Excellent video my friend, there are 7 degrees of Freedom.. the first 6 MUST control the motions... the 7th must control the emotions when it all works. However, no mention of Wind, Tide or external influences wake from passing vessels must be all taken in consideration when designing the perfect Hydofoil... The presentation flawless. Thank You.
My father was the captain of the H.S. Denison, a 90 ton hydrofoil with surface piercing foils designed by William Carl. In the early 1960's they did rough water trials south of Newport R.I. comparing the Denison with a 90 foot Coast Guard Cutter. The seas were roughly 10 feet or so with regular wave frequency as near as I can tell from the 16mm film dad showed us. The Denison could run at 55 ->60 knots at ALL angles to the wave state. When Denison ran parallel to the waves the roll was minimal. The cutter had to abort her run as roll became dangerous. At 60 knots the Denison's keel was 6 feet above the surface of the water.
As a aviation fan this video was very easy to understand,making research and study much easier. For more references look at the history of wing dihedral and fly buy wire systems The concepts are very similar (except in viscosity and compression ratios)
Thx Nick great video I sailed on a number of light weight multihulls cats and tris and always thought of the use hydrofoils especially after watching the Americas cup series in SF. FWIW I served on USS Tacoma PG 92 which was a light weight 200t ocean going high speed gunbot with planning hull, these boats were notorious for poor performance in heavy seas where they would experience rolls of near 70deg and pitching of 45deg we really could have used partial hydrofoils for stability in those conditions. FYI The USS Tucomcary you used the image of in your video was built shortly after the PG I served on and destroyed hitting a reef in the Caribbean sad to say. Can't wait to watch the next round of America's Cup with hydrofoil monohulls. Thx again for sharing your knowledge of flying boats Nick.
Oh awesome I was just making a comment on your other video about hydrofoils. Thanks! Could you make a video about the practical limits of energy efficiency of hydrofoils? Assuming computer control and optimizing for energy efficiency / speed. Personally I'm interested in a solar powered cruiser using minimal power to foil at good cruising speeds. But it would also be interesting in view of the need to use less fossil fuels for transportation, replacing air travel with fast hydrofoil ferries.
Partial hydrofoils are an interesting category of which I was unaware until watching this video. As a catamaran sailor I was intrigued to see the previous generation America's Cup design and look forward to seeing the new foiling monohulls in action. The raised foils on the upwind side look pretty dangerous though... I wouldn't want to be on the leeward side of a boat upwind of them in close quarters.
they have a more limited use than foils generally so they're a little less popular. But they are gaining in popularity, the current gen of IMOCA boats primarily run in a 'partial' mode, largely relying on the planing and buoyancy of the hull. Partly it's due to the limits imposed by the class rule, but it does work very well.
Also partiql hydrofoils are really hydroplanes, I made 3, 20 foot single seater hydroplanes with the tunnel effect, wing in ground effect. They work very well and get on the plane very quickly. I studied ekranoplans in the 90s to understand wig effects
Since it's been a year, I can share what I've read (non-engineering). The old concept of an icebreaker on the Shackleton expedition was to use very strong and steep sides to break ice at the bow. Later, they discovered that a shallow bow could ride up onto the ice, and break it using the ship's weight, which seems to have been much more effective. Disclaimer: there may have been some advances in the last hundred years or so!
One thing that isnt mentioned is wing shape and wing profile, angle of attack for forward and rear foils, height of skegs for a certain size weight. Positioning on the diagrams are flawed as most filers now carry forward foils under the mast position of a yacht for example. Interesting but need a follow up and more exploratory. I made ladder foils in 97 on my 28 foot single seat trimaran, coincidentally similar to the hobie trifoiler at the same time. Also adjustment wands on variable pitch surface piercing foils and connections to boat also a good video
Great information! Probably the subject of an entirely new vlog is the America's Cup AC-75s and Vendee Globe "semi-foiling" boats. Could the newest hydrofoiling designs be applied to everyday/commercial marine applications???
