R/D: Student Projects/Thesis etc.

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Wake Energy and Damage From Fast Ferries

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[Date/Time=03-21-2002 - 10:47 PM]    Name:webmaster@foils.org [Msgid=236659]

Cavitation

Cavitation Bucket Diagrams...

[2 Mar 01] We are French students working on foils and the problem of cavitation. In the FAQ of your web site, we have read a message of Mr Martin Grimm who speaks about cavitation bucket diagrams. We would like to find an example of these diagrams to illustrate a tutorial project. Could you help us by sending us a diagram or any valuable information? -- Mathilde Pascal ( Mathilde.Pascal@etu.enseeiht.fr) and Ludovic Léglise ( hya54@etu.enseeiht.fr)

Responses...
[2 Mar 01] I've attached an excerpt from the paper I just gave to the Chesapeake Sailing Yacht Symposium. It shows such a diagram and discusses its relevance to the hydrofoil design. I've also included an enlarged version of the diagram. I've chosen a somewhat idiosyncratic way of plotting this diagram. The X axis is often angle of attack, but I've chosen to use lift coefficient because different sections have different zero-lift angles of attack and lift coefficient is what really counts to the designer. But the biggest difference is that I have plotted velocity ratio on the Y axis instead of pressure coefficient or cavitation number. I did this because pressure coefficient is proportional to velocity squared, so it emphasizes areas of high velocity which are not of real interest. By plotting vs. velocity ratio I have expanded the bottom of the chart which is where the section will be operating when cavitation is a concern. The other thing you will find on this chart that I've never seen on any other diagram is an overlay of freestream velocities and foil loading corresponding to incipient cavitation. I found this really helped me to understand the section curves in the context of the boat's design. I haven't actually plotted it out yet, but I suspect that had I used pressure coefficient for the Y axis, the lines of constant foil loading would have been straight lines. Finally, my apologies for using English units. I'll leave conversion to metric as an exercise for you students! -- Tom Speer ( tspeer@tspeer.com) website: www.tspeer.com; fax: +1 206 878 5269
[6 Mar 01] Tom Speer has already given you a good reply following your request for examples of 'cavitation bucket diagrams'. I will however provide you one more example which is presented in the more usual manner with section cavitation number on one axis and foil angle of attack on the other. The attached diagram has been adapted from one of the figures in a very well presented and comprehensive book on the subject of marine propellers, namely: Marine Propellers and Propulsion, by J.S. Carlton (Senior Principal Surveyor, Technical Investigation, Propulsion and Environmental Engineering Department, Lloyd's Register) Butterworth-Heinemann Ltd, Linacre House, Jordan Hill, Oxford OX2 8DP First published 1994. ISBN 0 7506 1143 X.
There are no scales on the axes of the diagram as it is illustrative only. You can see from the shape of the curve where the 'cavitation bucket' term came from. Even though you may already be familiar with the terminology on the diagram, I will run though it for completeness:

The section cavitation number is defined as:
Sigma o = (po - pv)/(0.5 rho V2)
where:
po = Free stream pressure in absolute terms, i.e. not relative to atmospheric pressure (SI units would be Pa).
pv = Vapour pressure of the water in absolute terms (SI units of Pa).
rho = Water density (SI units would be kg/m3)
V = Free stream velocity, i.e. well upstream of the foil (SI units would be m/s)
(I have avoided using subscripts or the usual Greek symbols so that I can send you this message in plain text)

