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PostPosted: Sat Mar 21, 2015 9:39 am 
Brotherhood of the Golden Paddle

Joined: Sun Aug 16, 2009 10:05 pm
Posts: 1398
Location: South Salem, NY
Mark seems to be taking more interest in sailing over at Long Haul. He's headed to Texas right now with his daughter Madison to do some sailing and show off the boats and sails.

He's adding some new stuff to the line up which I think could be a lot of fun. He's going to be making the long sought hiking 'gunwale' seat so you don't have to sit on the washboard (ouch), with a leaning harness - a great way to stay connected. He's making a control board that fits just behind the mast and a sea anchor system that deploys from the stern of the boat for beach landings... and many other uses I might add...

But probably the most interesting thing is a keel sponson which looks like it will run the length of the boat giving the bottom a V shape rather than being flat. I thought about this once a long time ago but never had the extra sponson to try it out. Having obtained a second set of Quattro Add ON sponsons I might give this a try in my own Jerry Rig way.

For us mono hull sailors (w/o outriggers) I'm not sure this will be a huge improvement as we generally ride on the chine giving us a kind of V naturally. For the Balogh group though with the minimal lean BOSS system the V hull could make a considerable improvement and make these guys even faster.... aaargh.

Any thoughts? I'm thinking the V hull might make mono hull sailing even tippier and tendererererer.

Already have my name on the list for the hiking seats.

Anyway, check out the videos on the Long Haul Facebook page: https://www.facebook.com/long.kayaks

Thanks Mark!

d

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Kayaksailor 1.6 +genoa
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PostPosted: Mon Mar 23, 2015 3:12 pm 
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Interesting about a sponson under the keel: If air filled, I think more tippy. You could fill it with water, instant ballast keel (so more stable). I would also want to look into having it NOT run the full length, but only part way (maybe rear two thirds?). The idea is to improve tacking by more firmly planting the middle/rear of the keel in the water while letting the forward portion of the hull slide sideways during a tack. You do want to maintain, or increase the hull rocker towards the bow. Take a look at any older full keel sailboat hull for the idea.
One of the things that got me thinking about this is the radically different hull behavior of my two white water kayaks when turning. Both kayaks have significant rocker. My Klepper T67 tends to slide the stern more around when turning, while my Hartung Slalom keeps the stern more planted while the bow slides sideways. The Hartung is a bit easier to keep on track.

Chris O

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PostPosted: Mon Mar 23, 2015 9:13 pm 
Could the wooden keel be V shaped on the bottom to form the V shaped keel?


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PostPosted: Mon Mar 23, 2015 10:48 pm 
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Pakboats found that building a foam pad into the inside of the bottom of their canoe hulls significantly improved their resistance to abrasion on the rocks, etc. I imagine a V'd wooden keel would have the opposite effect. A sponson underneath, however, might work fine.

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Chris T.
~'91 Klepper A2 w/ BSD schooner rig.
'64 Klepper Passat/Tradewind and T12 restoration projects.
Non-folding: Early '90s Old Town Canoe.
Previously owned '04 Pakboat Puffin II and '05 Swift (prototype), as well as an '84 Hobie 16.


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PostPosted: Tue Mar 24, 2015 9:08 pm 
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Location: South Salem, NY
Chris O it seems to me that rolling the ends of the 'keel' sponson up so they don't inflate could be a nice way of experimenting with this.

Here's my question which your sailing expertise may be able to answer. I bought a set of additional sponsons made by Long Haul (from our fearless leader Michael - thanks again) that turn my Aerius II into a pseudo quattro. I've only sailed with it once or twice with this new arrangement but I think there was a slight improvement because as the boat heals it rides a little more on that additional sponson and the 'chine' is less flat (than with the single sponson).

Now, if I extend the hull into a V shape, won't that essentially flatten my chine again when I'm healing, and is that a good thing or a bad thing?

I'm thinking flatter is more surface area, and more surface area is slower, right?

On the other hand, for guys like Chris T and Frank that have the BOSS outriggers keeping the hull fairly flat, the V would maybe cut a little cleaner? I guess it would help to know if the additional sponson would lift the boat out of the water any more... I kinda doubt it. We're talking displacement hulls here right? So what's better, a flat displacement hull or a V shape down there?

Is it two different scenarios here - outriggers v. non outriggers, or am I overcomplicating the idea again?

d

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PostPosted: Tue Mar 24, 2015 9:16 pm 
Brotherhood of the Golden Paddle

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Location: South Salem, NY
Frank I think Chris T is right, you would want a little give between the rubber and the hull to absorb hard and/or sharp impacts.

Potentially the nice thing about this keel sponson is that you can leave it installed and decide when you go out whether to inflate it or not. In the video it sounds like they are inflating it with compressed air... I wonder if this is necessary or just easier. I've never seen Mark used compressed air for sponsons... this may be a little more heavy duty. I'm looking forward to learning more.

d

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PostPosted: Wed Mar 25, 2015 12:08 am 
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Joined: Wed Feb 12, 2014 4:48 am
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Location: Waukesha, Wisconsin and Shanghai, China
If you guys want more info on the use of an "under-keelboard sponson", I suggest you talk to David at BSD. He recommended it to me last fall as a way to increase speed with a BSD/BOSS rigged boat with outriggers....with BSD sails or other, like mine, with a Klepper S4 rig. So I assume that he has used this method on occasion, perhaps on numerous occasions, for this purpose. I expect that Mark Eckhart got this idea from David Valverde. I have not had an opportunity to try it yet, but hope to soon after getting back home next month.

