this science of hydrography has addressed issue of ocean and coastal navigation and has provided accurate charts for the route planning and operation of surface ships (Hare, 2001). This discipline emerged as a response to the need for reliable information about navigable waters for marine and human transportation. Marine transportation has large and compelling economic benefits, since 75% of the earth is covered by seas and oceans. Turkey connects Asia and Europe with road and marine transportation. Every year approximately 50,000 ships, of which 20% carry petroleum, cross the Bosporus and Canakkale straits. here under keel clearance (UKC)is very important in shallow canals and waterways so that the ships do not crash onto the seabed (Gourlay, 2007). From this point of view, hydrographic surveys are crucially important in order to provide safety and sustain economic gains (Aykut and alkan, 2010).
hydrography data is collected by different methods. Acoustic ad aieborne laser methods are currently used in hydrography for measuring the depths.draught of the vessel, which is known from the building project, is named static draught. In surveys, the draught of the vessel changes in real time and is different from the static draught value.
in this paper, the dynamic draught of the vessel is determinded in different survey speeds, with RTK GNSS measurements using ellipsoidal height in real time. determinded dynamic draught values are ompared with the static draught value and analzed for determinded the depth data for precise charts