I think that the recent baseless criticism of hard chined boats has been adequately refuted. However I would like add that hard chines boats are much more likely to surf better than rounded chine boats. Those who know me, know that I spend most of my kayak time in the river or in the ocean surf, and that surfing is "king". It is in fact, the most noble endeavor imaginable in any kayak. So I consider myself an expert on surfing, and have surfed a number of different sea kayak designs on wind waves. I have noticed some general observations... Hard chine boats plane up "higher" than soft chine boats. This allows the paddler more control of the boat by edging. In fact, I was quite amazed last summer when surfing my hard chined Pygmy Arctic Tern -- I was able to correct a large broach by edging into the broach and by placing a hard rudder on the opposite side. This kind of contortion is very hard to master outside of a river environment, but was surprisingly effective. I really didn't expect a 17' long boat to be able to "escape" a broach. It was because the flat bottom and sharp chines allowed the boat plane up and "spin" horizontally in the much the same way as a flat-bottom rodeo kayak would spin. Incidently, the last time I capsized unintentionally, was while surfing a CD Gulfstream in the same conditions (four feet wind waves). The boat broached, and I tried the same corrective technique. But the (very) round chines were sucked into the wave and the wave won. I capsized... the fact that this boat was designed by none other than Derek Hutchison must be purely coincidental ;) Matt Broze will also tell you that hard chines are more likely to resist the broach in the first place. I think he is right, but paddler skill is a much more important determining factor in resisting a broach. Surfing short, steep river waves in a river kayak is the absolute best way to learn how to resist a broach. Wind waves have more similarity to river waves than they do to ocean shorebreak waves. My summation is this... if you like to surf, hard chines are the best! Kevin Whilden *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Kevin Whilden wrote: > > My summation is this... if you like to surf, hard chines are the best! > > Kevin Whilden > How about when you mix them with a soft keel, like on a Silhouette or Rumour? -- ¤ Gabriel L Romeu ¤ http://studiofurniture.com + /diary or + /paint *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
----- Original Message ----- From: "Gabriel L Romeu" <romeug_at_erols.com> To: "Kevin Whilden" <kevin_at_yourplanetearth.org> > > How about when you mix them with a soft keel, like on a Silhouette or > Rumour? > \ Not having surfed one of those boats, I can't say for sure. However my guess is that performance would be controllable on the wave with edging, but that the ability to correct a broach would not be as good. Since this motion really felt like a flat spin, I would suspect that a very flat bottom is necessary. The Pygmy Arctic Tern is very flat underneath the paddler. I do not know exactly how far aft the hard chines and flat bottom need to continue in order for this performance to occur. However my intuition says that underneath and directly behind the cockpit is the critical area. The stern is less important, because it is probably sticking up in the air anyway. One thing that whitewater boat designers have learned is that the chine needs to be really sharp for flat spinning. Soft hard chines just don't work, so boats like Mariners with their softly defined chine would likely have some trouble in this maneuver. Note, I am trying to make a distinction between the rounded chines and less-sharp hard chines (e.g. soft). A couple of people have asked me which specific boats I think surf the best. My answer is that I have only surfed a handful of boats, and that I really liked the performance of the Arctic Tern because of the very sharp chines and flat bottom (for reasons that I described in my earlier post). However I cannot recommend anything else because I haven't paddled enough boats in big wave conditions. Incidently, my next kayak project will be a skin-on-frame boat designed specifically for surfing wind waves on the Columbia River. There is small group of paddlers in the Portland area who like to do this. Apparently the waves can get quite large, almost to the point where they are called swells. Kevin Whilden *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Kevin write early on Thursday: >> I > do not know exactly how far aft the hard chines and flat bottom need to > continue in order for this performance to occur. However my intuition says > that underneath and directly behind the cockpit is the critical area. The > stern is less important, because it is probably sticking up in the air > anyway. ahhhh yes grasshopper but when you are sliding down the wave the stern is actually well buried in the pile and IMHO very important. Won't the edges and volume aft either keep the stern floating <boxy stern> or let it sink into the pile <rounded, pointy stern> ?? I'm still experimenting on this one. Need to do an A/B on the same wave with a Pintail (pointy, soft) and something boxy and hard.(ie. Mariner or ??) > > One thing that whitewater boat designers have learned is that the chine > needs to be really sharp for flat spinning. Soft hard chines just don't > work, so boats like Mariners with their softly defined chine would likely > have some trouble in this maneuver. Note, I am trying to make a distinction > between the rounded chines and less-sharp hard chines (e.g. soft). yeah but with the ww boats they are gaining sooooo much wetted surface with the *planeability* of a crisp, flat edge. With a sea boat you need to hit a compromise. > > > Incidently, my next kayak project will be a skin-on-frame boat designed > specifically for surfing wind waves on the Columbia River. There is small > group of paddlers in the Portland area who like to do this. Apparently the > waves can get quite large, almost to the point where they are called swells. That group is growing. where does a wave end and a swell begin? That is the question, grasshopper! ;-) steve *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Kevin, that was a good post on surfing. What are your favorite surfing boats? Mike Kevin Whilden wrote: > My summation is this... if you like to surf, hard chines are the best! *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
