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  • 04 May 2021 20:39
    Reply # 10441895 on 10439586
    Anonymous wrote:

    And please, don't allow anyone to persuade you to launch before the boat is finished.  I can't remember how many times I have heard people say " a boat is never finished".

    This made me think. First I am thinking of launching before finishing in my case but my case is different. I have a boat that lives on a trailer and will never live on it (22foot). This year it will go in the water with no mast but with three bunks and a cooker so we can go camping. We have in the past filled our 16foot boat with camping gear and set up camp on a nearby island. This year we hope to not have to set up as much. after two weeks it is back on the trailer in the back yard for step two.

    However, for a home, finish first then launch will: give reason to keep working  and pushing to get finished. Allow work to continue without having to clean up for lunch, supper and sleeping. Finishing in the water means moving house to one end of the boat to work on the other and then moving house again when finished... maybe more than twice the work. So choose the yard wisely and finish before launch. Working on a boat you are also living in or even a boat that is on the water will be one big delay and merely add more truth to the "a boat is never finished" saying.

    This boat is a try out for my family, mostly my wife. We will find out if  we will continue to camp in a small boat for a few weeks in the summer, go back to land camping or go for a bigger boat for longer trips.

  • 04 May 2021 13:43
    Reply # 10440467 on 7155071

    Thanks Annie. 

    As far as systems goes, we are on the same frequency. ( guess where I got some of my inspiration from..). 

    Concerning finish I’m quite easily satisfied s long as it looks good to my eye. 

    Anyways, couple more years to go. 

  • 04 May 2021 08:10
    Reply # 10439586 on 7155071

    Well done.  The rest will take as long as it takes and will largely depend upon whether you are happy with a simple plywood interior or want something with more texture.

    Systems: if a boat has systems it's too complicated.  Installing my water tanks took the time that was required to buy the jerricans and stow them under the cabin sole.  Likewise the engine installation was asking a friend to lift it up for me while I secured it to the transom.  Oh! And I had to attach the petrol line.

    And please, don't allow anyone to persuade you to launch before the boat is finished.  I can't remember how many times I have heard people say " a boat is never finished".  Well FanShi is.  Some details yet to do, but if you think a lack of loose covers on the settee and toggles to keep the portholes open, make a liar out of me, then you are even more literal than I am!

  • 01 May 2021 17:05
    Reply # 10421026 on 7155071


    Last modified: 01 May 2021 17:06 | Anonymous member
  • 01 May 2021 15:41
    Reply # 10420612 on 7155071

    Baie baie dankie Oom Arp & good luck with the new rig for your boat. 

  • 01 May 2021 14:16
    Reply # 10420212 on 7155071

    Great progress.

    By your original budget you are 1/3 of the hours done and 32 to go.

    From South Africa I wish you voorspoed en genot.

  • 30 Apr 2021 21:54
    Reply # 10414885 on 7155071

    16 months later hull construction done.

    One good thing about not previously having built a boat, is not knowing what you’re in for..

    10 files
    Last modified: 30 Apr 2021 21:57 | Anonymous member
  • 19 Apr 2021 23:57
    Reply # 10329658 on 7155071

    Thanks Frederik for the further information about your chine runners – and to David Th for further interesting comments – especially for the photo of that unusual appendage on your new catamaran. The proof of the pudding is in the eating.  Your prior experience with catamarans will give you a pretty good idea of whether or not the appendage is earning its keep. You must be feeling very pleased with the result.

    I don’t think Mark is entirely correct.

    Here is the GPS track of a paradox sailing to windward.

    (For full details, click here.)

    This is not what you would expect for a flat bottom boat with no keel, skeg, leeboard etc and I think we can say that the chine runners are contributing something here (along with the hull shape and chine itself, and the large rudder). A certain amount of dinghy experience (we have all tried sailing with the centreboard up!) leads us fairly easily to this conclusion, without the need for controlled trials.

