Doug Lord 1,219 Posted September 29, 2015 Share Posted September 29, 2015 Fantastic development by Team Prosail Asia thanks to Corely and RHP on boatdesign.net: https://www.facebook.com/TeamProSailAsia Link to post Share on other sites
xonk1 128 Posted September 29, 2015 Share Posted September 29, 2015 Interesting. Still I find it quite sad to see a great one-design being tinkered with. My question would be " what is the goal? " Since my interest is racing my WETA in a strict one-design environment, I hope it does not work. There are enough foilers of all shapes and sizes right now. Don't wreck a great little boat. Link to post Share on other sites
jetboy 0 Posted September 29, 2015 Share Posted September 29, 2015 Why punch a hole right through the hull? This could be done with a bolt on bracket on the outside of the hulls - then it would be a marketable kit that would be removable for one-design racing. Link to post Share on other sites
RedTuna 44 Posted September 29, 2015 Share Posted September 29, 2015 Cool beans. I love science projects. Hope it's successful. But yeah, no way I'm cutting up the amas on my old boat. Not that I care about what is "strictly" class legal any more. I wonder what they intend to scale it up on. Link to post Share on other sites
Raz'r 3,670 Posted September 29, 2015 Share Posted September 29, 2015 no - note the major reinforcements to the joints. that's not a bolt in. I think you'd need a second set of amas to make the boat back to OD, assuming the hull sockets can handle the load, which they aren't designed fro. The weta is not a "stiff" or "light" platform - so it looks to be an interesting experiment, but still an experiment. And with all the dihedral it seems very odd, but good luck to them. Link to post Share on other sites
Raz'r 3,670 Posted September 29, 2015 Share Posted September 29, 2015 well, yeah, but it just doesn't seem to be the ideal platform. Now, as a test bed, which is what they imply, it might work well. Link to post Share on other sites
rbpatt 0 Posted September 29, 2015 Share Posted September 29, 2015 @ Turd Sandwich- better performance than a Hobie 14. We were beating H16s boat for boat a couple of weeks ago- in light and heavier winds. I still wonder why and to what end. Cheaper and easier just to get a Smythe set of sails to go faster Link to post Share on other sites
duwke 7 Posted September 29, 2015 Share Posted September 29, 2015 But smythe sails will help get you 5% more speed. This could add 30%. I don't know why everyone is down on the idea. If this is the base for a tri foiler that could be less than $20k, it seems like an interesting niche. The only other foiler in that range is a moth, and it takes considerably more tweaking, strength, etc. to foil. An easier, single hand foiler would be a nice additional to the market. Now, I think the Weta is too heavy with too small a sail plan to make this a worthwhile project, but again, as a base for something else, could be pretty cool. Link to post Share on other sites
Raz'r 3,670 Posted September 29, 2015 Share Posted September 29, 2015 Now, I think the Weta is too heavy with too small a sail plan to make this a worthwhile project, but again, as a base for something else, could be pretty cool. exactly Link to post Share on other sites
Lost in Translation 42 Posted September 29, 2015 Share Posted September 29, 2015 interesting project. C board will give lift but have not seen anyone foil them stably. C boards should still improve performance though with better speed downwind through less nose diving. Not sure why the are going so asymmetric on the C board. Perhaps that means they are planning to tack them or they are experimenting with lots of lift? If someone wants a singlehanded foiler under $20K they have the moth and the A-cat in the USA with the wazp coming. I don't know if any stunts are shipping here. Since this is multihull anarchy, here is an example with the A: http://a-cat.us/index.php?option=com_content&view=article&id=830:racer-x-icon&catid=7:a-class-catamarans-for-sale&Itemid=20 Link to post Share on other sites
Tom Kirkman 41 Posted September 29, 2015 Share Posted September 29, 2015 Me likey a lot. I have always loved the weta but 10,000 for the same speed as a hobie 14 was hard to overcome unless there is OD action nearby If you can't outrun a Hobie14 on a Weta you're doing something wrong... D-PN Numbers Weta - 78.5 H14 - 84 Link to post Share on other sites
