From a Wiki article on WW2 German Schnellboot: - Small rudders added on either side of the main rudder could be angled outboard to 30 degrees, creating at high speed what is known as the Lürssen Effect.[5] This drew in an "air pocket slightly behind the three propellers, increasing their efficiency, reducing the stern wave and keeping the boat at a nearly horizontal attitude".[6] This was an important innovation as the horizontal attitude lifted the stern somewhat, allowing even greater speed, and the reduced stern wave made E-boats harder to see, especially at night
Lürssen effect is very different (more like a pair of vertical adjustable trim tabs): www.modelwarships.com/reviews/ships/dkm/s-boat/s-100-72/72-S-100-p2.htm
Wow, 12-14% is HUGE savings for something so relatively simple.. Great Innovation...sharply lowers Fuel Cost, Maintenance, OPEX and GHG Emmissions! Congratulations....
Firstly, I love this tech. I don't have a degree in hydrodynamics, but I did once pick apart and disprove the work of a PHD in Hydrodynamics. Just because fun, and his work was messing with my mechanical design. Q&A: Any of these systems have variable AOA, for the purposes of and not limited to: fine tuning to an existing vessel, variable for power setting, vessel speed, sea state, other. Also variable positioning up/down, for/aft for same reasons. Also any option for one on the back of a dive boat with active hydraulics for mitigating aft deck pitching! After a scuba dive, It's no fun trying to board a ladder pitching past you a couple of vertical meters.
We are working on an active version (Dynamic Hull Vane), but the AOA is mainly a function of hull shape, and therefore not very speed-dependent. The purpose is to vary the AOA to vary the lift, and therefore increase pitch damping.
They should be made in a more of a swept wing shape, in order to hopefully freely dislodge any rope, buoys, kelp, or other floating debris that could otherwise get entangled in the vane.
Some of our Hull Vanes have a swept wing indeed. What you see in the video (5 years old) is the very basic TT-shaped configuration. Floating debris has never been an issue as the water coming over the Hull Vane has passed through the propellers and over the rudders first.
When 14 (1968), driving down the highway with my parents, I thought a scoop atop the cab of semi trucks would deflect wind from hitting the flat face of the 'box'. I think I told my parents of my idea, crickets.
Cool idea! A while after watching this video it crossed my mind that maybe something similar, though upside-down, could be applied to my car. I have a VW Bug, which has a steeply sloping rear end, which causes a lot of drag as the air flows down along it. A wing placed at the right angle and position in this flow, redirecting it toward the rear, might have a net thrust force, countering some of this drag and improving fuel economy. Would also provide some downforce, a secondary benefit (I'm not a racer) of making the car feel a little more solid at freeway speed. Probably not as much downforce as the lift the car generates, but to make more would add drag, the primary goal being fuel economy, not lap times. Somewhat related to the downforce wings racecars have, I see it as sort of combining that idea and this "hull vane," though said wings redirect horizontal air upward to generate a lot of downforce, plus drag, while this would redirect downward flow to horizontal, gaining thrust and some downforce. Two challenges I see are that this would place a low-pressure area near the engine cooling air intakes, which would make the engine run hot, and also I'd have no idea how to determine the optimal position, angle, airfoil shape, and size without either a wind tunnel or very sophisticated CFD, neither of which I have access to.
Hi Quill, a very good idea, and there are indeed car spoilers (wings) which produce a net forward thrust as they are positioned in a downward flow of air. This is the reason why the Hull Vane is sometimes called an "inverted underwater spoiler".
FYI, the term you are searching for at #3 at about the 3:00 min. mark is called "Squat", and is what the hull vane is actually compensating for, or correcting.
Squat is especially important in shallow water, and yes the Hull Vane is effective against squatting due to the large vertical force developed at a low speed already. But the effect is much more than that (e.g. forward thrust, wave reduction), and we hope the video illustrates that.
Cool invention that actually works. It is weird to think about though. Seems like it wouldn't work because it adds more weight to the vessel and anything below the water line will add more drag no matter how hydrodynamic it is. But the data does not lie, it does work.
There are many things that take up space and weight and still reduce drag by improving hydro- or aerodynamics. Bulbous bows on ships, corner vanes on trucks, wingtips on aircraught wings, shaped helmets on time-trial cyclists, to name a few.
