Peter Carter, of the New South Wales Sea kayak Club, has an interesting little article (Going Straight: a few thoughts) at http://www.mpx.com.au/~pcarter/dirstab.html detailing how a stern fin improves directional stability in a following sea. Diagrams, no less! -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Wow. Short, sweet, and informative. Anyone have thoughts on just lowering a rudder straight down (without "steering" it)? Would that change his (peter's) opinion on the relative worth of skeg and rudder? Milo Poughkeepsie, NY -----Original Message----- From: Dave Kruger <dkruger_at_pacifier.com> >Peter Carter, of the New South Wales Sea kayak Club, has an interesting >little article (Going Straight: a few thoughts) at >http://www.mpx.com.au/~pcarter/dirstab.html detailing how a stern fin >improves directional stability in a following sea. Diagrams, no less! > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
In a message dated 12/23/98 5:27:51 AM EST, dkruger_at_pacifier.com writes: << Peter Carter, of the New South Wales Sea kayak Club, has an interesting little article (Going Straight: a few thoughts) at http://www.mpx.com.au/~pcarter/dirstab.html detailing how a stern fin improves directional stability in a following sea. Diagrams, no less! >> Sounds just like Mat Borse explanation for his Mariner kayak design. Mat designed the kayak to handle following seas, with a Swede form (widest part of kayak behind cockpit) extended keel (built in skeg) and a sliding set to move Center of Effort. I have been interested in the idea of two small fixed fins set wide apart. They would have a neutral affect when the boat is level (not leaned) but would aid maneuvering when kayak is leaned and one fin is lifted clear? *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Milo wrote; >Anyone have thoughts on just lowering a rudder straight down (without >"steering" it)? Would that change his (peter's) opinion on the relative >worth of skeg and rudder? A rudder that does not move becomes a skeg (until you move it). I believe Peter's point about the rudder pertains to its use as a rudder. Another approach to the problem can be found in Matt Brose's boats and mine where achieving directional stability comes from hull shape and no skeg or rudder. One can easily imagine situations where skegs, rudders or no rudder or skeg might work well. Keep in mind that canoes rarely have skegs or rudders and manage fine. By the same token, sprint kayaks really do need rudders since one wants to maximise the forward propulsive effort and the slight drag of the rudder can be easily offset by the more efficient power application. Commonly skegs get mounted well aft in an effort to achieve directional stability. another approach mounts the skeg close to the center of gravity. This serves to reduce leeway and consequently, weather helm but still allows control. I know of a number of attempts to use double skegs based upon their use on surf boards but have not heard of an arrangement that worked better than the normal skeg. This may be due to the nature of the flow around a wide flattish surf board as opposed to the flow around a narrow rounded sea kayak. I experimented with two angled skegs mounted forward on a freestyle canoe. It worked but not as well as a well placed paddle blade. Of course, some one might discover the proper combination so one should not dismiss it out of hand. Anyone experimenting with double skegs might want to first study how boats turn and then get up to speed on water particle motion in waves. One can save a lot of trial and error that way. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
In a message dated 12/24/98 1:44:05 PM Pacific Standard Time, 735769_at_ican.net writes: << snipola Another approach to the problem can be found in Matt Brose's boats and mine where achieving directional stability comes from hull shape and no skeg or rudder. >> Isn't the aft most portion of a kayak's keelson referred to as a skeg? Some have deep skegs, <i.e.. Broze's boats, Eddyline Falcon>, and some have a retractable skeg, <i.e.. Current Design Gulfstream, Valley Pintail> and some have no skeg <i.e.. Dagger RPM, Perception 3-D> The depth of this portion of the hull would then dictate the hull's trackability, realizing that other aspects of the hull form would also play a role in the performance of said hull. Steve Scherrer President ACKS Alder Creek Kayak and Canoe 250 NE Tomahawk Island Dr. Portland, Oregon 97217 Web: http://www.aldercreek.com Email: aldercreek_at_aldercreek.com Phone: 503-285-0464 Fax: 503-285-0106 *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Steve wrote; >Isn't the aft most portion of a kayak's keelson referred to as a skeg? Some >have deep skegs, <i.e.. Broze's boats, Eddyline Falcon>, and some have a >retractable skeg, <i.e.. Current Design Gulfstream, Valley Pintail> and some >have no skeg <i.e.. Dagger RPM, Perception 3-D> > >The depth of this portion of the hull would then dictate the hull's >trackability, realizing that other aspects of the hull form would also play a >role in the performance of said