Page 26: of Maritime Reporter Magazine (January 2019)

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EYE ON DESIGN: Virtual Reality

Johan Dekker

Johan Dekker is project manager at MARIN’s Nautical Centre. MARIN offers simulation, model testing, sea trials and training to the shipbuilding and offshore industry and governments. e: [email protected]

Real Time Simulation to Test Propulsion Alternatives

MARIN helps yacht owners make vital decisions about the propulsion and thruster con? gurations best suited to their yacht by using virtual reality.

ARIN helps yacht owners make vital decisions about the propulsion and thruster con? gurations best suited to their yacht by using virtual reality.

If a motor yacht of 112x16 m has to sail a 20 m

Mchannel and turn in a basin of 120x116 m, what maneuvering characteristics are required? This was the challenge a

Dutch yard was facing for a new yacht, which was on the drawing board.

Several options were considered for the main propulsion, bow and stern thruster. For example, are ? xed pitch propellers (FPP) or con- tinuous pitch propellers (CPP) better for the main propulsion, and should these turn inward or outward? FPP and CPP were also the alternatives for the bow thruster, while three options with retractable azimuthing thrusters were considered for the stern thruster. To inves- tigate the in? uence of the different alternatives on the ship handling characteristics, the yard and owner’s representative decided to test the options in virtual reality using our full-mission bridge simulator, so that they could experience the difference ? rst hand.

Nine models

Using the results of a series of powering, seakeeping and maneu- vering tests that had already been carried out at MARIN, a math- ematical maneuvering model was prepared using SURSIM. The op- tions for the propulsion were made as accurate as possible, based on speci? c details such as the combinator curve for CPP main propul- sion, the time-thrust diagram of the bow thrusters, the time to turn 180 degrees for the retractable stern thrusters, etc. In total nine ship models were prepared.

Simulations at the design stage

A harbor basin of the required dimensions was prepared in the da- tabase of the Port of Rotterdam, which is available at MARIN. Dur- ing a 1-day simulator workshop on MARIN’s Full-Mission Bridge 1, the owner’s representative and the captain sailed the various yacht models in this database, witnessed and supported by representatives from the yard and one of MARIN’s simulator instructors.

By carrying out these real-time simulations during the design stage, the participants were able to select the most suitable propulsion op- tions for the yacht. Considering the extremely con? ned waters, it is probably not surprising that the bow thruster with the fastest build-up of thrust and the retractable stern thruster with the shortest time for 180 degrees azimuthing were selected as the preferred options.

26 Maritime Reporter & Engineering News • JANUARY 2019

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