Boat Motion Research Articles

Quantitative Analysis of the Complex Time Evolution of a Camphor Boat

The motion of a camphor boat on the water’s surface is a long-studied example of the direct transformation of chemical energy into a mechanical one. Recent experimental papers have reported a complex character of boat motion depending on the location of the camphor source. If the source is close to the stern, the boat moves at a constant speed. When it is shifted towards the boat center, oscillations of speed are observed. When the source is close to the boat center, pulses of speed followed by oscillations appear. Here, we focus on numerical simulations of camphor boat motion. We discuss approximations that allow us to reduce the numerical complexity of the problem and formulate a model in which the equation for boat velocity is coupled with a one-dimensional reaction–diffusion equation for camphor surface concentration. We scanned the phase space of model parameters and found the values that give qualitative agreement with the experiments. The model predicts all types of boat motion (continuous, oscillating, and pulsating) observed in experiments. Moreover, the model with selected parameter values shows that for specific locations of the camphor source, a spike in speed is followed by transient oscillations, which are an inherent part of speed relaxation.

A novel multi-degree of freedom kinetic energy harvester for self-powered low-power applications in ships

The utilization of kinetic energy from the motion of small fishing boats to energize ship-borne wireless sensors offers a promising solution to address the power supply challenges of these sensors in the maritime environment. Nonetheless, the constrained scope of retrievable kinetic energy in the prevailing ship-borne kinetic energy harvester has evolved into a hindrance, curbing its progression. Hence, this paper proposed a novel multi-degree of freedom kinetic energy harvester for low-power applications in ships, where the harvester is harnessed by combining a ball rod, sliding bearing, and slider body. Relying on this mechanical device, the ship's kinetic energy in the surge, roll, sway, and pitch directions is transformed into the swinging motion of the mass ball, subsequently converted into the movement of the slider body. Under the influence of the magnetic force between the slider body and the piezoelectric beam, the piezoelectric beam experiences frequent oscillations, ultimately translating mechanical motion into electrical energy. The experimental results show that the harvester can charge capacitors with capacities of 220 μF, 470 μF, and 1000 μF to 1 V within time intervals of 15 s, 24 s, and 36 s. The prototype has been effectively deployed on a ship in an artificial lake, achieving an impressive maximum average power output of 173.10 μW. This study serves as compelling evidence that the harvesting of kinetic energy from ships presents a promising solution for self-powering low-energy applications onboard while also introducing a novel design concept for applying kinetic energy harvesters on fishing vessels.

Towards Dynamic Velocity Prediction of NACRA 17

NACRA 17 is a small foiling catamaran used in Olympic sailing. Sailing in the NACRA 17 is truly unsteady, especially in the foiling conditions. Dynamic velocity prediction has gained a lot of attention in recent years due to the unsteady nature of foiling sailboats. Different approaches have been applied to predict the motions of foiling or skimming boats in unsteady conditions. Typically, the aerodynamic forces are computed by the quasi-steady theory assumption. Static coefficients are used, and the applied velocities are corrected with boat motions. The hydrodynamic forces of a fully foiling boat can be computed in a similar fashion, but this method fails to include the effect of changes in the free surface as well as added mass. This paper proposes an approach where dynamic coefficients of the NACRA 17 hydrofoils are determined based on unsteady Computational Fluid Dynamics (CFD) simulations with a free surface. In the simulations the foil is moved in prescribed motions in one degree of freedom (DOF) at a time and dynamic coefficients are extracted for different frequencies of motion. All coefficients are combined in a coupled system of equations, and the equations can be solved in 6 DOFs in the time domain. Test scenarios with time-varying conditions are simulated and compared with full dynamic CFD simulations. The initial investigation of the approach shows promising results, but more investigations are needed to validate the approach and to identify possible limitations.

New types of complex motion of a simple camphor boat.

We discuss the motion of a rectangular camphor boat, considering the position of a camphor pill in relation to the boat's stern as the control parameter. The boat moves because the pill releases surface active molecules that decrease the surface tension and support the motion. We introduce a new experimental system in which the boat rotates on a long arm around the axis located at the centre of a Petri dish; thus, the motion is restricted to a circle and can be studied under stationary conditions for a long time. The experiments confirmed two previously reported modes of motion: continuous motion when the pill was located at the boat edge and pulsating (intermittent) motion if it was close to the boat centre (Suematsu et al., J. Phys. Chem. C, 2010, 114(21), 9876-9882). For intermediate pill locations, we observed a new, unreported type of motion characterised by oscillating speed (i.e. oscillating motion). Different modes of motion can be observed for the same pill location. The experimental results are qualitatively confirmed using a simple reaction-diffusion model of the boat evolution used in the above-mentioned paper.