Question, when doing your research and development of this design how deep did you go into the design at the starboard and port horizontal end of the hydrofoil? Specifically, did you do analysis using "winglets and scimitar winglets like Airbus and Boeing?
Hi Apack, good question. Winglets can help in some cases, but not as general as on aircraft wings. It depends of the local flow and the speed range of the vessel (narrow vs. wide). Some of our Hull Vanes are U-shaped, which means the wing curves up at the tips, to become the struts.
Hi Carmel, that is a misconception. Optimizing just the trim angle will give you a few percent. The Hull Vane can save 10-15% on many ships by removing the trim tab (or wedge), even if you end up with the same trim angle eventually. It influences the trim of course (strong vertical force) but this is not always even desirable. The effect is really in the generation of forward thrust and the modification of the wave profile of the ship. I would say it's more similar to a bulbous bow than to a large trim tab.
An interesting video. I’m curious, does this provide more benefit to ships with a bulbous bow, through the synergy of keeping it at the ideal level it was designed for? Or as this adjusts trim, and the bulb was probably designed with the innate trim of the ship in mind, does this necessitate redesign of the bulb to see maximum gains? 🤔
Hull Vane works both on ships with bulbous bows and without. They work well together, but some ships (e.g. RPA 8) are too slender in the bow to gain from a bulbous bow, and can still have a big benefit from the Hull Vane. Hull Vane helps keep the vessel more even-keel throughout the speed range, which is advantageous for the bulbous bow.
I read that this concept has been install on a catamaran initially,there is not much review on the results of this attempt, i am interested in this concept mainly to sail under low wind and to keep the bow out the water for increased speed,can you shed some light on this?
Would it make sense to retrofit a sailing yacht with a wing? One couldn't install it to far aft, though (marinas, docking,...). Im aware that there are foils for sailing yachts, but they are advanced to manage, expensive and hard to retrofit.
Yes, it can make sense, but it depends of the sailing yacht's shape, displacement and speed. Just the optimisation is often already too expensive. Payback period is hard to achieve when you don't consume fuel...
Go to any outboard motor retailer, ask them to show you a set of 'Doel Fins', these have been in use for decades. Just a variation on hydrofoils, going back to 1890's from John Thornycroft.
so like an outboard hydrofoil ? those things suck. they add yawing forces and make steering difficult at speed/in waves. i have them on my boat but never again.
How much lift, as a percentage of the ship displacement, is generated by the Hull Vane? Is it the same percentage as the reduced resistance (or required power) you show in the video (12%)? Thank you
I am pretty shure that when large ships are anchored, or docked in a harbor canal, the flow of the water over this 'wing' will cause strong upward forces. Therefor the wing should in fact be able to move, this way it would act more like a pitch-damper (look up yaw-damper in aerodynamics). This would be more of a factory installment instead of a aftermarket product.
i dont think so even if you have like 4kn current this will have nearly none effect... Like an airplane wing will produce nearly 0 lift at 20 kn. Thats why they said it is suited for vessels for 15kn+ (Container, Offshore. milittary) on slower vessels the effect is to small (Tanker, bulker).
I was Ch Officer of a 100m long coastal tanker, max draft 6.0m. When fully loaded i kept a 0.5 -1.0m trim by the stern. Sea speed about 11.0 knots. Contrary to what was shown in the video, at sea speed my vessel takes a trim by the bow, even with initial static trim of 0.5 - 1.0m by the stern. When my ship moves ahead at sea, rain water and sea water on deck would flow forward towards the bow. When the vessel reduces speed on arrival port, the water flowed aft. Perhaps this aspect needs to be studied further. With the hull vane fitted, i presume the ship will be trimmed more by the head when moving at sea, lowering the bow height above water.
wonder if it would tear off in a heaving sea. they show it in still, calm water. mother nature would probably rip that spindly piece of steel right off the hull in an average squall =p
There is nothing new in boats. If you ever see anyone claiming that they have invented some new thing for boats, you can safely bet that someone did it decades ago.
