Shatterglassers, It is funny how in the world of skin boats (baidarkas and greenlanders), flex is praised for increasing speed and seaworthiness, but when it comes to flex in a plastic boat, the shatterglassers complain about it reducing performance. I've built a greenlander skin boat, and the amount of flex (bow to stern) is about the same in it as with my plastic kayaks. What do the shatterglassers have to say about that? Duane Strosaker Paddling Everything From Skin Boats to Plastic in Southern California *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
Okay-I'll bite, Fiberglass is lighter in weight near as I can tell. The color also *looks* better in most cases [IMHO]. I know my skirt fit my Pursuits' coaming better than my Necky-that has its down side to it, but over all, a securely fastened skirt is very important I think. [This is even after I got my skirt stretched out properly<g>] Due to storage requirements at my RVpark, I must "store" my Pursuit on top of the truck [just as shown in photo on my page] so, flexing is of course no real problem for me. I may be wrong, but I seem to recall finding out that it would be easier to repair glass than plastic...? I must admit however, that you bring up some interesting points in favor of plastic boats Duane, TomW... >Shatterglassers, > >It is funny how in the world of skin boats (baidarkas and greenlanders), flex >is praised for increasing speed and seaworthiness, but when it comes to flex >in a plastic boat, the shatterglassers complain about it reducing >performance. I've built a greenlander skin boat, and the amount of flex (bow >to stern) is about the same in it as with my plastic kayaks. What do the >shatterglassers have to say about that? > >Duane Strosaker >Paddling Everything From >Skin Boats to Plastic >in Southern California >*************************************************************************** >PaddleWise Paddling Mailing List - All postings copyright the author and not >to be reproduced outside PaddleWise without author's permission >Submissions: paddlewise_at_lists.intelenet.net >Subscriptions: paddlewise-request_at_lists.intelenet.net >Website: http://www.paddlewise.net/ >*************************************************************************** <gadfly_at_tscnet.com> homepage: http://www2.tscnet.com/~gadfly/ *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
In a message dated 12/3/99 8:19:56 PM, gadfly_at_tscnet.com writes: << I may be wrong, but I seem to recall finding out that it would be easier to repair glass than plastic...? I must admit however, that you bring up some interesting points in favor of plastic boats Duane, >> Okay, I'll bite. Glass my be easier to fix once damaged but it is MUCH harder to hurt plastic than glass. I don't have to wonder just how much water will dump into my boat before I can get my skirt on once I'm in the boat because I get in, put the skirt on THEN duck walk with my hands or push off with my lovely Greenland paddle. My boat may be a bit lacking in shine on its underside but it sure isn't damaged. Me, I'm a lot dryer <G>. OTOH, I do have a glass boat on order. I keep wondering if this $2300+++++ boat is worth all the grief I'm going to get when the boat shows up on the credit card this spring <G>. I'm buying stock in the company that makes 303. Tom, I sincerely agree with Sandy's admiration of your courage. Without knowing what happened to you I was moved and inspired by what I read. Knowing a bit more floored me. How lovely you are you. This summer we ran into a woman who was paddling with a friend. She was using the paddling as therapy after breast cancer treatment. She did her little bit out and back. All the time she was smiling. She gained in all the ways the water and the paddling feed out hearts, minds and souls. One minute more in each trip. Soon you will be out there on weeks long trips when you are in need of doing that. Remind me that your site is there. I like seeing it in the sig line. I'll check in when I have a moment or just the need to reconnect with something more basic than my daily struggle to make ends meet around the life I have carved for myself. You are a gift. Paddle smart and keep safe and well. thank you, Joan Spinner *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
On Fri, 3 Dec 1999 Strosaker_at_aol.com wrote: > It is funny how in the world of skin boats (baidarkas and greenlanders), flex > is praised for increasing speed and seaworthiness, but when it comes to flex > in a plastic boat, the shatterglassers complain about it reducing > performance. I've built a greenlander skin boat, and the amount of flex (bow > to stern) is about the same in it as with my plastic kayaks. What do the > shatterglassers have to say about that? hmm, time to figure out how to trade hats. My paddling choices include a skin/frame baidarka, and carbon fiber race surf ski. Skin/frame boats flex very differently than plastic boats. With a plastic boat the end to end hull shape stays roughly the same and the sides, and bottom, of the boat just flex inward as waves are encountered. With a skin/frame boat the boat will bend as it goes over waves. To me this was the most dramatic the day I paddled with a friend, he was paddling my VCP Pintail ('glass british heavy). We were paddling into a headwind with 1 foot chop. The PinTail was riding up over each wave and crashing off the top of each wave. My baidarka was cruising straight forward with the waves traveling along the gunwales. With the boat flexing as it adjusted to each oncoming wave. The baidarka was much faster than the pintail headed into the waves. My current take on this is a rigid boat is going to be the fastest on a flat water course - no flexing induced by the non-existant waves. In waves I think a skin/frame boat will be faster because it adjusts to each wave and less forward momentum is lost to the boat coming off of one wave and pounding down off of the back of the wave. The only use I have for a plastic boat is bouncing off rocks. I see no reason to abuse a boat by running it up on shore (except in surf landings). kirk *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
