Not Applicable
This invention relates to human powered boats, and more specifically, pedal powered displacement boats in the very-high performance range, and characterized by a long main hull with narrow beam and minimum cross sections.
Kayak traditions have traced their roots particularly in the waters of Alaska and Northern Canada for as far back as 5000 years. Different peoples including the Kadiak, Nunivacs, Makenzie, etc., each had their own kayak building traditions. The highest performing boats would have to be attributed to the Aleuts who like others, used dried driftwood, willow strands, all lashed together. They used sealskin rawhide, whale and seal fat to seal joints. The Aleuts, however took boat building for speed to a higher level in building their BAIDARKAS for example by using bone and ivory to make perpendicular rub points last longer in harsh wavy sea environments. Evidence shows that they used ball and socket joints to allow flexibility but keep alignment between the usually three lashed-together keel lap joint structures. The ball and socket kept alignment, the lashing around a lap joint held it together. (ZIMMERLY<, Qayaq . . . )
These advanced construction techniques allowed for a very narrow, but at the same time, very light craft. These were so narrow, that they were unstable in static floating. Like Greenlanders, the Aleuts had to use paddling techniques to keep their narrow boats upright.
A typical Aleutian single place baidarka in use between, say, the time of contact with Europeans in mid 18th century and continuing through the early 20th century may be as light as 20 lbs. and would be enviable to aerospace construction today. Dimensions for a single seat baidarka may include length 20 feet, WL width 1.17 ft, depth 0.3 ft draught with rounded sections that have a prism shape (to leave space for the keel while wrapped in sealskin) at the bottom center. They have been noted to be able to sprint at over 10 mi./hr. back in the 1700's (Dyson, 2000, Scientific American)
The front structure of baidarkas included a bifid bow similar to an open birds mouth. This inventor has observed such a structure to decrease a bow wave and break up the continuous “bone in teeth” splash, or spray to a small sprinkle thrown out to the side.
This inventor believes that the power saved is up to 2% when the trim is low (i.e. a payload of “sea otters”), when surfing, and going through waves as high as 30% of the freeboard of the bow. Also the upper half of some Aleut baidarka bows served as a “ski-skimmer” that apparently added bow buoyancy and fluid-dynamically (i.e. skimming or skiing) kept the bow angle higher when surfing (going a lot faster than normal down the face of a wave into the trough). These types of bow predates the ones presently used on cargo ships and the like to break up the bow wave and make the ship go faster under less power.
Generally for the past few millennia, hulls used in rowing and meant for speed, were built fast, light, and slender with small beam sections and long length. This is exemplified by Greek triremes. Other examples since than included low payload water taxies in London, Venice, various parts of Europe as well as other places. For the last century, and especially with the invention of the sliding seat, rowing shells designs have become especially slender and fast. They have developed to the point that designs have become unstable if left to stand alone. The center of mass is higher than the center of buoyant lift. Not only this, but as the boat rotates towards tipping, there is not much if any buoyant form to right the boat, so it keeps on tipping. They needed to be stabilized by sweeping the oars in the retrieval stroke, and deflecting them on the power stroke. Advanced rowers could depend on balancing the boat much as a tight rope walker uses a balancing pole, and therefore skim or sweep the water less on the retrieval stroke.
With cycling, the legs are stronger and biologically more power-efficient. In addition, pedaling technique is somewhat easier than with rowing and kayaking. With pedaling, the cyclist is facing forward and usually in a high recumbent or even upright position. Pedaling allows many possible methods for keeping upright a boat that is intrinsically unstable. Franz Frenzel 1889 (U.S. Patent 397,282) has a long, certainly unstable but potentially fast hull stabilized by counter weighting a keel well below the water.
Wilton Shiraki 1993 (U.S. Pat. No. 5,194,024), for a recumbent seat, as do Pierre Louis Parant 1994 (U.S. Pat. No. 5,362,264) Andre Gauthier (U.S. Pat. No. 5,672,080) with an upright seat, propose a fairly slender monohull in the form of a board. While these boards prove wide enough to support stability without the need for outriggers, ammas, aikos and the like, they also have to sacrifice considerable speed for this stability.
