K800

I will have to make two models to answer a question. If I stretch the design from front to back by roughly 10% will I see an increase in performance because the ratio of length to width changed? I like my new question!!! LOL! How far could I theoretically stretch a design from stem to stern and still have it handle decently?

That would make the model go from 30cm to 33cm right? so the beam to length ratio would be 10:33 right? Where the original design would be 10:30 beam to length. or maybe it could be written 1:3 vs 1:3.3 ? idk how boat guys do it for sure.

 

Now that I think about it, it's positive stability will decrease, but the reserve stability will increase so probably, that mixed with sail forces probably means a drop in close hauled performance.

If I finish it the way it is, I just sharpen and lengthen the bow from frame "F" forward 5mm it should not make much difference on a pond yacht, but the mast might need to come forward 2.5mm right?

 

I hope you guys don't mind me using this as a blog. It helps me a little.

So, today I did some calculations. I decided that stretching the boat is actually kinda nice and I think it will be fine at 10% stretch in length. I came up with a number for keel box weight of 1.2 kg, but have not decided the weight of the actual keel itself.

 

PolySeamSeal...

I just remembered an alternative to the nasty car dent filler I was going to use, but I might only use it on the frame inside. What I've done is taken a water based caulk and watered it down into a paint. I can put it on thick, or I can leave it thin depending on what I want. I coated the wood and paper with a coat of really thin polyseamseal so that it soaked into the material. I can sand it down and paint it with a second coat if I need to. I like that it is paint-able and sand-able and water based so I can thin it to any thickness I want and it will still dry completely all the way through.

On a real boat I would like to use paint and caulking that is good for use under the waterline, but for a toy that won't have condensation or sit continually in water it should be fine. =0)


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I also added support in a slightly soft spot on the hull. I will take pics of it later, but I didn't do it the best way possible I suppose... Anyways, I like the results so far, watering it down has caused it to dry in half the time when spread out thinly, and it hardens into a stiff chalky layer making the frame even stiffer and stronger.

 

Wait, was I just talking to the original designer?!? Sorry!! Your drawings are great Alik! I was just thrown off by not having an "o" frame when there are an N frame, and a P frame. I'm OCD so that kind of thing throws me off and makes me frustrated and I should stop working when that happens because when something isn't working right like only using 1208mm for the width, when it is 2416mm so I'm wondering why the length is showing up in my spread sheet as 660mm which is more than 2 ft, but the rest of the model is 1 ft and should be 30mm. When stuff like that happens I get stupid and start foaming at the mouth not realizing that I'm simply dividing by 120 instead of 240 because the numbers came out right in my head, but the full size width was twice what I was trying to be calculating.

 

Went to the neighbors and ordered pizza while waiting two hours for it to dry to the touch so I can make the next frame and build it. but I left it too close to the window and it stayed too cold to dry. Luckily, I stuck it over the furnace vent and with a little propane heat it dried right up in about 3 minutes. =0)

I think that actually making the top removable will be more of a challenge than I originally hoped. My plan I made in blander overlaps and does not work. Stupid blender does not show you if parts overlap, so I had to ditch the original plan. Now I'm just going to have to wing it.

Edit:: The frame is now so stiff I cannot move it with trying to crush it with my hand wrapped around it.

 

I can't type Russian into my computer and this is what it looks like. What does this mean?


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"building jig _ plane"
base surface of building jig you measure all distances off when building.

 

By the way, if you intend to put your model in the water, paper of almost any kind is very poor choice. No matter how well sealed, some pinhole leaks will remain and create really large swell-ups, which will be difficult to dry out.
In any case make realy large openings in all the bulkheads, so you can open all the internal spaces for drying/ventilation.
No way make the hull sealed -air trapped inside, when cooled, will suck in (damp) air and /or water trough any pinhole, or will create one for the purpose.
In Soviet Union there was a kind of impregnated cardboard, used for electro-technical purposes, strong, stiff and factory impregnated. I do not know if it was manufactured anywhere else.
My latest cardboard model for use in water is the last one I did build from cardboard for this purpose. Economy on initial stages of building in more than offset with efforts for extra careful sealing, strength and water-related problems.

