Executive Management
Coşkun AĞCA – CEO & Chairman of the Board
Graduating from Istanbul Technical University, Faculty of Maritime Studies in 1992, Coşkun Ağca began his maritime career serving on various types of crude oil, product, chemical, and gas tankers. After completing his sea service in 2003, he joined Aygaz as a Marine Superintendent, responsible for LPG tanker operations, marking his transition to shore-based roles.
In 2006, Ağca joined Ditaş Shipping and Tanker Management Inc. as Fleet Manager, and in 2010, he was appointed Deputy General Manager responsible for all maritime operations of the company. During this period, he oversaw a broad operational portfolio, including newbuilding projects, crude oil and product tankers, chemical and asphalt tankers, as well as terminal operations.
After leaving Ditaş in 2020, he served as General Manager at Unic Tanker Ship Management between 2020 and 2024. In 2024, he took part in the establishment of Stella Tanker Ship Management and assumed the role of CEO & Chairman of the Board. With his extensive maritime experience, operational leadership, and sectoral expertise, he guides the strategic growth and vision of the company.
He holds an Ocean-Going Master (Unlimited) qualification and a Marine Pilot license.
İshak Bora İŞERİ – Fleet Manager
He graduated from Dokuz Eylül University Maritime Faculty with a degree in Marine Transportation Management Engineering in 2006. He began his maritime career the same year as a Deck Officer at Ditaş Marine Operations and Tanker Management Co., serving on product tankers. He subsequently held Deck Officer and Chief Officer roles at Genel Denizcilik Nakliyatı A.Ş., and later continued his career as Chief Officer at Beşiktaş Group between 2010 and 2011.
From 2011 to 2014, İşeri served as Master on oil and chemical tankers within İÇDAŞ Ice Tanker. He expanded his shore-based experience with roles including P&I Surveyor at Kalimbassieris Marine Consultants, Supercargo & Port Captain, and Operations Manager at Arkas Bunkering and Trading S.A. Between 2016 and 2023, he returned to Beşiktaş Group as Master, gaining extensive command experience.
With 15 years of onboard service on chemical, product, and crude oil tankers ranging from 5,000 to 160,000 DWT, he later joined Unic Tanker Ship Management as Safety & Quality Superintendent and Fleet Manager during 2023–2024. İşeri became part of Stella Tanker Ship Management in March 2024 and continues to contribute with his comprehensive operational and managerial expertise. He holds an Oceangoing Master license.
Koray YAŞ – Technical Manager
He graduated from Istanbul Technical University Maritime Faculty in 1997 with a bachelor’s degree in Ship Machinery Management Engineering and later completed his master’s degree in Marine Management at ITU in 2016. He holds an Oceangoing Chief Engineer license.
He served at sea until 2006 on various tanker types, including crude oil, product, chemical and container vessels. He then began his onshore career at DİTAŞ, the ship management division of TÜPRAŞ, as Technical Superintendent. In 2012, he was appointed Technical and Newbuilding Manager, overseeing the entire fleet—including tugboats and mooring vessels—along with planned/unplanned maintenance, newbuilding projects and technical operations.
Murat AKGÜNER – Chartering Manager
He graduated from Istanbul University, Faculty of Economics, Department of Economics in 1996.
He began his career in 1998 at Ditaş Deniz İşletmeciliği, where he served as Commercial Affairs Supervisor for eight years, focusing on tanker chartering and post-fixture operations. From 2006 to 2023, he continued his tenure in the company’s Fleet Management Department, taking on key roles such as Ship Operations Supervisor, Agency Manager, and Crude Oil Operations Manager.
He became part of Stella Tanker Ship Management in April 2024, bringing extensive operational expertise and long-standing industry experience to the company.
Erkan KİPİK – Finance Manager
Erkan Kipik obtained his associate degree in Accounting from Celal Bayar University in 2003 and his bachelor’s degree in Business Administration from Anadolu University in 2005. In 2010, he was certified as a Certified Public Accountant (CPA).
Throughout his career, which began in 1999, he has held managerial positions across Finance, Accounting, Human Resources, and Administrative Affairs. His professional experience includes 6 years at Ekol Financial Consulting, 5 years at Anele Supply Chain Solutions operating in Gaziemir Free Zone, 8 years at OVAKENT & BİLLAS Rubber Group, and 2 years at Degam Oil & Chemicals.
In addition to his corporate career, he provides training and consultancy services in his areas of expertise. Since 2010, he has published over 50 professional articles on accounting, finance, human resources, corporate governance, and business management.
Zerrin KÖKTÜRK – Human Resources Manager
She graduated from Istanbul Technical University Maritime Faculty with a bachelor’s degree in Marine Transportation Management Engineering/Deck in 2013 and is currently pursuing her postgraduate studies in Maritime Business Management. She began her maritime career in 2013 as a Deck Cadet on bulk carriers at İnce Shipping, later serving as Deck Officer at Turkon and UN RoRo between 2013 and 2015.
From 2016 to 2020, she worked as a Maritime Lecturer at Bülent Ecevit University Maritime Faculty, specializing in chartering, port and terminal management, maritime economics, navigation, tanker operations, and agency services, and contributed to several academic publications. She then continued her shore-based career at Unic Tanker Ship Management, holding roles in operations, crewing, and human resources between 2022 and 2024.
She joined Stella Tanker Ship Management in March 2024 as Crew Manager. Mrs. Köktürk holds an Oceangoing Watchkeeping Officer license.