International Hydrofoil Society Correspondence Archives...
(Last Update 11 Nov 03)
[12 Feb 03] I am creating a presentation on government inventions, and I was wondering if you had any numbers concerning the economic value of the hydrofoil industry. Either how much revenue is derived internationally, or anything like that which can help me out. -- Kathleen Rooney (KATHLEEN.K.ROONEY@saic.com)
[15 Mar 02] Well it's gotten to the point where I am going to build a small working craft of about 7 m, but there is one problem. I cannot work out the math on the amount of power it will give (I build, design, and have a good idea how it all works) but when it comes to these sort of math, I am out of my depth. So I can calculate the weight and power of the generators etc. I have asked a few others, and nobody can give me a real opinion, as there would be a water slip factor, so the traction could be taken off. That's the problem with new ideas. So?? do you know any member who would like to help with this problem. Please read the attached article first; it will help you understand the drawings and how it works, why, what etc. -- Ken Upton (email@example.com)
[20 Aug 02] I am not at all convinced that foils traveling in a straight line are more efficient than those rotating about a hub as in a conventional turbine. The math is simpler, that is all. The main doubt that I have is that even if the efficiency is better, the efficiency of a tidal or river turbine is not important in itself. The energy is free. That which you don't capture is wasted anyhow. The measure of usefulness is power output per $. It seems to me that the conveyor of foils will be so much more expensive to build and maintain than a propeller that it will never compete. I do think more use should be made of renewable energy and less from fossil fuels, and if this conveyor of foils helps, that's great. However, it has to be cheap enough to compete. Anticipate the argument that if you are trying to get power out of a river, you can get much more out if you build a dam. The reasoning is this: In a river, the water looses potential energy as it falls, and gains kinetic energy. However it never gains much kinetic energy because the friction losses build up as it gets faster, which limits the speed to about 10 mph or less in most rivers. At that speed the kinetic energy is the same as the potential energy of a 3 ft drop. So to extract more energy than you get from a 3 ft drop, you can install multiple turbines with a 3 ft vertical difference at intervals along the river, or you can build a dam. The dam slows the water down so that there is negligible friction loss along the reservoir (or it would have a slope!) so the whole drop is available in one place for big turbines. -- Malin Dixon (firstname.lastname@example.org)
[10 Mar 02] With the untimely death of John Reeves, we have lost the best authority on Wing-in-Ground-effect craft (WIG) or Ekranoplans as they are also known [Such aircraft fly very close to the water surface (typically within a chord length). This improves the lift to drag ratio of their short wings - Editor]. However, ALL of the work that the Russians did, including Ekranoplan, was deemed a failure by the study group sponsored by DARPA, several years ago. John's work was on a completely different tack, and it offered real hope for success. I believe a Capt... Hillyer, at NAVAIR is continuing that work. WIG has too many problems in safety of flight and control to warrant serious study except in very special cases. -- Nat Kobitz (KobitzN@ctcgsc.org)
[10 Mar 02] I have Turkish, Japanese, Greek, American and Italian ferries photos and cruise ship photos. If you want to exchange, please write me. -- Fatih Takmakli Chicago-USA (email@example.com)
[10 Mar 03] IHS posts photos of hydrofoils in *.jpg formats but does not as an organization sell or exchange hard-copy photographs. There may well be individuals who as members or visitors to the site are interested in doing so, however. The Ebay auction site is a good source for such photos, especially in the form of postcards. You may also want to visit Tim Timoleon's Classic Fast Ferries website and Konstantin Matveev's Russian Hydrofoil site. Finally, you may want to visit the cruise ship section of http://www.usnavalships.com/ and contribute information and photos to help build the site. -- Barney C. Black (Please reply via the BBS)
[2 Sep 01] I think this will interest your members. I will join IHS soon. I am in AYRS and am just getting into hydrofoils. With reference to the attached draft design, I would like just to ask one question: What foil would give me the maximum combination of lift and drag factors working together... I think a fat camber foil . It will be only moving at 1-2 mts /second as the load factor will control the speed. This is opposite to all the uses of foils, so far as I know. Any help??? Ideas, etc. always welcome. -- Ken Upton (firstname.lastname@example.org)
[11 Sep 01] It seems you may be asking what foil profile would give you a good lift-to-drag ratio or both a high lift and a high drag? What you really need to do to maximise the power input on your device is to select a foil profile, planform and angle of attack relative to your conveyor that maximises the combination of thrust and velocity of the foils (ie: Input Power = T x v). I have never really examined such an issue before and I only have a few old aerodynamics books so I can't give you any good advice on foil profiles. -- Martin Grimm (email@example.com)
[11 Sep 01] (We have had one response that your design appears workable, but your emails were brief to the point of being a bit cryptic. The respondent tried to rephrase and expand upon your inquiry according to his understanding of it, as follows. - Webmaster): I am working on developing an invention I have for a water turbine in which multiple foil units are mounted on a horizontal conveyor belt type of arrangement. This arrangement is partially immersed in the flowing water of a river such that the foils on the lower section of the conveyor belt are submerged and on the upper section they emerge from the water again. The action of the water current on the submerged foil sections causes the conveyor belt to rotate and drive a generator unit mounted at one end of the conveyor system. The conveyor may best be positioned at an angle to the flowing water such that the foils when moving around the conveyor also travel downstream while submerged (and return upstream on their return travel along the top of the conveyor). I anticipate the foils on the conveyor will only be moving at around 1-2 metres/second depending on the strength of the current. I would like to know what foil arrangement would give me the best combination of lift and drag from the foils in order to maximise the power input to the generator. I think a larch chord length cambered foil may be suitable but would welcome your advice.