I was watching a ferry today at max power with its bow high up in the air and thought that could be fixed with a wing on the stern to shift the centre of pressure backwards. Then I logged onto here and see this video. Creepy.
Is this still effective when you have two propellers one behind the other on the same shaft that raises propeller efficiency from 60% to 80% .If both can be combined the potential for fuel saving is hugely increased .
Hi Ronnie, yes the Hull Vane would still be effective. Counter-rotating propellers recover energy from the rotation of the propeller flow. Hull Vane recovers energy from the "rotation" (or rather upward flow) given by the ship's hull to the water.
There is no potential application to smaller outboard powered vessels / trailerable craft? The vane has to be positioned behind the propellers? Can it work with surface piercing propellers? Sorry for the 101 questions, just trying to wrap my head around this interesting concept! 👍
there have been outboard cavitation plates for years that do the exact same thing.... i dont believe it has to be mounted behind the propellers because this is controling the water coming out from under the boat, not from the point of thrust
Outboard powered vessels are usually planing boats, and boats with surface piercing propellers most certainly are. There are other foil solutions for such high speed-to-length ratio vessels. Hull Vane is for semi-displacement and displacement boats.
As for trimming the vessel, that's what ballast tanks are for. No moving parts means it will be giving lift when it's not desirable and I wonder if they would break away in a serious storm and in so doing damage the ships structure possibly causing a hull breach?
In an accumulated 33 years of operational use so far, not a single damage or repair. The forces can be calculated accurately, and the Hull Vane is designed for it. Rudders don't fall off ships anymore either.
I have been at sea for 40 years, tankers, box boats, trampers, coasters, north sea standby and fast rescue, I have never seen one in all this time and not one naval architect, captain, engineer has ever mentioned one. I flew commercial hydrofoils in the 80s so fully understand the principle. Send me a list of these ships that have had them for 33 years so I can research them. Until then this looks like and sounds like crap.
Hi Paul, if you send an email to our general email address, I will happily reply with a list of installations and year of installation, on which the 33 years is based,
Looks good. I could justify this more if the tips were active to be used as anti roll stabilizers. But the only real benefit would be commercial vessels that could really see the fuel savings pay for the install more quickly before it broke or needed cleaning and offset any fuel savings.
Hi Michael, the beauty of the Hull Vane is in its simplicity. Very effective with no moving parts, purely from hydrodynamic effects. Similar to the bulbous bow in this respect.
Yes, definitely. Check out Vandervalk Yachts' new 32 m (105 foot) Jangada II for example. Several patrol vessels are under construction with such a hull shape with a Hull Vane as well.
Well, all I can see at the moment is that it is a large trim tab which could modify the angle at which the hull runs, I feel that if the hull alone is running at the right angle this would not bring about any benefits, but only drag. For a hull that is not running at the optimum angle, it many bring some advantages.
@@TechnoGlobalist Well, I have tried this on my displacement boat and since the transom and hull are lifted, then the flow of water will contain an upwards velocity or the rear part of the natural wave around the displacement hull. One is invited to think that putting in a horizontal Vane as suggested in this video one could surf on this rear part of the hull wave and so gain speed, but the drag of the vane and the suction due to the uplift at the rear of the ship's hull is nonlinear and rises at a higher rate and so what one gains, one loses. Nature itself thought it out before we did and so for the greatest efficiency the design must be in the hull itself and not any appenages introduced on the hull. Birds and fish and dolphins and orcas do pretty well without additional appenages. The best manner for efficiency is to design a good hull in the first place. Anything pushed along beyond its natural speed is expensive. Also just because there are no moving parts on the vane, it does not mean that there are no maintenance costs. With my vane, it certainly trimmed the hull to run straight, but at the expense of fuel at the top displacement cruising speeds. If it was not so inconvenient, displacement hulls would benefit if the propeller was put right under the midship as the high pressure at the back of the propeller would then forcefully fill in what in normal condition is a suction zone at the aft of midship run of the vessel. This arrangement would in fact cause the inclined aft part under the ship to act as the vane described in this video. But it is all so inconvenient to add a midship draft to a displacement vessel. I would like to hear about the explanation of the complex principles that you referred to as acting on this vane! for as far as I am concerned it is no more than a wing with the right angle of attack to surf the rear hull wave.