For a foil traveling say 1 metre below the water surface in salt water, po can be calculated as:
po = patm + rho.g.h
where:
patm = Atmospheric pressure, say 101300 Pa
g = Acceleration due to gravity, say 9.81 m/s2
h = submergence of the foil (in metres if using SI units consistently)
hence:
po = 101300 + (1025 x 9.81 x 1.00) = 111355 Pa
In salt water you can take the vapour pressure to be say: pv = 17000 Pa to be on the conservative side. The vapour pressure of distilled fresh water can be as low as 1700 Pa.
You can see from the diagram that at high angles of attack, cavitation will occur on the top side of the hydrofoil (called the 'back' in propeller terminology). At low or negative angles of attack, the low pressure moves to the bottom of the hydrofoil (this being called the 'face' on propellers). If the water flow past the foil is fast enough and the foil is not deeply submerged, then cavitation can even occur when the foil is at the zero lift angle of attack. This form of cavitation is referred to as bubble cavitation because of its appearance. This cavitation occurs simply a result of the thickness of the foil which causes the water velocity to increase slightly as it passes the sides of the foil and in turn the local pressure of the water drops below the vapour pressure.
These days, there are techniques available to design foils which are fairly tolerant of variations in their angle of attack and so can avoid the onset of cavitation. Such foil sections have a fairly wide cavitation bucket (defined by the parameter "alpha d" on the figure), though the limit at which bubble cavitation occurs may then shift to higher cavitation numbers so the bucket is no longer as deep. -- Martin Grimm ( seaflite@alphalink.com.au)
Follow Up...
[10 Mar 01]We have built a model of a foil with a NACA 0015 profile. Where could we find the cavitation bucket diagram corresponding to this kind of foil? Mathilde Pascal ( Mathilde.Pascal@etu.enseeiht.fr) and Ludovic Léglise ( hya54@etu.enseeiht.fr)
Follow Up Response...
[11 Mar 01] Here is how you build a cavitation diagram:
Go to http://raphael.mit.edu/xfoil/ and download XFOIL. This is the most powerful airfoil section design tool available. Do not think of using anything else you can download from the Web -they are all inferior to this program.
Put in the coordinates for your foil.
Analyze the section for a number of angles of attack, covering the intended range of operation. Examine the pressure distributions for each angle of attack.

For each angle of attack, record the minimum pressure coefficient that occurs anywhere on the section. The cavitation number, sigma, is simply the negative of the minimum pressure coefficient, Cp. (sigmai = -Cpmin where sigmai is the cavitation number for incipient cavitation and Cpmin is the minimum pressure coefficient)
Plot the minimum pressure coefficient vs angle of attack or lift coefficient, according to which you prefer.
Repeat steps 2 through 5 for each section you wish to consider.
I recommend you plot sigmai vs CL for the following reasons. If you disregard the vapor pressure of water, which is small, the critical speed for incipient cavitation at the surface is approximately
Vcrit = 14/sqrt(sigmai) m/sec
sigmai = (14/Vcrit)2
Vcrit is the freestream velocity above which cavitation may occur. Note that this is a horizontal line when superimposed on a cavitation diagram. If you know the freestream velocity (boat speed) and you know the lift coefficient, then you know how much load each square meter of the foil is carrying:
L = CL * 1/2 * rho * V2 * S
[L/S]crit = CL * 1/2 * rho * (Vcrit)2
[L/S]crit = CL * 1/2 * rho * 142/sigmai
sigmai = {1/2 * rho * 142 / [L/S]crit} * CL
Note that for any given foil loading (L/S), the quantity inside the braces {} is a constant so this is a diagonal line extending from the origin of a sigmai vs CL plot.
Finally, to put together the whole cavitation picture, do the following:
Lay out axes of sigmai vs CL
Plot horizontal lines corresponding to the critical cavitation boat speeds.
Plot diagonal lines corresponding to the foil loading for incipient cavitation. Note that this forms a grid which is independent of the choice of foil section.
Plot sigmai vs. CL for the hydrofoil section.

Now, not only do you have the cavitation diagram for the section, you can relate it to key design aspects of the boat as a whole. You can see immediately how heavily the foil can be loaded and how fast the boat can go before encountering cavitation. Since the grid is universal, it can be used to define the requirements for designing a hydrofoil section, which you can do with XFOIL as well.