unShirley 128 Posted September 29, 2015 Share Posted September 29, 2015 a few years back, Steve Clark drew up a wing sail for the Weta..........nothing came of it. Foils are fun to cogitate on, but not practical or economically feasible for mass appeal. However, if one shows up in SoCal, I would like to sail it. A fun experiment Link to post Share on other sites
sail(plane) 99 Posted September 29, 2015 Share Posted September 29, 2015 Even if you don´t do a foiler, the weta does not lift the center hull, the ama submerges first. Nose diving and ama submerging are the current limits to Weta speed. Partial lift ama foils + T rudder would reduce the tendency to nose dive and provide lift in the amas. So wouldn´t this mods extract a couple more knots of top end speed? (assuming nothing breaks) Link to post Share on other sites
Raz'r 3,670 Posted September 29, 2015 Share Posted September 29, 2015 The whole boat is engineered for the low RM of those hulls. Change that, and chase the breakages. But I think these guys are experimenting for something bigger. The Weta is a cheap platform for testing, so it might work for this. Link to post Share on other sites
unShirley 128 Posted September 29, 2015 Share Posted September 29, 2015 Nose diving and ama submerging are the current limits to Weta speed. I don't agree with this assessment. I have had my Weta surfing down a whitecap without the ama submerging and without nose diving and still only got it up to only 18.4 kts boat speed. In fact, I was seldom able to get it up over 16 kts. Those speeds are tons of fun in a 14 footer that is low to the water, but, a far cry from the speeds of A cats or Moths. IOW you can sail it perfectly flat in flat water, up on foils, and your speed will still be limited by sail area to weight ratio. Foils will help speed, but only by a limited amount that is marginally worth the expense and complications. There are many other variables involved, too. Having said that, tho, party on with the foils experiment. We all want to see the results. Link to post Share on other sites
sail(plane) 99 Posted September 29, 2015 Share Posted September 29, 2015 Maybe you are right. I was thinking high wind, one up and with my 70kg weight I have to ease sheets... two up is different. I thought foils could be a substitute for weight. Does it work like that? Link to post Share on other sites
Doug Lord 1,219 Posted September 29, 2015 Author Share Posted September 29, 2015 It would be interesting to put a foil-surface piercing T-foil(fully automatic)*- on the daggerboard if the structure was strong enough to lift the boat. That would get the main hull out of the water before it would with just wind pressure assuming the ama foil can keep the ama from burying. The ama foil needs to be able to automatically control altitude if it flies the ama instead of just lifting part of the load-a properly designed uptip foil would do that automatically. Lots of potential with the right foil configuration but for real speed the main hull has to fly-the lighter the air the better. *a wand controlled main foil would be less drag but more complicated to set up...... Link to post Share on other sites
Tom Kirkman 41 Posted September 30, 2015 Share Posted September 30, 2015 Even if you don´t do a foiler, the weta does not lift the center hull, the ama submerges first. Nose diving and ama submerging are the current limits to Weta speed. Partial lift ama foils + T rudder would reduce the tendency to nose dive and provide lift in the amas. So wouldn´t this mods extract a couple more knots of top end speed? (assuming nothing breaks) But, the Weta has a planing hull so it will exceed hull length limit speed. Longer Tri's aren't as concerned with having to plane on the hull as their length speed limit is greater. Shorter Tri's almost always do better with planing hulls. Link to post Share on other sites
unShirley 128 Posted September 30, 2015 Share Posted September 30, 2015 Maybe you are right. I was thinking high wind, one up and with my 70kg weight I have to ease sheets... two up is different. I thought foils could be a substitute for weight. Does it work like that? hopefully. So, foils will make it as fast in high winds (sailing upwind) as sailing 2 up. An improvement, but not by much. Link to post Share on other sites