[12 May 01] I would like to know where you can purchase hover craft skirts, or designs on skirt designs and what they are made of. -- Adrian Hibbard (firstname.lastname@example.org)
[12 May 01, updated 3 Nov 02] A good place to start is at The Hovercraft Cruising Club (THCC) whose purpose is to provide a common location to find information for all those interested in hovercraft cruising. Their Web address is www.hovercruiser.net/. [This site has dropped off the web. If anyone knows its new location, please notify the IHS webmaster!] Also checkout the website of the Hoverclub of America. Whether your interests lie in Constructing, Cruising or Competing your source for Hovercraft information. Their Web address is http://www.hoverclubofamerica.org/.
[18 Jan 01] Just a quick note to let you know that Mitsubishi is giving a paper on its experiences with the fully submerged hydrofoil catamaran, RAINBOW at the Fast Ferry Conference in New Orleans, 13th - 15th March. The second diesel driven fully submerged hydrofoil catamaran RAINBOW 2 operated by the company, entered service in 1998 following the 5 year operation of its sister vessel RAINBOW. The paper looks at the trials and tribulations of bringing both craft into service and how the technical upgrading of both craft allowed the pair to run a technically free service from 1999 - 2000. If you want to know more about the 17th Fast Ferry Conference & Exhibition, either drop me a line or go to the website and click on the conference logo at the bottom of the page. -- Giles Clark (email@example.com); Fast Ferry Conference & Exhibition; 4midable Ltd; Windmill Oast; Beneden Road; Rolvenden, Cranbrook, Kent TN17 4PF; Tel: +44 1580 240055; Fax: +44 1580 240066; website: www.4midable.net
[2 Dec 00] The Center of Ekranoplan Technologies (ALSIN) has a website with detailed info on WIGs including a small ekranoplan AQUAGLIDE, an achievement in aircraft and shipbuilding that can glide above water, snow and land in all climatic zones, all weather with speed up to 170 km/h. The Center has other developments in this field with information on the website.at field which You would be interested in organizing new tourist lines. -- ALSIN email: (firstname.lastname@example.org)
[10 Nov 00] Hi, I am a professional 3D modeler-animator, and I'm looking for some blueprints, diagrams or any schematics for a 4th generation cruiser boat, to construct it in 3D for a project. What I'm looking for is a turistic cruiser, those that operates with a crew of 3000 to 5000 and about 3000 passengers, and travels in the Caribbean region. I've been told those are "4th Generation" vessels, white and big. Do you remember "Love Boat", well, the new ones are twice the size, and I need blue prints, since I'm building it in 3D software. -- Fernando Gonzalez S. (email: email@example.com) ( website: www.digitalshopfx.com)
[10 Nov 00] You may be thinking of a project that was called 'Phoenix World City' - a huge ship for floating conventions with three hotel-size superstructures and about 1200 feet long. Not sure if the project is still being pursued, but at one time Title XI loan guarantees were being sought from MARAD (U. S. Maritime Administration). -- Mark Bebar (firstname.lastname@example.org)
[10 Nov 00] See also the Seascape website at http://www.seascape1.com/ - Barney C Black (Please reply via the BBS)
[13 Oct 00] Looking for all info/patent abstracts on fully-submerged Turbojet(s) that have be intergrated into hydrofoil designs. I am an investor who has been approached to become involved in a project. Your site is great! -- Louis Parker (LouisLFP@worldnet.att.net)
[13 Oct 00] --Turbojets are everywhere. If you are implying turbojet engines, 43 years ago I worked on and tested an underwater ramjet in a submerged foil. Worked fine, but like other ramjets needed a different means to start up. We tried ejectors with marginal success. I don't know of any recent work. Maybe this message will wake some memories in the IHS members. -- Nat Kobitz (KobitzN@ctc.com)