There is an excellent paper on the cavitation of hydrofoils in the latest issue of the Society of Naval Architects and Marine Engineers' Journal of Ship Research, written by researchers at the Institut de Recherche de l'Ecole Navale, 29240 Brest-Naval, France: J.-A Astolfi, J.-B. Leroux, P. Dorange, J.-Y Billard, F. Deniset, and S. de la Fuente, "An Experimental Investigation of Cavitation Inception and Development on a Two-Dimensional Hydrofoil," Journal of Ship Research, Vol. 44, No. 4, Dec. 2000, pp. 259-269. It shows more cavitation diagrams and also the degree to which experimental cavitation occurs at Cpmin. The agreement is excellent at the bottom of the bucket and Cpmin is a conservative estimate for the sides of the bucket. They also discuss the interaction of cavitation and laminar flow, which will be important for your low Reynolds number experiments. -- Tom Speer ( tspeer@tspeer.com) website: www.tspeer.com; fax: +1 206 878 5269
[Date/Time=03-22-2002 - 11:50 PM]    Name:webmaster@foils.org [Msgid=237110]

Hydrofoil Racers -- Power or Sail

Hydrofoil Racers -- Power or Sail


Student Project: Racing Hydroplane
[5 Mar 02] I am currently a student at Teesside University in England studying Computer Aided Design Engineering. As part of a project we have to improve on an existing hydrofoil design. The boat my team has chosen to improve upon is to be capable of racing in the 2002 Unlimited Hydroplane Series of which the boat MISS BUDWEISER is currently the title holder. Could you please advise me as to where I may find design specifications of such boats especially in relation to the cockpit area (safety) and the steering mechanism incorporated in the craft? -- Ben Coward ( bencoward1@hotmail.com)

Responses...
[5 Mar 02] You have an interesting project, however our site is concerned mostly with fully submerged and with surface piercing hydrofoil designs. We have next to nothing on hydroplane racing craft. I am sending a copy of this response to Leslie Field ( www.lesliefield.com/) and to Simon Lewis ( www.simonlewis.com/) in the hopes that they can suggest a source the design specs you seek. You may have luck by contacting directly the racing crews of specific craft or the racing association. -- Barney C. Black ( webmaster@foils.org)

[15 Mar 02] The American Power Boat Association puts out all the specifications for the various classes of hydroplane racing crafts. MISS BUDWEISER is in the unlimited class. I believe they are presently headquartered in Detroit, Michigan. I had some discussion at one time with a former crew chief of a hydroplane racing team who wanted to put hydrofoils on the sponsons. I believe he proposed it to the APBA but was rejected at the time. -- Sumi Arima ( arimas1@juno.com)
[Date/Time=03-23-2002 - 12:51 AM]    Name:webmaster@foils.org [Msgid=237128]

Archive; Hydrofoil-Related Student Projects

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http://www.foils.org/students.htm
[Date/Time=03-24-2002 - 1:20 AM]    Name:webmaster@foils.org [Msgid=237490]

Info wanted on Hydróptero      ViewThread

At 08:02 PM 4/24/02 -0400, you wrote:
Hellow,

I'm student of Transport, and I have to investigate for Hydróptero. I want to now if hydrofoils and hydróptero are the same type of boat?

If you have more informatión of characteristics, possibilities and restriccions for hydróptero, I apreciate you send me by E-mail.
Sonia Madera
somade@cantv.net
[Date/Time=04-26-2002 - 9:00 PM]    Name:Sonia Madera somade@cantv.net, [Msgid=252390]

Info wanted on Hydróptero

There are many magazine articles and books about hydrofoils. Visit the following page: http://www.foils.org/refpop.htm. Or, for a long list of technical references: http://www.foils.org/refs.htm.
[Date/Time=05-03-2002 - 7:20 PM]    Name:Barney C. Black webmaster@foils.org, [Msgid=255144]

Swath ships architecture Thesis      ViewThread

Dear Sirs,

My name is Giancarlo Raiola and I am a student of Naval Architecture at the Federico II University in Naples (Italy).

I write to you because I visited your web site and I found very interesting all the information about Swath ships. As a matter of fact, Swath ships architecture will be the subject of my graduation thesis, so I would be very pleased if you could send me some more detailed information about them, as for example their general plans and about active motion control sistem .

