Hydrofoils: Sailboats
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Latvian CATRI Sailing Hydrofoil
Latvian CATRI Sailing Hydrofoil (Aldis Eglajs)
[17 Feb 99] I received some further information from Aldis Eglais in Latvia (Lettland), the designer of the Catri 26R MicroFoiler. At the moment I'm still in the planning phase of my project but I intend to build the boat this summer here in Switzerland. Aldis is offering the plans for a very good price (US$ 1,300), and I'm very close to ordering them. I'm waiting now for his study plans. I will keep you informed. His E-Mail: aldis@catri.apollo.lv. -- Phil Schlund (106641.71@compuserve.com)
Response...
[17 Feb 99] There is a short article about the Catri 26 Trimaran on page 48 of Multihulls Magazine Mar/April 1998 edition. The address given is Aldis Eglajs; Maskavas 291/5-26; Riga LV-1063, Latvia; Tel/fax : +371 7258427. -editor
2nd Response...
[17 Feb 99] In Winter 1997-98 I did a project for a Dutch company called PJPC Multihulls. They wanted to build the Catri 26 for the European market to sell for about US$50,000. There were complete plans for making the (eastern European) ship suitable ( more comfortable) for the rest of Europe, which was part of my study (I was asked to design a mechanical device to lift the two swords). Unfortunately the Dutch company stopped their activities due to health problems of the owner, so I am at the moment looking for other tri-builders who could use my design. If you want to know more, contact me. -- Maarten de Jong (m.t.dejong@wbmt.tudelft.nl)
3rd Response...
[21 Feb 99] We are working out two types of Catri Foilers -- trailerable cabin boat range (22' 26' 30') and offshore cruising & racing range (35' 39' 45'). After very successful prototype tests in the Netherlands there are two shipyards in Latvia started with 22' and 26' and one in San Francisco starting with 26'. The first boats will be delivered this Summer. The 30' will be started in March for delivery beginning 2000. There are some homebuilders in Australia and elsewhere. You can find our presentation and description of Catri 22, 26R, 30 as well as the draft price list in the attachment. -- Aldis Eglajs, Catri Marine (aldis@catri.apollo.lv)
[Date/Time=03-21-2002 - 10:52 PM]
Name:webmaster@foils.org
[Msgid=236662]
Sailing Hydrofoils
Wants World Speed Record in Sailing
[13 Jan 02] This looks exactly like the site I need. I want to have a crack at the wind-powered water speed record, and I reckon the only way we're going to get the thing fast enough is up on a foil. The only problem is I have absolutely no idea. If anyone has info. it really would be appreciated (formulas/heights anything to help me build the hull) -- Ian Montgomery (primuscroydon@lineone.net)
Response...
[13 Jan 02] The world sailing speed record was once held by a hydrofoil - Greg Ketterman's LONGSHOT. This boat has since been adapted for production as the Hobie TRIFOILER . A used TRIFOILER would be a good way to get experience in high speed sailing. In my opinion, the world speed record has risen out of the reach of subcavitating hydrofoils. The current record holder used planing hulls, which you can think of as fully ventilated supercavitating foils operating at the surface, which is where a supercavitating foil is most efficient. Cavitation proved to be a barrier to Ketterman's pushing his hydrofoil to today's speeds, and I doubt if there's much you can do with section shaping to raise the cavitation speed much higher. Designing a supercavitating hydrofoil system that had a lift/drag ratio adequate for a sailing craft is just feasible, but requires very sophisticated hydrodynamics design. Hydronautics' experience with their supercavitating helicopter-towed sled demonstrated drag reductions on the order of 40% -60% just by doing a more sophisticated type of analysis of the spanwise hydrodynamics of their design. You'd have to do the same for a sailing hydrofoil. Something like the Windjet LANDYACHT adapted for the water might be a starting point for the hull and rig design. -- Tom Speer (me@tspeer.com); website: http://www.tspeer.com
Monohull Dinghy...
[5 Mar 01] Is there any website on a leeward-foil assisted faaast monohull dinghie, say an IC, Contender or 505 with a Bruce on a 3m lever ? -- Claus-C. Plaass - Pickert 10 - 24143 Kiel - Germany - email (plaass@foni.net), ph +49-431-36 800
Responses...