Euler's Navigation Variational Problem

In a 1747 publication, De motu cymbarum remis propulsarum in fluviis (“On the motion of boats propelled by oars in rivers”), Leonhard Euler (1707-1783) works out various instances of a boat moving at constant speed across a stream flowing in straight streamlines at assigned speeds, in which one of these gives rise to a variational problem consisting of finding the quickest crossing path between two points on opposite side of the river banks, which is generally known as the navigation variational problem. This problem together with the well-known catenary and brachistochrone problems, are considered classical examples in the calculus of variations. Here, we shall present a brief account on Euler’s recurrent interests in calculus of variations, mainly laid out in three publications that span between 1738 and 1744. Particular focus will be given to Euler’s navigation variational problem. A brief account on Lagrange’s contributions to variational calculus is also presented.

On the motion of boats propelled by oars in rivers

Euler considers the following problem: A boat with a perfect rudder moves at constant speed across a stream flowing in straight streamlines at assigned speeds. Assuming that the downstream velocity of the boat equals that of the river, how should the rudder be set so that the boat traverses a given path? He works out various instances, one of which gives rise to a variational problem, in detail. (From Clifford Truesdell's An idiot's fugitive essays on science: methods, criticisms, training, circumstances.)

Benchmark Sea Trials on a 6-Meter Boat Powered by Kite

This paper presents sea trials on a 6-m boat specifically designed for kite propulsion. The kite control was automatic or manual, dynamic or static, depending on the point of sailing. The measurement system recorded boat motion and load generated by the kite. A particular attention was paid to wind measurement with several fixed and mobile locations directly on the kiteboat or in the vicinity. A high resolution weather modelling showed that a classical power law, describing the wind gradient, was not satisfactory to get the wind at kite location. 5-min measurement phases were systematically recorded. In the end, 101 runs were carried out. Data were processed with the phase-averaging method in order to produce reliable and accurate results.

RETRACTED ARTICLE: Application of cognitive system engineering in development of dragon boat sports

Dragon boat is a traditional sport in China. A trajectory control model of dragon boat movement development based on cognitive system engineering is proposed to achieve quantitative planning and cognitive design of dragon boat movement development. The constraint parameter model of the evolution control which affects the development of the dragon boat movement is constructed, and the state optimization and adaptive game equilibrium design of the development of the dragon boat movement are carried out by using the game control method, and the cognitive structure of the development of the dragon boat movement is combined. In order to improve the cognitive control ability of the development of the dragon boat, the cognitive system engineering design of the development of the dragon boat movement is carried out, and the methods of small disturbance suppression and adaptive equilibrium configuration are adopted to recognize the pattern and plan the state of the development process of the dragon boat movement. The cognitive system engineering design and control optimization for the development of dragon boat motion are realized by using joint parameter estimation and adaptive search control method. The simulation results shows that it is of better self-adaptability using this method to launch the cognitive system control and planning of dragon boat sports development, and the ability of self-adaptive process control and system cognition on dragon boat sports development has been improved.

Center Manifold Theory for the Motions of Camphor Boats with Delta Function

Various collective motions of camphor boats have been studied. Camphor boats are self-driven particles that interact with each other through the change of surface tension on water surface by camphor molecules. Consequently, even in a one-dimensional circuit, a congested state or jamming can be observed (Suematsu et al. in Phys Rev E 81:056210, 2010). In this phenomenon, the unidirectional motion of each particle is considered a traveling wave, and the concentration of camphor molecules forms a pulse shape. Hence, each pair of particles interacts with each other like a pulse–pulse interaction. Thus, we expect that the center manifold theories proposed in Ei (J Dyn Differ Equ 14:85–137, 2002) and Ei et al. (Physica D 165:176–198 2002) are applicable for the analysis of the collective motion of camphor boats. However, spatial discontinuity in our model, in particular the existence of Dirac delta functions in a linearized operator, does not fulfill the requirement in the reduction process because the authors developed their theories in $$L^2$$ -framework and for smooth nonlinearity in Ei (2002) and Ei et al. (2002). In this article, we extend the results obtained in Ei (2002) and Ei et al. (2002) and establish a new center manifold approach in $$(H^1)^*$$ -framework. Finally, we succeed to rigorously reduce a mathematical model (Nagayama et al. in Physica D: Nonlinear Phenom 194:151–165, 2004) coupled with a Newtonian equation and a reaction–diffusion equation including delta functions to an ordinary differential system that represents the motions of camphor boats.

