The International Hydrofoil Society (IHS) Hydrofoil Correspondance Archives

General: IHS Administration Design of Foils: Foil-Struts-Controls-Performance Design of Vessels: Hull-Machinery-Costs-Performance/Ops History of Hydrofoils: People-Vessels-Operations Hydrofoils: Commercial Hydrofoils: Military
Hydrofoils: Models Hydrofoils: Pleasure Hydrofoils: Sailboats R/D: Student Projects/Thesis etc. Sources, Buy/Sell: Brokers-Builders-Designers-Operators Miscellaneous:Hybrids-Other High Performance Vessels-etc.

Updated last August 22, 2006

General: IHS Administration

General: IHS Administration      Scroll To Top Top

    Site Outage
      The IHS website dropped off the internet for several hours on Thursday 14 August 03 and into 15 August 03 as a result of a massive powerfailure in the Northeastern USA and extending into Canada. Our Canadian Internet Service Provider's (ISP's) hardware, the actual residence of our site, was plugged into the failed grid. The IHS site is back up now that power to our ISP has been restored. Hopefully this ISP will develop a remote backup capability that can come on line if the main computers cease to operate. It appears that no email to or from the site was lost (though delivery was delayed). We regret any inconvenience due to the outage.
      [Date/Time=08-15-2003 - 11:55 AM]    Name:Barney C Black, [Msgid=488408]

    Maintenance Outage 21 Aug 03
      The recent problems with the power blackout in eastern USA and Canada was a "wake up call" for our Internet Service Provider (ISP) and many others. As a result, our ISP is making significant infrastructure investments to upgrade their Data Center. This will all be turned on Thursday, August 21, 2003 with the result that the IHS website will be unavailable between 10 pm and 2am (Eastern Daylight Time). This upgrade will yield significantly higher levels of protection from outage due to floods, fire, or electrical failures in the future. It will also provide improved global network speeds for site visitors. Your patience, understanding and support during this scheduled outage are greatly appreciated.
      [Date/Time=08-20-2003 - 8:51 PM]    Name:Barney C Black, [Msgid=491450]

    Advanced Marine Vehicles CD-ROM #2
      New!!! Advanced Marine Vehicles (AMVs) CD-ROM # 2

      This AMV CD-ROM # 2 has 61 documents with 8650 pages:

      30 Documents on Hydrofoils.
      11 Documents Applicable to Multiple AMV Types.
      17 Documents on Air Cushion Vehicles (ACVs) and Surface Effect Ships (SESes).
      3 Documents on Planing Hulls.
      12 Rare Documents on Advanced Ship/Boat Design with Data.

      Note: Priced at $12.00 for IHS members; $15.00 for nonmembers.
      AMV CD-ROM #1, the first in this series, is still available.

      IHS is making available this CD-ROM collection of technical documents on Advanced Marine Vehicles. These documents have been generally unavailable, as they were in private or government files and archives. It is the Second of a series planned to be produced.

      IHS accepts payment by personal check, bank check, money order or cash.
      We have also arranged for payment by credit card (online only!) at

      The price includes postage, regardless of destination.
      Orders must be pre-paid.
      [Date/Time=08-21-2003 - 7:10 PM]    Name:William White, [Msgid=491987]

    Role of High Speed Craft in the USMC
      For IHS members in the Greater Washington DC Metro area, the IHS quarterly dinner meeting will take place on Thursday 18 September 2003 at the Days Inn, Crystal City, Arlington VA. Go to for the full announcement and details.

      Cost of the dinner program is $25.00 per person. Menu: Rolls, Garden Salad, Marinated Chicken Breast, Green Beans, Rice Pilaf New York-Style Cheesecake, Iced Tea, Coffee.

      The speaker will be LtCol Lawrence Ryder. LtCol Ryder will present an overview of High Speed Vessel (HSV) employment in Operation Iraqi Freedom and in Horn of Africa Operations. LtCol Ryder will discuss the growing importance of high speed craft in the implementation of Navy and Marine Corps transformation efforts. He will also provide an overview of the capabilities of the Navy and Marine Corps' newest ship, HSV 2 SWIFT, which was delivered 12 August 03. Finally, LtCol Ryder will provide an update on the Marine Corps' long-term goals for high speed craft.

