International Journal of Offshore and Coastal Engineering (IJOCE)

Analysis of Abrasive Materials dan Air Pressure Variations for Thermal Spray Aluminum Coating on Adhesion Strength and Corrosion Resistance in Seawater Environment

2025-05-28T11:40:09+00:00

Marine structures must withstand the marine environment for a
certain design life. However, corrosion causes a decrease in
structural integrity before reaching the design life. Thermal spray
aluminum coating becomes a protection method because of its
resistance to corrosion in the long term. This study analyzed the
effect of variations in abrasive materials and air pressure on
thermal spray aluminum coating on ASTM A36 steel. The steel
material will be blasted with two types of abrasive materials,
namely garnet and aluminum oxide, then coated using the electric
arc wire spray method at pressures of 2.5 bar, 3.5 bar, and 4.5 bar.
Testing was carried out using the pull-off adhesion test and the
three-electrode cell method. The results showed that the highest
adhesion strength of 12.2 MPa occurred at 4.5 bar aluminum
oxide, while the lowest was 6.3 MPa at 2.5 bar garnet. The lowest
corrosion rate of 0.001 mm/year was obtained at 4.5 bar garnet,
and the highest was 0.101 mm/year at 2.5 bar aluminum oxide.
Based on the results of the corrosion rate test, it can be concluded
that the increase in pressure is directly proportional to the increase
in coating performance in resisting corrosion. Conversely, the
increase in surface roughness is inversely proportional to the
coating performance in resisting corrosion.

Lazy Wave Flexible Riser Dynamic Tension Analysis with Variation of Diameter and Buoyancy Module Configuration in Extreme Condition

2025-05-29T19:40:55+00:00

ABSTRACT
Oil and Gas Production at floating offshore facilities is growing.
It prompted the design of the Flexible Riser as a solution to channel
exploration results to floating offshore facilities. In this final
project, dynamic stress analysis of lazy wave flexible riser is
carried out with variations in diameter and number of buoyancy
modules under extreme conditions. This study discusses the
maximum tension and minimum bending radius (MBR) on the
flexible riser due to variations in diameter and number of buoyancy
modules in extreme conditions with two system conditions, namely
intact conditions and damage conditions. From the results of the
analysis, the larger the diameter of the flexible riser, the greater
the maximum tension at the SPM point. While it will be smaller at
the PLEM point and the more buoyancy modules used, the smaller
the maximum tension at the SPM point, the larger it will be at the
PLEM point. The larger the diameter of the flexible riser, the
smaller the MBR in the SagBend area. The larger the HogBend
area and the more buoyancy modules used, the larger the MBR in
the SagBend area, while the smaller the HogBend area.

Lazy Wave Flexible Riser Dynamic Responses Analysis with Variation of SPM Offset from PLEM on Operation Condition

2025-05-29T20:02:22+00:00

The increasing use of flexible risers in oil and gas exploration
projects is a big challenge for engineers to design better riser
systems to improve further the efficiency and safety of exploration
and production activities in offshore oil and gas fields. SPM is
often used as an offloading facility connecting FSO or FPSO as
recipients of oil and gas products from subsea templates or wells.
Under operating conditions, SPM can move freely following the
movement of environmental loads. Drifting or changes in position
due to the load on the SPM can threaten the riser response,
whereas the riser response can be different whether the SPM is
moving or drifting in its stress or bending response. The results in
this study also contain the effect of this phenomenon on their
fatigue life. As a result, the difference in riser response due to the
distance from SPM to PLEM is that the farther the distance from
SPM from PLEM, the greater the stress response and bending
radius it has. Fatigue life also follows the same results, where the
farthest distance from the SPM configuration to PLEM has the
lowest fatigue life compared to the closest distance from the SPM
to PLEM configuration, with the highest fatigue life at 128.31
years and the lowest at 124.78 years.

Trunnion Structure Analysis with Rigging Variations at The Loadout Stage During Lifting Jacket Platform Process

2025-05-29T20:17:50+00:00

An offshore structure is a structure that is operated at an
offshore base and has the general function of oil and gas
exploitation and exploration. The making process of this
structure is called the fabrication process. Fabrication is the
process which is covered the whole activities to produce the
structure. Lifting is a process that is included in this
fabrication step.Many important lifting items correspond to
the requirement to let the lifting process is working. A
trunnion is a tubular member that helps lift the structure
because it is where slings can be convoluted. Trunnion can
be called lifting lugs, depending on the engineer at the
company used.In this research, the trunnion that must be
analyzed is the trunnion that has the general function for the
jacket-to-lifting processes. In contrast, the researcher
analyzed the effect of various rigging configurations. The
considered variable of rigging configuration is the shape
and amount of the spreader bar.

