History of the planing dinghy
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Re: History of the planing dinghy
So you don't have Toppers then?
sailed and abused in their thousands by kids in the UK. Definitely scow shaped and yet very easy to nosedive
And don't forget the classic Australian scow Moth, which also needed to be sailed well heeled. As, sometimes, does the semi-scow-like Fireball
Richard Woods
However, the Topper is a damnable version of the concept: soggy, overweight, undercanvassed, and poorly rigged.On the trailing edge of technology.
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Re: History of the planing dinghy
Interesting thead to read with this mornings pot of tea. Thanks for posting.
With regards to Nordic pram shapes possibly planing,i dont have any doubts that may have been possible. There are a lot of pram shapes,some that would be ripe for planing given the right conditions, even if not intended.Comment
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Re: History of the planing dinghy
Originally posted by The BigfellaNG Herreshoff 1877
Sounds like a planing dinghy to me.Here we get into the knotty problem of what constitutes planing. I don't think the narrow hulls of the catamaran are planing, because shapes that produce little lift are as fast or faster than those that are flatter. It seems to me that the hull's lift is part of what makes it planing, and of course, the effectively longer waterline as the water breaks cleanly from the transom. By most standards, it isn't planing until the boat reaches 2.4 X the square root of the waterline length in knots, so there are plenty of designs that will exceed hull speed but not plane. I'm not sure what to call what catamarans do other than going fast. There doesn't seem to be a transition point, whereas a planing boat suddenly needs less power to keep going than it needed to get out of the hole.I agree, catamaran hulls don't plane
If you have an hour or two spare you might like to read this thread
We have discussed this in several other threads, but this seems a good place to put the latest iterations. I recently approached some of the...
Richard Woods of Woods Designs
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Re: History of the planing dinghy
supported more by hydrodynamic forces than by buoyancy," leaves out the fact that the express canal boats of the 1830s used hyrdrodynamic bearing to travel at 10 knots while being towed by horse.
Some pretty good history here:
The boats were, if I recall correctly, about 60' long, so they were traveling close to hull speed but having the power needed to push them dramatically reduced by the lift they were getting.
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Re: History of the planing dinghy
That is a subset of conditions, where planing is promoted in very shallow water, the water reflected downward by the bow, is in turn reflected upwards by the canal bed and promotes lift. I've done it in a Laser, on a very broad reach because the rudder and daggerboard have to be up. It's the same mechanism as skimming boards on the beach. I knew a powerboat captain who would regularly seek out shallow water while transitiing the the intracoastal, to get more speed, of course if he had dropped off the plane, he would have had a major grounding,
As to whether a planing catamaran could be designed, if you can power it up over the hump with sail, yes. After all there are now racing cats on the motor race circuit, and water skis are long slender planing surfaces.It really is quite difficult to build an ugly wooden boat.
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Re: History of the planing dinghy
Cats are faster when they're kept fairly level, and they"re often barely touching the water, apart from their dagger boards and rudders. It looks a lot like planing to me!
Rick
,Rick
Lean and nosey like a ferretComment
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Re: History of the planing dinghy
I have sailed Toppers enough to be able to confirm ATTLG comments. But it works for kids, probably because they are much lighter than adults.
To plane a hull needs two things. A good lifting surface, which means some of the hull has to be flat and beamy, preferably aft. It also needs an angle of attack
So if a Tornado really did plane you would never nosedive, instead you would lift like a speedboat does. Waterskis are very inefficient planing surfaces, the aspect ratio is all wrong
Having said that, the real problem with vehicles at speed is control, not speed per se. Put enough HP on a IOR monohull and it will plane, but it will be so uncontrollable you will never manage to go in a straight line but roll it over. Look at how uncontrollable the racing cars from the 1930's were compared to today's cars, even though they were going slower than you do when driving to work with one hand while drinking a coffee or putting on makeup with the other.
Richard Woods of Woods Designs
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Re: History of the planing dinghy
Re the scow V 18 footer comments earlier, sometime in the 80's or 90's an A scow came out from the US for some reason. It was all hype and a media built grudge match was set up out on the harbour. The result on that day was a fairly conclusive win or set of wins to the 18 ft skiff. I can't remember the conditions or state of the harbour. Incidentally there was a similar match set up between our top racing cat at the time , Split Enz, and Bullrush the famous Australian ocean racing trimaran. The Cat won.Comment
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Re: History of the planing dinghy
Here's a sharp bow scow sailed out of Manchester Massachusetts 1910, note dual rudders and bildge boards.Comment
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On the trailing edge of technology.
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Re: History of the planing dinghy
The Herreshoff cat Amaryllis which still exists, has horizontal adjustable trimming boards, whether they promoted planing or perhaps more correctly inefficient hydrofoiling, is of course debatable, but I would think it did, this of course an outlier in the argument, since as far as I know no other cat has ever used that systemOn the trailing edge of technology.
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Re: History of the planing dinghy
Originally posted by The BigfellaHaving sailed Kittycats (with whopping great spinnakers) and Tornadoes extensively - I reckon they plane.... as does my original one design Windsurfer. We used to blast past the Manly Ferry, which does 18 knots, with tourist camera flashes popping away, quite easily. We were way over 2.4 times hull speed.
Small waterline area twin hull vessels are also fast, and they certainly don't plane. In fact, they look like a couple submarines joined above the waterline.
I'd say foilers, catamarans, submarines and SWATH vessels all exceed hull speed without planing.On the trailing edge of technology.
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Re: History of the planing dinghy
Great thread! In all this reflecting on hull form, I think that equal importance in the development of sustained planing can be placed in the "invention" of the boom vang (kicking strap to you Brits). I know from experience in my Fourteening days that a broken vang makes planing difficult. Also the recognition that weighted centerplates were better unweighted as they only helped when heeled and the boat were better sailed flat. This weight reduction and powering up the mainsail with a vang made the boats plane more readily as much or more than hull shape evolution.
We have a modern A scow on the Chesapeake and I think it would give most any other single hull boat a run for it's money, upwind or down. Huge asym spinnaker, bowsprit, carbon rig and 7 crew - all busy, the boat is as much fun as you can have on the water. Sailing a scow downwind is tricky. They still like some heel downwind in a breeze, as the bows will shovel in. Breaking them out is best done by heeling which sheds the water off the foredeck. Heeling the boat is about the last natural inclination you have in those conditions though!
TPComment
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Re: History of the planing dinghy
I have sailed Toppers enough to be able to confirm ATTLG comments. But it works for kids, probably because they are much lighter than adults.
To plane a hull needs two things. A good lifting surface, which means some of the hull has to be flat and beamy, preferably aft. It also needs an angle of attack
So if a Tornado really did plane you would never nosedive, instead you would lift like a speedboat does. Waterskis are very inefficient planing surfaces, the aspect ratio is all wrong
Having said that, the real problem with vehicles at speed is control, not speed per se. Put enough HP on a IOR monohull and it will plane, but it will be so uncontrollable you will never manage to go in a straight line but roll it over. Look at how uncontrollable the racing cars from the 1930's were compared to today's cars, even though they were going slower than you do when driving to work with one hand while drinking a coffee or putting on makeup with the other.
Richard Woods of Woods Designs
www.sailingcatamarans.com
And since the transom must be kept out of the water for the boat to function properly in displacement mode going to windward, the resulting shape looks pot-bellied to Nick, but it seems to be fast on the water. The only problem is that they don't do well to windward in lumpy water.On the trailing edge of technology.
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