I look forward to receiving your answer soon.
Best regards
Raiola Giancarlo
[Date/Time=07-04-2002 - 3:23 PM]    Name:Raiola Giancarlo raiola.roberto@tin.it, [Msgid=278810]

Swath ships architecture Thesis

Dear Raiola,

The International Hydrofoil Society is primarily concerned with hydrofoil craft and to somewhat of a lesser extent the application of hydrofoils to other marine vehicles. As a consequence, you will not find a significant amount of information about Small Waterplane Area Twin Hull (SWATH) vessels on the IHS website.

A good overview of SWATH vessels is provided in Naval Engineers Journal, Volume 97, Number 2, February 1985. ISSN 0028-1425. Published by the American Society of Naval Engineers, Inc. (ASNE). More details of that issue can be found on the IHS website under the section about magazines related to hydrofoils.

There is a hybrid between a hydrofoil and a SWATH known as Hydrofoil Supported Small Waterplane Area Single Hull (HYSWAS) and you may find more information about that craft on the website.
[Date/Time=07-13-2002 - 3:57 AM]    Name:Martin Grimm seaflite@alphalink.com.au, [Msgid=281953]

Info wanted on Hydróptero

Hi Sonia, there is a French hydrofoil with name of "L'Hydroptere" go to http://perso.wannadoo.terrasse.web/hydroptere800.html (No longer available as of 060130WNW)

Brush up on your French, as the site is French.
[Date/Time=09-19-2002 - 5:13 PM]    Name:Vivian Dewey vvdewey@yahoo.co.uk, [Msgid=312049]

Hydroplane Formula`s?      ViewThread

I am wondering how do i figure out the lift of a foil and the lift coefficients (what formula's do i use).

This is for a fourth year mech eng project. Basically iam looking at a V-shaped waterplane and a torpedo shaped one with winglets on the front and back of the torpedo. The boat we are trying to design is about 1m in height, 2m in length and 1m in width and weighs about 1500 lbs and has to hydroplane at 20 knots(min). So if anyone could help me out with advice or formula's i would greatly appreciate it. Thanks
[Date/Time=09-29-2002 - 9:26 PM]    Name:Kris MacKenzie krismackenzie@hotmail.com, [Msgid=316589]

Hydroplane Formula`s?

There are a number of different ways to calculate lift and drag of simple hydrofoils. For following two NACA papers are useful.

http://naca.larc.nasa.gov/reports/1958/naca-tn-4168/naca-tn-4168.pdf

http://naca.larc.nasa.gov/reports/1955/naca-report-1232/naca-report-1232.pdf

Alternately if your library has a copy of Du Cane's "High Speed Small Craft" the is a chapter which presents somewhat simpler formulas for hydrofoil calculation.
[Date/Time=09-30-2002 - 12:09 PM]    Name:Gunther Migeotte gmigeotte@artanderson.com, [Msgid=316835]

Hydroplane Formula`s?

thanks for the info
i'll read the 2 papers and see what i can come up with
[Date/Time=10-01-2002 - 12:58 PM]    Name:Kris MacKenzie krismackenzie@hotmail.com, [Msgid=317375]

Info Source for Foil Profiles      ViewThread

I am a mechanical engineering student at the University of Nottingham, England. As part of my course I have been given the task of designing a human-powered hydofoil designed to carry two people. The craft needs to travel at a speed of 5m/s and be small enough to fit on a trailer. I have decided that a two-hull design would be best with a fan-powered propulsion system using simple gears and chains to transmit power. The problem I am having is finding information on foil designs, and in particular, foil profiles with information on how much lift and drag each profile generates with information on how these values are determined. I would be extremely grateful if you could send me any information you have on foil profiles or any links for me to follow up. Also if you have any information on human- powered hydrofoils and how I should aproach my design.

[Date/Time=10-21-2002 - 6:49 PM]    Name:Ben Jones emyubdj@gwmail.nottingham.ac.uk, [Msgid=326753]

Info Source for Foil Profiles

There is very little literature on hydrofoil sections, but all the equations and software available for aeroplane wings works for hydrofoils. One of the standard works is "Fundamentals of Aerodynamics" by John D Anderson. The latest edition is quite expensive, but if you can find a previous edition they are a lot cheaper.