Your videos are interesting, this is the first one I've watched and I plan to watch more. You should devote a few seconds at the beginning of each video to give some evidence of your knowledge, "I am a naval architect, I designed x boats, I received x awards, I speak regularly on hydrofoils, I also live in a yacht I designed on which I sailed around the world." I can tell from your videos that you have knowledge but it was only at the end of the video that I found out you are a naval architect. I watch Tony Jeffries boxing videos and I get sick of his little spiel at the beginning "olympic silver medalist, european champion, english champion, undefeated professional boxer, blah blah blah" but at least I know he's a legit expert.
Dankie Nick. This quite intresting. I am wondering why was the hydrofoils not use more? If it better that the normal design. And what is the fuel burn of this hydrofoils? Hydrofoils is like the 3rd level op boat design. Normal sailboats with a keel are plenty. Cats R less plenty and the hydrofoils only on YT!
I don't know the exact fuel burn rate, but it can be very high. For comparison, I looked up fuel burn rates for a 3000 hp gas turbine engine. Hydrofoil boats normally use turbine engines. This is a rough estimate, based on some sketchy data. But the fuel burn for that type of engine would be in the range of 300 gal/hr. Hydrofoils are not used more for several reasons. - They only work for light craft. Ships normally specialize in carrying heavy things. - Fast speeds are not always possible in a heavy storm. - Hydrofoil craft are far more expensive. Compare the cost of a fighter jet to a ship. Similar difference between a hydrofoil and normal ship.
Partial Hydrofoil was invented by Prof. KG Hoppe of Stellenbosch University - South Africa. Lots of failed copies. But his system works - and always has. There is the HYSUCAT and HYSUWAC foil systems.
Can you suggest books or research papers on hydrofoil design? I suspect I could get an active design working right sooner than a passive one by developing my own control systems. I'd like to learn what would be involved in retrofitting an old monohull sailboat with hydrofoils. My budget is roughly zero, but I have enough time to learn to an amateur level. Edit: I started watching your America's Cup video, and I will never be in that class. My interest is in making improvements for pleasure cruising as a hobbyist.
Great Video except....... I wish you had given a little nod to the inventor of the Hydrofoil, Alexander Graham Bell (the telephone guy) and showed a picture of his 1912 boat. BTW: it did over 60 miles per hour.
Interestingly the Bras d'Or, which is what it was called (because it was first tested on the Nova Scotian lake of the same name) gave its name to two other hydrofoil boats down the line. I think the most interesting is HMCS Bras d'Or, the Canadian navy's equivalent of the Boeing and Lockheed's projects for the US military and was recorded at 63kn, which makes it the fastest military surface ship up until the 21st century.
Hmmmm... at 5:25 you say that roll stability requires partially submerged foils. I don't think that this is correct. In the same way that wing dihedral gives aircraft stability (fully submerged in air), I think that fully submerged foils with dihedral have roll stability. The lift from the foil is proportional to cos(theta) where theta is the angle between the normal to the foil and vertical. When partially submerged they have more stability but fully submerged they are also providing roll stability. :)
Good video, thank you! Q about passive roll control which you suggest needs to come from surface piercing. Yet, airplanes handle spiral divergence though being fully immersed...
I don't think I can comment too much on airplanes, since I'm not an aeronautical engineer. But airplanes and hydrofoils do share some similarities. Hydrofoil roll stability can come from submersion of additional foil area. But it also comes from the foil dihedral angle, the same as an airplane. In addition, the the elevators, rudder, and ailerons on an airplane are all examples of what I would call active control in the nautical world. And I have never personally seen an airplane without at least some of those active controls.
@@DatawaveMarineSolutions with a submerged foil and dihedral, can you get lateral stabilitty (no rollover even with fixed, zero rudder?) I expect that to be hard because of high cg, vs an airplane.
Why are hydrofoil craft not more popular, especially with smaller to medium-sized vessels? Also, could a pilot maintain manual control of a 40-foot hydrofoil, foregoing the need for a computer control system?