[13 Oct 00] I am not sure how to interpret this request. Are you making a reference to waterjet units that are fully submerged? Of course there have been several waterjet propelled hydrofoils built over the years, namely the Patrol Hydrofoil Missile (PHM) and the Jet Foil. These actually only have the waterjet intake ducting submerged and the waterjet impeller (or pump) is mounted in the hull above the foilborne waterline. The water emerging from the waterjet impeller is simply expelled out of the back of the foilborne hydrofoil through a nozzle well above the waterline. I vaguely recall seeing a French hydrofoil concept (possibly in Jane's Surface Skimmers of around the mid 70's?) which featured what appeared to be almost like a submerged waterjet unit mounted at the intersection of the rear foil and its support strut. If on the other hand 'Turbojet' is a reference to a gas turbine engine, there are also such units driving a range of hydrofoil types, including fully submerged hydrofoils. In that case the gas turbine engine itself is still in the hull above the water and is drawing in air rather than water!
[5 May 00] I thought you might be able to help, since there would seem to be some similarity between hydrofoil sections and those for free-flow tidal turbines. Having spent 20 years developing and building wind turbines in Britain and California, I am now looking to develop electricity-producing turbines for strongly tidal areas. These will eventually be up to 20m diameter or so, with a capacity of about 500 kW per rotor. My website, address below, shows what these might look like. The first thing I want to do is build a small demonstration model, about 5 ft diameter, and test it in the Thames near to my home in London. However, I am stumped on what hydrofoil section to use, and where the cavitation limits on speed will be. For the model, the chord at 75% radius will be about 0.1m, traveling through the water at say 8 m/s (i.e. 11 m/s tip speed), giving a Reynolds number of about 800,000. This is low, compared to the data in Abbott and von Doenhof, however it is roughly comparable to a 5m diameter wind turbine rotor. Most of these have airfoils with gentle and predictable stall, and are given taper and twist resulting in a flat-topped limit to power (at constant rotational speed). I would think underwater mills could operate in the same way, subject only to a cavitation limit and, of course, lower speeds and turbulence than in air. I am assuming 11 m/s (22 knots) is about the limit to avoid cavitation, and that a standard NACA 15% or so airfoil would be OK. Do you agree? What about cavitation speed limit - any other comments? -- John Armstrong (email@example.com); Work Tel/fax: 0(044)181-994-2645; 76 Dukes Avenue, LONDON W4 2AF; Mobile Tel: 0(044)831-398492; Home Tel: 0(044)181-994-0685; Websites: www.jac.ndirect.co.uk and www.windenergy.co.uk.
[5 May 00] A cursory look leads me to say that there is no problem whatsoever at the speeds anticipated. Cavitation is not a problem if designed for. We ran the SES efficiently with supercavitating props at 80+ knots, with no damage. More of a problem that can be expected is logs, debris, etc. in the water. Also remember, water is incompressible, and high aspect ratio, thin foils tend to oscillate destructively. Good luck. -- Kobitz, Nat (KobitzN@ctc.com)
[5 May 00] I have the following response which I know is not a full answer to your questions:
1. As you have already noted, there should be many similarities between wind turbines and water turbines as the basic physics behind their operation remains the same. The differences are all in the nature of the fluid the turbine is operating in as follows:
Air Salt Water
1.223 kg/m3 1025.9 kg/m3
~1.4x10-5 m2/s 1.188x10-6 m2/s
10 m/s (say, in a good breeze) 3 m/s (say, in a tidal stream)
The fact that salt water density is about 840 times greater than air density means that for the same inflow conditions, including the flow velocity, a given turbine (if strong enough to handle the extra load) would produce about 840 times as much power in water than in air!
2. I have not had the chance to look at your web site yet as I currently can not get access to Internet. Your description of the demonstration model is sufficient for me to understand your intentions.
