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Title:
A METHOD TO PROVIDE DYNAMIC LIFT AND DRAFT REDUCTION IN SHIPS
Document Type and Number:
WIPO Patent Application WO/2018/042451
Kind Code:
A1
Abstract:
Between boundary lines of surface water line and impressed water line, due to mass of an object which is buoyant, there exists pressure difference. From the state of equilibrium of a floating body, a little force in the direction of buoyancy forces will help the body to lift up easily. An upward lift on buoyant objects is obtained as a direct reaction of propulsion from plurality of propellers placed along the keel line that will reduce displacement and draft levels. To sustain new draft levels and to maintain stability of ships, with the help of Artificial Intelligence by getting inputs from hydrostatic pressure sensors and gyroscopic sensors, thrusts of respective keel propellers are adjusted. When draft and displacement of a vessel becomes low, due to dynamic lift, various water borne resistances such as frictional drag, traverse wave resistances will reduce. Thus the overall cost and sail efficiencies will greatly improve.

Inventors:
V, Narayanan (No.23, Plot 99B Kulasekaran Street,Sundaram Colony,,East Tambaram, Chennai 9, 600059, IN)
Application Number:
IN2017/050323
Publication Date:
March 08, 2018
Filing Date:
August 06, 2017
Export Citation:
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Assignee:
V, Narayanan (No.23, Plot 99B Kulasekaran Street,Sundaram Colony,,East Tambaram, Chennai 9, 600059, IN)
International Classes:
B63B1/00
Foreign References:
US2213611A1940-09-03
DE3518516A11986-11-27
Download PDF:
Claims:
Claims

I claim,

1) A method to provide dynamic lift and draft reduction in ships comprising:

plurality of propellers;

placing the propellers on the bottom side along the plane of the ship adjacent to the keel line on either sides;

propelling the said plurality of propellers in unison;

obtaining vertical upward lift as a direct reaction of propulsion from the propellers;

sustaining the new draft levels after obtaining vertical upward lift;

increasing or decreasing the propulsion to adjust the draft levels;

increasing or decreasing the propulsion to maintain the stability of the ship

2) The method described in claim 1 in the step of plurality of propellers wherein the said propellers are shielded externally or are of rim type in such a way the flowing water beneath the ship during the sail time will not affect the dynamics of the propulsion

3) The method described in claim 1 in the step of placing the propellers further comprising of:

wherein one pair of propellers is placed in the bow or front side at the bottom of the ship;

wherein one pair of propellers is placed in the center portion at the bottom of the ship;

wherein one pair of propellers is placed in the aft or rear side at the bottom of the ship

4) The method described in claim 1 in the step of placing the propellers further comprising of:

placing the propellers facing downwards;

the motion of the ship due to the propulsion of the said propellers happen in vertical upward direction along the Z axis

5) The method described in claim 3, wherein, the propellers are placed in

equidistance to each other and at equidistance from the keel of the ship

6) The method described in claim 1 in the step of propelling wherein the propellers propel in unison with uniform thrusts 7) The method described in claim 1 in the step of sustaining wherein the vertical uplifting of the ship is within the scope of the water surface line

8) The method described in claiml in the step of increasing or decreasing the propulsion to adjust the draft levels wherein to sustain the new draft levels by measuring and understanding the present draft levels through means of hydrostatic pressure sensors

9) The method described in claim 1 the step of increasing or decreasing the

propulsion to maintain the stability wherein the stability of the ship is maintained by adjusting the thrusts of the respective set of propellers

10) The method described in claim 1 the step of increasing or decreasing the

propulsion to maintain the stability wherein to maintain the stability of the ship by measuring and understanding the angular moments through means of gyroscope sensors

Description:
A METHOD TO PROVIDE DYNAMIC LIFT AND DRAFT REDUCTION IN SHIPS

Detailed description of the invention:

Referring to Fig-i, a ship which is empty or unloaded in waters 99 with a draft hi 200. The ship's main propeller 100 which is at the AFT or rear end is responsible for the ship's forward movement 600, while the water flow in the opposite direction 601. Some ships have bow thruster 110 which is responsible for the angular movement and meant for changing direction of a ship and provides better maneuverability, while others have rudder (which is not shown here) to change directions. The surface water line 300 is the top most level of water that interfaces with ship and the keel line 310 is the bottom most of the ship. Draft 200 is the height between the surface water line 300 and keel line 310 of the ship. Fig-2 shows a loaded ship. When there is an increase in weight, the ship will level down deeper and deeper into the water increasing the draft level h2 210. To explain further, referring to Fig-4, shows a normal water line 320, when a buoyant object is placed it impresses the water line 330 as shown in Fig-5 and the impressed water line 330 takes the shape of the ship. Referring to Fig-5, while the gravitation forces 400 due to the mass 401 of the ship acts in the downward direction, the buoyancy forces 500 will act in the upward direction on the ship. When the forces of gravity due to the mass of the ship is equal to the buoyancy forces, equilibrium is achieved.