Kirk Olsen wrote: > > hmm, time to figure out how to trade hats. My paddling choices include > a skin/frame baidarka, and carbon fiber race surf ski. > > Skin/frame boats flex very differently than plastic boats. > With a skin/frame boat the boat will bend as it goes over waves. To me > this was the most dramatic the day I paddled with a friend, he was paddling > my VCP Pintail ('glass british heavy). We were paddling into a headwind with > 1 foot chop. The PinTail was riding up over each wave and crashing off the > top of each wave. My baidarka was cruising straight forward with the > waves traveling along the gunwales. With the boat flexing as it adjusted to > each oncoming wave. The baidarka was much faster than the pintail headed > into the waves. > > My current take on this is a rigid boat is going to be the fastest on a > flat water course - no flexing induced by the non-existant waves. In > waves I think a skin/frame boat will be faster because it adjusts to each > wave and less forward momentum is lost to the boat coming off of one wave > and pounding down off of the back of the wave. I am not certain it has to do with you observed but rather with some other phenomena. Back about 3 years ago, one of my readers, a physicist of some renown with some 150 patents to his name and voted to all kinds of lists such as Industry Week's Top 50 R&D Stars To Watch, etc., took a crack at it in an article for my newsletter. It is quite a detailed article that I would share with anyone who asks via back channels. The key point he makes is cited below in an excerpt. The phenomenon is phrased in terms of folding kayaks but would apply equally as well to any skin kayak such as Kirk's. >From Folding Kayaker Sept/Oct 1996, pp. 1-5 Scientific Look At Rough Water Drag For Folding Kayaks Vs. Hard-Shells "Flexible Skin In Action <subhead> In chaotic seas, a folding kayak’s skin sections defined by its stringers and crossribs pump in and out like a drum head and destabilize laminar flow of water along the surface of the kayak (Handbook of Fluid Dynamics, ibid, page 11-30). The vibrating skin of a folding kayak is extremely effective in pushing the critical Reynolds number of the drag crisis down to lower Reynolds numbers. There also may be a small geometric effect from the less regular surface generated by the framing effect of stringers and cross ribs on the flexible-skin analogous to dimpling on a golf ball. This “dimpling” of the surface of the flexible-skin kayak also tends to lower the critical Reynolds number of the drag crisis. However, because of the large lateral size and small height of such “dimples” on a folding kayak, the destabilization effect due to this static morphology of the kayak skin is much less than for the dimpled golf ball. Of the two effects, we believe that the dynamic in-and-out motion of skin sections of the flexible skin kayak is the dominant one that causes the critical Reynolds number of the drag crisis to fall. Such in-and-out motion occurs readily in rough chaotic waters and is a common phenomenon that many of you have often exclaimed about, i.e. the feel of the water as it passes along the skin. For the drag crisis regime to cause a difference in drag between hard-shell and flexible-skin kayaks, the Reynolds number associated with kayak motion through water must be near the drag crisis regime. By one of those quirks of nature, it is." By now I am certain James Lofton is scratching his head saying to himself "What! My little ole Folbot is doing all that s**t?" Kinda my reaction too. :-) Anyway it is good reading. happy paddling, ralph diaz *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
ralph diaz wrote: > > >From Folding Kayaker Sept/Oct 1996, pp. 1-5 > Scientific Look At Rough Water Drag > For Folding Kayaks Vs. Hard-Shells > > "Flexible Skin In Action <subhead> > In chaotic seas, a folding kayak’s skin sections defined by its > stringers and crossribs pump in and out like a drum head and destabilize > laminar flow of water along the surface of the kayak (Handbook of Fluid > Dynamics, ibid, page 11-30). The vibrating skin of a folding kayak is > extremely effective in pushing the critical Reynolds number of the drag > crisis down to lower Reynolds numbers..... > we believe that the dynamic in-and-out motion of skin > sections of the flexible skin kayak is the dominant one that causes the > critical Reynolds number of the drag crisis to fall. Such in-and-out > motion occurs readily in rough chaotic waters and is a common phenomenon > that many of you have often exclaimed about, i.e. the feel of the water > as it passes along the skin. "Dynamic in-and-out motion of skin sections." Isn't that the same as "oil-canning"? At least by the definition that Mark B and I use? But maybe it doesn't work exactly the same way because .... > For the drag crisis regime to cause a difference in drag between > hard-shell and flexible-skin kayaks, the Reynolds number associated with > kayak motion through water must be near the drag crisis regime. By one > of those quirks of nature, it is." > I don't understand that paragraph. I always thought that a drag crisis was when some queen's evening gown and size 11 pumps didn't make it back from the cleaners in time for the 9 PM show. Steve *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
ralph diaz wrote: > > I am not certain it has to do with you observed but rather with some > other phenomena. Back about 3 years ago, one of my readers, a physicist > of some renown with some 150 patents to his name and voted to all kinds > of lists such as Industry Week's Top 50 R&D Stars To Watch, etc., took a > crack at it in an article for my newsletter. It is quite a detailed > article that I would share with anyone who asks via back channels. > (rather large snip of things I think of each time I paddle):-) > > By now I am certain James Lofton is scratching his head saying to > himself "What! My little ole Folbot is doing all that s**t?" Kinda my > reaction too. :-) Anyway it is good reading. > > happy paddling, > > ralph diaz Ralph, don't you just hate it when science comes up with answers like that.? All this time I had been pretty happy with thinking it was either magic, or the spirits of the anchient sp? ones watching out over us "skin" paddlers!! James, who would love to read the whole thing tho. *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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