----- Original Message ----- From: "Steve Scherrer" <Flatpick_at_teleport.com> > > ahhhh yes grasshopper but when you are sliding down the wave the stern is > actually well buried in the pile and IMHO very important. Won't the edges > and volume aft either keep the stern floating <boxy stern> or let it sink > into the pile <rounded, pointy stern> ?? Steve, I'm not sure we're envisioning the same scenario. I am talking about smaller wind waves, with no pile. Also I describe correcting a broach once it has started, but while the boat is still pointing forward down the wave. The boat has not fully broached, but is only 30 degrees or so off course from straight down the wave. At this angle, most sea kayaks (and indeed most paddlers) are beyond the point of no return in terms of preventing the broach. I was surprised to find that I was able to recover from this point in the broach, and continue on surfing the same wave. But back to your question, I really don't think the last 2-3 feet of the stern has much impact while the boat is only 30 degrees off course and into the broach. Often times it will be out of the water, and when it does hit the water, it will act to correct the broach, not enhance it. So in this case, a sharp, pointy stern would help. But again, this effect is much less important than the ability of the amidships hull to break free from the wave while the paddler to gives a HARD rudder stroke and maintains the proper edging angle of the kayak. > > > > One thing that whitewater boat designers have learned is that the chine > > needs to be really sharp for flat spinning. Soft hard chines just don't > > work, so boats like Mariners with their softly defined chine would likely > > have some trouble in this maneuver. Note, I am trying to make a > distinction > > between the rounded chines and less-sharp hard chines (e.g. soft). > > yeah but with the ww boats they are gaining sooooo much wetted surface with > the *planeability* of a crisp, flat edge. With a sea boat you need to hit a > compromise. > > Yep, the knock against my Arctic Tern is that it is a little slower than a round-hull boat due to the extra wetted surface area of the crisp hard chine. I'll take a 5% reduction in cruising speed any day for maximizing rough water and surfing performance! Incidently, it is my theory that whitewater boats need wide flat hulls with lots of wetted surface area because of the paddler's inability to hold a boat perfectly flat to the wave's local surface. This is a crutch for non-pro paddlers like me. A 23" wide flat bottom rodeo boat would spin just as well a 26" boat if the paddler is good enough. However a wider boat is probably an enhancement for balanced volume distribution during cartwheeling, and hence we'll never see a supper skinny rodeo boat (only squirt boats). You're going to add me to the email list for Columbia River surf mongrels, right? Cheers, Kevin *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
From: "Kevin Whilden" <kevin_at_yourplanetearth.org> > Incidently, it is my theory that whitewater boats need wide flat hulls with > lots of wetted surface area because of the paddler's inability to hold a > boat perfectly flat to the wave's local surface. This is a crutch for > non-pro paddlers like me. A 23" wide flat bottom rodeo boat would spin just > as well a 26" boat if the paddler is good enough. However a wider boat is > probably an enhancement for balanced volume distribution during > cartwheeling, and hence we'll never see a supper skinny rodeo boat (only > squirt boats). Actually, long boats need higher speeds to plane. To plane in white water, you'd need a short boat. (I'm not going to partake in the debate over planing vs surfing anymore). Basically, to plane, you need to hit a speed/length ration of 1.5 or greater. The speed/length ratio is the speed divided by the square root of the length. This is familiar, as hull speed is defined as a speed/length ratio of 1.34. So you have to go at least 12% above hull speed to plane (ICF racers in kayaks excede this without planing - not a planing hull). A long, wide WW kayak will be a displacement kayak unless you get into some really scary water velocities. A short narrow kayak will sink :-) Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Thu, 17 Jan 2002 17:05:53 -0500 "Michael Daly" <michaeldaly_at_rogers.com> wrote: > >Basically, to plane, you need to hit a speed/length >ration of 1.5 or greater. >The speed/length ratio is the speed divided by the square >root of the length. >This is familiar, as hull speed is defined as a >speed/length ratio of 1.34. For those of you not familiar with the numbers, that's speed in knots and length in feet. I'm guessing that anyone who didn't recognize the numbers (and therefore know them already) was probably wondering about that. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