Draft reduction:

It is observed that from the state of equilibrium, for a buoyant object, a little force in the direction of buoyancy forces will provide upward lift. The additional forces Fa 501 as shown in Fig-6. These additional forces Fa 501 are obtained from the keel propellers 120 as shown in Fig-3. Referring to Fig-3, these keel propellers 120, that are responsible for the upward lifting of the ship is key to the invention. The effect of these additional forces Fa, is the reduction in draft I13 220. So I13 220 in Fig-3 is less than h2 210 in Fig-2. The additional forces Fa required to provide uplift, from the state of equilibrium to the water surface line will be of increasing order. However, the scope of uplift, by using this method of draft reduction, is beneath the water surface line only. For example, hydrofoils; which will be discussed further in a later section, provides uplifting above the surface water line.

Propeller placement:

Referring to Fig-7, which shows placement of keel propellers, KPi 121 through ΚΡό 126 are the plurality of propellers that are placed at the bottom of the ship along the keel on either sides. KPi 121, KP 3 123, KP 5 125 are shown on one side of the keel and KP2 122, KP 4 124, KP6 126 are shown on the other side of the keel.

The distances along the beam of the ship di 251 is equal to d2 252 for the propellers KPi 121 and KP2 122, d3 253 is equal to d4 254 for the propellers KP 3 123 and KP 4 124, ds 255 is equal to d6 256 for the propellers KP 5 125 and ΚΡό 126.

The distances dy 257 and d8 258, along the longitude of the ship are equal for the pairs of propellers KP1-KP2 (top pair), KP 3 -KP 4 (middle pair) and KP 5 -KP6 (bottom pair).

The placement of these keel propellers are very important. The number of keel propellers and the placement of them at equidistance shall vary from one ship to another depending on its length. When all the keel propellers are made to propel at unison, to get a balanced thrust, provides upward lift for a ship. After obtaining necessary reduction in draft, the thrusts of these keel propellers are adjusted to maintain the draft levels.

Fig-8 shows the bottom view of the ship along with the keel propellers, Fig-o, shows the front view of the ship and Fig-io shows the back view of the ship.

Stability of ship:

Referring to Fig-n, which shows the ship tilted toward left and hence

instable(assuming the tilt is beyond accepted angles). By providing additional thrusts from propellers, say KPi 121, KP 3 123, KP 5 125(which are on the left side of the keel line, where KP 3 and KP 5 are not shown in the figure), the stability will be regained as shown in the Fig-12.

Similarly, if the ship tilts toward the right side, by providing additional thrusts from the right side propellers, say KP 2 122, KP 4 124, ΚΡό 126 the stability will be regained.

How much of additional thrust to be provided to regain stability will be determined by getting inputs from the gyroscopes or gyro sensors which are part of ship's instrumentation. These gyroscopes or gyro sensors will provide angular

measurements. Thus stability of ships will be maintained without additional need for buoy tanks inside the ships.

Ship resistances:

Referring to Fig-13, when power is given to the main thruster 100 the ship will move forward. As the thrust is increased the ship will speed up. When the speed of the ship increases, the submerged portion of the ship will face resistance from the water. The resistance will be in the order of cube the velocity of the ship. So higher the draft level higher the resistance when ship speeds up.

To explain further, resistances include wind resistance 450 acts on the free board area(area of the ship above the water level), water resistance 550 acts on the face of the ship in the opposite direction of the ship's movement, wave resistance 575 and frictional drag resistance 585. These are the main resistances that act on the ship that resists the ship's motion. There are other resistances as well but not discussed here. The impact of the invention on the resistances which are pertaining to the water level, i.e. the submerged portion of the ship will be discussed further here.

Referring to Fig-13 that shows a loaded ship, due to weight the draft h2 210 is high. As the submerged portion of the ship in the water is high, the resistances will be more on the ship for it's movement. There are three main factors that are present here;

1) Area facing the water: As per hydrodynamics law, power required to push an object through a fluid increases as cube the velocity. When the draft is high it implies that the area of the ship facing the water is large and therefore high volume of water flows in the opposite direction during the ship's movement.

2) Frictional drag resistance: When draft is high it implies that the wetted surface area is larger and it increases the frictional drag resistance. Frictional drag resistance is also known as viscous drag as it depends on the viscosity of the fluid in which the object is moving. Viscous drag is directly proportional to p-density of water, s-wetted surface area and v-square of the velocity of the ship.