Hi ! I think there is a mistake at 2:14. FX is opposed to the way of the ship (resistance must be backward), isn't it ? Thank you to tell me if I'm right or wrong so that I can understand.
Hi Timothée, it's not a mistake. This Fx is pointing forward and pushes the vessel. Where this forward force comes from is explained more clearly in this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-56HvN5114TY.html . The point is that even though drag is pointing along with the flow, and lift perpendical with the flow, the resultant of lift and drag can still be angled forward, and therefore have a net positive Fx in horizontal direction.
@@hullvanebv2550 Let me please introduce myself : I'm a french student in a engineering school specialized in see technology called SeaTech. I'm mostly interested in renewable energies and ways to reduce our impact on the environment, and I am currently searching an internship. Is it possible to explain you my motivations in a mail, and send you my CV and cover letter ? Thank you to let me know !
Sleek, the equations & multi forces at work might b complicated but the design is perfectly simple. Just behind the ship u a generating lift 1 & 2 the prop & wing r postioned so as to maximize this lift. At rear u hve the most leverage, & lifting force helps to bal out rolling wave force. Smoother ride less drag candy ass simple.
Definitely! In addition to saving fuel, increasing range and top speed, there are interesting side benefits. An aircraft carrier becomes useless when it reaches a certain pitching angle, so reducing the pitch excitation is extremely valuable. Both vessels would also benefit enormously from the visual and acoustic signature reduction.
If a person fell off the deck and landed on top of the hull vane while plunging through the water and sank and landed on the hull vane, would they damage it? Is it sturdy enough to take the weight of a person falling on top of it from the height of a Aircraft Carrier deck while plunging through the water?
The plating on the Hull Vane on such a ship is more than 20 mm thick. I'd be more worried about damage to the person than to the Hull Vane. But apart from the struts, it's a couple of meters below water, so even that is unlikely. Better not to fall off the deck of an aircraught carrier though, you could drown in the aerated water behind the transom, which gives much less buoyancy than normal water.
The Hull Vane results in less pitching angle, regardless of whether the ship has a tumblehome design or not. Anything you add under water is good for seakeeping, it's just that most things also have a drag penalty. For Hull Vane, it's the opposite.
Certainly not negligible. It's a tradeoff: there's a small penalty on frictional drag for a big gain on pressure (or wavemaking) drag. That's why the Hull Vane doesn't work on ships that have only frictional drag.
Interestingly, the International 14 class and the Moth class have found many of these same effects in the past 20 years too, but on sailboats with a "T" foil rudder.
Foiling boats are about creating vertical lift to reduce the wetted surface of a very light ship. Hull Vane is for much heavier and much slower ships, and uses the flow around the aft ship to generate a propulsive force. It's a very different application of a wing.
@@hullvanebv2550 Could they be used in combination? small bow lift foil in addition? Or is it that at lower speeds any additional drag will not be offset by the lift produced?
Would it work on Fishing vessels at speeds of around 5kn? it would be benefitial since the maximum power allowed for fishing vessels is restricted. (but the regulation dating from 1975 never took the shape of the ship into account) If this can help the fishing vessel reach the ideal 'fishing speed' at around 4.5- 5.5 knots, combined with better fuel efficiency and stability that would be very interesting.
if you have a vessel that does a lot of pitching where it operates.. you might want to create a one of your wings that has hinges close to the front edge and can be remotely unlocked on the rear.. this can create forward thrust from the pitching. why dampen it totally when you can use pitching to add thrust. it won't work on vessels that don't have enough pitch during normal operation but some.. there was a study about 25 years ago .. about a sailing hull with a design that had a lot of pitching designed in with hinged wings to create forward thrust.. somebody designed a reversing pitch blade to use with air boxes over swells allowing the change in airflow to spin small generators in the same direction no matter which way the air was flowing thru the fan..
Hi Wayne, good ideas, but as is often the case with good ideas, it has been thought of. We have a version which hinges and has an actuator for additional pitch dampening, called Dynamic Hull Vane. Pitching causes a lot of added resistance, so you generally want to reduce it as much as possible. The (passive) Hull Vane generates forward thrust out of the pitching motions through something we call "the pumping effect", similar to what surfers do on hydrofoil surfboards. The Hull Vane converts both the stern wave and the ship motions into forward thrust, making the ship quieter, more efficient and more comfortable.