George W Tatum 1998 (U.S. Pat. No. 5,722,865) proposes canard balanced marine bicycle (U.S. Pat. No. 5,722,865). This canard which is as much like a pivoting vertical hydrofoil fin is located and functions amidships.
Tatum went on to market and race this class of boat, with considerable success in speed performance. Static and slow-speed stabilizing were done with deployable outriggers not addressed in his application. When the boat was static, the outriggers were deployed; when the boat was moving fast enough, the outriggers were hauled in and the fin could do the job.
This craft is a truly balancing machine where the canard/foil is used to dynamically keep the boat upright.
In aeronautical terms, of roll, pitch and yaw, this fin, foil keeps the boat balanced by supplying counteractive forces in the roll axis.
While this methodology was possible to operate and start from deep water, i.e. “untip” the craft in the static mode (if the outriggers were not deployed, the boat would settle sideways; the inventor managed a deep water start and deployment from this sideways floating position), it was very challenging to manage the gear. Upon starting, one would have to keep the boat upright with the canard/foil, steer, and using ropes and pulleys, and pawls to haul in the static outrigging gear. Methodology similar to this can be found in Mier-Maza (U.S. Pat. No. 6,309,263).
Tatum must have also found that there did not need to be a counterweight to help keep the boat upright as in later years he used only the vertical hydrofoil or canard to keep his boat upright.
In going high speeds however, the foil or canard being large enough to right a boat while pivotally mounted substantially amidships would produce considerable extra drag the faster the boat went. Foil drag force, and subsequent power is dictated by the equations:
F=Cd(1/2 rho) V̂2 S
And respectively,
P=Cd(1/2 rho) V̂3 S
Where F=Force; Cd=Drag Coefficient, Rho=Fluid density, V is velocity, S=Surface Area, P=Power
One can see with these equations that as velocity increases on a foil (like a constant area rudder or Tatum's fin), force increases as the square, and power as the cube! Two of the variables that can be reduced in the equations are the Cd and surface area S. It would be hard to reduce the Cd too much in Tatum's proposal since there would need to be structure there to absorb the forces on the pivoting vertical foil or canard. Also the righting moment correcting tipping forces would need some space to fit the structure into. Lastly, while the structure for the correcting forces would be manageable, there would have to be a vast increase in the pivoting structure to absorb underwater impacts, groundings and the like which would occur under normal instances in operation of the boat especially since the vertical foil/canard will have the first encounter with such objects. Reduced surface area is also not manageable since if there was too much reduced surface area, there would not be enough of it to control against tipping. While Tatum's proposal is essentially committed to the surface area of the fm foil, skimming means as a righting force allows for less drag. According to Gilmer (Modern Ship Design, Thomas Gilmer Naval Institute Press, 1981, p. 292, 296), skimming or plaining surfaces provide opportunities for great increases in speed with only slight increases in power as opposed to predictable increases in power for hull and constant area hydrofoils.
Hoerner and Brooks (HOERNER, SIGHARD, 1965, 11-26 to 11-32; BROOKA, ALEC HUMAN POWER, Spring, 1987: Vol 6 no 1) imply that surface skimmers have twice the drag per area that submerged foils do. But if significantly less surface area can be used in righting the boat, allowing for less overall drag and faster speeds.
My invention in aeronautical terms controls the craft in the roll axis (other axes: pitch and yaw controlled by longitudinal displacement stability and rudder respectively) with each hand left or right controlling port or starboard on an as-needed basis. The main component for this is an AMAVON, the combination of the traditional float or AMA; and ELEVON the trailing edge control surface of an airplane delta wing that controls lift (pitch axis) and side to side stability (roll axis). The actuation of my invention is fairly similar controlling the airplane. While in static mode, i.e. when the craft is at rest, the float part supports the boat. While at speed, the sweeper (derived from the recovery stroke in rowing called sweep), skims or planes across the surface dynamically supporting the hull.