[5 Mar 01] Not only foil assisted, full flying: http://imca-wa.freeyellow.com/index.html. -- Tom Speer (tspeer@tspeer.com); website: www.tspeer.com; fax: +1 206 878 5269
[6 Mar 01] I have designed a 16' 100lb 2-person monohull foiler using two(only) fully submerged foils; should be sailing in 2-3 months. Take a look at the Hanno Smits website (listed under websites of IHS members) for info on his work with SP foils and a FLYING DUTCHMAN. Personally, the Aussie work on their Moths is most inspirational and should lead to light weight production monohull foilers that while not as fast (top end) as some multihull foilers will provide the thrill of flying to a much wider audience. -- Doug Lord (lorsail@webtv.net)
Hydrofoils Excluded From TheRace2000...
[9 May 00] TheRace headquarters has admitted that they limited the entry of our hydrofoiler for the No Limits Race around the world. Their discrimination against foils has seriously impeded the development of effective offshore sailing hydrofoils. Our potential sponsor withdrew when our entry was denied. If they reverse the decision now, there is still a chance to pull it off. The prototype is complete. Our nine foot wide horizontal spans are designed to retract when we hit the inevitable obstacles. Please email kevin.church@disney.com with a copy to stephanie.schroeder@therace.org and ask them why they are discriminating against hydrofoils and why they still call this a "no limits" event. You can make a difference. Thank you for your support. Peter Murray therace2000@hotmail.com Tel.#(1)561-286-2643
VOLANTIS 60' Sailing Trimaran...
[12 Feb 00] I just attended a meeting of the Northwest Multihulls in Seattle where Duff Sigurdson of Canada presented the latest news on the 60 foot trimaran planned to be built in Hawaii. Sam Bradfield has designed the foils thus she will have inverted T-foils and small amas. Nigel Irens is the designer. They plan a solid wing with reefable/furlable center section, and a hard vertical tab on the lower leech of the rig for depowering. It looks like a more delicate Rave Trifoiler, with a single CF gull-wing crossbar. I was impressed, even considering that Queen Elizabeth II is supposed to christen it. It is not immediately clear that "Volantis" is meant for The Race. Burt Rutan will build the foils in his "Composites" shop in the Mohave Desert, and the majordomo is Adm. Stuart F. Plott, formerly head of seaborne infiltration efforts during the late unpleasantness in Vietnam. Duff also talked about aquatic satellites- small versions of the hardsail trifoiler that would be permanently at sea, monitoring the shipping lanes and seaport accesses, video-monitoring incoming ships for oil dumping/bilge pumping. Solid wings again? Please contact Duff Sigurdson for more accurate news- he is the new publicist: formerly associated with the Ronin project for The Race. -- Dave Carlson (dacarls@nersp.nerdc.ufl.edu) website: www.fastsail.com/catcobbler/
Moth Class Sailboat Races With Foils...
[25 Feb 00] In a world first, Western Australian International Moth Class dinghy sailor Brett Burville has cracked it with a Foiler Moth, winning outright two heats of the World International Moth Class Championships held in Perth last week and finishing a creditable 10th place overall. The International Moth class is one of the few truly development International sailing classes and also allows foil development. At times Brett was travelling at up to 1-1/2 times the speed of the top existing designs and easily won the races in which he stayed upright. This is no mean feat, keeping in mind that an existing Moth can outpace a 505 and is already the fastest 11' monohull in the world. Brett's boat is a standard Moth, with a larger-than-usual T-foil on the rudder and forward V-foils mounted at the end of the wings. It appears he showed bursts of incredible speed in the stronger winds, punctuated by many capsizes. Clearly there is scope for further development, perhaps with some form of sensor control. He was foilborne above about 8-10kts of wind and sailed both downwind and also upwind on the foils. In the light wind races he removed the foils from the simple mountings in a couple of minutes. This is a major achievement, as most foilers to date are only reaching speed machines, like sailboards. This is the first time ever for a foilborne craft to compete successfully around the buoys in all conditions in a truly international standard sailing competition. It is hoped that Brett will produce some further details and it is expected a lot of further development will now proceed, as it is possible to take any existing Moth and truly revolutionise its speed in winds over 10 knots! Who will be first to take it further?? -- Ian Ward (ianward@ozemail.com.au)
Response...