At 5:05 PM -0500 1/17/02, Michael Daly wrote: > >Actually, long boats need higher speeds to plane. To plane in white water, >you'd need a short boat. (I'm not going to partake in the debate over >planing vs surfing anymore). > >Basically, to plane, you need to hit a speed/length ration of 1.5 or greater. >The speed/length ratio is the speed divided by the square root of the length. >This is familiar, as hull speed is defined as a speed/length ratio of 1.34. >So you have to go at least 12% above hull speed to plane (ICF racers in >kayaks excede this without planing - not a planing hull). > >A long, wide WW kayak will be a displacement kayak unless you get into some >really scary water velocities. A short narrow kayak will sink :-) I think as a practical matter this is probably true. But as a thought experiment get a short little WW kayak surfing on a wave and up there planing along nicely. Now start building a lightweight extension on to the bow. Light enough that it doesn't effect the trim or displacement. At what point does the fact that the boat is longer make it so it stops planing? If you were able to extend the bow out 20 ft without effecting the trim, would the fact that the boat is now 26' long and the water speed has not changed really made it so the boat is no longer planing. I think a definition based on speed/length ratio does not really capture what we understand planing to really be. I think a definition that incorporates the actual actions of the boat is more meaningful than the one that specifies the power source or length vs speed. I like the definition where the boat lifts up and drag is reduced. If a long boat can do this a low speed or a short boat can do this with an external power source, so be it. Of course since I am not the arbiter of the English language I guess it is not my call. -- Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 (860) 659-8847 *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
In a message dated 1/17/2002 11:48:42 AM Pacific Standard Time, kevin_at_yourplanetearth.org writes: > Yep, the knock against my Arctic Tern is that it is a little slower than a > round-hull boat due to the extra wetted surface area of the crisp hard > chine. I'll take a 5% reduction in cruising speed any day for maximizing > rough water and surfing performance! > I agree. When travelling confused waters (eg surf, clapotis, standing waves) I find the hard(er) chines of a Khatsalano a better ride than the round chines of my Nordkapp. The Nordkapp, to me, is faster, but on a week long cruise...I'm just not in all that big a hurry. Rob Gibbert *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
At 10:13 PM -0500 1/17/02, Rcgibbert_at_aol.com wrote: >In a message dated 1/17/2002 11:48:42 AM Pacific Standard Time, >kevin_at_yourplanetearth.org writes: > > >> Yep, the knock against my Arctic Tern is that it is a little slower than a >> round-hull boat due to the extra wetted surface area of the crisp hard >> chine. I'll take a 5% reduction in cruising speed any day for maximizing > > rough water and surfing performance! As a practical matter chines don't end up adding all that much wetted surface because they also tend to add volume which makes the boat float higher which reduces the wetted surface, so it very nearly comes out as a wash. The worst possible difference (a perfectly rectangular hull section vs a perfectly semi-circular section) for two boats of the same width and displacement is the rectangular hull has 13% more wetted surface area (if I did my math right). This is significant, but in practical terms, neither the rounded chined or hard chined are anything like "perfect". Much more important to how much wetted area there is is the width of the waterline and the overall shape of the bottom (round, flat, deep "V"). The chines have a somewhat secondary effect. > > >I agree. When travelling confused waters (eg surf, clapotis, standing waves) >I find the hard(er) chines of a Khatsalano a better ride than the round >chines of my Nordkapp. >The Nordkapp, to me, is faster, but on a week long cruise...I'm just not in >all that big a hurry. Why are you attributing the performance difference to the chine shape. Are the Khatsalano and NordKapp exactly the same except for chine shape? Isn't the Khatsalano a folding boat and the Nordkapp fiberglass? Don't they have different lengths and widths. Aren't they actually completely different boats other than being vaguely "Greenland Style". Why is it the chine shape making the difference and not some other aspect of the design? Isn't that like tasting an apple and an onion and saying the apple tastes better because its red. It would be just as wrong to assume the chine shape has nothing to do with the performance. Performance is dependant on hull shape and the chine is part of the hull and thus must have some effect on the performance. But, there is so much more to the hull than just the chine. Why insist that one aspect trumps everything else? Nick -- Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 (860) 659-8847 *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Mike wrote: <SNIP>>>>>>Basically, to plane, you need to hit a speed/length ration of 1.5 or greater. The speed/length ratio is the speed divided by the square root of the length. This is familiar, as hull speed is defined as a speed/length ratio of 1.34. So you have to go at least 12% above hull speed to plane (ICF racers in kayaks excede this without planing - not a planing hull).<<<<<<SNIP> This is from memory, but it is my understanding that the range between a speed/length ratio of 1.5 to (something like) 2.5 (or was it 2.25) is considered the semi-planing range and that true planing is only happening at speeds above that. Fast ships such as Naval Destroyers operate in this range. So a kayak with a 16 foot waterline (and a planing hull) wouldn't be fully planing until its speed was up to 9 or 10 knots. Even Greg Barton can't do this speed in a sea kayak (but I've seen him do almost 7.9 knots in a 19' 8" long Seda Glider). I think it is considered to be true planing when the bow comes back down in relation to the stern and the boat is approaching a more level orientation again after have climbed out of its own hole in the water against the force of gravity (?using a moving inclined plane?). Matt Broze http://www.marinerkayaks.com *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
