This study investigated seafarer satisfaction and perceptual evaluations regarding cabins, recreation, and social areas on cargo ships over 10,000 GT, and also examined the relationship between gross tonnage (GT), accommodation area size, and floor area per person on cargo ships. In the preliminary stage, the floor areas of the accommodation area were calculated using the plans of 20 cargo ships grouped according to MLC-defined GT categories. In the main study, a survey was conducted with 179 Turkish seafarers working onboard cargo ships over 10,000 GT. One-way ANOVA and chi-square tests were applied to measure differences among rank groups. According to preliminary-stage findings, although total accommodation area tends to increase with GT, the floor area per person does not have the same tendency, as crew capacity plays a significant role. H1, H2 and H3 were partially supported, cabin evaluations differed by rank and GT, ratings reported the most negative assessment regarding cabins. H4 was partially supported, with social areas generally considered partially adequate. The findings suggest that MLC's GT-based thresholds alone may be insufficient to ensure the adequate accommodation areas; crew capacity should be explicitly incorporated into the standards, and physical compliance does not guarantee seafarer satisfaction.
A detailed numerical investigation of the calm-water hydrodynamic performance of an azimuth stern drive (ASD) tugboat is presented. Unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations are performed to predict the total resistance, trim, and sinkage over a wide range of Froude numbers at model scale. The free-surface flow is captured using the Volume of Fluid (VOF) method with a high-resolution interface capturing scheme, while turbulence effects are modeled using the SST k–ω formulation. To account for dynamic hull response, the vessel is allowed to move freely in heave and pitch through a Dynamic Fluid Body Interaction (DFBI) approach. A systematic mesh and time-step convergence study is conducted to ensure numerical accuracy and solution independence. The numerical predictions of resistance coefficient, trim angle, and sinkage show good agreement with available experimental data, validating the adopted computational framework. In addition to global performance metrics, detailed analyses of the flow field are carried out, including free-surface wave patterns, hull pressure and skin-friction distributions, and stern wake characteristics at the propeller plane. The results provide physical insight into the resistance mechanisms and stern flow features of ASD tugboats operating in calm water. While employing established numerical methods, the primary contribution of this work lies in providing a comprehensively validated dataset and detailed flow physics analysis for a benchmark ASD tugboat—a bluff, unconventional hull form that remains underrepresented in high-fidelity CFD literature. The validated methodology and flow-field findings support the application of CFD as a reliable tool for tugboat hydrodynamic assessment and design optimization.
In marine environments, the main cause of degradation of reinforced concrete structures is corrosion induced by the penetration of chloride ions. Durability design approaches have gradually evolved toward performance-based approaches, which are capable of more accurately assessing the behavior of structures over time and their resistance under specific environmental exposure conditions. Due to the high variability of the parameters affecting the durability of these structures, a probabilistic performance-based approach tends to provide results closer to reality by considering the uncertainties of materials and degradation phenomena as random variables. In this work, a probabilistic service life analysis is carried out for concretes produced with RCA from the precast industry at different replacement levels under marine environment exposure conditions. The non-steady-state chloride diffusion coefficient was obtained using the Multi-Regime Method (Asociación Española de Normalização, 2012) and subsequently used as an input parameter in the analyses. The Duracon model was used to estimate the probability of failure of these structures over time, considering a 100-year analysis period and different values of concrete cover, temperature, and environmental aggressiveness levels. The service life estimation was performed considering a target failure probability of 10%.
The torpedo pile is a Brazilian technology widely employed for anchoring offshore structures. Studies indicate that the use of vertical water jets applied at the pile tip can increase penetration efficiency and reduce inclination during installation. Considering the high costs and logistical challenges of full-scale testing, investigations using reduced physical models become a viable alternative. This study presents the development and application of an experimental apparatus based on the Froude Number Similarity Law, designed to perform penetration and pullout tests on reduced-scale torpedo pile models without fins, at a 1:76 length scale. To validate the system, an initial series of tests was conducted in fine granular soil using jets with a diameter equivalent to 12.5% of the pile's outer diameter. The results confirmed the proper performance of the apparatus, successfully reproducing in laboratory conditions the penetration process assisted by water jetting. A significant increase in penetration was observed compared to the self-weight condition, even at low flow rates (0.5 L/min), with an asymptotic trend as flow rate and jet velocity increased. Despite the substantial rise in jet velocities due to the smaller jet diameter, penetration depths were similar to those reported in the literature, indicating that jetting efficiency is more closely related to flow rate than to jet velocity. Scale effects inherent to the system were also recognized, reinforcing the importance of future analyses based on dimensionless groups derived from the Vaschy–Buckingham Π theorem to enable the transposition of laboratory results to field conditions.
This study investigates the post-graduation career planning preferences, influencing factors, and expectations of 138 students enrolled in maritime education programs at İskenderun Technical University in Türkiye, using a structured survey administered to students from the Maritime Technologies Vocational School to examine career intentions, sectoral awareness, salary expectations, and perceptions of institutional support. The collected data were analyzed using descriptive statistics and non-parametric tests (Mann-Whitney U and Kruskal-Wallis). The findings indicate that 41.3% of students reported no specific sector preference, while 26.1% preferred the public sector, 21.0% the private sector, and 11.6% were undecided. Among students favoring public employment, Port Authorities, Customs Directorates, and the Coast Guard/Marine Police emerged as the most preferred institutions. Salary expectations were largely concentrated in the 30,001-50,000 TL range. No statistically significant differences were observed across gender and education level (p > 0.05). However, significant differences emerged for the third empirically derived factor among students with prior sector knowledge and internship experience (p < 0.05). These findings highlight the importance of strengthening internship opportunities, career guidance services, and industry–academia collaboration to support more informed and sustainable career planning among maritime vocational students. Overall, students attached high importance to promotion opportunities, job security, and employment in international companies. However, the findings should be interpreted with caution due to the single-institution design, which limits broader generalizability. These findings suggest that integrating compulsory internships and strengthening career counseling services may significantly enhance students' career readiness and alignment with labor market needs.