Waynemarlow 138 Posted September 30, 2015 Share Posted September 30, 2015 Guyings before you really " Wet" a yourselves, thats a really big chunky foil with almost no thought on tip losses and drag, think of the consequences of that foil on a boat that is already under powered, over weight and not structurally designed to take the loadings. I have to give DL a hand clap on his restraint in waiting to post 21 before throwing in the centre foil nugget, I thought that would have been in post No1 Guys sorry it ain't goner work as advertised and my betting is that in 95% of its sailing life, it will be slower than a standard Weta. Link to post Share on other sites
Doug Halsey 66 Posted September 30, 2015 Share Posted September 30, 2015 ... thats a really big chunky foil with almost no thought on tip losses and drag ... When I look at the photo, my impression is that it's a stubby little thing. Maybe it's just the angle though. Anybody got any actual dimensions? Link to post Share on other sites
sail(plane) 99 Posted September 30, 2015 Share Posted September 30, 2015 Wayne, dont think many really care, this is all just what-iffing. I for one wouldnt touch the boat, its great fun as it is Link to post Share on other sites
sail(plane) 99 Posted September 30, 2015 Share Posted September 30, 2015 And doug knows perfectly well the weta floats do not support lifting the main hull. He had to post his foil idea anyway. Link to post Share on other sites
Doug Lord 1,219 Posted September 30, 2015 Author Share Posted September 30, 2015 And doug knows perfectly well the weta floats do not support lifting the main hull. He had to post his foil idea anyway. I know no such thing. Hopefully, the guys doing this know what the structure will support because regardless of whether there's a center t-foil, if the ama foil lifts sufficiently the main hull will want to fly-only it will be in fairly strong wind where the center t-foil could lift the main hull in relatively light air w/o the whole load being on the crossarm structure. Link to post Share on other sites
Laurent 1,792 Posted September 30, 2015 Share Posted September 30, 2015 I saw that boat at my sailing club! I talked to the owner while they were doing the 'poxy work. The foil is a 3D print exercize (3D print the plug, then make the mold, and then the foil). One of the ideas is to have only one mold for both foils. Looking from the front of the boat, you rotate the foil a quarter turn clock wise, and you have the foil for the staboard ama... That may explain the square stubby end. The owner knows all well that it is a compromise for the hydrodynamics, but it simplifies manufacturability. I talked to him have his first sail and asked how it went. The answer was "oh yeah! much faster!". I did not ask for more factual analysis... I will try to get more information next time. Link to post Share on other sites
RedTuna 44 Posted September 30, 2015 Share Posted September 30, 2015 Awesome, Laurent. Great info. Looking forward to it. Hey, maybe even invite him to join us here in the monkey house. Link to post Share on other sites
Doug Lord 1,219 Posted September 30, 2015 Author Share Posted September 30, 2015 Thanks, Laurent-good info. Using the same foil tooling for both sides seems like a good idea- making the foils interchangeable. See if you can find out what their plans are for the rudder T-foil--will it be a cassette type or kick up like the foiling Laser? Link to post Share on other sites
vaplaya 7 Posted September 30, 2015 Share Posted September 30, 2015 Interesting. Still I find it quite sad to see a great one-design being tinkered with. My question would be " what is the goal? " Since my interest is racing my WETA in a strict one-design environment, I hope it does not work. There are enough foilers of all shapes and sizes right now. Don't wreck a great little boat. What is the goal!?!?!? Everything/everyone seems to be into or want to foil these days. I swim, and I am looking into foiling swimmings suits. Hey who knows, they may be here soon? :-) Cheers, Link to post Share on other sites
Waynemarlow 138 Posted October 1, 2015 Share Posted October 1, 2015 Sometimes things don't quite work out in predicted terms and sometimes they work out even better, nice concept and in a lot of ways I hope it does work, without actually trying something we will never know and for the owner to get this far they have to be applauded. I do think there is an awful lot of armchair pundits on this forum who talk the talk but never walk the walk, its nice to see someone actually having a go. Link to post Share on other sites
Waynemarlow 138 Posted October 1, 2015 Share Posted October 1, 2015 If he is into 3D printing then simply make two end plugs with a nice hydrodynamic shape for either end of the foil and glue it on depending on which float the foil is on. Link to post Share on other sites
