Fig.1 Rivershark on action.
March2021 - April 2022
As back up Rivershark Mod II was modified to Rivershark Mod III and tested due to lack of time and the great reliability of Rivershark in the former races. The pilots were trimmed and trained in Rivershark Mod III for the races. Original Rivershark was introduced first in the subraces of 2013 and was modified several times so far while the basic propulsion system of MirageDrives and the hull stayed the same. Rivershark competed the last time in 2018 achieving the best biomimetic and the best female pilot award. Several improvements were planned and done on Rivershark Mod II. Due to several other projects only the hull, the propulsion system, the drivetrain, and the transmission were left of the Rivershark Mod II. Therefore, different changed have been planned and executed. Firstly, the attachment of the foam to get the method of getting Rivershark neutrally buoyant has been improved. Due to problems with stabilisation and reaction time of the control surfaces in the past, stabiliser fins and a new system for the control surfaces has been manufactured. As a consequence of the failure of the opening system of the hatch from the inside of the submarine in the past, the system of opening the hatch was improved. During the modification of Rivershark the pedal stepping was changed to a cycling system due to the higher efficiency of a cycling system. Even though this is the case for cycling on land with a bicycle the efficiency is not adaptable to Rivershark to the lack of space for the pedalling motion which need about a diameter of 70 cm. Therefore, the cycling system has been changed to a stepping system again