3. Cavitation is a phenomenon which, of course, does not occur for wind turbines but could be a problem with water turbines. The cause of cavitation is straightforward. If at any location on the blades of a hydrofoil (in this case, the blades on the water turbine), the water pressure is reduced below vapor pressure for water, then it will change state and become steam. Normally we are familiar with steam being produced when water is heated beyond 100 degrees Celsius at atmospheric pressure. In the case of water flowing over a hydrofoil section, the combination of an ambient water temperature of say 15 degrees Celsius combined with a very low pressure will produce the same result. The vapor pressure below which water turns to gas (or cavitates) is quite variable and depends on whether we are dealing with fresh or salt water, the water temperature and even the gas content in the water. Gas content and other "impurities" in the water can trigger cavitation at a higher pressure than would otherwise be the case.
4. The onset of cavitation can have the following detrimental effects on hydrofoils, including propeller blades and water turbines:
- A lift breakdown occurs for hydrofoils and in the case of propellers, this corresponds to a thrust breakdown in comparison to the thrust which would have been produced without cavitation occurring.
- The collapse of the cavitation bubbles on the blades or downstream causes underwater noise and can also induce vibration.
- Under certain conditions, the collapse of cavitation bubbles, as the pressure rises above vapor pressure again, can cause erosion of the hydrofoil surface / propeller blade. This is evident by distinct pitting of the surface of the hydrofoil / propeller blade. In the case of propeller blades, it is often visible at the leading edge near the outer tips or also at the blade root near the propeller hub.
5. There are foil sections for both hydrofoil craft and for propeller blades which are specifically designed to operate in a fully cavitating condition. These are known as supercavitating hydrofoils or propellers. In that case the hydrofoil or propeller blade profile is wedge shaped with a blunt trailing edge. The idea is that the water turns to vapor (steam) at the leading edge of the foil on the low pressure side and this vapor cavity remains over the whole of the low pressure side of the foil / blade and only collapses back into water well downstream of the blade. Such hydrofoils or propellers are however not as efficient as the more conventional subcavitating or fully wetted hydrofoils / propellers.
6. A final clarification: Cavitation is not the same as ventilation. Ventilation occurs when air is sucked down from the water surface and onto a hydrofoil or into a propeller due to the low pressure it is creating. On outboard propeller legs, "anti-cavitation plates? are often fitted. I believe these actually act as fences which help to stop air being sucked down from the surface and into the propeller. Ventilation also causes propeller thrust to be reduced just as cavitation will do. The same is possible for a water turbine and you will have to ensure ventilation is avoided to get the best performance from your turbine.
7. For ship's propellers there are some rules of thumb concerning the avoidance of cavitation and also far more sophisticated methods of calculating the pressure distribution over the blades to check on the risk of cavitation. I don't know how well the rules of thumb will apply to turbines which take energy out of the water rather than put energy into the water as propellers do. The simplest propeller cavitation criteria I am aware of is the Keller Criteria which sets the required blade area for a given propeller design and depends on the submergence of the propeller below the waterline, the thrust required to be produced, the number of blades and the vapor pressure. At this stage, I am unclear how the formula can be applied to a water turbine as a turbine does not produce a thrust, but rather has a drag force acting on it as it spins. I will give that some further thought.
8. A more rigorous approach for designing propellers is to use what are commonly known as "cavitation bucket" diagrams. These show the limits of cavitation free performance on a hydrofoil / propeller blade profile at various angles of attack as a function of their cavitation number. The cavitation number is in turn dependent on the ambient water pressure at the location of the foil, the flow velocity over the foil and the vapor pressure of the water. The diagrams vary depending on the blade shape selected. Limits for both cavitation on the face and back are provided on such diagrams. Thus the diagrams show the range of angles of attack, both positive and negative, which the foil section can tolerate without cavitating for a particular flow velocity and head of water pressure (or in other words, foil submergence). I do not have any cavitation bucket diagrams handy at the moment so I can't give you a worked example. In any case, to do that, you would need to give me more details of the RPM vs. torque characteristics of the generator load on your turbine, and details of the envisaged pitch and number of blades etc. on the turbine impeller. Better still, if you defined the inflow conditions (flow velocity past blade and angle of attack of blade) at various radii on the blades then a direct check on cavitation could be made using a suitable diagram.