Hi, no we haven't. Which 125m yacht can go at 40 knots? The cliosest to what you describe would be the Freedom class LCS of the US Navy (115 m / 47 knots).
Yes, it helps. It reduces the added resistance from pitching and yawing in waves. And it has a pumping effect, like any hydrofoil or wing which is moved up and down in a flow generates forward thrust (like a pumpabike).
I wonder if it increases parametric rolling on fast container ship hulls - or similar? Pitching the nose down in large oceanic seas would seriously affect the ships stability.
I would imagine not. As the stern moves down, the angle of attack of the wing would increase, increasing lift and the force in the opposite direction to motion. As it moves up the angle of attack would be reduced causing the force to be reduced. Thus the force graph would be 90° out of phase with the pitching of the ship and dampen the motion.
Show me a vessel that has it now, has had it for a while, or since it's launch 33 years ago . I have requested a list of vessels employing this as you will see from the online discussion, nothing, and yet no solid reply. honest opinion - this is bullshit.
Paul, you missed the word "accumulated". No ship has it yet for 33 years. The ships that have it, have sailed with it for 33 years alltogether (accumulated). Some examples: Karina, Alive, Thémis, Nieuwe Maze, 18-2, Lola, RPA 8, one of 7, Jetten 65. Check out these videos before you call this bullshit: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-VGjt_y0Scjo.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BWI38IH7ruE.html
Today, I have taken a rib past 9 tankers at Fawley, 3 car carriers, 4 box boats and 3 cruise ships, not one of them has one and the masters I spoke to -OCL, BP Oil, Shell, said they either hadnt heard of it, or wouldn't sail on a ship with it.
Hi Paul, there are over 500.000 ships and boats (with AIS) in the world. Hull Vane is applicable to maybe 5% of them. Only 13 have been built so far. Good luck searching around Fawley, but I do recommend the internet.
Depends which kind of ship, and of how it's used. Tankers and bulk carriers are too slow for this, and you will never get payback. On some others we get less than 3 years, and on some newbuilds 0 years (because the saving on propulsion power is bigger than the cost of Hull Vane). The latter are usually faster than typical cargo ships (e.g. crewboats,).
Generally sailing catamarans are too light and their hulls are too slender for Hull Vane. Better look at fully foiling catamarans, like those of www.dnaperformancesailing.com
Great for reducing drag until barnacles build up on it, thus interrupting the foil shape and essentially canceling out any benefit, but rather adding more drag. Just gotta keep it clean I guess.
This is valid for all surfaces of a ship, but in particular the rudders and propellers, because they see a higher flow speed and are not in the boundary layer. Almost nothing has a better return on investment than regular cleaning (by diver) of propellers and rudders. While you're at it, give the Hull Vane a cleaning as well ;) This also depends of your anti-fouling of course and how often (and at which speed) you sail. Reducing the benefit somewhat is possible, but to cancel out the benefit (10-20% resistance reduction), you'd need an extreme amount of fouling over the entire ship, not just on the Hull Vane.
We have a semi-custom Hull Vane to provide an affordable solution for displacement motoryachts of 10 to 20m with a maximum speed of about 14 knots (trawler-type yachts).
Hi Kevin, that depends of the length of the ship. For a rough idea: for a 20 m about 6 knots, for a 50 m about 9 knots, for an 80 m about 11 knots and for a 140 m about 15 knots. But this also depends of displacement and hull form.
The Hull Vane adds weight, but is often net-weight-negative: it saves more weight in fuel capacity (for a given range) and engine weight (for a given top speed) than its own weight. It can be applied as a weight-saving measure. Also, the penalty of the extra weight is much smaller than the hydrodynamic benefit.
@Hull Vane Bv That's the trick, penalty vs benefit. Now given this device adds stern lift, does that interfere with the protruding bow bulb design ?? Which creates an opposite wave effect and cancels out waves going down the sides of the ship...