[25 Feb 00] See also the article and photos in the Jan 25, 2000 Sailing News from Boating Oz. Also, information and photos from various sources was reprinted in the Spring 2000 edition of the IHS newsletter.
Racing Boat Design Source...
[2 Apr 99] Does anyone know where you can get designs for jet boats (sport/racing versions - not fishing/commercial)? Please email me. -- Mathew Davies (porsche@porsche-enthusiasts-club.freeserve.co.uk)
Response...
[3 Apr 99] The following groups run both propeller boats and JET (impeller) boats in various classes. The prop boats are quicker but both achieve speeds in excess of 200 mph regularly. Contacts (Hope the phone numbers are current.):
Liquid Quarter Mile magazine (909) 989-1169
IHBA International Hot Boat Assoc. (714) 634-4422
ADBA American Drag Boat Assoc. (216) 543-9647
NJBA National Jet Boat Assoc. (714) 993-2664
SDBA Southern Drag Boat Assoc. (817) 662-0774
-- Ken Cook (kencook@hydrofoil.com)
[Date/Time=03-23-2002 - 12:58 AM]
Name:Webmaster@foils.org
[Msgid=237130]
Archive; G Baker Hydrofoil MONITOR
Archive; Add Hydrofoils to Sailboats
Archive; Sailboards, Windsurfers, Surfboard
Archive; Hydrofoil Racers - Sail/Power
Flying Keelboat
ViewThread
Has any one any knowledge of a monohull KEELBOAT using hydrofoils in a full flying manner?My company at microsail.com is about to introduce a canting keel model 42" in length that I believe may be the first fully flying hydrofoil keelboat called the aeroSKIFF. Any comments with substantiated information would be very helpful.I amm working on a version of this design for full size sailboat applications particularly in the Open 60 Class..
[Date/Time=04-20-2002 - 4:44 PM]
Name:Doug Lord
lorsail@webtv.net,
[Msgid=249625]
Flying Keelboat
Doug
I have seen many multihulled sailing Hydrofoils and a few Centerboard/daggerboard/leeboard Monohulled sailing Hydrofoils. I have also seen Cantable Daggerboards and keels. I have never seen the combination you describe.
Are the Foils fully submerged and attached to the keel or are the foils separate from the keel?
At 42 inches, you might want to also post this message in the Sailing model section.
[Date/Time=04-20-2002 - 4:59 PM]
Name:Bill White
whitewn@speakeasy.net,
[Msgid=249626]
Flying Keelboat
Doug,
When you say Keelboat, I understand that to mean a sailboat with a centre keel? I am not aware of any such boat adapted to run foilborne. Looking though a publication by AYRS on sailing hydrofoils indicates that most experiments with sailing hydrofoils have tended to use hydrofoils mounted on outriggers or catamarans. In the case of monohulls, the foils are usually mounted off wide crossbeams and there is no keel below the hull in those case. The nearest I can come up with compared to what you outlined are a number of International Moth class sailboats that have been designed with hydrofoils fitted rather than the usual centreboard. Photos of these craft can be seen on the International Moth Class Association of Western Australia website at:
http://imca-wa.freeyellow.com/index.html
I am curious about your own concept so I hope we will hear more about it from you down the track?
[Date/Time=04-25-2002 - 7:47 AM]
Name:Martin Grimm
seaflite@alphalink.com.au,
[Msgid=251569]
Adding foils to 27-ft catamaram
ViewThread
I am interested in adding hydrofoils to a 27-foot stiletto catamaran. Can you send me any information on how to start designing the foils and how they could be installed?
[Date/Time=05-04-2002 - 8:24 AM]
Name:John Thomason
newboats@quik.com,
[Msgid=255277]
Adding foils to 27-ft catamaram
There are resources for you on the IHS website, but no quick and easy answer. Some thoughts that occur to me include:
Take a look at our books page http://www.foils.org/popbook.htm. There are some titles on this subject, all out of print I believe. However they can be obtained with a bit of effort from a library, used bookstore or the eBay on line auction site.