hull. No, a skeg as defined by my dear friend Thomas Gilmer the professor of naval Architecture at the US Naval Academy (and others) is -"A projection from a fixed appendage applied to the underwater hull, generally to increase the lateral area and give increased swing damping and dynamic lateral stability to the hull. A skeg is usually of large lateral area compared to its transverse thickness, is usually fitted in the vertical plane, and is in the after part of the vessel." Why the distinction? To define clearly the difference between a boat with steep deadrise aft and a boat fitted with an appendage. Matt's boats do not have skegs, they have a steep deadrise aft and a relatively straight keel line aft. Naval architecture uses a precise language to enable designers to converse clearly about complex three dimensional shapes. For example, Steve mentions a keelson. To a naval architect a keelson is a fore and aft above the bottom shell on either side of the keel. A kind of auxiliary keel if you will. I suspect that what Steve was talking about was the bottom hull profile not the keelson. Sounds like nit picking but if you tell a shipwright to deepen the keelson when you mean the profile you will be a bit surprised by the result. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
My dear wife surprised me with a West Marine Mistral VHF this morning, along with a waterproof bag for it. The Mistral is not even water resistant, let alone submersible. Should I exchange it for a truly waterproof model, or is the bag good enough? Thanks. Steve Cramer Test Scoring & Reporting Services Sometimes you never can University of Georgia always tell what you Athens, GA 30602-5593 least expect the most. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Steve Cramer wrote: > > My dear wife surprised me with a West Marine Mistral VHF this morning, > along with a waterproof bag for it. The Mistral is not even water > resistant, let alone submersible. Should I exchange it for a truly > waterproof model, or is the bag good enough? Depends on how you intend to use it. I've been using a pair of ICOM IC-10A's for three seasons plus. This model is not really water resistant (battery compartment is basically open to the elements, though the guts of the radio are pretty well sealed against water). So I keep it in a plastic radio bag, and except when using it for a transmission, also inside a neoprene sleeve (padding only), and a small dry bag. Never had any problems. When monitoring (95% of my use), I just lanyard it to a deck eye, and stuff the whole thing under a deck bungie. In gnarly conditions, it goes under the deck in the cockpit, still lanyarded to a deck eye. In an emergency, I'd open the dry bag and haul out the radio (a 2-hand job) to make a transmission. If your use would involve a lot of transmitting -or- storage in a pocket in your PFD, so there would only be one waterproof barrier (the plastic radio bag) protecting it, then I'd be nervous about mishaps. I've had the plastic radio bags develop small tears where something works against a hard edge on the radio. These are field-repairable with a tube of vinyl cement to "weld" the edges back together, but lots of abrasion would increase the number of tears. -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
I have used a variety of handhelds in bags for many years without trouble. Granted most of this use was on boats that are not quite as wet as kayaks, but getting spritzed, sprayed, splashed, dunked etc. was not at all uncommon. Check the bag for leaks before every trip. Even with a waterresistant/waterproof/submersible radio I still use a bag, first to keep from testing the seals and second to provide a handy neck strap. I hang the radio around my neck and tuck it inside my PFD. I often find older VHF radios that only need a new battery for free or a few dollars. None of the old radios are waterresistant so the bag is needed. michael cramer_at_coe.uga.edu wrote: > > My dear wife surprised me with a West Marine Mistral VHF this morning, > along with a waterproof bag for it. The Mistral is not even water > resistant, let alone submersible. Should I exchange it for a truly > waterproof model, or is the bag good enough? *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
That depends on your relationship with your wife! :) If you can get away with exchanging it, I strongly recommend it. Do you really want to trust a plastic bag with about $200 in electronics? Are you certain the bag will never rip? I have the same West Marine bag and the clip is starting to become loose. I store the radio in the bag so I am not using the clip that often. I THINK that is why they made the clip double sided, so you can flip it over. The point of this paragraph is things can and will go wrong. Spend the extra few bucks and get a waterproof model. The submersibles were too much more for me when I did plan on using the bag. I figured between it and a waterproof model I would be safe (not bombproof, but safe). *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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