      As usual, the meeting schedule will be Social Hour/Cash Bar: 5:30 - 6:30pm; Dinner: 6:30 - 7:30pm; Program: 7:30 - 9:00pm. Make reservations no later than September 15 (Noon) if you plan to attend. Contact: Dave Kaysen: 301-775-2458,; or Bill Hockberger: 301-699-5137,

      [Date/Time=08-26-2003 - 7:02 PM]    Name:Barney C Black, [Msgid=494668]

    Re; Re; Compuserve Bans IHS
      Perhaps to get your site noticed on Compuserve, you must subscribe. Although it was free of charge, the search engine Hotbot required users to register if they wanted their pages to get hit. It could be that the IHS has simply chosen not to pay a fee to Compuserve when Google will hit their site for free.
      [Date/Time=08-31-2003 - 4:31 PM]    Name:Mike K. ame2000, [Msgid=497703]

    Date Change - IHS Dinner Meeting
      In view of the approaching hurricane and its possible effects on our area, we have decided to delay the joint IHS/ASNE SD-5 meeting one week, from Thursday, September 18 to Thursday, September 25. Everything else in our original announcement remains the same: location, time, menu, speaker and topic, etc. See the revised announcement at

      For those who were unable to come on Thursday the 18th, perhaps you can attend now that the date is moved to the 25th. If so, please make a reservation.

      We hope that people who made a reservation for the 18th will still be able to come on the 25th, but we cannot assume this. It will be necessary for you to reconfirm (or cancel) your reservation for the new date by calling or emailing either Bill Hockberger (, 301-699-5137) or Dave Kaysen (, 301-775-2458).

      For anyone who is inconvenienced, we regret the necessity for these last minute hurricane avoidance maneuvers.
      [Date/Time=09-16-2003 - 8:50 PM]    Name:Bill Hockberger, [Msgid=508553]

    Autumn 2003 Newsletter      ViewThread
      The Autumn 2003 edition of the IHS newsletter is available to IHS members from the website at . An email notice was sent to all members for which we have working email addresses. If you are a member and missed the email announcement, send an email requesting the password to In particular, a few recently-joined new members may not have gotten the email.
      [Date/Time=11-21-2003 - 10:20 PM]    Name:Barney C Black, [Msgid=548422]

    Meeting - Seaplanes for Seabase Support
      For hydrofoilers and others in the metro Washington DC area, IHS will sponsor a dinner meeting on December 9. A presentation on Seaplanes will be given as follows:

      The Center for Innovation in Ship Design was tasked by the Office of Naval Research and NAVSEA 05 to investigate the utility of seaplanes for supporting an offshore seabase. Our speakers will outline the history of seaplane development and operation and then present the main results of their study. They will discuss the potential uses and importance of seaplanes for future seabased military missions. They will also identify current technology boundaries and technical issues that need further investigation, including those related to integrating seaplanes into a seabasing environment. Finally, examples of potential design concepts will be shown.

      For details, see the attached Adobe Acrobat file.
      [Date/Time=11-21-2003 - 10:27 PM]    Name:Barney C Black, [Msgid=548428]
      Attached File  "" - size 9192   Click Here To Download

    Re; Autumn 2003 Newsletter
      hello barney my name is steve and i have a small problem. about fifteen years ago i purchased two hydrofoil kits and had evey intention of building them and because of family duties i was never able to get to them. it is now fifteen years later and i was looking for help in order to build these and i realize through your web site that these are rare models and someone who really knows what they are doing should build them. i do not wish to make any profit on these kits , but i would like to see someone who would do the right thing recieve them , unless i could get help and buid them myself. please advise me . they are by the way the Hegi Police hydrofoil rc ship model and the32nd parallel Schnellbopte model. once again i am not offering this as a joke of any kind i really have these two kits , i just never realized what was going on in the model hydrofoil hobby world. up until 24 hours ago i did not know there was a hydrofoil model society, after reading about the hydrofoil models i realized it would be better to talk to you before i did anything with these kits. the kits are complete with all parts and instructions and i have the origional bills of sale , made out to me. so it is in your hands , i appreciate your time and hope to hear from you soon . p.s. by the way i have not built a model in 20 years and even then i had my problems thanks again Stephen Mc Donald New York U.S.A. if you need photos i will send upon your request
      [Date/Time=12-13-2003 - 2:29 PM]    Name:Stephen Mc Donald, [Msgid=558639]

    Thai Hydrofoil Venture Investor Sought
      Message for Thailand Hydrofoil business opportunity,seeking investor, placed in "Sources,Buy/Sell:Brokers-Builders-Designers-Operators" section.

      [Date/Time=04-20-2004 - 12:28 PM]    Name:Garry Fry, [Msgid=633917]

    underwater noise level re;dugongs      ViewThread
      I'm trying to translate a document from Japanese to English where, as a comparison for the underwater noise level produced in a seismic survey (145dB at 100 metres), is given the noise level of a hydrofoil (146db at 100metres).
      I realise that the dB scale is not the same as for dB in air, but not how or why.
      What I would like to know is; Is this a realistic figure? What kind of hydrofoil would this be for? Or is the wool being pulled over my eyes? Are the operators of the survey trying to convince us that the noise level is not significantly high?
      By the way, there are dugongs in the area which are in danger of extinction and may be affected by loud noises.
      For more info on the problem see

      Thanks for your time.