The Amateur Yacht Research Society has published a number of technical papers on the subject of hydrofoils, and these are all still available. There is a link to AYRS from our links page at http://www.foils.org/linksout.htm
The IHS has for sale the set of David Keiper files on adding foils to cats, however this design work was aimed at much smaller Beach Cats. Info on these files is at http://www.foils.org/ihspubs.htm. After David Keiper died, his work was continued and perfected by Dave Carlson. His email and website addresses can be found on our site by using the search engine on the main page. He is a good source of practical as well as theoretical information.
You might want to consider getting a boat that is already foil equipped and was designed for it. The Catri is such a vessel. Information is on our site at http://www.foils.org/catri.htm and at http://www.foils.org/catri.pdf. When the designer Aldis Eglais first corresponded with us, he was offering to sell just the plans or the plans plus kit as an alternative to buying and shipping a fully manufactured vessel... don't know if this is still an option.
Anyway, just some thoughts that may be of use to you.
[Date/Time=05-04-2002 - 8:27 AM]
Name:Barney C. Black
webmaster@foils.org,
[Msgid=255279]
Adding foils to 27-ft catamaram
John
Over the years I have seen many mods made to Stiletto Cats. The Stilletto has always seemed to draw out the adventurers in the sailing world due to their High performance and rasonable price. They have very light foam sandwich hulls which might be very difficult to attach foils to, if you can not entirely use the crossbeams.
I have not seen any Hydrofoil conversions but many other Stilletto projects can be found in back issues of Multihull Magazine, Quincy Mass.
They have a web site and their owner publisher is very user friendly.
Best of Luck
Bill White
[Date/Time=05-04-2002 - 9:23 PM]
Name:Bill White asst Webmaster
whitewn@speakeasy.net,
[Msgid=255479]
PK - A Small Hydrofoil Sailboat
Dear IHS members,
Bill White of IHS asked if I would share my experiences in developing and sailing a small sailing hydrofoil. I am happy to do so. Below is a brief account of my 10 year adventure with PK.
Thanks to my web site (and the International Hydrofoil Society site), I look forward to and receive a lot of e-mails on PK Hydroptère de loisirs (Small Hydrofoil Sailboat. The address of this site changed last month.
The new address is: http://membres.lycos.fr/monsonnec/
(Editors note: This is an extensive personal site of sailing hydrofoils)
PK History:
I started the design of PK in 1992 and the construction in 1993.
This boat is exclusively made with some "Recycled materials"! For example the rail of the "rotary bench", is an old bicycle wheel! As a result, I designed and built PK for approximately $800 £.
PK flew the first time in 1997 without the system for the modification of the incidence and with a classical cat boat sail. When I sail I don't want to have some spectators chuckle (if PK don't fly!) and that's the reason why, I just have bad photos of PK in flight!
The latest version, (it's the same hull and floats since the start, but I changed all the other parts), has been ready since last summer (July 2001). Unfortunately I have had a problem with my backbone since the same date! As a result, I don't know if I am going to sail soon and I don't have photos of this version on the sea!
The particular points of this latest version of PK are:
Rotary bench
Rigid rig and sailboard sail
T foils with " incidence control system"
Rotary floats (to protect the foils)
Main dimensions:
Length Overall 5 m
Length Hull 3.85 m
Beam 4.8 m
Sail area 7.5 m2
Weight 70 Kg
Built For Only $800.00£!
Please note that I cannot send the plans of PK, because I am not a naval architect and I think PK is not perfect, it's just a prototype! However, I would be happy to discuss her design and construction over the IHS Bulletin Board.
