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The 1950's hydrofoil, using a mechanical computer they sailed at 30 knots.

#@hanno; june 1995 Back »

Monitor Video's

Video's taken from an old VHS cassette from the original movie. The resolution is coarse the action very interesting.

#@hanno; sept 1999 View »

Monitor 3d Model

Both the original design and the real Monitor were modelled in 3D. The dual wingmasted original design is amazing.

#@hanno; oct 2001 View »

Baker sailing hydrofoil. Info & Photo's

Photograph scanned from the Neil Lien report.

Short Bibliography discussing Monitor:
"Hydrofoil Sailing"; Alan Alexander, James Grogono, Donald Nigg; Juanita Kalerghi; ISBN 0 903238 00 4; 1972
"ICARUS, the boat that flies"; James Grogono (a famous hydrofoil enthusiast); ISBN0-229-11803-8
"Aero-hydrodynamics of sailing"; C.A. Machaj; ISBN 0-229-98652-8) and
"Faster Faster"; David Pelly; ISBN 0-688-02389-4
"Monitor Hydrofoil Sailboat, Design in review" mr Neil C. Lien; Ordering printed or CD-ROM versions, contact the author mr Neil C. Lien at or +1 608-882-5551.

She sailed first in 1955 with fully battened cotton sails, but the hydrofoils are special, a cord-length of 5 inches front (127mm) and 4 inches (101mm) back.

From the patent (US patent office 2,856,879 Oct 21 1958) I know that she had full automatic mechanical stability control, for pitch and roll. Looking at the good quality black and white photographs, the windspeed seems to be very low (no whitecaps of any sort and still an oily appearance to the water), maybe as low as Beaufort 4!. David Keiper of "Williwaw" fame was the first who told me this, MONITOR required 13 knots of wind to fly her approximately 400 kg. All this is confirmed in the Neil Lien report.

I think that with the large resistance of the hull (some kind of skull, rounded flat bottom) and the large foil-area, at low speeds; the limited sail area of the MONITOR is not able to start the craft under the conditions of the photograph. Has the MONITOR been towed to flying speed? Dave Keiper confirms having heard about MONITOR needing to be towed to speed. From description I have read that MONITOR could tack on foils, taking into account the large increase in hydrofoil area when further submerged this does not surprise me.

Bob Johnston about sailing MONITOR:

My time on Monitor was limited to two half days but what a thrill it was, and again that was 50 years ago. Gordon and I had two great days sailing her. We had 10 to 20 knot winds which let us take the boat off without assistance. In that breeze Monitor sailed most beautiful. We sailed in all wind directions and the boat handled each wind direction. We could tack, gybe, and reach. As I remember the boat pointed higher than I was used to on conventional sailboats. The control system functioned as planned in all these conditions letting us handle the lake waves, the wakes of other boats and inland lake gusts. I had sailed Bakers other V-foil boats in which we could not gybe without having to take off again and had pitch poled. The design had corrected both of these situations. The after foil was basically controlled by the load on the aft stay. On a reach the after foil angle would go negative to prevent pitching.

Even now she is more advanced than many modern hydrofoil sailboats. Using all we now know, a rebuild of MONITOR with modern materials, redesigning her a bit and even considering the rumoured about hardsail John Gordon Baker had in mind, could make a very interesting hydrofoil sailboat.

  1. What has happened to Baker's MONITOR, can we find her?
  2. She's at the Mariner's Museum in Newport News, VA. G." From my first source I have received the following information: Monitor is, as far as I can tell, complete. This vessel is about 20-25 feet in length, six foot beam. The hull looks like a modified scow with near plumb sides. Her two main foils are retracted at the sides, but the sailing rig appears to be incomplete. The foils are of a ladder type construction with relatively wide chord. There are two pictures of her under sail, -flying-, and the photo credits are to the US Navy. She currently resides in the climate controlled -Small Boat Exhibits- outbuilding which is open to the public along with the rest of Mariner's Museum's grand collection."
    Monitor was donated to the museum and form what I have heard recently is one of the most asked after craft in the museum. Maybe thanks to some of the publicity the internet has created.
    The donation was done by mr Neil Lien, who I was lucky to contact.