3) Wave related resistances: When the draft is high it implies that the energy required to push the water out of the way of the hull is larger and it increases the wave related resistances. Wave related resistance is a very major factor for ship's movement. Waves are created while a ship starts moving in the water and waves become larger when the speed of the ship is increased.

Wave related resistance can be reduced through means of a) Reduced displacement b) Fine entry and c) Bulbous bow.

In the present invention, the method of draft reduction using dynamic uplift which will help to reduce the above mentioned resistances. Referring to Fig-14, showing the reduction in draft I13 220 through means of thrusters 120. When the draft becomes low, the following factors will be effective;

1) The area facing the water is reduced, therefore the power required to push the object through the water will be lesser; lesser by the factor of cube the velocity of for the area raised above the water level.

2) By reducing the area of contact with the water, the wetted surface area becomes less thereby the frictional drag resistance 585 will be brought down.

As the viscous drag is directly proportional, to a) p-density of water, b) s-wetted surface area and c) v-square of the velocity of the ship, the present invention supports point b) s-wetted surface area, by reducing the wetted surface area the friction offered to the ship due to the water contact will come down.

3) As the ship is pushed up with the help of keel thrust ers/propellers 120, the sense to acquire the natural equilibrium will diminish at every moment during the sail that results in reduced displacement therefore the wave related resistances, especially the traverse waves 575, will be brought down.

Wave related resistance can be reduced through means of a) Reduced displacement b) Fine entry and c) Bulbous bow, the present invention supports point a) Reduced displacement. As the ship is having dynamic up lift it results in the effect of reduced displacement.

Referring to Fig-13A that shows speed versus resistance curve for a ship. It is clear that resistance increases as the speed of the ship increases and the resistances steeply increases when the speed of the ship is further increased. Wave and wind resistance offers maximum resistance, while viscous or frictional drag resistance also offers resistance as speed increases. These resistance will vary from ship to ship depending on the shape and displacement of the vessel.

By reducing the draft, the free board(the area of the ship above the water level) increases. This will increase in wind facing resistances 450, however, reducing drafts will exponentially bring down the majority of the resistances that affect the motion of the ship. This is because the density of water is 1000 times higher than the density of air and so wind resistance effect is relatively lower than having higher drafts. Thus by reducing draft of a ship, using the keel propellers, all the important forms of water borne resistances that affect the ship's movement are reduced thereby giving efficiency for sailing. Draft calculation:

For draft calculation purposes, referring to Fig-15, the height (I14) 230 should be taken in to account for ground clearance calculations with the ship base contact level as 320, especially when the ship is sailing in shallow waters or while harboring.

However, for the resistances calculations on the submerged portion of the ship, the draft height I13 220 should be taken for calculations. The resistance on the propellers will be less because of its dynamics and area facing the water flow is less.

Shallow water sailing:

During sail times, a ship can encounter various natural conditions. Referring to Fig- 16, the ocean or sea floor levels may be in raised conditions. Sometimes there will be canal passing. In these conditions, to pass the raised flooring or shallow waters portion 710, the ship must raise above to avoid grounding, which means the drafts of the ship have to be raised. The present invention can be of help here, the keel propellers 120 will provide enough thrusts to push up the ship and raise it to pass the high floors. So to pass from portion 700 to 720, while portion 710 is at raised levels, the ship can raise before 710 and lower after crossing 710. Thus draft reduction helps to ships to sail in shallow waters with surface water level 320 and ocean's high floor areas.

Propeller shielding:

Referring to Fig-17, 'A' section shows the keel propeller with open blades, when ship is at sail, the flow of water 550 under the ship might affect the dynamics of the propulsion of these keel propellers. So, to prevent this, enclosing the blades or shielding to propellers should be done. In Fig-17, 'B' section shows one such enclosed blades with rims. Fig-17, C' section shows another such model. Rimming the blades will prevent water flow 550 hitting the blades directly.

Referring to Fig-18 shows the body of the ship with concave surface 900 and in the cave the propeller 120 is placed. By doing this, the way water flow 550 will tend to flow past the propellers saving the dynamics of blades from the water forces directly hitting them.

Referring to Fig-19, a shield protrusion 901 surrounding the propellers. This way the water forces will not hit the blades directly thereby dynamics of propulsion of these keel propellers are not affected.

Thus by means of rimming or shielding the keel propellers or thrusters 120 the blades are protected from the flow forces of water and propulsion dynamics are not affected.