There are various software applications that can calculate the lift and drag coefficients for any foil section and angle of attack. I have used an application called "Panda" from Desktop Aeronautics Inc for this. I think that these applications use 2-dimension finite element analysis to work out the flow patterns and pressure at each point on the foil.

The actual lift and drag can be calculated from the coefficients and the liquid density, speed and dimensions, with suitable adjustments for the aspect ratio. All the equations are in Fundamentals of Aerodynamics. They are quite complicated.

This approach is probably only valid for high aspect ratio wings, and won't model the interaction with any struts. However human powered hydrofoils will certainly have high aspect ratios. Strut to wing interaction is not a big problem. Even Boeing has only recently learned how to model it, so it must have been relatively unimportant.
[Date/Time=10-22-2002 - 7:53 PM]    Name:Malin Dixon gallery@foils.org, [Msgid=327252]

Info Source for Foil Profiles

In addition to Malin's excellent suggestions, here are a few additional resources you may find helpful:

http://www.humanpoweredboats.com/Links/L_Research.htm - Various links to research articles and informational web-sites. Not all hydrofoil specific, but some will be helpful to you.

http://www.amazon.com/exec/obidos/ASIN/0873228278/o/qid=947990877/sr=8-1/104-9565347-4271660 - "Human Powered Vehicles Book" by Abbott & Wilson. This has a very detailed chapter on human powered hydrofoils, written by Dr. Allan Abbott, co-builder of the "Flying Fish" series of boats. You will find just about all the calcs needed for human powered hydrofoils in this book.

http://www.humanpoweredboats.com/Photos/HydrofoilHPBs/HydrofoilHPBs.htm - Photo gallery of successful human powered hydrofoils.

http://lancet.mit.edu/decavitator/Decavitator.html - Web-site for MIT's "Decavitator", which won the DuPont prize for fastest human powered hydrofoil in 1991.

http://www.orange.or.jp/~jsha/ - Japanese Solar and Human Powered Boat Association. The Japanese teams are currently the best in the world, and recently set the multi-rider world-record at 34.59 km/h over a 100m course.

[Date/Time=10-24-2002 - 9:02 AM]    Name:Ron Drynan Ron@humanpoweredboats.com, [Msgid=328140]

Info Source for Foil Profiles

The Society of Naval Architects and Marine Engineers (SNAME) has published the technical bulletin Blade and Hydrofoil Section Design. This bulletin includes the Blade and Hydrofoil Section Design Codes with a 29-page Owner's Guide, and a 184 page Technical Report. It updates and complements T&R Bulletin 1-17. The Design Codes and Owner's Guide provide tools for the design and performance evaluation of blade and hydrofoil sections. The programs are provided in both DOS and Mac formats and will run on most personal computers. The Technical Report provides analytical background information and is of interest primarily to those who wish to adapt or enhance the programs. This new publication is identified as Technical and Research Bulletin 1-45. It is being issued as a CD-ROM, and may be ordered by contacting cpujols@sname.org or by calling +1-201-798-4800. It is priced at USD50 (USD25 for SNAME members).
[Date/Time=10-29-2002 - 7:20 PM]    Name:Barney C Black webmaster@foils.org, [Msgid=330718]

Ways to Cross the Channel      ViewThread

I am doing a research project on different ways to get across the English Channel. I was wondering if you have any useful links or information about using hydrofoils.
[Date/Time=10-31-2002 - 5:43 AM]    Name:Tracy Bickford tracybickford@hotmail.com, [Msgid=331484]

Ways to Cross the Channel

IHS does have a links page at http://www.foils.org/linksout.htm. You should also check our page on popular books (http://www.foils.org/popbook.htm). You may be able to find some of these books such as Hovercraft and Hydrofoils in your library. We have a similar page for popular magazines at http://www.foils.org/popmags.htm. Finally, I note that Steve Gillett of the Red Funnel ferry company recently sold two of the Shearwater hydrofoils through a notice on the IHS site. I don't know if he would answer you, but there is an email address and phone number for him in his notice, which is on our page at http://www.foils.org/buyferry.htm. Hopefully one of those resources will get you started.
[Date/Time=10-31-2002 - 5:50 AM]    Name:Barney C Black webmaster@foils.org, [Msgid=331485]