Thank you very much
Best regards
Frédéric Monsonnec
PS:
I have enclosed different photos of PK at diverse ages below:
Before the first test of the fifth version in 1997: PK5 Stern-97 
and PK5 Bow view-97: 
Central hull during the first flight in 1997: 
First test of the "incidence control system" in 2000: 
PK6 in my garden last year! : 
[Date/Time=07-04-2002 - 4:22 PM]
Name:Raiola Giancarlo
raiola.roberto@tin.it,
[Msgid=278825]
 Attached File "PKxICS-00~jpg.zip" - size 40357 Click Here To Download
Kite Sail Possibilities
ViewThread
Last week I read an article about hydrofoils on yahoo's boomerangtalk... Besides building rangs I like driving my kitebuggy. Unfortunately the beaches here are small, but.... with a lake nearby, such an article and an interest in foils....... ;-). Modern powerkites are very efficient sails with some great advantages over
normal sails. I wonder if one could power some sort of lightweight 1-seater hydrofoilbuggy. It's obvious though (after finding the IHS-site ;-), that I still have quite some reading to do... Thanks to everyone at the IHS for making that possible ! -- Bart Derks,
the Netherlands
[Date/Time=07-12-2002 - 7:57 PM]
Name:Bart Derks
bderks@zeelandnet.nl,
[Msgid=281893]
Kite Sail Possibilities
Scott
There is a lot of Kite Board sailing on the Outer Banks at Cape Hatteras where I vacationed a few weeks ago. The boards are short versions of windsurfers boards or more like snow boards.
If I had the time and was a bit younger I think one could add a set of Hydrofoils to these kite boards and about double the speed. The foils would be similar to the ones that have been adapted for water skiing. There are several on our IHS web site at http://www.foils.org/linksout.htm#buyit
A good example is the sky ski http://www.skyski.com/home.htm
Best of luck
Bill White
[Date/Time=07-13-2002 - 12:00 AM]
Name:Bill White
whitewn@speakeasy.net,
[Msgid=281938]
Windrider Rave Top Speeds
ViewThread
Very nice website, lots of interesting and useful information! I'm interested in sailing hydrofoils, since I saw a Windrider Rave sailing near Toronto, Canada a few weeks ago. It is a commercially
available hydrofoil trimaran. I see a lot of articles on your website about sailing hydrofoils, but nothing about the Windrider Rave. Their website is http://www.hydrofoils.com, and http://www.windrider.com. The Dutch over here claim a max speed of 41.5 knots, and I read that a French sailor has even gotten to 43 knots with the Rave.
Another sailing hydrofoil I noticed, is the hydroptere, http://www.hydroptere.com, and is mentioned on your site.
[Date/Time=09-14-2002 - 11:27 AM]
Name:Mark-Jan Bastian
markjan@xs4all.nl,
[Msgid=309662]
Built hydrofoil sailboat for only $800
Windrider Rave Top Speeds
Mark
Thanks for the inputs. We do mention the Windrider Rave model on our Links page at http://www.foils.org/linksout.htm. Their web address keeps changing, so we appreciate the input so we can keep it current. The Rave is an exciting boat to see in action, though I have never seen it at the speeds you mention.
Bill White
IHS BBS manager
[Date/Time=09-23-2002 - 7:04 PM]
Name:Bill White
whitewn@speakeasy.net,
[Msgid=313647]
Windrider Rave Top Speeds
Check out:http://www.monofoiler.com for a whole series of monofoiler sailing hydrofoils. Some sail on just two foils,one on the daggerboard and one on the rudder. Generally, monofoilers won't be as fast as boats like the Rave that develop their own righting moment--but they have tremendous "fun" potential...
[Date/Time=09-24-2002 - 9:15 AM]
Name:Doug Lord
lorsail@webtv.net,
[Msgid=313860]
Windrider Rave Top Speeds
Check out the Hobie Tri-foiler. The Windrider and Tri-foiler are both fast designs, and both similar. But the Hobie has a better control system. The Hobie uses a surface follower system that is very effective. The Windrider uses a system that has it's control input beside the strut instead of in front of it. It requires you to adjust bungee's to keep the foils trimmed. What is the sense in that? It seems to me that the foil control system should do just that, control the foils. There are plenty of other things to keep the pilot busy in a 35+ mph sailboat, without having to keep the foils trimmed. I have heard that there are some people that can successfully tack a Windrider without coming off the foils, but nobody has ever been able to do it in front of me. But I have seen a first-timer tack a Tri-foiler with little difficulty. Either way, both of these boats bring a whole new dimension to sailing.
