Skilltrade team

A company that specializes in hydrographic training and courses for the hydrographic survey, dredging and offshore construction industry since 2000.

Johan Stam

Managing Director

Having obtained a degree in civil engineering he began his career in the dredging industry in the newly/formed survey division of Stevin Dredging. There he worked as Hydrographic Surveyor providing survey input for harbour design and project support. The following 10 years he spent working on international harbour construction in projects around the world. In 1982 he became Personnel Manager for the Oceonics PLC at Intersite Surveys in Haarlem, The Netherlands and later Group Personnel Manager. In 1988 he founded Dutch Onshore Offshore Recruitment BV (D.O.O.R.) an agency providing qualified Hydrographic-, Geophysical- and System/engineer personnel to the international oil and gas industries. In 2000 Skilltrade was set up in order to address the growing need for training of hydrographic personnel. Survey modules were developed for short/term courses, at that time primarily for the Dutch market, and has continued to develop new modules and additional course material resulting in a comprehensive programme in survey education. Johan Stam is currently engaged in cooperative efforts with both governmental agencies and representatives of industry in order to establish and promote survey education in Europe and abroad.

Huibert-Jan Lekkerkerk

Sr. Lecturer hydrography

Huibert-Jan started working for Skilltrade in 2000. He has been course-coordinator, editor and principal lecturer hydrography for all Skilltrade courses including the Hydrographic Survey Course. Huibert-Jan holds a BSc degree in Hydrography (Cat A), a BEe in Maritime Electronics (BEe) both from the Higher Nautical College in Amsterdam as well as a joint MSc in Geographic Information Management from Utrecht U, Delft U, Wageningen UR and the ITC in Enschede.  

Since starting to work in the early 1990's he has mainly worked for government agencies with short stints at dredging and offshore companies. Since 1999 he has specialized as a client representative on large(r) scale projects such as the sanitation of Ketelmeer-Oost, the construction of Maasvlakte 2 and the sandy beach reinforcement of the Hondsbossche and Pettemer Zeewering. Parallel to this he works as Information Manager at an inter-governmental body (Informatiehuis Water) which is responsible for collecting and distributing water related information . Finally Huibert-Jan has authored and edited many articles on GNSS, Geodesy and Standardization as well as both a book on GPS Surveying and the Handbooks of Offshore Surveying.


Rob Luijnenburg

After his study Offshore Engineering at the University of Technology Delft, Rob joined the Hydrographic Department of the Royal Netherlands Navy for his military service. This was the beginning of a 45 year career in marine survey, offshore construction and dredging. Following the Hydrographic Department, Rob joined RJ Brown and Associates, an American consulting company involved in offshore pipeline design and marine survey. Following a two year stint with NeSA in Rotterdam, in 1990 Rob joined ACZ Marine contractors, later Van Oord NV, as Survey Manager responsible for all survey activities of the company.  In 2000 Rob moved to Fugro NV as Resource Manager for the Marine Survey Division. Following acquisition of Thales Geosolutions, former Decca survey, Rob assumed the position of Regional Director responsible for the European and African activities, global Positioning, Oceanography and Hydrography. Rob completed his career in Fugro as Director Strategy and Communication. In the latter role, his was closely involved in the search for the lost Malaysian Airlines aircraft MH370.  Rob is the former chairman of the Hydrographic Society Benelux and executive member of the Board of the IRO, the Dutch trade organization for offshore construction.  

Jan Appelman

Logbook Verifier

Jan started to work for Skilltrade in 2014. Jan graduated at the Nautical College Noorderhaaks, Den Helder (NLD) in 1975.  In 1978, he joined the Royal Netherlands Navy (RNLN) with special interest in hydrography and oceanography. After a number of seagoing hydrographic and oceanographic positions, Jan ended his hydrographic career afloat in 1994, commanding the survey vessel HNLMS Blommendal. During this period afloat he passed IHO-Cat. B in 1981 and IHO-Cat. A in 1986 at the Royal Navy Hydrographic School, Plymouth (UK). From 2000 onwards Jan was stationed in the NL Hydrographic Office in The Hague (NLHO), participating in procurement of hydrographic equipment, survey management and the build of the survey vessels HNLMS Snellius and Luymes. Later positions within NLHO included international hydrographic affairs and the full management of civil & military survey, meteorology and oceanography within the RNLN. He ended his naval career in 2011 when he was honourably discharged from the RNLN. Jan continued his hydrographic career as a self-employed consultant (CristalClear Consultancy) and volunteer. 

Manaf Zora

Educational consultant

Manaf Zora from Halifax, Nova Scotia, Canada joined Skilltrade in 2017 as an education consultant after completing Skilltrade Hydrography Cat B program.

Manaf holds a BSc degree in Geology, minor in Archeology, diploma in engineering, Advance diploma in Marine geometrics, Pilot diploma and he is a marine first aid and scuba diver instructor.

Since graduating from university, he has been involved in fiber optic cable installation, pre-lay survey, port development, drugging, coral reef monitoring, water quality, Drilling, environmental monitoring, shark and turtle monitoring, IHO charting, hydrographic and geophysical survey, and more.

Recent offshore experience includes Planning and managing of hydrographic and geophysical survey (Side scan, Multibeam, Sub bottom profiler and gravity/piston/box/vibra core).  He regularly supervises the mobilization of equipment, data acquisition, data processing, and logistic planning.  Final presentation to clients for survey results involving Multibeam, Side scan Sonar, and Sub bottom profilers.


As part of his continuous thrives to learn, Manaf is always keen to attend or speak in scientific conferences related to environment, hydrography, marine science equipment and recruit processional surveyor to obtain their IHO certifications.