pwormwood 24 Posted October 1, 2015 Share Posted October 1, 2015 If he is into 3D printing then simply make two end plugs with a nice hydrodynamic shape for either end of the foil and glue it on depending on which float the foil is on. Or just have the tip shape on both ends of the foil - who says the top end needs to be square? Having driven the ama on my Weta under multiple times off the wind, I've thought about the foil idea too. However, I bought the Weta to have one completely simple boat to sail, so I'm glad someone else is experimenting with it. Link to post Share on other sites
dacarls 11 Posted October 2, 2015 Share Posted October 2, 2015 I bought a pair of commercial curved foils (C-foils) for $100 built for a German A-cat. They fit into the daggeroard trunk of my (new to me) A14 eXploder where the J foils fit. just checked this out today. I'll bet they would fit a Weta and make it nearly fly. (Gotta be better than those little shorties I saw here). Link to post Share on other sites
3Hulls 0 Posted October 3, 2015 Share Posted October 3, 2015 Get those foils in connection with the laser kit on solidwingsails.com http://www.solidwingsails.com/foiling.html Link to post Share on other sites
Sailingkid 3 Posted October 4, 2015 Share Posted October 4, 2015 Wouldn't surprise me if they show up with a t foil rudder and end plates on the c foils after reading this... Link to post Share on other sites
Laurent 1,792 Posted October 4, 2015 Share Posted October 4, 2015 Well, actually Danny (sorry for the spelling), the owner of the boat, is not reading this... but stil came to these ideas. He installed an end plate and tested a fixed T rudder today. There was not enough wind for him though to really make the C foil work... (his feedback after his sail). He is happy with the T foil; even though he knows that it is not adjustable, or at least not without affecting the balance of the rudder. For those who do not know, there is a rod with like a chainplate adjustable thingy on top of the rudder head. By threading it in or out, you change the angle of the rudder to have more or less toe in... I hope my explanation is understandable... By playing with this, he can change the angle of attack of the T rudder foil. But this is not an adjustment you can easily do on the fly, like on a Moth. This is a set up you do on the beach, before sailing, I would think. Right now, the rudder is apparently starting to generate lift at very low speed (Danny told me 2 knots). At that speed, he can hear and see that the rudder assembly is pushed up against the top pindle bracket. The end plate benefit is still TBD; there was not enough wind to really take advantage of the foil. I can tell that Danny is having fun tinkering with it; that's what matters! Link to post Share on other sites
Doug Lord 1,219 Posted October 4, 2015 Author Share Posted October 4, 2015 Great info, thanks Laurent! I wish Danny luck-sounds like great-interesting- fun.... Link to post Share on other sites
Yah00 0 Posted October 5, 2015 Share Posted October 5, 2015 T rudders on planing or fast displacement boats are intended to pull the stern down and keep the bow up, not provide lift that pushes the bow down. Forget the end plate on the C foil, just fair the tip. If endplates provided some magical extra lift for no drag penalty, all aircraft would have shorter wings with end plates. They don't because it's more efficient to make the wing longer until it gives the required amount of lift (and since the extra lift from an endplate is minimal, the wing doesn't need to be very much longer to equal it). If the intention is to reduce tip loses then consider that an endplate replaces one tip with two, so how about end plates on the end plates… ad infinitum. Just make the span longer. Link to post Share on other sites
Doug Lord 1,219 Posted October 5, 2015 Author Share Posted October 5, 2015 Actually, on the Rave, Osprey and some other foilers the rudder T-foil lifts up at takeoff and as the boat speeds up, it reaches a crossover point where it begins to pull down-automatically.On the Rave the rudder foil is set to zero degrees angle of incidence relative to the static waterline and the main foils are set at +2.5 degrees referenced the same way. Link to post Share on other sites