 

Actually I see no point to build model; 99% of those who start with a model never end up with real boat.

 

Thanks for the advice. I'm really not happy with my model like I was a few days ago. I think I need to go spend money in a hobby store in order to make a really good model.

Oh well, It has been a real learning experience. I'm going to have to wait till I can get a ride to the hobby place so I can buy more wood and do it the right way.

I folded my paper template for my frame "H" in the wrong place. That means it was about 2mm too wide and I broke the wood trying to glue the wood to frame "J" so now I am ticked off at myself. The model is close enough to accurate that I think I might want to just cover it with fabric once I get the last frame as well as the transom and see if it actually floats.

I guess I can replace the paper with wood, except for the very front where it is mostly glue. I have foam I can cut and sand into shape, but that to me is cheating. Actually I like it now that I have cut the bulkheads out.


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The reason I'm building a model is because I can build a model and I can't build a real one no matter how much I want to. I even figured out a good weight for the thing around the keel for a real one. approximately 661lbs or 300kg as far as I can figure out, but I am NOT a pro so, don't use that if you are building one yourself, and this one is stretched in length 10% so a normal one would maybe be a little different. So, when I divide 300kg by 240 I get 1.2kg, or a little over 2 lbs which is more than I thought it would need.

How do I calculate the extra distance when I want to know the right weight for the centerboard itself? I want to add some length too since it will be a pond yacht. I might even start making RC yachts and see if I can't trade two for a nice fat big 1 or 2 meter RC. (I have a big pond in my yard.)

 

Oh, while making the model I discovered a slightly weak spot in the deck where it transitions from flat to angled like in the picture. It is probably fine once stitched and glued, but it is still the weakest point. Yeah, I know, there will always be a weakest point, but I thought I should show you. I never would have thought it would be weak looking at the plans, but I'm just thinking it is a bad spot to be weak because the force of slamming the bow into a wave that is breaking over it could cause it to crumple and crack since the prow sees upward force, while the deck sees a downward force.



I really don't want you to take this the wrong way!!! I want to help you because you have designed a very beautiful boat and everyone I have shown the pictures to thinks so too. I imagine that it is probably pretty fast and efficient for a mono-hull too. =0)



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EDIT:: Now that I look at it, maybe it is an illusion... I don't really know. If 116 and 112 were were one piece and straight it would probably solve it =0) I don't know how it would go together for sure though.

 

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Well, some very successful performance sailboat designers built and sailed RC models following that up with successful boats:
1) Bill Burns, CBTFco> numerous successful boats
2) Greg Ketterman > Long Shot, Hobie trifoiler
3) Dr. Sam Bradfield > 40' hydrofoil SKAT
4) Yves Parlier > 60' stepped planing hull cat
5) Paul Larsen > speed record contender
6) Hugh Welbourn> numerous full size DSS equiped boats,
7) Alain Thebault> Hydroptere, the fastest sailboat in the world.
Every one of these guys started with an RC model to prove their technology and went forward with one or more full size boats-and this is only a small list..

Pictures-L to R: 1) Model of Parliers stepped planing cat,2) model of Hydroptere with Alain Thebault, 3) Hydroptere full size, 4) model of Sailrocket with Paul Larsen,
5) model used to test Bradfield's SKAT concept, 6) Parliers fullsize stepped planing cat, 7) Paul Larsens full size Sailrocket, 8) Bradfields 40' Skat.

 

Yes, we build RC models also, when we need - see
http://albertnazarov.blog.ru/114050851.html
http://albertnazarov.blog.ru/99712499.html
http://albertnazarov.blog.ru/90375187.html
etc. etc.

But what is the point to make model for EXISTING DESIGN? There is nothing to test there, there is nothing innovative! Scale of model TS is making is not suitable for testing. And also K800's are built and tested - real boats. So, from my experience, amateur boatbuilders starting from a model almost never build real boat.

 

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You're 100% right,of course: it's got to be the right model!