Yes, a pilot can maintain control manually. They do it on the Americas Cup boats. As to why we don't have hydrofoils everywhere. As an analogy, it is the same reason we don't have everyone buying racecars. A hydrofoil boat is complicated to operate, very expensive, and requires extra maintenance. They are specialized ships, and few people can justify the cost.
@@DatawaveMarineSolutions, thank you. I'm trained in mechanical engineering, and yet to further study naval architecture. I intend to design and build a ~40-foot motor yacht with retractable hydrofoils for cross-oceanic voyages cruising at ~40-knots. My preliminary thinking is that such a craft will be faster, and more fuel efficient than conventional motor yachts, whether catamaran or monohull. I intend to construct the yacht myself, to make it financially viable as a project. Do you think this is realistic for one with only mechanical engineering undergraduate studies behind him?
This is all good stuff on this channel. Mind you the chappie giving the lecture rather does have an air of 'Open University' about him :-) which will mean little to nothing to those not of a certain minimum age and of a British persuasion :-)
An ironic reference considering my Masters of Engineering from University of Southampton, with first class honors. Southampton also being a British university.
"Why would a aircraft manufacturer design a ship?" TBH they have done from the beginning ..... ever heard of flying boats? Those hulls were more ship than aircraft.
I love when these videos come out
Excellent video my friend, there are 7 degrees of Freedom.. the first 6 MUST control the motions... the 7th must control the emotions when it all works. However, no mention of Wind, Tide or external influences wake from passing vessels must be all taken in consideration when designing the perfect Hydofoil... The presentation flawless. Thank You.
Nice presentation and clear organisation of interrelated topics! Thank you!
My father was the captain of the H.S. Denison, a 90 ton hydrofoil with surface piercing foils designed by William Carl. In the early 1960's they did rough water trials south of Newport R.I. comparing the Denison with a 90 foot Coast Guard Cutter. The seas were roughly 10 feet or so with regular wave frequency as near as I can tell from the 16mm film dad showed us. The Denison could run at 55 ->60 knots at ALL angles to the wave state. When Denison ran parallel to the waves the roll was minimal. The cutter had to abort her run as roll became dangerous. At 60 knots the Denison's keel was 6 feet above the surface of the water.
I very much appreciate your series as a widening experience for an EE, thank you.
As a aviation fan this video was very easy to understand,making research and study much easier.
For more references look at the history of wing dihedral and fly buy wire systems The concepts are very similar (except in viscosity and compression ratios)
Thx Nick great video I sailed on a number of light weight multihulls cats and tris and always thought of the use hydrofoils especially after watching the Americas cup series in SF. FWIW I served on USS Tacoma PG 92 which was a light weight 200t ocean going high speed gunbot with planning hull, these boats were notorious for poor performance in heavy seas where they would experience rolls of near 70deg and pitching of 45deg we really could have used partial hydrofoils for stability in those conditions. FYI The USS Tucomcary you used the image of in your video was built shortly after the PG I served on and destroyed hitting a reef in the Caribbean sad to say. Can't wait to watch the next round of America's Cup with hydrofoil monohulls. Thx again for sharing your knowledge of flying boats Nick.
I'd like to see more content regarding hydrofoils!!
Oh awesome I was just making a comment on your other video about hydrofoils. Thanks!
Could you make a video about the practical limits of energy efficiency of hydrofoils? Assuming computer control and optimizing for energy efficiency / speed.
Personally I'm interested in a solar powered cruiser using minimal power to foil at good cruising speeds.
But it would also be interesting in view of the need to use less fossil fuels for transportation, replacing air travel with fast hydrofoil ferries.
I was just researching partial hydrofoils. You read my mind!
Partial hydrofoils are an interesting category of which I was unaware until watching this video. As a catamaran sailor I was intrigued to see the previous generation America's Cup design and look forward to seeing the new foiling monohulls in action. The raised foils on the upwind side look pretty dangerous though... I wouldn't want to be on the leeward side of a boat upwind of them in close quarters.
they have a more limited use than foils generally so they're a little less popular. But they are gaining in popularity, the current gen of IMOCA boats primarily run in a 'partial' mode, largely relying on the planing and buoyancy of the hull. Partly it's due to the limits imposed by the class rule, but it does work very well.