Laurent 1,792 Posted October 5, 2015 Share Posted October 5, 2015 T rudders on planing or fast displacement boats are intended to pull the stern down and keep the bow up, not provide lift that pushes the bow down. Forget the end plate on the C foil, just fair the tip. If endplates provided some magical extra lift for no drag penalty, all aircraft would have shorter wings with end plates. They don't because it's more efficient to make the wing longer until it gives the required amount of lift (and since the extra lift from an endplate is minimal, the wing doesn't need to be very much longer to equal it). If the intention is to reduce tip loses then consider that an endplate replaces one tip with two, so how about end plates on the end plates… ad infinitum. Just make the span longer. So why do Boeing and Airbus add "winglets" to their commercial airline plane models? Those planes obviously already have enough lift without the winglets... The role of an endplate is not to "provide some magical extra lift for no drag penalty" as you stated, but simply to reduce drag, by killing the end-of-wing vortex. For that very reason, it is indeed stupid to add an end plate to an end plate. At the second iteration, the additional drag is not offset by the gain on secondary vortex reduction. Link to post Share on other sites
SCARECROW 601 Posted October 5, 2015 Share Posted October 5, 2015 Because the wingspan is limited by airport terminals. And structural engineering means a longer wing is much heavier. Link to post Share on other sites
Terrorvision 138 Posted October 5, 2015 Share Posted October 5, 2015 There's always video: Link to post Share on other sites
Raz'r 3,670 Posted October 5, 2015 Share Posted October 5, 2015 T rudders on planing or fast displacement boats are intended to pull the stern down and keep the bow up, not provide lift that pushes the bow down. On International 14s, the rudder provides lift upwind for more speed, maybe through changing the following wave per Paul Bieker, maybe through stabilizing the sail plan fore/aft. Also adds safety downwind.... Link to post Share on other sites
RedTuna 44 Posted October 5, 2015 Share Posted October 5, 2015 The bow really is up considering how far forward he is. Good find, Terrorvision. Pretty dang cool. Looking forward to more. Link to post Share on other sites
unShirley 128 Posted October 5, 2015 Share Posted October 5, 2015 seeing is believing Link to post Share on other sites
Sailingkid 3 Posted October 6, 2015 Share Posted October 6, 2015 Well, actually Danny (sorry for the spelling), the owner of the boat, is not reading this... but stil came to these ideas. He installed an end plate and tested a fixed T rudder today. There was not enough wind for him though to really make the C foil work... (his feedback after his sail). He is happy with the T foil; even though he knows that it is not adjustable, or at least not without affecting the balance of the rudder. For those who do not know, there is a rod with like a chainplate adjustable thingy on top of the rudder head. By threading it in or out, you change the angle of the rudder to have more or less toe in... I hope my explanation is understandable... By playing with this, he can change the angle of attack of the T rudder foil. But this is not an adjustment you can easily do on the fly, like on a Moth. This is a set up you do on the beach, before sailing, I would think. Right now, the rudder is apparently starting to generate lift at very low speed (Danny told me 2 knots). At that speed, he can hear and see that the rudder assembly is pushed up against the top pindle bracket. The end plate benefit is still TBD; there was not enough wind to really take advantage of the foil. I can tell that Danny is having fun tinkering with it; that's what matters! I saw it on Facebook and just wanted to be first, shouldn't have been so cryptic. That looks like a brilliant modification, can't wait to see more. Link to post Share on other sites
Yah00 0 Posted October 6, 2015 Share Posted October 6, 2015 T rudders on planing or fast displacement boats are intended to pull the stern down and keep the bow up, not provide lift that pushes the bow down. On International 14s, the rudder provides lift upwind for more speed, maybe through changing the following wave per Paul Bieker, maybe through stabilizing the sail plan fore/aft. Also adds safety downwind.... In general, I14 T rudders are designed to be near the surface and aren't really designed for lift upwind as much as energy recovery (see T–foil rudders PDF 523kB), lift is a side effect. AoA adjustment and crew positioning is used to maintain trim. Downwind they help with pitch stability, the speed of the boat means the