  3. Who has design information and sailing results.
  4. I now know that there is a logbook and a 8mm film of MONITOR. A mr Neil Lien has shown these items to a French journalist, Daniel Charles, sometime in the 1970's.
    I have now had contact with both gentlemen and I now own a copy of the movie, which shows some interesting burts of speed and also a very short sequence of monitor being towed by a car. Monitor was fitted with special wheels, directly hooked to the hull.
    Mr Lien is in the process of making an article for the International Hydrofoil Society. He gave me some more Monitor stuff, most of which I however cannot show you.

  5. Who knows of a reputable museum which, wants MONITOR on a longterm loan?
I am not sure if this offer still stand I presume not as MONITOR has become one of the more asked after craft of the museum.

Scan of some of the 14 figures regarding MONITOR patent.

United States Patent Office 2,856,879;

Patented Oct. 1958;


John Gordon Baker, Evansville, Wis. Application september 13, 1956, Serial No. 609,613 18 Claims (Cl. 114-66.5)

This information is enough for anyone to request a copy from any patent office in thh world.


  • Length of Hull 26 ft, 7.92 m.
  • Overall width 21 ft, 6,4 m
  • Sail Area 230 sqft, 21,37 m2
  • Weight hull app. 800 lbs, 360kg
  • Flying height app 2ft 6 inch, 0,76 m
  • Take-off speed app 9.5 kn, 5 m/s
  • Take-off windspeed 13 kn, B5
  • Top speed 30.4 / 38 kn, 15 / 19 m/s


  • Number of crew 2
  • Automatic trim regulation
  • Rolling moment partly compensated by differential; adjustment of foil angles.
  • All foil incidence angles adjustable in flight.
  • Estimated price of production model USD 20.000,- (1957!)
Data taken from Research reviews august 1957, J.G. Bakers; St Francis Yacht Club Harbor, San Francisco

The scans presented on this website do no justice to the quality of the photographs. I have also cropped them. All show the complete boat with all rigging. These pictures would have been too large for use in a simple webpage.

The content is nevertheless so interesting that I really wanted to share them. Remember what you are looking at. A 1950's sailing hydrofoil doing in excess of 30 knots. Look at the relaxed sailers mr Neil Lien and John Gordon Baker, the inventor.

From a unidentified magazine article by mr Daniel Charles and was translated and adapted by me for use on this site. As my French is limited I hope not to have made too many mistakes.

From the Neil Lien movie that mr. Daniel Charles saw, he describes that MONITOR had wheels attached directly to the hull, which were removed once afloat. These wheels had suspension on the attachment. I wonder if the strange nose-plate is the attachment to the car.

The hull is painted red.

Once afloat a crew member goes aft and winds the rear foil down with a turning lever.

As is obvious from the patent, all sailforces are use to correct foil angles of attack and consequently hull attitude. This leads to the strange sight of the mast moving around as if the rigging is not tight enough.

Mr Charles also describes that on the film is a sequence in which MONITOR passes a pushtow to leeward to reappear, to tack without returning to the water and passing the pushtow to windward.


Who has design information.?

Mr Neil Lien has and the good news is that he is working on an comprhensive article about MONITOR.

Who has the logbook.?

This item remains elusive, if it exists. The same goes for real measurement data.

Who knows about the rigid wings.?

Thanks to mr Neil Lien, you can now order his design review. See below where to order.

Who can get me a copy of the 8mm movie?

Thanks again to mr Neil Lien I have a VHS copy of a 8mm MONITOR movie. A special page of this website is dedicated to the movies, which I have digitized and made into 5 small movies, showing quite well how well monitor sailed.

The information on Monitor on this website is a combination of many letters and e-mails with several people involved in the project. I want to thank them all!!!

Monitor Photographs

click on any image to enlarge

How she now is.


Monitor was donated to the collection of:
the Mariners' Museum;
100 Museum Drive
Newport News VA 23606-3759
Where as I understand it can now be seen in the small boat collection. The pictues below were taken by Barney Black and mr Coleman, one is from the museum itself.
I still have not been to the museum, as I probably should after all the work on Monitor.

NEW now Available and Highly recommended
Monitor Hydrofoil Sailboat
Design in review
Ordering printed or CD-ROM versions, contact the author mr Neil C. Lien at or +1 608-882-5551.

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