Yrvind

[Angélique]

Originally Posted by GTO

There seems to be only two ways the chine runners can work: thru a high drag vortex or creating a wing-like effect with the bottom of the boat as Matt Layden suggests. So I guess it's possible Yrvind simply got the bottom/runner design wrong.

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(cilck pics to enlarge)

^ June 25, 2008: DOING THE OUTSIDE

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(cilck pics to enlarge)

^ January 11, 2011: LIGHTNING CONDUCTOR (shows the shoe + bottom pic)

- March 24, 2009: THE BRONZE KEEL - - - November 23, 2010: THE BRONZE SHOE

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(cilck pics to enlarge)

Last 3 pics come from July 10, 2008: MATT LAYDENS CHINERUNNERS BASED ON SWAMP THING, PARADOX & ENIGMA, ETC.


Note the sharp cornered chines and the flat bottom of the 'Paradox'.

Sven has rounded the edges of the chines on his foam core boat, Matt's designs are in plywood with sharp cornered chines, maybe that's necesary to get effect from the chine runners . . ? ?

And Sven's bottom isn't really flat, especially since the bronze keel shoe is fitted, maybe a flat bottom is also necesary to get the chine runners working as on Matt's boats . . ? ?

Cheers,
Angel

[Angélique]

Originally Posted by GTO

There seems to be only two ways the chine runners can work: thru a high drag vortex or creating a wing-like effect with the bottom of the boat as Matt Layden suggests. So I guess it's possible Yrvind simply got the bottom/runner design wrong.

I've extended above post and added pics to illustrate. Could the difference in chine form (rounded edges v.s. sharp cornered) and/or the differences in the bottom form (keel shoe v.s. flat) have a bad influence on the working of the chine runners on Yrvind's boat v.s. the Paradox . . ? ?

Cheers,
Angel

[GTO]

In whatever article I read about Matt's comments on the chine runner design, he did state that he felt that the runners worked because of the blending of the runners, bottom, and hull side. Creating an effect similar to a lifting body design for aircraft. Lifting_body

Although it's possible that Yrvind just didn't get it right, I can't see the runners working that well in rougher water when attached to a light weight, shallow draft boat.

It would be nice if the keel-smart folks on this forum would weigh in on the potential of the chine runners.

Thanks for the photos and links Angel. Interesting reading.

[Manie B]

What we have to keep in mind is that these chine runners are working like bilge keels when the boat is heeled.
A completely flat and straight chine runner will act like a long thin narrow leeboard. As soon as you add shape to it it becomes a foil. What Sven has, is a very poorly designed asymetrical foil. Add that to the fact that the under water body of the heeled hull is also very asymetrical and the one cancels the other.
Teach yourself Freeship or Delftship. Now when you have drawn your dream hull you can turn it any way you like in 3D. This will help you to "see" what the underbody of the heeled hull could look like.
If Sven had flat straight planks attached to the sides at approx 45 deg. he would have been far better off.
What they are doing now is what we call "polishing the turd"
Keep in mind that if the flat bottom is that important to you for beaching, this would mean that your straight and flat chine runners on the side would be less effective because they dont penetrate the water deep enough, when heeled.
Many a dinghy sailor that has sailed an "Oppie" optimist pram will understand that by getting the hardchine in the water he can pull up his center board.

Fact is, that to bring something new to the table after thousands of years of mankind sailing and now the modern "Volvo" generation in carbon fibre and computers, wont be easy, if unlikely.

When you look at this video of an Optimist thundering along in the sea you start realising that there is nothing wrong with a hard chine flat bottom boat AND A CENTRE BOARD

http://www.youtube.com/watch?v=WFaVrQp4qPo
http://en.wikipedia.org/wiki/Optimist_(dinghy)

These kids can sail! Oppies rule!

So get back to basics.
Learn to sail an Oppie, or next one up, a Laser, and later a Hobie.
Then the whole picture will become clear.

I must admit that I am as dissapointed as you folks are. I kinda had it that maybe they had something going here. But if you want to do the Horn wrong way round in a bath tub, build a "smart" bathtub. In other words, do the homework, do the math, if you cant, get somebody that can. And then test the damn thing PROPERLY. All boats require TIME to set up. Do the Time Thing or else end up with egg in your face. In todays time and age, failure is not necessary.

One thing that this Forum - BD.net has shown over and over, is what happens when the NA is completely ignored

So by the time that he gets this boat "working" one will ponder the question "Is the turd polished ok"

Leeboards will solve his problem BEEEEG TIME
Will he go for it?
Probably not

Anyway I still love Sven

[Angélique]

Originally Posted by GTO

It would be nice if the keel-smart folks on this forum would weigh in on the potential of the chine runners.

That would be nice

Is it worth to ask the moderator to move this thread to the Boat Design part of the forum to get more input on technical issues..?

Manie, you started the thread, what do you think about this..?

Cheers,
Angel

[Manie B]

When I see these kids sail like that
I ask please Lord, cant I just be 15 for one day again, to sail an Oppie.
Just imagine ROCK HARD STOMACH MUSCLES - no old fart beer belly.