      [Date/Time=05-17-2004 - 9:42 AM]    Name:Simon Varnam, [Msgid=648647]

    Re; underwater noise level re; dugongs

      My familiarity with noise measurements is limited, however for airborne noise monitoring there are different scales that are used to account for different applications. Humans for example can tolerate noise pressure levels better at some frequencies than others. If I recall correctly, the dB(A) scale is often used when measuring the impact of noise on humans. This scale weights the noise level differently for each frequency component being measured before adding their effects together.

      I would say that the same would apply for marine animals, namely that Dugongs could also handle noise levels better at some frequencies than others. Comparing the noise level measured for a hydrofoil (which could be expected to be fairly broad banded) against the output of a seismic system (which may be very narrow banded and in a frequency range harmful to the animal?) could therefore be problematical... regardless of how the dB measurements compare.

      Good luck with you quest for a sound assessment of the risks in this case. By the way, you seem to have forgotten to include the website link you intended to provide.
      [Date/Time=05-24-2004 - 10:26 AM]    Name:Martin Grimm, [Msgid=652999]

    Re; underwater noise level re;dugongs
      I could not help analyzing the noise issue because I doubted seriously the noise measured by the Japanese report can be attributed to the hydrofoil principal alone, and had some potentially useful measurements of my own for comparison.

      From, I find the comparison from air to water is +62db for water. The example cited is a supertanker generating 190 dB is roughly equivalent to 127 dB in air. Ambient noise for the open ocean is 74-100 dB. A blue whale also generates 190 dB. They don't list what Dugongs emit.....

      While the frequency would probably not necessarily be 'broadband', the likely source for a hydrofoil (alone) could be the turbulence in the boundary layer surrounding the foil, various turbulent eddies from vortices, cavitation, ventilated surface bubbles from surface piercing, etc. Weightings may be used (comparing sound levels to the sensitivity of the human ear)and included in the measurement, but any weighting scheme should be reported with the results. Also, the propulsion system (props, water jets, etc.) or support generator sets, etc. would be a major noise contributor.

      The peak to peak amplitude of a time history of surface pressure can be estimated by 4 times the RMS (or also closely by Std Deviation) of the time history, then converted to Db by 20*Log10(P1/P2), P2 being the reference pressure which is 1MicroPa for water. We recently did some dynamic pressure measurements on the surface of a hydrofoil to measure transition of the boundary layer from laminar to turbulent, for which I have RMS values. A sample I looked at today measured 198 Db average (broadband) at 25 Knots on the foil surface itself. The number was similar for 15 Knots. The above web link relates transmission loss as the sum of spreading and absorption loss. The absorption loss is variable with frequency. Neglecting any absorption loss, 198 dB at the surface translates to 4.9 dB at 100 meters. With absorption included the number is smaller yet.

      So, if the foil system is sub-cavitating and operating in a cavitation free operating envelope, my opinion is the foils themselves are highly unlikely to cause such a noise level alone.

      [Date/Time=05-26-2004 - 3:37 PM]    Name:Rick Loheed, [Msgid=654516]

    Re; underwater noise level re;dugongs
      Many thanks for the advice.
      BTW Rick, my e-mail of thanks was returned. Maybe your mail box is full.

      Best Wishes
      [Date/Time=06-02-2004 - 10:40 PM]    Name:Simon Varnam, [Msgid=658001]

    IHS Newsletter Call for Inputs
      To All IHS Members,

      For several years I have served as Editor of the IHS Newsletter and have struggled to obtain appropriate articles to place in the Newsletter each quarter of the year. Martin Grimm, our Sailor's page editor, has been a great help, not only for such articles, but others as well. Others of you have also contributed material from time to time, and this has been appreciated.

      The purpose of this message is top solicit you greater support for interesting hydrofoil material -- particularly NEW and upcoming events and designs that are not published elsewhere (like FFI and Speed at Sea).

      Therefore please send me such articles. A single to 1 1/2 pages including a picture or two would be great!! Of course there is no guarantee that your article will appear in the very next issue of the NL, but we will make every attempt to fit it in ASAP.

      My best regards and thanks,

      John Meyer
      IHS Newsletter Editor
      [Date/Time=07-12-2004 - 8:33 PM]    Name:John Meyer, [Msgid=678443]

    Engine Torque
      Iím currently reviewing a design for a small one-person hydrofoil powered by a 15hp-25hp long shaft outboard. The question of engine torque has arisen and the need for an engine mounted torque converter however; in reading a lot of the design material on these pages (excellent guidance by the way) I have yet to come across this issue being discussed. Is torque a major design consideration on small (<9 feet) hydrofoils?
      [Date/Time=07-27-2004 - 11:14 AM]    Name:Philip, [Msgid=685371]

    need help putting foils on 40ft cat
      Hi folks, I am consinering putting foils on my 40 custom power cat (aluminum) I need some help with the design of the system and foils, if there are any experts that would be able to give me some advice please email or call me 904-669-8488 thanks Gene Echols
      [Date/Time=08-19-2004 - 7:50 AM]    Name:gene echols, [Msgid=696531]

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