Scott Smith
[Date/Time=09-24-2002 - 10:37 AM]
Name:Scott Smith
ssmith@syntheon.com,
[Msgid=313899]
Windrider Rave Top Speeds
Hi Scott,
The Hobie Tri-foiler certainly has a neat and simple foil control system, but the 'wand' approach used on the 'Rave' also seems to work well. From what I have read about sailing the Rave, it should not be necessary to manually control the foils to keep the boat flying in a stable manner. There is however a capability to control the foils manually if that is what the crew want to do.
Christopher Hook, who first developed a workable fully submerged hydrofoil craft, employed manual surface skimming attitude sensors that projected far forward of the bow foils. Apart from looking somewhat ungainly, these would undoubtedly have been subject to a fair bit of damage in service, even if just bumping into a wharf occasionally. I have often wondered whether it is really necessary for such mechanical surface sensors to actually project far forward of the foils. The Rave seems to demonstrate well enough that this isn't necessary as it runs well in waves while foilborne. For small waves that are typically short, it is not necessary for the hydrofoil craft to react to them by rising up, rather it can just continue through them straight and level. Having a foil sensor far forward is therefore no advantage in that case. For long waves relative to the boat it does not matter much whether they are detected directly in line with the foils or one or two metres in front of the foils as the wave elevation will not be very different between those locations. It would therefore only be for waves that are around the length of the boat that the position of the surface sensors would have a noticeable effect on the motion of the craft.
A question someone may be able to answer: For large electronically controlled fully submerged hydrofoils like the Boeing Jetfoil and PHM that could happily cruise in large waves at 40+ knots, how far ahead of the boat did the bow mounted surface sensor actually look to detect oncoming waves? How did the signal from that sensor get coupled with the signals from all the accelerometers mounted around the boat that were also used to achieve a smooth ride?
By the way, there is some nice footage in the video by Arcadia Entertainment "Hydrofoils - Flying on water" that shows a Rave doing a 180+ degree turn (downwind) in the blink of an eye, and remaining foilborne for a good portion of that evolution. Given that can be done, tacking the Rave while remaining foilborne would seem straightforward.
[Date/Time=09-26-2002 - 7:41 AM]
Name:Martin Grimm
seaflite@alphalink.com.au,
[Msgid=315018]
Windrider Rave Top Speeds
There is much truth to what you say, but don't get sailboat dynamics confused with powerboat dynamics, and scale means a lot as well. A Boeing Jetfoil is a big, long boat. The length of the boat, coupled with it's weight, means that it pitches forward and back comparitively slowly compared to a smaller boat. So the inputs to the control system require a slower rate than for a small boat. It's the difference between balancing a broom on your finger and balancing a pencil. For most foil powerboats, the best ride is achieved when there is little control input from waves (fast rate input), and most input is from the height above surface sensor (slow rate input). Basically, fly it straight, compensate slowly for altitude and large, slow swells, and the smaller waves will pretty much take care of themselves. Grumman demonstrated this with a variant on their foilboat that used submerged foils. The control system was actually mounted directly to the trailing edge flap of the front foil. The system worked well. Also, powered foilboats don't have to continuously deal with large side to side forces, except while turning. It gets different for sailboats like the Windrider and Tri-foiler, however. The foils aren't just compensating for altitude, they also have to control heeling forces (left & right) and pitching forces (front & back). In variable winds, the forces acting on the sail(s) can be very high, then a split second later drop to nothing as the wind dies, or worse, changes directions. On a powerboat, the thrust line doesn't change, so the distribution of weight among the foils is predictable. Not so with a small sailboat. As I recall, the sensor on the Windrider is spring-loaded towards the down position with a bungee strectched across to the cockpit. While on a reach, you adjust the tension on the bungee until the foil rides at the proper height. If you change direction, or if the wind changes, you have to re-trim the sensor tension to keep the boat stable. This may be why they show a downwind tack in the video. There is only a momentary loss of power, and the pilot doesn't have a large burden to keep the boat up. Tacking upwind is trickier, as the powerloss can be longer and have more effect on the foilboat's trim. But the real proof is in the pudding. I have seen an amateur tack a Tri-foiler in moderate wind, with no apparent trouble. I have yet to see anyone tack a Windrider in any wind, with any pilot. If someone out there has a video of that, I would love to see it. The Windrider seems to have a growing popularity lately. It is a little cheaper, but is there another reason for this? Maybe it can do some things I am not aware of. If anyone out there has had any real experience with both the Tri-foiler and the Windrider, I would love to hear it. Maybe I'll even apologize and shut up :)
Scott Smith
[Date/Time=09-26-2002 - 8:38 AM]
Name:Scott Smith
ssmith@syntheon.com,
[Msgid=315058]
Windrider Rave Top Speeds
Martin,
As for the height sensors they where mounted looking directly down at the water. The ACS control system was set up to maintain a constant 1 "g" force on the deck via accelerometers and gyro's. The Hull mounted accelerometers where located on the PHM at the to rear struts and the forward one was mounted just aft of the forward strut. The accelerometers dampen out the effects of the height sensors seeing chop by clamping the signal to the hydraulic systems.
