WHO WE ARE
& WHAT WE DO
TOGETHER WITH ITS CONTRACTORS, OFFSHORE TRANSFER DEVICES HAS NOW PROVEN THAT THE TUBE DOCKING DEVICE (TDD) CAN CHANGE THE WAY OFFSHORE TRANSFERS ARE CONDUCTED. WE ARE NOW LOOKING TO PARTNER WITH AN ESTABLISHED MARINE ENGINEERING FIRM WHICH CAN PROVIDE FURTHER EXPERTISE, VENTURE CAPITAL AND GLOBAL MARKET EXPOSURE.
THE TDD ACCESS / TRANSFER SYSTEM IS A PATENTED CONCEPT; BACKED, FUNDED AND SUPPORTED BY THE CARBON TRUST’S OFFSHORE WIND ACCELERATOR (OWA). THE OWA IS A LEADING INTERNATIONALCOLLABORATIVE R&D PROGRAMME, BRINGING TOGETHER NINE LEADING OFFSHORE WIND DEVELOPERS, WITH THE AIM OF IMPROVING THE ECONOMICS OF OFFSHORE WIND FARMS THROUGH THE DEVELOPMENT OF INNOVATIVE TECHNOLOGIES.
PROOF OF CONCEPT
During the first quarter of 2017 the TDD endured vigorous trials and tests at EON’s ‘Scroby Sands Wind farm’ together with vessel owners / operators Iceni Marine Services. The device was installed on vessel ‘Iceni Courage’ (South Cat 15 meter) by vessel builders ‘Alicat Workboats’, integrated and powered by hydraulic specialists ‘Hercules Hydraulics’ in Great Yarmouth, UK.
By the end of stage trials, the TDD outperformed expectations from all parties involved. A wave rider buoy issued by the OWA was deployed to provide accurate feedback and was followed by a thorough trials programme carried out by Carbon Trust members. Results from the OWA trials demonstrated that the TDD was able to hold its pivoting jaws with negligible vertical movement in wave heights of up to 2.7 meters. Sea states included seas from ahead, astern and a beam. This achievement was deemed outstanding by OWA partners which reinforces the team’s belief that an innovative access / transfer system can improve and conduct safer transfers at sea, even in challenging conditions with wave heights of up to 2.7 meters with a CTV as little as 15 meters in length.
The TDD can deliver a safe, reliable, measurable, economic and simple solution to the business of transferring personnel and equipment offshore. This will afford greater access and workable weather windows, resulting in increased productivity and reduced losses, caused by failed transfers in conditions where conventional access fender methods are not viable.
The TDD is light and simple to install, it provides high performance and is extremely reliable, whilst also being easy to service and maintain. This compact device takes up only a small amount of ‘low’ level deck space and it is foreseen that the device can be housed completely inside the bulwarks of many vessels, or potentially be under-slung.
There are several ways to apply the TDD, such as vessel-to-offshore structure transfers, vessel-to-vessel transfers and / or aidingthe connection from offshore structures to compensated gantry applications (walk-to-work). The TDD can be made to fit any size of vessel, from a daughter craft using an ultra-light 150kg device or the larger 26m+ CTV / WFSVs who would benefit from a full size device. For the larger vessels minimising the pushing force is vital, as is reducing the possibility of impact loads whilst docking which is becoming ever more imperative.
DESCRIPTION & ADVANTAGES
The priority throughout the development process has been to make the TDD fail-safe, ensuring that the risk of mechanical entanglement to any offshore structure is completely mitigated. This is achieved by making the amount of grip applied to the offshore structure relative to the propulsion applied not protruding 180 degrees of the receiving cylindrical tube. The key features required from the design and model testing work were to create a simple and lightweight device which can effectively stabilise, pin and grip the transfer position.
Offshore Transfer Devices and Hercules Hydraulics have created a cushioned approach which will minimise impact loads and offer protection to the device, vessel and offshore structures in greater wave height conditions. In addition this will aid fuel economy, as well as wear and tear to vessels engaged in prolonged transfer operations with personnel or equipment.
The TDD goes through a primary phase where the jaws take the shape of the cylindrical fender tube. This is shortly followed by a secondary phase known as “thrust-out”. A combined dampened stroke of 750cm enabled by hydraulic rams and accumulators.
The TDD is able to deploy on to a tube whilst the vessel is simultaneously in a roll, pitch and off centre whilst addressing all 6 motions of freedom – heave, pitch, roll, yaw, sway and surge. Conversely, due to mechanical advantage a vessel can obtain a higher level of grip with a proportionally reduced amount of propulsion, thus minimising pushing force required to maintain a stable platform against offshore structures.
An additional (but optional) hydraulic assistance mode can be implemented, which operates in a similar mode to applying a brake pedal of a car. This optional ability to add clamping will also allow substitution or minimal propulsion, enabling transfers to light anchored structures such as floating LiDAR’s, anchored barges or jack-up vessels. This optional ability, whilst using little or no propulsion, also enables transfers in adverse weather conditions to ships under DP (where CTV’s / WFSV’s are instructed to push on with minimal propulsion as it can upset the mathematical model of the DP vessel).
Another key feature of the system is the ability to alter the lateral position without disengagement. This can be achieved by simply reducing forward propulsion and re-applying when at the desired height, enabling clamping with its RG Seasight-Fenders.