Supercavitating Propellers      ViewThread

I am a student at Naval Architecture and Ocean Engineering Faculty of Istanbul Technical University. I have homework about supercavitating propellers. If you have any text,photos,videos or CD about supercavitating propellers, could you help and post me?
[Date/Time=11-05-2002 - 8:37 AM]    Name:Yasin Uslu usluyasin@hotmail.com, [Msgid=333656]

Supercavitating Propellers

The SES S/C prop data is still classified.
[Date/Time=11-07-2002 - 8:23 AM]    Name:Nat Kobitz KobitzN@ctcgsc.org, [Msgid=334738]

solar hydrofoil      ViewThread

might be a usefull link for anyone researching this stuff.
www.ses.marquette.edu
would love to hear comments from anyone.
[Date/Time=11-17-2002 - 1:07 AM]    Name:Terrence Breitsameter Bensenvill@aol.com, [Msgid=339189]

solar hydrofoil

Terry
Thanks for the reference to the Solar Hydrofoils.

I will add it to our IHS links page. They are very interesting. If you have any more performance details we would welcome your comments.

Bill White
[Date/Time=11-23-2002 - 6:47 PM]    Name:Bill White whitewn@flash.net, [Msgid=342528]

Surf Hydrofoil Project      ViewThread

hi there, I am studying Surf Science at the university of Plymouth. I am looking into the application of hydrofoil technology to surfboard fin design for my third year project.
I am going to construct a hydrofoil fin that can lift a surfer at between 8-20 knots.
I have been researching foil cross sections but am at a bit of a loss as to which one too choose due to the vast amount of sections and data
presented. My initial thoughts were to use a symmetrical NACA 0012 foil but then thought that something like the NACA 2412 would be more suitable and provide more lift. I also noted that many of the Eppler E8's such as E874 were reccomended for hydrofoil use. How do symmetrical foils compare to non and do you have any recommendations for foil cross sections that I could use.
Thank you for your time.
Ben Bryant.
[Date/Time=02-07-2003 - 1:26 PM]    Name:Ben Bryant benjamin.bryant-mole@students.plymouth.ac.uk, [Msgid=374049]

Re; Surf Hydrofoil Project

You might take a look at this section, http://www.nasg.com/afdb/show-airfoil-e.phtml?id=1187, since it was specifically designed for sailing hydrofoils.

The main benefit of a cambered section over a symmetrical section is that camber shifts the section characteristics to a nonzero lift coefficient. Maximum lift is generally increased, and the minimum drag can be centered on the operating lift coefficient instead of zero lift. Of course, this means you also have to estimate what the operating lift coefficient is, and this will come from the foil loading (weight carried per unit area) and the speed.

The Hydronautics handbook on the AMV CD has an excellent chapter on foil sections and optimizing the foil span and planform.
[Date/Time=02-08-2003 - 2:15 PM]    Name:Tom Speer me@tspeer.com, [Msgid=374620]

Re; Surf Hydrofoil Project

The AMV CD referred to by Tom Speer is the collection of Advanced Marine Vehicle design documents available on CD-ROM from the International Hydrofoil Society at a cost of USD 5.00, including shipping worldwide. For details, see the IHS website at http://www.foils.org/ . Note that IHS is very close to releasing a second AMV-CD with additional documents. The Hydronautics handbook is on the first (original) CD-ROM.
[Date/Time=02-09-2003 - 7:06 AM]    Name:Barney C. Black webmaster@foils.org, [Msgid=374969]

Re; Surf Hydrofoil Project

In my humble experience with playing with hydrofoil wave-riding vehicles, I've found that the most critical problems I've faced are related to stability and control. I've used both symmetrical and asymmetrical airfoil sections, but so far I've not been able to discern any significant difference in speed as I've been too busy with control issues.