@High Velocity, There's not much interaction with the bulbous bow, except that the running trim can have an influence on the bulb's efficiency. The bulbous bow works on the bow wave, the Hull Vane on the stern wave. We have it on both ships with and without a bulbous bow.
Theoretically it could, but it may be cost-prohibitive compared to the benefits (relatively small speed gain on such vessel, higher pointing and better seakeeping). Modern racing yachts (where cost is less of an issue) are too fast for Hull Vane (planing and even foiling hulls).
@@hullvanebv2550 what do you consider to be a small speed gain? On a heavy displacement cruising boat that sails at 8-10 knots a "small" gain of one knot is indeed significant. The damping of pitch would be a nice comfort benefit as well.
It's possible but this only gives resistance reduction at higher speeds than the typical application range of the Hull Vane. For seakeeping it's very interesting, and Hull Vane can be a good combo with a (retractable) T-foil forward.
Capn BillL, My buddy had a 38ft Silverton. It came with trim tabs......We took the boat out to the continental shelf, 'bout 95 miles from Sandy Hook NJ. ( Mako SharkFishing) . We hit some rough water on the way there. So I don't know how efficient those tabs were....Guess maybe in calmer waters they're feasible?
@@tedhernandez2394 Yes, with heavy seas the inertia of the boat when hit by a wave overcomes the lift of the trim tabs. Also they are more effective with speed, hard to attain when you are climbing significant waves.
Hi Captain bill. Hydraulic trim tabs do one of the four effects (see video) of the Hull Vane: trim correction. They do this by creating a lift force which is angled aft. Hull Vane does this with a lift force which is angled forward. This makes a big difference in resistance.
Do you mean interceptors with cav plates? There is a paper comparing Hull Vane with interceptors at various speeds for a typical round bilge displacement hull on our website (AMECRC series 13): www.hullvane.com/papers/
@@hullvanebv2550 Interesting. I'm curious as to the differences between the fixed propulsion you diagram and outboard propulsion. The cav plates/ appended vanes I've seen on either side of outboard driven boats help with planing. I believe that your treatise is also. As well as efficiency.
The recreation market is lower in unit price but larger in total sales. How about a vanes for smaller recreational vessels? Your accountants can explain this to you.
We are shortly bringing out a semi-custom Hull Vane for the recreational market, in particular for displacement motoryachts of 10 to 20 meters with a speed up to 11 knots. There are a lot of those in the Netherlands, Belgium and Germany (a lot of inland waterways) but most recreational vessels elsewhere are fully planing boats, and too fast for the Hull Vane.
yes, but upside down. And water is different than air, and on ships we have a water/air interface, which causes wave formation (and therefore saving potential). There are indeed car spoilers (wings) which also have a negative resistance (downforce+forward force) because they're placed in a downward flow.
The numbers in this video are quite outdated. We've since done several vessels where the measure savings are well over 20%, such as the 52 m OPV Thémis (retrofit) and the 25 m patrol vessel RPA 8. Both are in videos on our RU-vid channel and on our website.
I don't agree with it being complicated, it's like the wing on the back of a van....turned upside down. Reduce drag, and make it more stable. I'm sure I saw this on a RU-vid video about a year ago, thinking what a good idea. What else can we take from the automobile industry, and apply it to boats?
Yes, when a plane fly's horizontally and the air flow comes from the front. But when it comes from the front and below, it is the same as if the airplane is flying slightly downwards, in which case it accelerates. That's how any glider flies. When the wind is coming from below, the plane can fly horizontally and still accelerates, this is how slope gliding works. Same effect here, the water current under the ship moves slightly upwards, and thus the foil can generate lift up and forwards.
This is an IMPORTANT item!! There should be government grants FOR addition of this item to ALL current vessels! I like this, and appreciate the work that has gone into the R&D here! #Conservation #Instagood #BeTheChangeYouWantToSee #SocialMedia #Environment #Efficiency #Maritime #Business #Ship #CargoShip #ContainerShip #MEARSK #STOLT #EXXON #ODJFELL #BP #Aramco
No grants are necessary for many ships, and in particular governmental ships (patrol vessels and naval ships), it's just a really good investment. The payback period is really short on such ships. But be aware that this doesn't work on all ships (only on about 5% of the ships, but on those it works really well).
