Sound Velocity Profile (SYP) at Strait of Malacca for Maritime Warfare Usage

Nowadays, many tragedies and accidents happen in the oceans due to human negligence in handling equipment and also the ship itself. Therefore, it is important to do the hydrographic survey as it is the study about the physical of the sea. In the other words, the hydrographic survey also comes out with the prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activities, including the economic development, security and defences, scientific research, and environmental protection. The sound velocity profile is a plot of propagation speed or velocity of sound as a function of depth and it is a fundamental tool for predicting how the sound will travel. The sound velocity profiles around the world are different. There are three factors affecting the sound velocity profile which is temperature, salinity, and pressure. The survey to get the sound velocity profile is using the sound velocity probe. The survey was done at 9 chosen locations at Straits of Malacca to get their sound velocity profile. The data from the sound velocity probe from the survey being collected by the hydrographic department and the sound velocity profile for 9 chosen locations at Straits of Malacca have been plotted. Therefore, the profile can be used as a reference for the tactical warfare usage and also for calibration of the echo sounder on board the ship

Acoustic Approach to Determining Seabed Substrates Distribution at Mandi Darah Island, Sabah

Marine ecosystems and natural habitat play the important role of the Earth’s life support system. They significantly contribute to economies and food safety and help preserve ecological processes. However, the devastation of the marine ecosystem in Malaysia due to the human factor and climate change is quite alarming. Therefore, spatial marine information, especially on the distribution of seabed substrates and habitat mapping, are of utmost importance for marine ecosystem management and conservation. Traditionally, seabed substrate and habitat mapping were classified based on direct observation techniques such as photography, video, sampling, coring and scuba diving. These techniques are often limited due to water clarity and weather conditions and only suitable for smaller scale surveys. In this study, we employed an acoustic approach using the RoxAnn Acoustic Ground Discrimination System (AGDS) with a high-frequency single-beam echo sounder to examine the distribution of seabed substrate at the Mandi Darah Island, Sabah. The acoustic signals recorded by AGDS are translated into hardness and roughness indices which are then used to identify the unique characteristics of the recorded seabed types. The analysis has shown that fifteen types of substrates, ranging from silt to rough/some seagrass, have been identified and classified. The findings demonstrated that the acoustic method was a better alternative for seabed substrate determination than the conventional direct observation techniques in terms of cost and time spent, especially in large scale surveys. The seabed substrate dataset from this study could be used as baseline information for the better management and conservation of the marine ecosystem

Development and Experimental Investigation of a Marine Vessel Utilizing the Energy Ship Concept for Far Offshore Wind Energy Conversion

The energy ship is a concept for offshore wind energy capture which has received very little attention until today. To this date, there had not been yet an experimental proof of concept. In order to tackle this issue, an experimental platform and data acquisition system has been developed. A 5.5m long sailing catamaran served as a platform equipped with a 240mm diameter water turbine. The energy ship platform has been tested several times in the actual river to investigate the workability of the platform and data acquisition system. Results show that energy ship platform can produced 500W electric power for a true wind speed of 10 knots

Investigation of Numerical Hydrodynamic Performance of Deformable Hydrofoil (Applied on Blade Propeller)

The hydrofoil is a hydro-lifting surface that significantly contributes to marine transportation such as a boat, ship, and submarine for its movement and maneuverability. The existing hydrofoils are in fixed-shaped National Advisory Committee for Aeronautics (NACA) profiles, depending merely on the variation of Angle of Attack (AOA) such as rudder, hydroplane, and propeller blade. This research is concerned with the deformable hydrofoil that aims at modifying its NACA profile rather than its AOA. However, there is still a lack of knowledge about designing an appropriate deformable hydrofoil. Therefore, a numerical investigation of hydrodynamic characteristics for selected hydrofoils was conducted. After undergoing the 2D numerical analysis (potential flow method) at specific conditions, several NACA profiles were chosen based on the performance of NACA profiles. NACA 0017 was selected as the initial shape for this research before it deformed to the optimized NACA profiles, NACA 6417, 8417, and 9517. The 3D CFD simulations using the finite volume method to obtain hydrodynamic characteristics at 0 deg AOA with a constant flow rate. The mesh sensitivity and convergence study are carried out to get consistent, validated, and reliable results. The final CFD modeled for propeller VP 1304 for open water test numerically. The results found that the performance of symmetry hydrofoil NACA 0017 at maximum AOA is not the highest compared to the other deformed NACA profiles at 0 deg AOA. The numerical open water test showed that the error obtained on K.T., K.Q., and efficiency is less than 8% compared to the experimental results. It shows that the results were in good agreement, and the numerical CFD setting can be used for different deformed profiles in the future

Feasibility Study of Monsoon Effect on Wave Power for Wave Energy Converter in Sabah, Malaysia

This paper presents a research to determine the effects of the Northeast Monsoon (NEM) and the Southwest Monsoon (SWM) on wave power along the coastal area of Mandi Darah Island, Sabah. This study identified the daily data of wave height and wave period for 6 months from June to December 2018. The following period was chosen because it consisted of two monsoon seasons in Sabah. The data obtained from the Acoustic Doppler Current Profiler (ADCP) were thoroughly analyzed to estimate the wave height and the wave period to identify the wave power at Mandi Darah Island. The wave heights ranged from 0.01 m to 0.47 m while the wave periods ranged from 1.0 s to 8.6 s. The wave height range during the NEM was higher by 0.12 m than SWM, while the difference of wave period was significantly higher by 2.17 s during the NEM. The maximum wave power recorded at Mandi Darah Island was 1.57 kW/m throughout the period. During NEM, the wave power was significantly higher than during SWM, by 0.70 kW/m. These findings led to determining the wave energy type converter that suits the wave conditions at the Mandi Darah Island coastal area

Measuring severity of downtime influence factors to naval ship operational availability: a Delphi study

Rapid development in shipbuilding and ship repair calls for “cradle to grave” approach in ship maintenance to maximize growth. Organisations typically struggle to balance ideal maintenance philosophies against ongoing cost reductions whilst maintaining high availability of vessels. Due to limited research on Downtime Influence Factors (DIFs) on ships, improvement efforts could not be allocated precisely in tackling issues involving combined “human and equipment” aspects impacting ship availability. The purpose of this study is to generate RMN ship maintenance DIFs and their severity measures via a Delphi approach. The research pinpointed to 15 Severe DIFs as the key problem areas for prioritization of efforts in improving RMN ship availability