As such, the WHEEL floater comprises an upper tank which provides the required buoyancy and a lower tank which houses the ballast weight. The upper buoyancy tank is conveniently submerged in operation to keep it away from the concentrated wave energy in the surface: fighting the force of the sea with large structures on the surface facing huge storm waves, like semisubs or barges do, is, in our view, probably not the best option. We deem wiser to let the waves pass above you with only a slender transition piece crossing the surface: when facing a 50-year return period storm, you’d rather be in a submarine below the surface than in a ship fighting the waves.

Once sufficiently deep waters are reached, the lower tank can be deployed in a controlled manner and WHEEL will achieve an ultra-stable transparent configuration for operation and survival conditions. Lowering of the ballast tank is performed by regulated water ballasting so lowering speed is adequately controlled; once the lower tank reaches its final position its ballasting shall be completed with solid infill to provide the required ballast weight for operation.

Triangularised configuration
This makes possible to transmit any force or moment between the Upper Tank and Lower Tank only through variation of the axial force in the cables and with no relevant relative movements between both bodies.

Tendon pretension
It is provided by the Lower Tank submerged weight, which maintains the tendons under tension, so that they will resist axial force variations just as if they were rigid bars and will remain permanently in tension.

Tendon strength and durability
Tendons are based on the highly proven fiber lines commonly used for multiple offshore applications, delivering excellent durability and fatigue strength performance. Tendons used by WHEEL are midsized as compared to other multiple offshore applications.

Overall, WHEEL is excellently suited to allow for significant cost reduction while allowing for simple and effective construction processes which can be industrialized and implemented in a wide range of harbours.

It delivers at the same time the key advantages of the two main existing floater concepts: full onshore assembly of the floater and WTG and very low waterplane area in operation.

The WHEEL technology will allow for drastic reduction in the width of the floater as compared to equivalent semisubmersible solutions, which is a major benefit for construction and load-out means and infrastructure.

It will allow for unparalleled reduction in the draft of the floater for inshore operations (harbour and tow-out), which is a key advantage regarding usability and availability of suitable harbours, making it possible to effectively profit from lower cost existing harbour infrastructure and construction means, enhance local production and marine spatial planning, and also ease exportation of this European technology to regions with lower infrastructural development.

Major reduction in carbon footprint due to reduced material usage and local construction strategies minimizing transport related emissions.

Slow motions. Despite its very low material usage it will provide very high mass inertia and thus deliver very high pitch/roll natural periods, far above wave periods, and slow motions, reducing accelerations and forces on the WTG for enhanced production.

Optimized mooring system due to its transparency to wave loading. WHEEL allows for cost-savings in the mooring system as it drastically reduces loads as compared to semisubs. It also allows for the most optimum combination of conventional chains and synthetic ropes, which enchance load management by reducing peak and cyclic loads.

Circular Economy and carbon footprint. The materials, construction and installations methods to be used will allow a substantial reduction of the carbon footprint.