9. My gut feeling is that 22 knots combined with a small blade angle of attack and a streamlined blade section should be OK for cavitation free operation, but I would prefer to see that is actually the case by reference to the appropriate cavitation bucked diagram.
10. A NACA 15% (or NACA 0015) foil profile is symmetrical for both its upper and lower surface. Such foil sections are typically used for surfaces which need to produce an equal amount of lift in both directions such as ship's rudders, yacht keels etc. I believe you would get a more efficient turbine if an asymmetrical foil section was used (such as is the case on the wings of an aircraft or the blade sections on a propeller). I also have a feeling that a thinner foil section (with a thickness to chord ratio more like 10%) would give greater efficiency and hence more output power. This will depend on the strength required of the turbine blades as there is no point in having too thin a section only to see it snap in half! For typical ship or aircraft propellers, the thickness to chord ratio increases the closer you go from the tip towards the hub of the propeller. The same would apply to a turbine where the bending forces increase as you near the hub.
I hope this partial response helps you in the meantime but I will give your questions more thought and try to give a more complete answer as time permits. -- Martin Grimm (firstname.lastname@example.org)
[14 Feb 00] I am searching for information on LARGE hydrofoils; those over 250 tons. Jane's has some information and illustrations of Russian miltary hydrofoils, but this is very sparse. I know that the largest Russian hydrofoil was BABOCHKA at over 400 tons. There was also SARANCHA which was somewhat smaller. I'm not sure of the dispalcement and dimensions. Also, did the Russians do any conceptual designs of very large hydrofoils, say 1,000 tons or larger?? Any pictures? I would appreciate it photos (color prefered) of all of these and some technical information on each. Also, I would like any information as to how many commercial passenger hydrofoils are operating in Russia at this time. I had heard at one time there were over 1,000. Is that true? -- John Meyer (email@example.com)
[23 Jan 00] I would like to draw your attention to a new virtual magazine, CLASSIC FAST FERRIES, of which the premiér issue is just out. As its title suggests, CFF is not o n l y about hydrofoils, but incorporates also other "traditional" fast ferries such as catamarans and hovercraft. What you will not find in CFF though are stories about conventional ferries or ships in general, as these are being covered in multitude by others already. I do not intend to start charging money for CFF at least not in its present form. and right now I cant see it in any other form. but I might just reconsider the minute a big spender walks in the joint and offers me to fund the transformation of CFF into a real magazine, glossy paper and all! How will it survive? By means of a lot of devotion to and enthusiasm for the subject! It isnt always money that makes the world go around (though it usually helps) some of the best works are those made out of love for the subject in question; i.e. wherever a natural cant-help-myself enthusiasm is allowed to flourish and be the driving force. My interests lie in this topic fast ferries in general and hydrofoils in particular and my decision to lauch this venture is no sudden impulse. Ive been collecting info/photos/memorabilia for years and wish to think that I know what Im talking about. However, CFF will not survive without help. Hopefully IHS members and others will consider donating some photos. As to writers guidelines for submitting articles... cant say Ive drawn any such up yet as to what depth or breath an article should have. As long as the prospective author writes about what he (she) knows best, and it slots in with the magazines coverage. For instance, we do not intend to include military craft (unless converted into passenger vessels) or hobby craft not to be confused with scale models of (commercial) fast ferries which are indeed welcome. -- Tim Timoleon (firstname.lastname@example.org)
[7 Aug 99] I wonder if you know if anyone in the DC/Maryland/Virginia area has a Windrider Rave (hydrofoil) sailboat? Perhaps even in Annapolis? I'm not a pro sailor, but just an interested recreational sailor who has an interest in 'foiled' craft. -- Greg Lennon (email@example.com)
