Do slugs plane? Perhaps we need clarification. Jim et al *************************************************************************** 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/ ***************************************************************************
Definitely soft chined, I know that much ~ or maybe "variable chined" ~ Diane > Do slugs plane? Perhaps we need clarification. > > > Jim et al *************************************************************************** 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 Schade wrote: > > At 9:36 AM -0500 1/17/02, John Winters wrote: > >However, Dr. Savitsky pointed out that > >the rise in CG during surfing could occur but you could not call it planing > >any more than you could say a person falling off a building was flying > >because he generated some lift. The distinction between planing and not > >planing is the vertical rise caused by the boat's power not an outside > >source. > > OK, I guess there is a definition out there that precludes using the > word "planing" when the boat is "surfing". Can you use "planing" to > describe what is happening with a water ski? How about if you put a > model of a planing boat in a tow tank? Is the data collected > meaningless because the power comes from an outside source? How about > one pontoon of a catamaran where it is the other pontoon that has the > motor. The source of the power strikes me as a funny way of > discriminating how a hull moves through the water. > I've never seen a definition of planing that specified where the propulsion came from. Whether it's from a following wind in a sailboat, a following wave in a surfing kayak, a towline pulling a skiff, or a propellor pushing a motorboat, I'd consider them all to be planing if their hulls rose in the water due to their movement. *************************************************************************** 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/ ***************************************************************************
Peter Rathmann wrote: Nick Schade wrote: > > At 9:36 AM -0500 1/17/02, John Winters wrote: > >However, Dr. Savitsky pointed out that > >the rise in CG during surfing could occur but you could not call it planing I ve never seen a definition of planing that specified where the propulsion came from. Whether it's from a following wind in a sailboat, a following wave in a surfing kayak, a towline pulling a skiff, or a propellor pushing a motorboat, I'd consider them all to be planing if their hulls rose in the water due to their movement. I'm forgetting who has written what here in this thread, but I am finding the level of discussion, and all the twists and turns it's taken (including the square footed slugs) to be extremely well thought out and presented. There was a fundamental disconnect in the use of the term planing initially and it's getting sorted out. If I may, could I throw out two questions/2 cents/observations ? 1. I seem to remember that "planing" occurred when a displacement hull made a transition to a planing hull and that transition corresponded to a discontinuity in the speed power curve ( y=f(x) cubed) sorry I can't put exponents in here. Is this wrong? The VCG would also rise during the transition. Can't argue with that. This past summer I was paddling the channels in the bay behind Avalon, New Jersey. I noticed that the boats that went past my wife and I were mostly thoughtful and throttled back, came down off plane until they were past us and then fired it up again. The wakes from the planers and non planers were very different with planers being easier to handle. What! you say, well, it suprised me also! Some of the larger displacement boats (sport fishers) threw out big wakes when off plane, with similar sized boats up on plane putting out much smaller waves. Does this mean there is noticeably less energy going into wave formation? I think the answer is yes because when the hull is up on a plane, the hull shape is much different with unique wave patterns itself. Therefore, if there is a big transition in wave formation from displacement to planing it seems there should be a discontinuity or transition in the speed power curve. And that is where planing starts. I sure wish I still had my old texts here so I wouldn't have to do this by memory. 2. Way back when the discussion started, the question of "planing" as it was used to describe "climbing the bow wave" has had me thinking. The energy you impart while paddling overcomes both frictional resistance, and form related resistance. Form resistance manifests itself in all the waves moving away from the hull. As I remember, there are 4 points along the hull where the waves crests are generated, bow, fore and aft transitions to max beam and the stern. There's standing wave crests at the bow and probably near the cockpit, the faster you paddle, the bigger the distance from crest to trough of this standing wave will be, and from the cockpit it would look like the bow is climbing the standing wave. By the time you are up to max hull speed (either your or the boats physical limits) I'll bet that wave is pretty steep. Does this seem a likely explanation for what people were talking about? Fine hulls would have a noticably smaller wave height, causing the observation that that hull isn't "planing" . Another thought, your own bow to cockpit standing wave will always look bigger 'cause of your perspective! 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/ ***************************************************************************