Also partiql hydrofoils are really hydroplanes, I made 3, 20 foot single seater hydroplanes with the tunnel effect, wing in ground effect. They work very well and get on the plane very quickly. I studied ekranoplans in the 90s to understand wig effects
I have a dream to build a hybrid, foiled PWC. Amazing to have access to this sort of education.
Cool vid. I have a topic suggestion: Icebreakers! Especially what kinda hull shape is good for them.
Nice idea! I will add it to the list.
Since it's been a year, I can share what I've read (non-engineering). The old concept of an icebreaker on the Shackleton expedition was to use very strong and steep sides to break ice at the bow. Later, they discovered that a shallow bow could ride up onto the ice, and break it using the ship's weight, which seems to have been much more effective.
Disclaimer: there may have been some advances in the last hundred years or so!
One thing that isnt mentioned is wing shape and wing profile, angle of attack for forward and rear foils, height of skegs for a certain size weight. Positioning on the diagrams are flawed as most filers now carry forward foils under the mast position of a yacht for example. Interesting but need a follow up and more exploratory.
I made ladder foils in 97 on my 28 foot single seat trimaran, coincidentally similar to the hobie trifoiler at the same time.
Also adjustment wands on variable pitch surface piercing foils and connections to boat also a good video
Excellent coverage, thanks
Great information! Probably the subject of an entirely new vlog is the America's Cup AC-75s and Vendee Globe "semi-foiling" boats. Could the newest hydrofoiling designs be applied to everyday/commercial marine applications???
Your videos are interesting, this is the first one I've watched and I plan to watch more. You should devote a few seconds at the beginning of each video to give some evidence of your knowledge, "I am a naval architect, I designed x boats, I received x awards, I speak regularly on hydrofoils, I also live in a yacht I designed on which I sailed around the world." I can tell from your videos that you have knowledge but it was only at the end of the video that I found out you are a naval architect. I watch Tony Jeffries boxing videos and I get sick of his little spiel at the beginning "olympic silver medalist, european champion, english champion, undefeated professional boxer, blah blah blah" but at least I know he's a legit expert.
Dankie Nick. This quite intresting. I am wondering why was the hydrofoils not use more? If it better that the normal design. And what is the fuel burn of this hydrofoils? Hydrofoils is like the 3rd level op boat design. Normal sailboats with a keel are plenty. Cats R less plenty and the hydrofoils only on YT!
I don't know the exact fuel burn rate, but it can be very high. For comparison, I looked up fuel burn rates for a 3000 hp gas turbine engine. Hydrofoil boats normally use turbine engines. This is a rough estimate, based on some sketchy data. But the fuel burn for that type of engine would be in the range of 300 gal/hr. Hydrofoils are not used more for several reasons.
- They only work for light craft. Ships normally specialize in carrying heavy things.
- Fast speeds are not always possible in a heavy storm.
- Hydrofoil craft are far more expensive. Compare the cost of a fighter jet to a ship. Similar difference between a hydrofoil and normal ship.
Great lucid presentation!
Partial Hydrofoil was invented by Prof. KG Hoppe of Stellenbosch University - South Africa. Lots of failed copies. But his system works - and always has.
There is the HYSUCAT and HYSUWAC foil systems.
Can you suggest books or research papers on hydrofoil design? I suspect I could get an active design working right sooner than a passive one by developing my own control systems.
I'd like to learn what would be involved in retrofitting an old monohull sailboat with hydrofoils. My budget is roughly zero, but I have enough time to learn to an amateur level.
Edit: I started watching your America's Cup video, and I will never be in that class. My interest is in making improvements for pleasure cruising as a hobbyist.
One book to look into: "Hydrodynamics of High-Speed Marine Vehicles" by Odd M. Faltinsen.