[2 Jun 99] I have a Chaparral 1830SS with a 4.3L 190hp Mercruiser Alpha One I/O. This boat tends to porpoise a lot in choppy water, which is often, as I cruise on Lake Erie. I'm considering adding a "hydrofoil stabilizer" to the sterndrive to reduce porpoising, and am wondering if any of your members have any specific experience with such an add-on on a similar boat. Brands are: StingRay, Cobra Professional, Doel-Fin, Tiger SharkVG, Cabella's Speed Wing XI, or SE Sport 300. Some must be better than others for certain characteristics, since there are significant variations in the designs. -- Marty (Winogeek@aol.com)
[25 Aug 98] I'm thinking about buying a pair of Hydrofoil Stabilizers for my 31' powerboat. They are fitted over the propellers on my stern drive I/O motors. The maker claims they will give me a smoother ride and bring the boat on plane at speeds as low as 10 mph. Is any of this true? They cost about $200 a pair. -- James Eric (JamesEric@compuserve.com)
[25 Aug 98] IHS has received several queries about the effectiveness of these stabilizers, and we have links to several manufacturers of them in our links page. However, we have yet to receive any comments, positive or negative. So if you do buy these, please let us know how they work out for you so we can share your results with others who write in. Thanks. -- Barney C. Black (Please reply via the BBS)
[26 Aug 98] My experience with this mod is com si com sa. They do tend to flatten the low speed running angle, but it is not on plane. Is merely apparent aft displacement augmentation and, depending on mounting location, could affect propeller efficiency. -- Nat Kobitz (firstname.lastname@example.org)
[28 Aug 98] I had a 17 foot open bow I/O runabout. I installed a hydrofoil fin on the Volvo outdrive. I did not make any measurements but have only my feelings of the performance changes. Initially, when starting out, the bow starts to lift, giving the foil a larger angle of attack and thus increased lift on the stern. This helps the boat get on plane faster in time. I believe the minimum planing speed did not change. The drag of the foil decreased the top speed by a couple of knots. In my case, it was not my concern. Since I generally had a group onboard, I feel it helped balance the pitch. Being bolted on one outdrive, it did nothing for roll. -- Sumi Arima (Arimas1@juno.com)
[26 Nov 01] The following advice from R. Baker, Jr. is reprinted without comment from http://www.scaryfast.com. "Hydrofoils: These have been marketed to guys with John Boats and little aluminum boats for years, but racers know the importance of adding planing surface to your gear case in order to help it idle flatter and get up on plane quicker. There are a couple of secrets that I've found through the years. One, is that the planing surface should NOT extend back further than the anti-cavitation plate does already. This can reduce your top end by 200 rpms. The other is that the plates built by Allison and Johnson Racing in Minnesota have the outsides curled down in order to keep water around the prop. This increases the efficiency of the propeller and allows it to hook up better even when mounted at higher engine heights. This can be one of the best ways to spend $100 for your boat. For Bass boaters, the extra planing surface will also reduce the "squatting" of your boat when coming off plane and will reduce the backwash of water coming over the back of the boat." -- Barney C. Black (Please reply via the BBS)
[5 Dec 98] We are running a English-built hydrofoil in Queenstown New Zealand. Would you be able to help us as we have only taken over. Here is a photo and what info I have come up with: Built by Porthleven Shipyard Limited Porthleven Cornwall. In 1966 the model PT4 Hydrofoil was built as a patrol boat, but unlike our hydrofoil, only had a small cockpit which would carry only 4 people as ours had a custom top built and can carry 18 people. She is 30 feet long and powered by a 440 Chrysler V8. --David Esler (email@example.com)
[6 Jan 98] It is pleasing to hear that the New Zealand PT 4, originally named METEOR III, is still well and good. Back in 1994, my friend Garry Fry (Sea Flight Cruises) in Sydney Australia was interested in obtaining the PT 4 for operation in Sydney Harbour before deciding a larger craft would be more suitable. He subsequently imported the Rodriquez PT 20 MANU WAI, also from New Zealand. Garry and I had discussed some technical issues concerning the PT 4 when he was considering its acquisition. Supramar AG, who were the designers of this hydrofoil, provided Garry with some technical information but they had little of the original design data remaining. Only a handful of the PT-4 craft had been built, and that was many years back. If you can gain access to the early issues of Hovering Craft and Hydrofoil magazine, then you can read an article written about your very own boat on page 40-43 in Vol. 5, No. 3&4, December-January 1965-66. I will send a copy if you can not get access to it. The article refers to it as a Wykeham-Supramar PT 4 and includes overall technical details, a photograph of the craft and some general arrangement drawings. Please look after this treasure of a hydrofoil. I would be keen to take a ride on it if I ever get over to New Zealand. -- Martin Grimm (firstname.lastname@example.org)