At 5:37 PM -0800 1/17/02, John Blackburn wrote: > >This past summer I was paddling the channels in the bay behind Avalon, >New Jersey. I noticed that the boats that went past my wife and I were >mostly thoughtful and throttled back, came down off plane until they were >past us and then fired it up again. The wakes from the planers and non >planers were very different with planers being easier to handle. What! >you say, well, it suprised me also! Some of the larger displacement >boats (sport fishers) threw out big wakes when off plane, with similar >sized boats up on plane putting out much smaller waves. Does this mean >there is noticeably less energy going into wave formation? I think the >answer is yes because when the hull is up on a plane, the hull shape is >much different with unique wave patterns itself. Therefore, if there is >a big transition in wave formation from displacement to planing it seems >there should be a discontinuity or transition in the speed power curve. >And that is where planing starts. I sure wish I still had my old texts >here so I wouldn't have to do this by memory. I always appreciate the thoughtfulness of the people who throttle down to pass. Their intentions are good and they should be commended. I just wish they would get a clue and not do it. As you say, the wake they produce is much greater unless they slow down to the point where they are going the same speed as a kayak and can't pass. The whole reason boats are designed to plane is because it reduces drag when they are up on plane. Less wetted surface means less friction and less boat in the water means less energy wasted that goes into waves. The downside is the design that planes efficiently is very inefficient at lower speeds and create all kinds of waves. The upside is if you wait at the mouth of the harbor where all these boats accelerate up to speed, you can catch some great waves for surfing. The best waves are when they have the trottle pushed all the way forward but have not yet gotten up on a plane. -- 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/ ***************************************************************************
"Nick Schade" writes: The upside is if you wait at the mouth of the harbor where all these boats accelerate up to speed, you can catch some great waves for surfing. The best waves are when they have the trottle pushed all the way forward but have not yet gotten up on a plane. -- One of the most fun things to do in a kayak, IMHO, is to sit in an eddy in Deception Pass, WA, during a big tidal flow and wait for the BIG cruisers <30-80'ers> to push through the pass. Soon as the wakes they set up bounce off the vertical, granite walls of the pass and push the tidal stream into awesome waves, you can ferry out and find BIG waves perfect for surfing. It'll really test your skills! Mid channel traffic, fast tidal stream current (5-8 knots), large waves (3-6'), clapotis, huge eddies, cold water, etc. You get the picture. ;-) 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/ ***************************************************************************
Nick Schade wrote: >The upside is if you wait at the mouth of the harbor where all these >boats accelerate up to speed, you can catch some great waves for >surfing. The best waves are when they have the trottle pushed all the >way forward but have not yet gotten up on a plane. Yup, yup, yup!! Colorado P'wiser Mark Colvin and I had a good time this summer hanging outside the harbor after a nice day paddle. It was right in the middle of summer...about 2:00pm on a Saturday afternoon, and all the power boaters had slept off their hangovers and were headed out for another day of fun and being seen. In the larger bay outside the harbor entrance, there's a nice, shallow shelf, so the wakes really got tall when they felt bottom. If only it were safe to be out in the middle of the channel when two boats are simultaneously powering up and headed out to the open lake/ocean. I've always thought that riding that "zipper" where the wakes intersect would be great fun! Shawn By the way, **this statement is presented for educational purposes only and is not intended to be actually tried in real life...or something like that**, it is entirely possible to surf behind a ski boat. Use a somewhat short tow rope so you can maintain position behind the boat while it increases speed. Instruct the driver to maintain speed just below planing (tell them to stay "in the hole"). Lots of fun!!! Send FREE video emails in Yahoo! Mail! http://promo.yahoo.com/videomail/ *************************************************************************** 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: "John Blackburn" <digipixs_at_erols.com> > > Does this mean there is noticeably less energy going into wave formation? Yes, but there are other things that kick in. Spray resistance can be almost as great as the wave-making resistance it replaces. Wetted surface is reduced, so skin friction is reduced as well. The latter accounts for most of the reduction in resistance when on plane. 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 Fri, 18 Jan 2002 13:11:25 -0500 "John Winters" <jwinters_at_onlink.net> wrote: > >I said quite clearly that planing began when the >wavemaking resistance >dropped with increasing speed. Perhaps earlier, but this time you added the requirement of that planing begin by internal power sources. (I am completely satisfied with the above definition of planing, btw. The no external power source issue is what I object to.) >> And how does it differ for a sailboarder, who also has >>no >> internal power source? I have often heard that >>described >> as planing. > >Sailboards do have an internal power source. They call >them sails. The wind >is the fuel sort of like gas is a fuel. The distinction I >made was between >the forces applied by the water to propel the boat as >opposed to the forces >applied by the water to retard it. Hmm, forces applied by the water to propel the boat. And here I thought it was gravity that propelled the boat on a wave, and that the water still provided drag. You've made the physics much clearer now! (Or maybe not.) <sarcasm off> John, the water still provides drag since it is not moving at the speed of the wave. Hydrodynamic drag is still meaningful, same as on flat water - having a sloped surface does not affect drag. We can still define planing by your above definition, where the wavemaking resistance drops with increasing speed, without adding a requirement for internal power sources for that speed. Why add such a requirement? *************************************************************************** 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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