An MRI-guided medical device includes an elongated sheath, an elongated dilator, and an elongated needle. The integrated signal splitter is configured to be in electrical communication with an overvoltage protection component and to output the DSLPOTS tip output signal and the DSLPOTS ring output signal to the overvoltage protection component. When the Servlet is recognized at the web server side, a plurality of part beans that are stored by being related to display-area specifying information are specified. The amount of pre-compensation can be determined statically or dynamically. A plurality of power units, such as gear trains or force pumps, are coupled respectively to the float members to rotate a driven shaft in a uni-direction so as to drive a propeller, thereby propelling the hull body forward. The fastener means include assembly means suitable for co-operating with the assembly means of the hatch for the purpose of securing the hatch to said fastener means, and securing means for securing said fastener means to the bodywork part.