[1 Jan 99] please can you help me to find the address of your former President Baron Hanns von Schertel or his family? I try to get some contact to the Schertel-Sachsenberg-Group in relationship of high-speed ships. -- Dr.Ing. Juergen Heinig (email@example.com)
[31 Dec 98] I am doing genealogical research on the surname Schertel. I would like to find out if there is a record of Baron von Schertel mailing address or that of his descendants. There is a reasonable chance, with such a rare name as Schertel, that he and I may have common ancestors. It is interesting to note that Baron(Freiherr) von Schertel was also "von Burtenbach." I have been able to retrieve a print of the original Baron von Schertel who is listed as Baron Sebastianus von Schertelius von Burtenbach. He lived in the town of Burtenbach (which still exists today) in Bad Wurttemberg, Germany. Based on the telephone white pages for Germany there are no Schertels living in Burtenbach (unfortunately!!). At that time the nobility would "latinize their names" perhaps it sounded more distinctive. The name Schertel is rare. Apparently there are only about 400 families in the world. Of course there could be more, but according to the records there are not. The Schertels of the last 400 years were scientists, writers, etc.; even one painter ( Joseph Schertel ((1810-1867)). I have found my genealogical search to be interesting to say the least. Supposedly my great grandfather operated the first steam locomotive in Bavaria for which he was awarded a sword which I have in my possession. -- Herman Max Schertel (firstname.lastname@example.org)
[6 Jan 99] For Herman Max Schertel: I hope I am writing to a relative of the Baron's. The Baron and I were close friends for several years. I never met any of his personal family but we visited on several occasions and played some golf. He was a tough competitor on the golf course.. I always enjoyed our get-togethers both with men and women. I never understood why he never married. With no immediate family our get-togethers were primarily technical and business related. Perhaps addresses of his places of business might be helpful to you: He opened his design and business office for hydrofoil boats in Switzerland. Supramar Hydrofoil Limited, Ausserfeld 5, CH-6362, Stasstad. Switzerland. His principal builder was Rodriquez Cantiere Navale, Spa. Via S. Raineri 22, 98.100, Messina, Italy. -- Bob Johnston
[8 Jan 99] For Dr. Ing. Juergen Heinig and Herman Schertle: Baron Hanns von Schertel died some years ago The company he founded with assistance from Gotthard Sachsenberg, Supramar AG is still listed in Jane's High Speed Marine Craft as a consulting firm, refer to Jane?s for the details. In an article in the IHS Newsletter of Summer 1996 concerning Gotthard Sachsenberg, Robert Johnson reported that the Sachsenberg shipyard fell into Russian hands after World War 2. You may also wish to contact Thomas Wuhrmann who had written to the IHS in mid 1997 indicating he had hoped to write a book about the (Supramar designed) hydrofoils on Lake Lucerne, Central Switzerland. It is a long shot, but he may have some information you need. His address is Bahnhofstrasse 18, CH-6370 STANS Switzerland. -- Martin Grimm (email@example.com)
[31 Dec 98] If anyone is interested, I have some university (Tokyo, Yokohama) prepared reports of studies and towing tank tests on these low speed hydrofoil propulsion devices. - The Chinese Yuloh, the Japanese Ro, also known as the oriental sweep, or over the transom sculling. Other sources I have identified so far: (1) Junks and Sampans of the Yangtze, by GRG Worcester, 1940, (2) Ozawa Rowing article on traditional Japanese Ro. -- Richard Watson (firstname.lastname@example.org)
[20 Mar 98] Do you have any data on Rodriguez hydrofoil FLYING FISH converted to DISCO VOLANTE for the James Bond film Thunderball? Last known in Jane's High Speed Marine Craft, 1990. If you have any data, please contact me at [contact information deleted at request of author - ed.]. Thank you!!!