Chris

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1965 Klepper S4 sail rig, with 14 sq ft jib; Sail Rite 32 sq ft genoa; and 41 sq ft main
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PostPosted: Wed Apr 01, 2015 12:47 am 
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Location: Oakland, California
Dennis,

To respond to your questions about chines:
Yes, it is very different if you use outriggers or really use your sailing kayak as a true monohull. I you do not heel over, a V shaped keel keeps you on track (you will slide less sideways). A hard chine will do the same when heeled over. That is why in old wood sailboats having a few cracked frames at the turn of the bilge makes you faster: You have just created a harder chine = more bite.
With stability two main elements do their thing. One is relationship between center of gravity and center of buoyancy. The ideal is to have the center of gravity below the center of buoyancy (like you get with a ballast keel on a sailboat), you will not go over (just swing sideways like a pendulum -> seasickness anyone?). On a kayak, you can improve this relationship with internal ballast, such as water jugs (I would resist the temptation to use old window sash weights, when going turtle you will sink...). The other element is the effective waterline beam coupled with the cross sectional hull shape: A wide flat hull profile (harder chines) when heeled over will "dip" the leeward chine deeper into the water, the increased buoyancy at that chine increases your stability. But caution!: A very flat and wide cross sectional shape with hard chines will flip you over fast once you heel over far enough where the original wide waterline beam suddenly becomes narrow. That is how I flipped my Nautiraid once. In that regard, I find the Klepper hull shape very nicely balanced.
So, a center sponson under the keel won't help stability, but will improve tracking. And for sailing you want to allow the hull to be able to pivot around while limiting side slip, that is why all modern performance sail boats have fin keels.

Does this makes sense?

Chris O.

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PostPosted: Wed Apr 01, 2015 11:49 pm 
Brotherhood of the Golden Paddle

Joined: Sun Aug 16, 2009 10:05 pm
Posts: 1398
Location: South Salem, NY
Hi Chris, thanks for that. Let me see if I have this straight, and I have at least one more question...

So a rig using the BOSS system might benefit by the center keel for tracking and possibly lighter steering. Yes? Could it be faster with the V hull?

A mono hull AII sailor benefits by leaning a bit and riding on the chine which improves tracking and possibly lightens steering. Yes? So the keel sponson on the mono hulled sailing boat would not be so beneficial because it would give the boat a flat spot while healing over. But could be beneficial if the mono hulled sail boat were kept fairly level while underway... maybe increasing speed and improving handling. yes? I guess one question here is how much will the keel sponson affect the monohulls stability without outriggers?

Here's the question I alluded to above - I've always heard that the most efficient and fastest way to sail the Klepper was to keep the hull level. That keeping the flat bottom down is most efficient. I have not really found this to be the case. Any insights on this? Perhaps it has more to do with the efficiency of the sail above water than the hull below water? Just thought of that... ok, back to you.

d

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PostPosted: Thu Apr 02, 2015 3:56 pm 
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Dennis,

One thing to keep in mind is that when sailing on any point of sail except dead down wind both your sail and the keel/dagger board/lee boards have to act as a foil. Both need to generate lift, the sail to propel you, and the keel to keep you on course. So, a deeper V keel helps. And yes so does a hard chined keel heeled over (to engage the chine).
As to how far you want to be heeled over, it depends! More on a hard chined boat (to engage the chine), less on a dish shaped hull without much of a chine (keel needs to do all the work). Other variables are hull shape (sailing lines = best angle of heel) sail shape and aspect ratio. Then wind strength. Heeling over allows you to spill excess wind to some degree, especially with twist in the sail, but it also means that less of your keel/lee boards is effective. Heeling over too far is always a speed killer.

Funny thing with all this is that on the one hand it gets very theoretical. Some good books were written on this: CA Marchai "Aero and Hydrodynamics of sailing" and Ross Garrett "The symmetry of sailing" to name two good ones. Back in the day (1990's) I even took two classes on this from North Sails... Why? While I was getting better on my own, I still could not pass the "old hands" in the fleet. Sailing competitively gets to be bloody serious! Why? Well you win on that tiny margin over the other guy.
On the other hand, a lot of this explains itself in practice when you actually start racing, especially in a one design fleet. You get quickly dialed into if what you are doing makes you faster or slower than the other guy! Contrary to popular belief, this is not necessarily only for the well heeled: There are a fair number of small dingy classes with active fleets, starting with El Toro's around here (really 8' sailing prams). Of course, if you need a yacht to impress people with ->$$$ouch$$$.
I was told way back when, and agree 100%, that the best way to learn to sail well is to race. And dingy one design fleets are the best teachers.

Chris O.

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PostPosted: Thu Apr 02, 2015 8:38 pm 
Brotherhood of the Golden Paddle

Joined: Sun Aug 16, 2009 10:05 pm
Posts: 1398
Location: South Salem, NY
Thanks Chris. If only there were some other AII sailors in the neighborhood that wanted to get together and have some fun. So far I'm in a class by myself, at least in this neighborhood. Many BSDs, but few S2 sailers that I see.

Fortunately I love the folders enough to slog away on my own and not get involved with other boat sailing if possible... besides, I don't know where I would put all my fishing, snorkeling and navigation gear on those other boats!

Thanks for the insights, again.

d

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