Replace Experimental and Numerical Study on Ocean Current Turbine Performance with Innovative Idea Using Toroidal Propeller

2025-05-29T20:37:16+00:00

According to the HEESI, the share of renewable energy production
is only 13.29% of the total energy production, with a target of 23%
by 2025. One promising renewable energy source with a potential
of 41 GW is ocean currents. To harness this potential, propeller
turbines can be used. Propellers are a critical component of these
turbines, typically designed based on the Wageningen B series.
However, this series still exhibits issues such as cavitation and
noise during operation. Toroidal propellers offer advantages by
eliminating tip vortices, resulting in quieter operation, and
reduced fatigue. This study aims to enhance the efficiency of
propeller turbines through modifications using toroidal propellers.
The study employs ANSYS Fluent for simulation and experiments.
The process includes designing toroidal propellers with a
maximum diameter of 3 meters, blade pitch angles of 60°, and
blade counts ranging from 3 to 9. These designs are then simulated
to analyze power and efficiency. Performance testing will measure
RPM, and observe cavitation. The results are for blades ranging
from 3 to 9 generates 42.6 to 63.2 kW. Therefore the best design is
9 blades that generate 63.7 kW of power with a maximum RPM of
89.9.

Analysis of the Pretension Angle of Mooring Lines SPM and Its Effect on the Tension and Strength of Subsea Marine Hose

2025-05-29T20:57:20+00:00

The industry of oil and gas industry have developed along with
advances in technology, so does the mooring system. Mooring
system is a series that functions to keep the ship station or floating
platform at all water depths. Currently, there are many types of
moorings that can be used, one of which is Single Point Mooring
(SPM). SPM itself consists of various types of mooring legs, as well
as other supporting components such as subsea hose or riser.
Subsea hose and mooring lines are closely related because in the
application, the length of the mooring lines also determines the
offset or limitation of motion of the SPM, while the subsea hose
also has a maximum limit of pull caused by the movement of the
SPM. In addition to the length of the mooring lines, another factor
is the pretension angle. Therefore, in this study, an analysis was
carried out by varying the pretension angle (45°, 50°, 55°, 60°)
under extreme conditions and inline loading by reviewing the
tensile forces on the mooring lines and risers. The larger the angle,
the smaller the tensile force, so the offset would be larger, and vice
versa. The results of this study indicate that the pretension angle
applied must be appropriate so that the tensile force on the
mooring lines that occurs can also be appropriate.

Influence of Geometric Parameters on Fatigue Life of Two-Planar Tubular DKT Joints Based on Fracture Mechanics Under a Combination Loading

2025-05-31T07:56:16+00:00

According to SKK Migas, Indonesia has operated 613 units of offshore platforms which is 54.65% of the platforms are more than 20 years old, and 24.63% are between 16-20 years old. With the extension of its operation time, the structural integrity of the old platform will decrease. One of the potential consequences is structural failure due to cyclical loading caused cracks. . This research aims to determine the influence of geometric parameters in DKT twoplanar tubular joints on fatigue life based on fracture mechanics. By varying geometric parameters, we can see the influence of geometric parameters on fatigue life under combined loads of axial, in-plane bending, and out-of-plane bending moments. The tubular joints are modeled locally and analyzed using Finite Element Analysis (FEA), and the crack is modeled as a semi-elliptical form. Fatigue life analysis is performed by varying geometric parameters under the combined loads. After carrying out a sensitivity analysis on all geometric parameters, it was concluded that the gamma parameter had the most influence on the combined load with a sensitivity of 89%.

Resource Empowerment and Optimization of Beach Tourism Facilities in Delegan, Gresik, East Java

2025-05-31T03:32:14+00:00

The discipline of Integrated Coastal Zone Management
(ICZM) is still growing, especially in Indonesia, but its
implementation is still relatively young. This study focuses on
beach tourism. Ecotourism development and management is
one of the efforts to utilize local resources that must be optimal.
Delegan Gresik Tourism Beach, East Java, is a management
research area for ecotourism development. This research aims
to determine the potential of existing resources in Delegan
Beach attractions and make scenarios for development plan
efforts. This is done through Strengths, Weaknesses,
Opportunities and Threats (SWOT) analysis and interviews to
determine resource potential, development alternatives and
priorities, both through analysis of internal and external
factors. The results of this study show that forms of stakeholder
participation influence the determinants of the development of
natural tourism areas on Delegan Beach. The resulting
development directions include the use of various resources,
the development of facilities as community business
opportunities, the empowerment of community skills, the
Improvement of regional socialization, and efforts to preserve
the environment.