Testing a Boat with Different Wave Propulsors in a Hydrodynamic Channel

The paper presents the results of the comparative testing of wave propulsors of five types, including the propulsor of the underwater sail type, a rigid foil with elastic couplings, and a propulsor without movable elements using the effect of the nonlinear interaction between a wave and the working body of the propulsor. The rigid foil operation is numerically simulated using the XFlow software package. The influence of the wave propulsor location on the boat frame, the depth of its immersion, the elastic coupling parameters, and the presence of stabilizing aft devices on the propulsor performance is studied. It is shown that for a rigid swinging wave propulsor with elastic couplings mounted on the bow of a boat the velocity of the boat motion is proportional to the bow swinging.

Reduced model of a reaction-diffusion system for the collective motion of camphor boats.

The unidirectional motion of a camphor boat along an annular water channel is observable. When camphor boats are placed in a water channel, both homogeneous and inhomogeneous states occur as collective motions, depending on the number of boats. The inhomogeneous state is a type of congestion, that is, the velocities of the boats change with temporal oscillation, and the shock wave appears along the line of travel of the boats. The unidirectional motion of a single camphor boat and the homogeneous state can be represented by traveling wave solutions in a mathematical model. Because the experimental results described here are thought of as a type of bifurcation phenomenon, the destabilization of traveling wave solutions may indicate the emergence of congestion. We previously attempted to study a linearized eigenvalue problem associated with a traveling wave solution. However, the problem is too difficult to analyze rigorously, even for just two camphor boats. Therefore we developed a center manifold theory and derived a reduced model in our previous work. In the present paper, we study the reduced model and show that the original model and our reduced model qualitatively exhibit the same properties by applying numerical techniques. Moreover, we demonstrate that the numerical results obtained in our models for camphor boats are quite similar to those in a car-following model, the OV model, but there are some different features between our reduced model and a typical OV model.

PENGARUH MODIFIKASI BURITAN SPEED BOAT TERUBUK EXPRESS 6 TERHADAP KECEPATAN KAPAL

Speedboat Terubuk Express is a fast ship that is used as a means of sea transportation to carry passengers with a capacity of 60 people. Because it continues to experience losses, currently the Terubuk Express speedboat is modified by adding capacity and replacing the main drive engine which previously used an outboard engine with 4 x 200 horse power replaced with an internal engine that uses diesel fuel with power 1140 kilowatt. This study aims to determine the effect of stern shape changes and interaction total resistance before and after being modified on the hull to the speed of the ship.In this study several stages were carried out, namely a field survey to obtain the effect of size addition, making a model using Maxsurf 13.0 software, input data and running simulations using Hullspeed 13.01 then analyzing the results which included obstacles and speed.Based on the results of the analysis and calculations showed that the change in stern shape on the express speed boat speed caused L / B to increase by 1.2%, an increase in the comparison of the L / B value could affect the ability of the boat's motion and stability. The total resistance of the ship increased by 1.05% which at a speed of 35 knots before the change in total resistance was 33.5 kN while after the change in the total resistance became 35, 1 kN. Changes to the installed power engine can give a maximum speed of 49 knots with a total barrier of 47.5 kN. Increased speed greatly affects the engine seat and the strength of construction and the location of the longitudinal of bouyancy.

An Oblique 2D+T Approach for Hydrodynamic Modeling of Yawed Planing Boats in Calm Water

Determination of forces acting on planing hulls in maneuvering has been turned into an interesting problem during the last decade. Different methods, based on mathematical or empirical approaches, are elicited to compute hydrodynamic forces and moments acting on the boat in different simplified conditions, such as steady yawed or heeled conditions. Modeling of different conditions and combining them with each other may lead to initiate a final simulation model for 6DOF motion of planing boats in calm water. These simple modeling approaches, in other words, can be considered as basics of a final 6DOF model. The current article address hydrodynamic modeling of yawed motion for hard-chine planing boats in calm water. The current research paper is primarily focused on the determination of horizontal force and yaw moment acting on the boat as it moves forward in a steady yawed condition. The derivation approach is based on mathematical formulation of 2D+T theory and added mass variation in longitudinal direction. Virtual mass of a wedge in horizontal direction is analytically found and then the final force and moments are computed using extension of sectional forces, acted on wedge section of the boat, over entire wetted length of the vessel. The precision of the proposed model is verified by comparing the computational values against previous experimental data. An improvement for the model has been considered to conquer some of the drawbacks reported by previous researchers. The comparison exhibits an improvement of the model; the increase in added mass which was previously discussed by previous researchers can be seen. Also, it is observed that in the case that the wetted length of the boat is small, the transom reduction works well and leads to an accurate prediction of sway force. Finally, it is viewed that the computed yaw moments are in a fair agreement with previous experimental data.

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea.