[16 Oct 99, updated 3 Nov 02] There is a picture on the Rodriques Cantari Navali webpage on this subject: An ad placed subsequent to filming states, "Safe, thrilling, spectacular, FLYING FISH was used in Thunderball, one of the most popular 007 James Bond [movie] sagas. FLYING FISH was the first commercial hydrofoil [for] sightseeing use in the Western Hemisphere. The advertisment: All-aluminium, 20 tons, 65 feet long, propeller-driven. She moves at 20 m.p.h. with her hull in the water. When up on her foils, she glides smoothly above the seas at 40 m.p.h. Comfortable, all-enclosed, wide window passenger compartments. Deep cushioned aircraft-type seats. Forced-air ventilation. Capacity: 60 passengers. Completely safe, Coast Guard approved. Unsinkable hull has eight watertight compartments for buoyancy. Diesel powered, no fire hazard. Smoking permitted at all times. Type: PT 20 ; Seats: 72; Yard building number: 052 ; Delivered in: 1957; Line: Manila-Corregidor; Country: Philippines" -- Barney C. Black (Please reply via the BBS)
[18 Aug 98] I wish to build a very tall foil vessel for extremely rough water conditions. can you tell me if you think it possible to get a 20 to 30 passenger vessel flying as high as 15 or 20 ft' off the surface? -- Kahanu (email@example.com)
[25 Aug 98] To Kahanu: There are two problems: 1. The mass of the foil system will be very big for this rather small ship. This give results in significant increasing of propulsion. 2. It will be necessary to apply deeply immersed foils and automatic control system. So the cost of this ship would be very high! -- Konstantin Matveev (email: firstname.lastname@example.org) (hydrofoil website: www.hydrofoils.org)
[26 Aug 98] To Kahanu: Another problem might be the transmission of propulsion power to the water. If it is propellor or waterjet driven, the shafting or water intake piping would add considerably to the weight. (This was the problem for the early "Jetfoil design - longer struts meant more water, which added to the weight, which in turn increased the power required, etc. etc.) If reaction jet (gas turbine) powered, that would not add a great deal of weight, but these tend to be power limited for take-off, and of course the noise is a factor. -- Ralph Patterson (RAPatterson.email@example.com)
[29 Aug 98] To Kahanu: the first question is whether the tall strut is necessary. All the US Navy hydrofoils were designed for sea state six or less. One needs to study the sea condition data and the odds of encountering the situation where longer struts would enhance the ride. Some hull contact with the waves does not necessarily degrade the ride quality. Naturally, the longer struts has to be traded for increased structural and hydrodynamic forces. -- Sumi Arima (Arimas1@juno.com)
[7 Nov 97] We own a 17' Oldtown Scanoe (square stern canoe) powered by a 5HP Yamaha outboard. The scanoe weighs 120lbs, and is well balanced if I sit in the center and row it. At this point she only draws only 2" of water. However, when I add the outboard (45lbs) and myself (190lbs)to the stern she draws 6" of water at the stern and never levels out. The nose always rides high. Does anyone have a design that I may build that will raise the stern at a moderately low speed, say 2 knots so it will plane and only draw 2" of water? -- The Lenehans (firstname.lastname@example.org)
[16 Oct 97, updated 8 Feb 01] Anyone curious about the operation of the Boeing 929 Jetfoil, feel free to respond. I operated the first boats in Hawaii and then moved to Seattle working with Boeing Marine Systems as captain in their test group. -- Hal Burchard (email@example.com), Burchard Marine Consultants
[17 Oct 97, updated 8 Mar 99] Hal was one of the original skippers in Hawaii. When operations shut down there, Hal signed on with Boeing for a time, as did one other PSTL (Pacific Sea Transportation, Ltd) skipper, Loren Thurston. Hal later went on to be the skipper of the Boeing yacht that spends most of its time in Alaska, entertaining company customers. -- Joseph H. Schobert (Dirigo99@aol.com)
[2 Sep 97] I read in the Summer '97 issue of the IHS Newsletter about the American Bureau of Shipping (ABS) rules for high speed craft and will order a set. Do you know if there is a set of Coast Guard rules for safety? --Stan Siegel (firstname.lastname@example.org).
[2 Sep 97] The U. S. Coast Guard publishes a multi-volume "Marine Safety Manual" which can be downloaded from their website in Adobe Acrobat format. The Table of Contents does not mention high speed craft specifically, but there may be info buried in the individual chapters. The USCG (and IHS) participated actively in reviewing the International Maritime Organization's (IMO's) safety standards for high speed craft, published as Chapter X of the International Convention for the Safety of Life at Sea (SOLAS), available from from various booksellers. See the IMO home page for more info. -- Barney C. Black (Please reply via the BBS)
[3/1/97] I've come across an interesting mechanical device for stabilizing submerged foils on small craft. It consists of a weighted pendulum that, of course, swings on a pendulum and turns a bellcrank to kick foils up and down. Any knowledge of such a thing? I'd appreciate a reply from any who could even speculate on this. -- Evan Riddle (ERiddle229@aol.com)
[3/15/97] The concept of using a pendulum to control port and starboard foils to make a coordinated turn was tried when mechanical control systems were being studied. I think the experimenter was Gordon Baker. The whole concept of mechanically controlled foil systems was in due course overtaken by the use of electronic systems. I don't know of any attempt to control foils longitudinally in a seaway with a pendulum. -- Bob Johnston
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