Artificial intelligence:

Referring to Fig-20, to show how using artificial intelligence will help to maintain the draft levels and maintain stability of the ship. Manual ways to adjust the propulsion of the keel propellers by looking the instrument readings at every moment is difficult. So an automation to manage the set draft levels and to make stability of the ships is in need. Computing system with Artificial intelligence techniques, which acts by learning from the input sub systems to produce desired output is shown here for the said automation. In Fig-20, the various blocks to show how the flow of actions will result for a desired output. The block computing system 950 will learn from the input system 951, do analysis and instruct output system 952 to take corrective action. The input system 951 will receive inputs from various sensors in the system such as hydrostatic pressure sensor 953 and gyroscopic sensors 955. The computing system is defined with pre-configured algorithms that will learn from the input system 951 and instruct output system 952 to act. The control settings 956 will take inputs from different sub blocks to set threshold levels. Linear input 957 is given to set threshold for draft levels. Angular input 958 is given to set threshold for stability maintenance. The input system 951 will continuously be sending signals that are detected from hydrostatic pressure sensors 953 and gyroscopic sensors 955. The computing system 950 will be continuously monitoring the input system 951 and output system 952. When the input signals crosses the set threshold by the control system 956, the computing system will analyze this and send signals to the output system 952 for corrective measures. The output system 952 send appropriate signals to the drive system 954 and accordingly the propulsion of the keel propellers 120 are adjusted.

To explain how artificial intelligence(AI) system for the draft level management, referring to the Fig-21, section 'A' which shows in the normal draft level 200. Section 'B' shows when the ship is loaded with mass 401 and due the weight the draft level 220 increases. As explained in Fig-20, the hydrostatic pressure sensors 953 input pressure signals on the draft level to the input system 951 which in turn sends data to the computing system 950 where the information will be continuously monitored. Assuming the threshold data is set to draft level I13 210 through control settings 956, the change in threshold data will be detected by the computing system 950 and it instructs output system 952. The output system sends signals to the drive system 954 to increase the propulsion of keel propellers 120 in unison and the reaction is the draft level reduction to I13 210 which is shown in section 'C of Fig-21.

To explain how artificial intelligence(AI) system helps to maintain the stability the ship, referring to Fig-22, section 'A' that shows the normal angle of the ship which is stable. A threshold angle θι is set through the control system 956, that the ship should stay stable. Due to some reasons, like load shifting or side waves impact, the ship might become unstable and the angle of the moment sifts from stable region to unstable region as shown in section 'B' of Fig-22. As the input system 951

continuously receives signals from the gyroscopic sensors system 955 and the data is fed in to the computing system 950 as referred in Fig-20, the computing system 950 will detect the change in angular moment from θι to Θ2. As there is a change in the threshold level, it will instruct the output system 952. This will in turn send out appropriate signals to drive system 954 to increase the propulsion of the respective keel propeller(s) say 121 and therefore the angle of moment from unstable region Θ2 is shifted back to stable region θι which is shown in section 'C of Fig-22.

It should be noted that the above explanation stands for only one set each of input of threshold levels and output as the corrective measure for draft level maintenance and stability maintenance. The AI will learn from various parameters such as input, threshold levels, reaction as output at various conditions, for example different levels of displacement of the ship, weather conditions and then the AI will act of its own from the learning.

Referring to the Fig-23, which depicts the flow chat diagram for the draft level management, where M is the mass and its weight in tons, D is the draft and its height in meters, P is the propulsion of keel propellers and its speed in rpm. To show how the AI would respond to input values, below is the algorithm for single input as a sample.

Algorithm:

Step 1: Input all values

Step 2: For Ml read values of Di, D2, D3

Step 3: Check if (D2 is greater than Di) then Step 4

else

Maintain Propulsion PN

endif

Step 4: Check if(D2 is greater than D3) then Step 5

else

Maintain Propulsion PN

endif

Step 5: Increase Propulsion PN

Step 6: Check if(D2 is greater than D3) then Step 5

else

Maintain Propulsion PN

endif :

Referring to the Fig-24, which depicts the flow chat diagram for the stability management, where M is the mass and its weight in tons, Θ is the angular moment in degrees, PN is the propulsion of respective keel propellers and its speed in rpm. To show how the AI would respond to input values, below is the algorithm for single input as a sample.

Algorithm:

Step 1: Input all values

Step 2: FOR any M, READ θι, θ 2

Step 3: Check if (θ 2 is greater than θι) then Step 4

else

Do nothing

endif Step 4: Increase Propulsion of respective side keel propellers

Step 5: Check if (θ 2 is greater than θι) then Step 4

else

Do nothing

endif

Thus the artificial intelligence system will help the ship to maintain the required draft levels and maintain stability of the ship in the stable region.