CWind's Innovation team is developing a new fender, to improve the efficiency and safety of its CTV fleet. The fender which has already been in trialled on a CTV, has proven to be very effective at maintain a constant and safe contact with the wind turbine.
CWind’s Innovation team is developing a new fender, to improve the efficiency and safety of its CTV fleet.
The fender which has already been in trialled on a CTV, has proven to be very effective at maintain a constant and safe contact with the wind turbine.
The new fender will deliver:
> Safer conditions for crew transfer to a wind turbine
> Reducing the possibility of CTV slips or heaves
> Reduction in lost O&M days on the turbine and lower transfer efficiency as the vessel is able to operate in higher sea states.
> Ability to transfer crews in conditions CTV’s with standard fenders are unable to operate
CTV Fender – Maximising Transfer Safety and Efficiency
Transferring technicians from a CTV to the turbine in an increased sea state, is a known risk activity that can lead to unreliability as well as potential injury.
The transfer operation is dependent on a creating a friction hinge between the rubber on the CTV’s fender and the metal bumper bar of the foundation, applying bollard push to maintain the friction hinge. Issues occur when the friction levels are decreased on the hinge and the CTV slips or heaves, resulting in unsafe conditions for technicians to transfer safely, lost O&M days on the turbine and lower transfer efficiency.
In Field Fender Trails
This new fender design was trialled in field on CWind’s MPC Alliance over four sets of trials, initially in flat calm and up to the last trial in Hs 1.4m with 40 knots wind over the beam.
Results have been conclusive with the fender performing better than the conventional design in all respects, with no compromises. In rougher conditions (Hs 1.5m +, 25knots wind on the beam) the new fender had reduced movement to the point where the vessel would be able to safely transfer personnel.
Interestingly the normal CTV assigned to this field had remained in port that day due to the conditions being unsuitable.
Redesigning the CTV Fender
The key to improving the transfer efficiency is through improving performance in higher sea states, increasing reliability and reducing the possibility of slipping. CWind’s innovation team explored several engineering concepts to address this challenge. The team initially manufactured a non-mechanical cup to increase the contact area with the bumper bar and therefore increase the friction between the two.
Whilst it initially worked, extended tests and robustness assessments showed an unacceptable increase in wear, leading to a degrading of the interface with the foundation and causing increased, sudden movements which could have created a safety risk. Developing the solution further, the design evolved to increasing local force on the bumper through the fender rather than by the thrust of the vessel. A hydraulic mechanism for the bumper was designed and prototyped that applied compressive force when in contact with the landing area.
TRL (Technology readiness level) Scale