Surge stability seems worth noting as a theoretical lesson but it’s hard to fathom when that would ever become an issue.
nice
Great Video except.......
I wish you had given a little nod to the inventor of the Hydrofoil, Alexander Graham Bell (the telephone guy) and showed a picture of his 1912 boat.
BTW: it did over 60 miles per hour.
Interestingly the Bras d'Or, which is what it was called (because it was first tested on the Nova Scotian lake of the same name) gave its name to two other hydrofoil boats down the line. I think the most interesting is HMCS Bras d'Or, the Canadian navy's equivalent of the Boeing and Lockheed's projects for the US military and was recorded at 63kn, which makes it the fastest military surface ship up until the 21st century.
Hmmmm... at 5:25 you say that roll stability requires partially submerged foils. I don't think that this is correct. In the same way that wing dihedral gives aircraft stability (fully submerged in air), I think that fully submerged foils with dihedral have roll stability. The lift from the foil is proportional to cos(theta) where theta is the angle between the normal to the foil and vertical. When partially submerged they have more stability but fully submerged they are also providing roll stability. :)
Good video, thank you! Q about passive roll control which you suggest needs to come from surface piercing. Yet, airplanes handle spiral divergence though being fully immersed...
I don't think I can comment too much on airplanes, since I'm not an aeronautical engineer.
But airplanes and hydrofoils do share some similarities. Hydrofoil roll stability can come from submersion of additional foil area. But it also comes from the foil dihedral angle, the same as an airplane.
In addition, the the elevators, rudder, and ailerons on an airplane are all examples of what I would call active control in the nautical world. And I have never personally seen an airplane without at least some of those active controls.
@@DatawaveMarineSolutions with a submerged foil and dihedral, can you get lateral stabilitty (no rollover even with fixed, zero rudder?) I expect that to be hard because of high cg, vs an airplane.
Love the new intro!
wondrful .. thank you
Thank you naval architect.
I was hoping to hear about cavitating and super-cavitating foils too
Why are hydrofoil craft not more popular, especially with smaller to medium-sized vessels? Also, could a pilot maintain manual control of a 40-foot hydrofoil, foregoing the need for a computer control system?
Yes, a pilot can maintain control manually. They do it on the Americas Cup boats. As to why we don't have hydrofoils everywhere. As an analogy, it is the same reason we don't have everyone buying racecars. A hydrofoil boat is complicated to operate, very expensive, and requires extra maintenance. They are specialized ships, and few people can justify the cost.
@@DatawaveMarineSolutions, thank you. I'm trained in mechanical engineering, and yet to further study naval architecture. I intend to design and build a ~40-foot motor yacht with retractable hydrofoils for cross-oceanic voyages cruising at ~40-knots. My preliminary thinking is that such a craft will be faster, and more fuel efficient than conventional motor yachts, whether catamaran or monohull. I intend to construct the yacht myself, to make it financially viable as a project. Do you think this is realistic for one with only mechanical engineering undergraduate studies behind him?
Do you have any book recommendations?
Ray Vellinga's "Hydrofoils..."
is there any free literature about hydrofoil passive stability? if anyone knows pls link me
Awesome!
This is all good stuff on this channel. Mind you the chappie giving the lecture rather does have an air of 'Open University' about him :-) which will mean little to nothing to those not of a certain minimum age and of a British persuasion :-)
An ironic reference considering my Masters of Engineering from University of Southampton, with first class honors. Southampton also being a British university.
Very nice. Thx you very much. =)
You are awesome
a multi hull boat mitigates most of the issues raised
"Why would a aircraft manufacturer design a ship?"
TBH they have done from the beginning ..... ever heard of flying boats? Those hulls were more ship than aircraft.
Another reason for Boeing or Grumman to make them?
Weight , not important to ships critical to planes And hydrofoils ….
It would be nice to look at the current Americas Cup. All the sailboats run on foils.
Ah yeah... Please design some military ship live. Some battleship with big guns or something. =)