Damn I am going to work on my boat tonite AND NO BEER



believe that and you will believe anything

[Angélique]

September 14, 2011 #1: - - ‘‘A black out’’ - - (not Sven himself of course ) - - and pros of the AIS-transponder...

Tracked down the french Tim’Jak he mentioned, they wrote an article about Sven in Porto Santo with lots of photos of him and the boat.

Here's a google translation of Tim’Jak's site and their post about Sven.



Cheers,
Angel

[Manie B]

Is it worth to ask the moderator to move this thread to the Boat Design part of the forum to get more input on technical issues..?

Manie, you started the thread, what do you think about this..?

Angel, in all my years as a member of BD.net, I have learned that these folks will only answer when they feel like it, regardless of where it is.
Problem is that these "small boats" and their eccentric owners are not popular at all. When you look at how little is written about this trip on the entire interent, you get the feel for it. There is no interest. That is why I am always grateful that at least there are a couple of folks out there that enjoy this kind of "adventure sailing"

What has surprised me beyond belief, above all expectations, is the interest in my build, BUT we have come to the conclusion, it is because it is a "regular" boat. My blog now gets 1400 visits per month, which is crazy if you think about it - a 5 metre boat?

I suppose you can never really be sure.
Anyway enjoy

[Manie B]

Nice post Angel, on Tim'Jak thanks

finally we can see the inside of the fininshed boat

[Angélique]

Manie, enlightening post#124

Thanks..!!

Cheers,
Angel

[Angélique]

Originally Posted by Manie B

When you look at this video of an Optimist thundering along in the sea you start realising that there is nothing wrong with a hard chine flat bottom boat AND A CENTRE BOARD

http://www.youtube.com/watch?v=WFaVrQp4qPo

What about an off-center-board (just one) so Sven still can sleep beside it..?


click pic for source --> Tim’Jak

Cheers,
Angel

[Angélique]

Sven is in the typing mode , new update... September 14, 2011 #2: ARE SMALL BOATS DANGEROUS?

Cheers,
Angel

[Angélique]

Originally Posted by Angélique

Tracked down the french Tim’Jak he mentioned, they wrote an article about Sven in Porto Santo with lots of photos of him and the boat.

Here's a google translation of Tim’Jak's site and their post about Sven.

The Tim’Jak folks wrote also an earlier post + pics about Sven's arrival on Porto Santo. - (translation)



Cheers,
Angel

[Manie B]

On a small narrow boat like this, one board with a good NACA profile, say one metre deep, on one side would be good. The better option would be to make two slots on either side with two small light boards, one port one starboard, probably no bigger than that on a Oppie.

Also with two boards, he can put the one deeper than the other, to have less drag one side, it could help with steering ?
Problem is now we are all guessing and theorizing

Probably the best would be to have two slots outside the boat. This is easy to retrofit and would not affect the integrity of the hull structure.
I have seen the old Dutch boats with the big swing leeboards on both sides, that would be easy.

[Manie B]

I just did a search on BD.net to see what has been posted in the past by some of the old hands.

Here is a very interesting drawing that gives you an idea of sizes of the sail plan to centre board to rudder, very interesting.

Dutch barge for lake Ontario

good post here

Lee-board Sailboats

and I quote

PAR Yacht Designer & Builder

Leeboards, like everything else have good and bad points about them. Terry, fixed bilge appendages are bilge keels and commonly seen in areas where there are large tidal ranges, such as Great Britain.

Leeboards are the most efficient retractable appendage for their deployed depth. This is because they are effective lateral area from the LWL down, where as all other retractable appendages begin to be effective lateral area at the hull bottom. Leeboards can use less draft and have the same effective lateral area for this very reason. Tumble home or flare isn't that much of a consideration, though it would seem to be. The mount and pivot arrangement are key to success with this type of board. First it has to be surprisingly strong and second it has to permit the board to hang straight down, regardless of the hull shape. Most employ a wedge shaped element for this. If allowed to cant outward they offer even more efficiency.

On the down side they have to be placed at the widest portion of the hull, which in modern hull forms is further aft then desirable for the bulk of your lateral area. The type of hull that seems to work best with leeboards is those that have a relatively flat portion (in plan view) around midship. So, Gonzo, you can see why your canoe worked well with a leeboard, it's shape is just about what you want. On a more modern hull, where the entry is fine and displacement is carried further aft for sail carrying and bearing area, the boards will be too far aft if mounted on the widest portion of beam. If placed where they need to be on the hull to balance the sail plan, then the hull over laps the flow "shadow" on the trailing edge side of the board, effectively turning the flow, so you'll have a heavy "leeing" effect. Progressively more so the harder you push her.

Couple these things, with the way a big 'ol board can clutter up the sweeping curves, on the side of a yacht and it's pretty easy to see why they aren't that common. In small craft they can solve a lot more then they create, but you better have a good grip on where they need to live on the side of the boat and have a set of waterlines that will tolerate their optimum placement.

search lee boards - some good reading there since 2005