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

Dynamic Analysis of High-Speed Boat Motion Simulator by a Novel 3-DoF Parallel Mechanism with Prismatic Actuators Based on Seakeeping Trial

In this study, we focused on a novel parallel mechanism for utilizing the motion simulator of a high-speed boat (HSB). First, we expressed the real behavior of the HSB based on a seakeeping trial. For this purpose, we recorded the motion parameters of the HSB by gyroscope and accelerometer sensors, while using a special data acquisition technique. Additionally, a Chebychev high-pass filter was applied as a noise filter to the accelerometer sensor. Then, a novel 3 degrees of freedom (DoF) parallel mechanism (1T2R) with prismatic actuators is proposed and analyses were performed on its inverse kinematics, velocity, and acceleration. Finally, the inverse dynamic analysis is presented by the principle of virtual work, and the validation of the analytical equations was compared by the ADAMS simulation software package. Additionally, according to the recorded experimental data of the HSB, the feasibility of the proposed novel parallel mechanism motion simulator of the HSB, as well as the necessity of using of the washout filters, was explored.

Vertical Motions Damping Model Test of a Lifeboat Lowered Onto a Flat Sea Surface

Abstract The article presents the experiment’s results of the lifeboat model lowered with an initial speed and then released to fall onto a flat water surface. The purpose of the research is to determine the trajectory of the vertical boat motion and describe it with a mathematical model. This is closely related to determining the damping factor since the vertical motion is damped and the lifeboat gets balanced and stops moving after some time. The procedure of selecting parameters in the mathematical model to adjust to the results of the experiment was described in details. The summary describes the imperfections of the presented damping model and their probable causes.

Dynamics of a camphoric acid boat at the air–water interface

We report experiments on an agarose gel tablet loaded with camphoric acid (c-boat) spontaneously set into motion by surface tension gradients on the water surface. We observe three distinct modes of c-boat motion: harmonic mode where the c-boat speed oscillates sinusoidally in time, a steady mode where the c-boat maintains constant speed, and an intermittent mode where the c-boat maintains near-zero speed between sudden jumps in speed. Whereas all three modes have been separately reported before in different systems, controlled release of Camphoric Acid (CA) from the agarose gel matrix allowed the observation of all the three modes in the same system. These three modes are a result of a competition between the driving (surface tension gradients) and drag forces acting on the c-boat. Moreover we suggest that there exist two time scales corresponding to spreading of CA and boat motion and the mismatch of these two time scales give rise to the three modes in boat motion. We reproduced all the modes of motion by varying the air–water interfacial tension using Sodium Dodecyl Sulfate (SDS).

Results of Single Sculling Technique Analysis Using 1D Mathematical Model

Sports results in rowing depend on two the most important factors: the athlete physical features and the motion’s techniques. Both assessment and optimisation of rowing techniques are possible only when one disposes the reliable mathematical model predicting the regatta results, that is the time to cover the assumed distance. A single scull participating in the 2000 meters distance’s regatta is our subject. The purpose of this study is to create a simplified mathematical model to simulate the rowing boat dynamics. The boat-rower system is treated here as a material point here. The oar has a prescribed angular motion vs. oarlock depending upon the time. The way of hydrodynamic force developed on the oar’s blade was modelled here. Then the boat motion, with the influence both of wind and water current, was described by a single nonlinear ordinary differential equation (NODE). The used simple model gives the possibilities of fast and reliable simulation of the single sculling technique and of forecasting the result of rowing regattas. The parametric sensitivity coefficient was defined here, as well the efficiency coefficient of sculling.

Motion modes of two self-propelled camphor boats on the surface of a surfactant-containing solution

HypothesisThe existence of a surface tension difference and a surface flow around self-propelled objects, such as camphor boats, has been confirmed by many studies. However, the interactions in the collective motion of several camphor boats have not been explicitly discussed. Here, a model system of two camphor boats was investigated for the first time from the viewpoint of surface tension and surface flow. ExperimentsThe behavior of one fixed boat and one movable boat on a sodium dodecylsulfate aqueous solution in an oval track has been studied as a model system of two-body interactions. The surface tension around the movable boat was measured using the non-invasive, double-beam quasi-elastic laser scattering method. The Marangoni surface flow was quantitatively estimated using a mock boat in order to evaluate the net repulsive interaction between the two boats. FindingsWe succeeded in controlling the motion of the two camphor boats by varying the boat characteristics and the surfactant concentration. The balance/unbalance between the surface tension distribution and the surface flow around the boats was found to drive two different behavior modes: stationary and oscillatory. These results allow us to gain further insight into the dynamics of the interactions in the collective behavior of autonomous inanimate objects.