The importance of the foil section also will also depend on your primary design goal. If your primary goal is pure speed (and you will be towed into a wave, as with the Air Chair-based hydrofoil boards under development by Laird Hamilton), then the section choice becomes more significant than if you're interested in traditional surfing (i.e. paddling to catch the wave) and/or in maneuverability.
[Date/Time=02-20-2003 - 12:13 PM]    Name:Terry Hendricks thendricks@pacbell.net, [Msgid=381786]

Re; Re; Surf Hydrofoil Project      ViewThread

thanks a lot friend, im draving cad plans to my model, your help and experience is apreciate, regards from spain.
fernando palacio
[Date/Time=02-26-2003 - 4:44 PM]    Name:fernando palacio edreira armadillo@teleline.es, [Msgid=385452]

Re; Re; Re; Surf Hydrofoil Project

Please note that there is no need to post identical messages in each forum of the BBS. In the future, please select the one forum most appropriate for your message and post it there one time. Thanks!
[Date/Time=03-11-2003 - 12:49 PM]    Name:Barney C Black webmaster@foils.org, [Msgid=393772]

Stability of planing vessels      ViewThread

I am a student at Plymouth University (UK) and am doing a project on the stability of high speed planing vessels. Any suggestions? I need info! Thanks.
[Date/Time=03-21-2003 - 7:28 AM]    Name:Nick Farrer nickfarrer@hotmail.com, [Msgid=400452]

Re; Stability of planing vessels

I don't know your exact interest, but if you're good with the Internet, you'll find it all. My favorite linear theory porpoising papers were by Peter Payne and Milton Martin. Some experimental work was done recently by students at USNA and in Korea. Lateral stability is a little tougher. Blount and a few others have looked at nonlinear effects. A good starting place is the old Peter DuCane book. We've been working on augmenting stability for small planing boats (like ferry ride control systems) here in the US. I can probably help you track down what you need.
[Date/Time=03-22-2003 - 12:14 PM]    Name:jim hynes jhynes@socal.rr.com, [Msgid=401113]

HELP ; how to build a hydrofoil boat      ViewThread

hi i am a student in the 9th grade. my partner and i are doing a project on mini hydrofoil boats for our science class. could you give us a list of materials and stuff to build a small hydrofoil boat, about 10x5 in.
[Date/Time=03-25-2003 - 8:05 PM]    Name:Jabari Gilkes greatone__316@hotmail.com, [Msgid=403010]

Plans and parts list for model needed      ViewThread

I presume you propose to build an operating, radio-controlled model hydrofoil as opposed to a static model that just sits on display. This sounds like a fun project, although there will be some costs associated with the control equipment. To get an overview of different models that other people have done, and also to get the names and email addresses of people who you might want to ask to advise you, please see the following pages on the IHS website:
http://www.foils.org/modelrc.htm
http://www.foils.org/gallery/models.htm
http://www.foils.org/linksout.htm#plans

For a good example of a motor-powered model hydrofoil boat, see Graham Taylor's website at http://www.home-taylor.freeserve.co.uk/content/rapier%20page.html

For a good example of a sail-powered hydrofoil boat, see the 750mm sailing yacht model website at: http://www.home.aone.net.au/cybernautics//750.html

After you are successful with your model this year, you may want to build a hydrofoil that you can actually ride in for next years project. There are plans available in back issues of Popular Science and Science and Mechanics. The May 1960 issue of Popular Science has plans for a 4' x 8' wooden boat with wooden foils. The June 1960 provides mounting instructions to add the foils from the prior month's issue to any existing boat up to about 16 feet.

The Feb 1960 issue of Science and Mechanics has plans for foils made of steel frames and fiberglass foil surfaces. The following issue (Apr 1960) has plan for building a small runabout that you can add the foils to.

For information on these magazines and suggestions where to find copies of these old issues, see our page at:
http://www.foils.org/popmags.htm#hob

Hopefully that information is of some use to you. Good luck on your project.
[Date/Time=03-26-2003 - 5:07 PM]    Name:Barney C. Black webmaster@foils.org,