Journal of ETA Maritime Science

101-115

Authors: Kadir ÇİÇEK

During the last 20 years, regulatory enforcements regarding with the protection of marine environment have been significantly increased. Especially, starting from 1 January 2010 a new regulation, consisting of waste water treatment plants in ships and new effluent limits, took effect. The new limits comprise a stricter review of prior limits. The strict reduction in the effluent limits for the treated wastewater discharged from ships intimates International Maritime Organization (IMO)’s intention to provide more severe control on wastewater discharges and to demand on installation wastewater treatment system that meet international requirements. Furthermore, the new limits constitute a further challenge for the manufacturing companies specified in design and manufacturing of waste water treatment systems. To way out from these points, this study focuses on development a knowledge-based expert system for selection of appropriate shipboard wastewater treatment system. Within this scope, the study proposes a hybrid approach combining AHP and TOPSIS under fuzzy environment. The three most commonly preferred shipboard wastewater treatment system types are examined and evaluated in terms of various design, operation and environment criteria.

127-136

Authors: Şakir BAL

This paper addresses the skew effects (a significant geometric property) of marine propellers on cavitation phenomenon numerically. DTMB 4381, 4382, 4383 and 4384 model propellers with different skew values have been chosen to investigate the cavity patterns on the blades under open water conditions. A lifting surface method has been applied for both non-cavitating and cavitating propellers. Numerical results (nondimensional thrust and torque coefficients, efficiency values and cavity patterns on the blades) have been validated with experimental results. It has been found that the present numerical method is accurate and reliable for predicting the hydrodynamic performance of both non-cavitating and cavitating propeller under open water conditions. It has also been found that under certain conditions the skewed blades of the propeller can cause lesser cavity patterns and improve the propeller performance.

151-163

Authors: Hakan DEMİREL

For all areas where operational activities exist, human error possibilities are of critical importance. In this sense, maintenance, management and monitoring of all components in ships powered by gas turbine systems is a condition that must be observed. At this point, the importance of human impact is great and plays a critical role. In this study, the probabilities of human error on the 14 critical faults described in the literature for gas turbine components are calculated by the CREAM method in the sense of expert opinions. The results clearly indicate the importance of human impact on faults, and guide the technical personnel to be employed on board ship during the operation. This study provides the basis for further studies in this area.

179-191

Authors: Murat Selçuk SOLMAZ , Alparslan BAŞKAYA , Atilla SAVAŞ , Mehmet AKMAN

Artan enerji talebi, akaryakıt fiyatları ve fosil yakıtlardan kaynaklanan olumsuz çevresel etkiler, yenilenebilir ve sürdürülebilir enerjiye olan talebi artırmaktadır. Bu nedenle, rüzgâr ve güneş enerjileri günlük hayatta kullanılabilir hale gelmiş ve bu tür sistemlerin verimliliği konusunda çalışmalar hızlanmıştır. Denizcilik sektöründe de benzer bir durum yaşanmış ve yakın zamanda yenilenebilir enerji gemiler için popüler hale gelmiştir. Bu çalışmada, yakıt tüketimini ve çevre kirliliğini azaltmak amacıyla çalışma zamanının çoğunu demirde ya da iskelede geçiren bir barca rüzgâr ve güneş enerjisini kaynak olarak kullanan yenilenebilir hibrit bir enerji sistemi kurulmuştur. Kurulan sistem HOMER yazılımı ile optimize edilen konfigürasyonlarla mukayese edilmiştir. Sonuçlara göre, hibrit sistemin gemide kullanılmasıyla hesaplarda dikkate alınan süreçte yakıt tüketiminde ve emisyonlarda yaklaşık %39 oranında azalma sağlanmıştır. Sistemin geri ödeme süresi ise yaklaşık iki yıl olarak hesaplanmıştır.