[Date/Time=09-28-2002 - 11:30 AM]
Name:"Jake" Jakobson
Jakobson@bellsouth.net,
[Msgid=316107]
Windrider Rave Top Speeds
Scott,
Thanks for your reply. I follow what you are saying about the dynamics of sailboats and the effect of the scale on the motions of a craft.
Just reinforcing your point about scale, for a case where all proportions of a boat and the waves it is travelling in are scaled down and if the speed of the boat is also "Froude Number" scaled, the time period in which successive waves are encountered is reduced by a factor of the square root of the ratio of model to full size length. For example, a 1:20 scale model of a hydrofoil boat will encounter the corresponding "1:20 scale" waves in only 22% of the time of its full size counterpart, or around 4.5 times faster.
Although there is an agent for the sale of the Windrider Rave in Australia, I have not seen any first hand. I have not seen any Trifoilers either so I can't comment about their relative characteristics!
[Date/Time=09-28-2002 - 9:12 PM]
Name:Martin Grimm
seaflite@alphalink.com.au,
[Msgid=316268]
Windrider Rave Top Speeds
Jake,
Thanks for that straightforward response to my question. It beats trying to find that out by tracking down and then reading through long and complex technical papers!
[Date/Time=09-28-2002 - 9:16 PM]
Name:Martin Grimm
seaflite@alphalink.com.au,
[Msgid=316270]
First sailing Bi-foiler
Dr. Ward ,it looks like you have done a tremendous job! Check out monofoiler.com for other monofoiler's such as Brett Burvills Moth sailing on just two foils(one on the daggerboard and one on the rudder).And recently ,John Ilett's monofoiler sailing the same way but with an addition of a wand based altitude control system. Also included on the site are pictures of David Lugg's International 14 sailing on just two foils with manual control.
If you would like I'll be more than happy to add your boat to the others on www.monofoiler.com
When did you first sail your boat on two foils?
Congratulations on a great job! Doug Lord lorsail@webtv.net
[Date/Time=11-11-2002 - 8:19 AM]
Name:Doug Lord
lorsail@webtv.net,
[Msgid=336328]
Rich Miller`s Hydrofoil Sailboard
Catri Hydrofoil in Guaraní and Tupi
With regard to the glossary of hydrofoil-related terms at http://www.foils.org/glossary.htm, There was no word for "Hydrofoil" in South America's main native languages, the Guarani and Tupi, BUT both languages use the same word for "Water" ("Y" or "I") as well as the same word for "Wing" ("Pepó").
Also, adding words is a valid resource in both languages, exactly as in Latin or Greek. For example: "pepó" is derived from "pe" + "pó" = "flat" + "hand".
As a consequence, the word "Hydrofoil" can be translated directly into "Y'pepó" and the meaning is clear in the course of normal conversation. The roots were double checked in three different Guarani dictionaries and two Tupi dictionaries and the correctness of the composed word was verified with many Guarani speakers, among them two teachers of the language.
I searched for this word while trying to find ideas to name my future hydrofoil assisted folding trimaran model "Catri 27R" designed by Mr. Aldis Eglajs, from Latvia. By the way, I found and read his te |
