be significantly worse than those from epoxy.
  • 07 Jan 2021 11:57
    Reply # 9742196 on 7155071

    Great progress Frederik, I'm also watching very closely. Are you glueing the two layers of plywood together with (lots of) epoxy? I've wondered about using a PU (D4) glue for this, it's cheaper and gap filling and it's probably what the ply is made from but it may be impossible to work with big sheets of ply fast enough and it won't seal the ply as well as epoxy. Anyone else have thoughts on this?

    Also, I'm intrigued by Chris Morejohn successfully going against all advice I've ever seen (including his friend Reuel Parker) and using polyester resin over plywood. Any thoughts on this?

       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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