    This is not to say that the chine runner is the sole factor, or that this device can be transferred successfully to a different flat bottom hull. (Leydon himself makes no such claim, and actually suggests the contrary). In fact we have a counter-example: Dave Zieger put a substantial chine runner on his Trilobyte 16 and found that, to cut a long story short, it didn’t work.

    In my build, I am not expecting a similar gps track to windward as we see above. My hope is only that with the deeper immersion of a heavy flat bottom hull, with considerable rocker (both being characteristics of the Paradox) that I may be able to get some benefit from the chine runners if forced into very shallow water. This seems to be very much in line with the expectations and hopes of the designer of Erik’s boat. In both cases I think it is something of an experiment, and in both cases off-centreboards are still present as a primary provider of lateral resistance.

    If I can get a gps track such as the one above - with boards up - I will be very pleasantly surprised. You will be able to read about it here first!

    (The other factor in the decision is that my boat has off-centreboards built into the two sides of the hull, and the chine runner performs a secondary, structural  role of bolstering the outside of the off-centreboard case). 

    Anyway, back to Erik’s build, and chine runners. I did not mean to suggest they are too small – simply remarking on them with great interest. I will be most interested in your impressions, after the boat is launched, and I think you will have a fair idea if the chine runners are contributing some benefit.

    How much benefit (in the form of lateral resistance) is due to the chine runners themselves – that is a question that would require a bit more experimentation, and in that respect I think Mark is right.

    Addition: Bilge-runner Application to the 5-plank

    Following David Th's post here, regarding his bilge-runners: I have just been having another look at Arne's and David's 5-plank designs. There is certainly plenty of scope for a decent-sized bilge-runner on these midship sections, without any increase in draft. Maybe the extra drag would spoil the rowing a little?

    I don't know, it might be worth a try, and David Th might be on to something. I'd rather try it out on a dinghy than a full-size SIBLIM and it wouldn't surprise me if it worked. 

    Would something like this be worth a try?

    I've popped the same question onto the dinghy-design-competition thread.

    Last modified: 20 Apr 2021 05:31 | Anonymous member
  • 19 Apr 2021 21:15
    Reply # 10329323 on 10327894
    Mark wrote:

    But had you tried it without beforehand?  If not you cannot tell if the runners help or hinder. 

    You are of course entirely correct, with no control how can we know the effectiveness of an alternative leeeway preventing device. However I am not about to cut the keels off and try sailing the boat without them, just to see what happens. But based on my many decades of sailing and cruising experience I am very confident that without those little keels there is nothing to stop the boat going sideways when trying to go to windward.

    The whole point though is that as with the junk rig as an alternative to the more complex and expensive bermudan rig, it is good to know that there are other simple alternatives out there in other areas of boat design, such as the hull, and leeway prevention. The chine runners have been well proven on the little flat bottom Paradox designs, and for a boat such as the SibLim design wouldn't it be good if there was an alternative leeway device which more simple than the complex construction of either a conventional keel, or the retractable bilge boards such as Annie built.  

    Anyway given that this thread is about the construction of Fredericks boat, it is great to see him making such rapid progress on his build. It is also good to see another purpose designed and built junk rig yacht under construction. We have had Annie's recent launch, Frederick with his build, Kris with the construction of his 6 meter junk scow cruising yacht, and Graeme is making progress on his junk rig scow. Whereas most junk rigs are retrofitted to previously bermudan rigged boats, these four new junk rig yachts have stepped away from convention not just in the area of rig, but also in hull design and cruising interior layout. Annie's boat, designed by David Tyler is a truly unique eight meter cruising yacht. It will also be good to see the completion of the other 3 boats as I am sure that each of them will also be a unique and effective cruising yacht.

  • 19 Apr 2021 12:01
    Reply # 10327894 on 10327674

    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

    But had you tried it without beforehand?  If not you cannot tell if the runners help or hinder. 
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