energy recovery aspect is minimal (the foil needs to be much further aft). Adjustability on the water is essential since the AoA required varies quite a bit depending on speed and up/down wind. Wetta rudders are mounted on the transom, to get the same effect as an i14 upwind they'd need about a 0.5m gantry and the foil needs to be close to the surface. We haven't seen this Wetta rudder, I just assumed a typical flying foiler T with the foil at the bottom to help with downwind pitch, rather than an I14 style rudder with the foil near the surface. The OP says it was lifting at 2kn, so given lift is a function of a square of the speed, what's it doing at 12kn? There's also a concern if the rudder is lifting at the same time the forward ama foil is lifting. Lots of torsion between the main hull and ama. Link to post Share on other sites
xonk1 128 Posted October 6, 2015 Share Posted October 6, 2015 Great video! I'll agree that the foils are WAY COOL, but , how about some speed comparisons of the foiling starboard gybe V.S. the non-foiling port gybe. Is the goal to reduce the heel? If so, that has been accomplished. If the goal is more speed, then let's see some speed puck readings. I am fairly sure that lift ( from the foil ) always comes with drag. What is the net effect? Regardless, still COOL. Link to post Share on other sites
Raz'r 3,670 Posted October 6, 2015 Share Posted October 6, 2015 well, in the video he's being paced by another Weta - looks slightly faster Link to post Share on other sites
Laurent 1,792 Posted October 6, 2015 Share Posted October 6, 2015 We haven't seen this Wetta rudder, I just assumed a typical flying foiler T with the foil at the bottom to help with downwind pitch, rather than an I14 style rudder with the foil near the surface. Exactly. The ownwer attached an inverted T foil at the bottom of the existing rudder. Link to post Share on other sites
Boink 679 Posted October 7, 2015 Share Posted October 7, 2015 Just for the record, I14's do aim to achieve energy recovery from the stern wave system - in simple terms - it flattens out the stern wake a lot. BUT At the same time they are producing between 80-90kg of total lift - which is why you see the crews flat wiring at the very stern of the boat whilst sailing upwind. Yes the boats are short - so you are never far from the stern compared to others. The effect is to transform a 14ft boat into one that behaves (upwind) more like an 18ft skiff. Yes the rudder definitely helps with pitch attitude downwind when reversed - try sailing a modern 14 downwind without a T foil..... The depth of the horizontal foil is relatively close to the surface not only for energy recovery bit also so you can clear the weed off it - which in itself is easier said than done. But do not be fooled by the Yahoo's comment about not being deigned to lift - 80-90 kg of lift effectively removes the displacement caused by one of the two crew allowing the boat to ride higher on its lines and plane earlier - lots of win win cycles going on here. I do also question however what is going to happen if a foil that lifts at 2 knots, when it gets going so much faster...... Apart from ripping the rudder attachments clean off the stern (which are not originally designed to take a force in this direction) I suspect that the crew are actually feeling the damping effect on longitudinal pitching that horizontal foils give - rather than true lift. The Weta is after all also somewhat short for length. I can also foresee some serious platform racking going on when the two systems do get a wriggle on. Link to post Share on other sites
duncan (the other one) 670 Posted October 7, 2015 Share Posted October 7, 2015 T rudders on planing or fast displacement boats are intended to pull the stern down and keep the bow up, not provide lift that pushes the bow down. Not always. Boats like National12's use them to provide significant lift in displacement mode. Crew moves aft with boatspeed to compensate and keep hull trim. Foiled lift is more efficient (less draggy) than displacement lift. Link to post Share on other sites
Doug Lord 1,219 Posted November 6, 2015 Author Share Posted November 6, 2015 More on the Weta story: http://www.wetamarine.com/news-and-events/video-weta-foiling-experiment/ Link to post Share on other sites
joke989 3 Posted November 6, 2015 Share Posted November 6, 2015 how do it handel in 12kn of wind? got to be faster the more wind it gets? Link to post Share on other sites
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