JB. v. Doesburg
I am TopBob Engineering
Services offered

Freelance Engineer

@ your office

  • in the role of Mechanical Engineer, Structural Engineer or Deep Sea Mining Engineer
  • in any of the project phases: Concept Design, Feasibility Studies, Detailed Design, Design for Fabrication, but also for Research and Development.
  • available on short notice to staff up your project - to meet deadlines,
  • or, for the duration of the complete project
  • engineer working amidst your team and performing as a highly functional team player
  • in the role of Engineer or Lead Engineer.
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Your project realised by:

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  • performing the complete Engineering and Design scope of work
  • performing Finite Element Calculations (FEM)
  • preparation of 3D CAD models and CAD design drawings
  • preparation of Engineering Reports
  • projects in the field of Mechanical Engineering, Structural Engineering or engineering for Deep Sea Mining applications
  • for Onshore, Offshore or Marine applications


Deep Sea Mining

Feasibility studies

  • Technological feasibility; determination of the best possible solution
  • Economic feasibility; CAPEX & OPEX

Engineering and Design of equipment

  • Seabed Crawler with excavation tool
  • Flexible riser
  • Vertical Transport System
  • Installation Tower
  • Deck handling crane; for crawler, booster stations, riser and flexible pipe
  • Deck Equipment for slurry processing
  • Deck equipment for slurry handling
  • Return riser

Lab testing and R&D

  • Product development by testing
  • Engineering and Design for lab testing
  • Formulation Test Plan
  • Lab testing

Concept design

  • Generation of concept solutions
  • Technical Readiness Level determination
  • Trade off studies
  • FMEA (Failure Mode and Effect Analysis)

Detailed design

  • Engineering calculations; detailed hand calculations, FEM calculations
  • Structural, Flow, Production calculation
  • CAD modelling 2D and 3D

Design for Fabrication

  • Fabrication drawings
  • Component specification
  • Material Take Off
Booster Station Concept
Basics Sampler Crawler
Crawler Concepts
Detailed Calculation Beam

Oil and Gas

Engineering and Design of installations

  • Top sides
  • FPSO modules
  • Deck Equipment
  • Tower structures; flare tower, communication tower
  • Equipment supports

Performing calculations using

  • MathCAD tools, Excel tools

FEM calculations, calculations for detailed design

  • Calculations based on codes: API, NORSOK, NEN, DNV, etc.
  • Operational, Extreme, Transport, Lift, Accidental conditions
  • Static, Dynamic (fatigue, motion), Non-linear (materials, buckling, explosion)


  • Technical document writing to obtain qualifying authority approval
  • Review and approval role
Transport Brace Connection Detail

Mechanical / Structural Engineering

Engineering and Design

  • Research and Development (R&D)
  • Concept Development
  • Engineering calculations
  • CAD Design
  • Fabrication and Testing

Marine Engineering and design

  • Deckhouse structures
  • Deck layout
  • Equipment supports
  • Seafastening
Web shear stress
Doorlock Invention
Beam Type and Offsets Plot



SACS software
  • FEM - Beam models, Code verification, Offshore structures.
  • Modelling of topsides and FPSO modules to analyse for operational, extreme, lifting, transport and accidental (impact, explosion, etc.) conditions.


Staad software
  • FEM - Beam models with plate modelling capabilities, Code verification, Offshore structures.
  • Modelling FPSO modules and modules for MODU (jack up structure). Analysis performed for operational, extreme, lifting, transport and accidental conditions.


Ansys software
  • FEM, 3D models, Structural details or complete structures. Multi-physics analysis
  • Beam, plate or solid structures, linear on non-linear analysed.


FEMAP software
  • FEM, 3D models, Structural details or complete structures.
  • Beam, plate and solid structures, linear or non-linear analysed.


MathCAD software
  • Calculation tool / Reporting tool
  • Performing and reporting detailed calculations.
  • Calculationtool with possibilities to provide comprehensive explanation.

Excel with VBA

Excel with VBA
  • Calculation tool / Reporting tool.
  • Performing and reporting detailed calculations.
  • Creating calculation tools and/or tools for data processing.


SolidWorks 3D CAD
  • Tool to make a 3D model of the design. The model can be used to generate parts lists, Material Take Off and Design and Fabrication Drawings.
  • Modelling of topsides and FPSO modules to analyse for operational, extreme, lifting, transport and accidental (impact, explosion, etc.) conditions.


  • 3D sculpting tool for reporting.
  • Creation of pictures for technical reports. Explanatory pictures for detailed calculations.


Clients / Professional career

- TopBob Engineering - Over 16 years of experience - TopBob Engineering - Professional career as Structural Engineer, Mechanical Engineer and Deep Sea Mining Engineer - TopBob Engineering - Functions performed are Engineer, Lead Engineer and Mentor/Instructor - TopBob Engineering - Posted recommendations can be found on my LinkdIn profile - TopBob Engineering -


J.B. v. Doesburg is co-author of the publication:
"Assessment of different technologies for vertical hydraulic transport in deep sea mining applications".

This article was published for the Proceedings of the OMAE2012, or the 31st International Conference on Ocean, Offshore and Arctic Engineering. It was held on July 1-6, 2012 in Rio de Janeiro - Brazil.

The original publication can be found using these references:
    OMAE2012-83156 , ISBN 978-0-7918-4490-8.

Main components of a deep sea mining installation are the Seafloor Mining Tool, the Vertical Transport System and the Mining Support Vessel. In the article the pro's and con's of different slurry transport system are investigated.
Systems investigated are the hydraulic transport using centrifugal or positive-displacement slurry pumps, conventional and unconventional airlift systems, vertical offshore mining systems and vortex slurry transportation systems.
All these systems are considered for their applicability at different water depths for the different resources to be mined and for different production rates in terms of the efficiency, reliability and state of the art of the technology.
Using the findings presented in the article the best suitable slurry transport concept can be concluded.


J.B.v.Doesburg is listed as co-inventor on two patents assigned to IHC Holland.

Patent WO 2015/005785 A2, 12-7-2013, title "Tailing deposit tool".

Claims (summary):
Means to spread the non valuable slurry from a deep sea mining operation back to the seabed in a controlled manner.

Patent WO 2015/005782 A1, 12-7-2013, title "Riser Flow Control".

Claims (summary):
Means to prevent gas formation, for example during deep sea mining of gas hydrates, in the production and return riser by controlling the riser system pressure by the application of flow restrictors, systems of bends, controlled or non-controlled turbines or pumps in the return riser.



JB. v. Doesburg


Correspondence address

  • TopBob Engineering
  • Pegasusring 16
  • 3328HP Dordrecht
  • The Netherlands

Company details

  • KvK 64328937 (COC)
  • BTW NL.1807.21.380.B02 (VAT-id)
  • IBAN NL42.ABNA.0578.6556.32

  • VAR 2015 statement available
  • RVOI-2001 General Conditions filed at the District Court of the Hague
© Copyright TopBob Engineering. All rights reserved. Updated April 2017.