At 12:23 AM -0800 1/18/02, Matt Broze wrote: > >This is from memory, but it is my understanding that the range between a >speed/length ratio of 1.5 to (something like) 2.5 (or was it 2.25) is >considered the semi-planing range and that true planing is only happening at >speeds above that. Fast ships such as Naval Destroyers operate in this >range. So a kayak with a 16 foot waterline (and a planing hull) wouldn't be >fully planing until its speed was up to 9 or 10 knots. Even Greg Barton >can't do this speed in a sea kayak (but I've seen him do almost 7.9 knots in >a 19' 8" long Seda Glider). I think it is considered to be true planing when >the bow comes back down in relation to the stern and the boat is approaching >a more level orientation again after have climbed out of its own hole in the >water against the force of gravity (?using a moving inclined plane?). This shows the problem with the definition of "planing" everyone has a different one. However, by this definition I think some surfing kayaks plane. I've measured ground speeds of over 20 mph while surfing and at the point of acceleration, the bow tends to drop down the wave and the boat takes off. Some of that speed was probably due to the water on the wave moving, but it was a non-breaking wave so I don't think the water was moving very fast. -- Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 (860) 659-8847 *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Matt Broze wrote: > This is from memory, but it is my understanding that the range between a > speed/length ratio of 1.5 to (something like) 2.5 (or was it 2.25) is > considered the semi-planing range and that true planing is only happening at > speeds above that. That's right, it's all coming back now. I had forgotten that the transition period encompassed such a wide speed range. I'm also going to be a student of wakes this coming summer, rooster tail hunting! :-) John Blackburn *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Nick Said: > However, by this definition I think some surfing > kayaks plane. I've measured ground speeds of over 20 mph while > surfing and at the point of acceleration, the bow tends to drop down > the wave and the boat takes off. How are you able to measure speed? That sounds like a difficult but interesting thing to do. Do you use a radar gun from shore or a GPS? That's about all I could think of. How does one go about picking up a used radar gun anyway? Any health risks to the paddlers you're zaping? :-) John Blackburn *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
>Nick Said: > >> However, by this definition I think some surfing >> kayaks plane. I've measured ground speeds of over 20 mph while >> surfing and at the point of acceleration, the bow tends to drop down >> the wave and the boat takes off. > >How are you able to measure speed? That sounds like a difficult but >interesting >thing to do. > >Do you use a radar gun from shore or a GPS? That's about all I >could think of. >How does one go about picking up a used radar gun anyway? Any health risks to >the paddlers you're zaping? :-) I used a GPS. It is pretty accurate for such things. Again it is "ground" speed not speed through the water. -- Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 (860) 659-8847 *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
From: "Nick Schade" <schade_at_guillemot-kayaks.com> > At 5:05 PM -0500 1/17/02, Michael Daly wrote: > > > >Basically, to plane, you need to hit a speed/length ratio of 1.5 or greater. > > I think as a practical matter this is probably true. But as a thought > experiment get a short little WW kayak surfing on a wave and up there > planing along nicely. Now start building a lightweight extension on > to the bow. Light enough that it doesn't effect the trim or > displacement. At what point does the fact that the boat is longer > make it so it stops planing? If you were able to extend the bow out > 20 ft without effecting the trim, would the fact that the boat is now > 26' long and the water speed has not changed really made it so the > boat is no longer planing. Changing the hull while planing isn't necessarily the same thing as changing the hull and then trying to plane. If you changed the hull and then started moving, you'd have to exceed the hull speed of the long hull before planing begins. Once planing, the surface area in contact with water will reduce. The length that matters is the length at the start. > I think a definition based on speed/length ratio does not really > capture what we understand planing to really be. I think a definition > that incorporates the actual actions of the boat is more meaningful > than the one that specifies the power source or length vs speed. Referring to the speed/length relationship assumes that we already have figured out what a planing hull shape is all about etc. I was just trying to address Kevin's hypothesis about why planing or surfing WW kayaks are short. The length of the hull limits what they can do. The speed/length relationship demonstrates that a short kayak will plane over a wider range of water speeds (hence on more rivers) than a long one and will plane more easily. This is a marketing feature. Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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