The paper describes an experimental web-based environment for teaching and testing. The application named Nautilus has been developed using Virtual Reality Modeling Language (VRML) and Java language with two special libraries: DILEWA and Vrmlworld. Although the resulting system is intended for low-level virtual reality systems without any specialized hardware support it is powerful enough to accurately simulate various situations and scenarios. Currently implemented multi-user environment for training and testing of yacht captains serves as an experimental workbench for creation of general applications where a developer combines a simulated environment from simpler simulation elements. Design and implementation of the system are presented together with several practical observations concerning efficiency of the real-time rendering and the level of implementation difficulty.