My invention takes advantage in that the skimming planing devices can use less power:
The bigger the diameter of propeller there is, the more efficient it is. The depth of any propeller will require deep draught and make beaching or bringing the boat ashore very difficult unless there is some way to retract it
The boating activities of this inventor (U.S. Pat. No. 6,712,653) have included development of a dagger board type drive unit that can be laminated in to a watercycle shell. Laminating in the unit saves weight over bolting or locking as with Gauthier (U.S. Pat. No. 5,872,080). And with this inventor having built prototypes reaching over 6.5 miles/hr for over an hour under the foot of a moderately trained cyclist, it cannot be overemphasized that weight saving is VERY important. The draught of this high efficiency drive, or with a craft like Tatum (U.S. Pat. No. 5,722,865), once assembled, is very difficult to enter or exit the water. My invention applied to Tatum's proposal, as well as his subsequent activities and methods, and additionally, the application of my previous patent would allow quick assembly and beach entry and exit as opposed to having to assemble a cumbersome structure on shore and wade out to water depths of four feet before being able to get on and off to ride it.
My invention allows the propeller to be retracted and cleaned of weeds by hull rotation It is therefore an object of this invention to provide for the stabilizing aiko and ama structure and system to a very narrow hull that would be otherwise unstable, and to do so with the least possible resistance
It is another object to provide for stability of the low drag but long narrow inherently unstable craft throughout the range of speeds it may go from standing still to full speed, and stabilizing at each speed with as low a drag as possible.
It is a further object of this invention to provide for the lightest, and therefore the fastest application of a long narrow hull that is also easy to assemble and easy to beach, put in and take out of the water
Another object of this invention is to provide as a platform or package the long narrow hull proposed that uses the least amount of drag for a displacement boat as it applies to human powered boating of varying means of propulsion, pedal boating, recumbent seat boating, upright seat boating, single as well as multiple seat boating, hybrid powered boating, i.e. solar electric, wind and so on, motorized boating and the like.
Other objects will become clear as the invention is further disclosed.
Moving now to the drawings,
The following preferred embodiment and alternative embodiments are presented to give a general idea of the invention and by no means and under no circumstances do they represent the only form the invention could take.
In [
While in the static mode, i.e. while the craft is at rest [
The principals of this invention can be explained by Newton's Law “For every action there is an equal and opposite reaction” and moments which are guided by the equation
T=F*r
Where T=torque, F=force, r=lever arm.
In [FIG 6], operator's hand 20 pulls back on hand grip and arm 8, creating force 21 on lever arm 22, and transferring torque through inner aiko sleeve 3 about inner aiko sleeve pivot axis 23, to rotate amavon 7, and push sweeper 9 down against the waterline 18 to plane 24 using force 25 along lever arm 26 against sweeper lifting force and boat righting force (not shown)
Dynamically speaking, in [
In [
In [
Beaching the craft and launching it and handling it in shallow water and cleaning weeds from the propeller 32 and drive 2 (in [
In [FIG 12], hinged rack 15 that fixes aiko 3 orientation with hull 1 is locked in place while boat is in operation.
Hinged rack 15 secures seat support 5, seat 13, seat support arms 14 and aiko 3 in an all-connected superstructure. While hull 1 is sideways [
Docking is possible by means of a vertical axis hinge 37 in [
In [
In [
[
Large air-lifting foil sections 6b make up outer aiko section to provide potential extra buoyancy and use the same hand grip control 8 to stabilize the craft, especially in a strong headwind. Air flowing under the section would not have to be great as sections 6b would be near the surface 18.
The amavon in this embodiment [
A higher axis for inner pivoting aiko sleeve 3b is either on a horizontal axis or a tilted axis 23b in order to clear higher waves 18c. This embodiment [
An alternatative embodiment of [