SpiderFLOAT Design Progress

We are happy to report that our paper on the preliminary design of the SpiderFLOAT legs and cables has now been published in Ocean Engineering. In this article, we present an innovative structural beam theory that is being used in the optimization of the SpiderFLOAT components.  We are excited to confirm the structural efficiency of the concept that has now been proven at least on paper. The cables provide both the functional shape to the substructure as well as the necessary leg pre-compression. Therefore, the legs are extremely slender and easy to fabricate with conventional reinforced concrete manufacturing techniques.  The stem, however, must withstand the tower base loads, which can be substantial if not contained with proper control, and additional pre-stressing may be required.

Unfortunately, the journal editing team failed to fix a few typesetting errors. For a corrected version of the manuscript see here.

Within the USFLOWT project, we are collaborating with NREL, Colorado School of Mines, University of Colorado Boulder, University of Virginia, and ABS to bring the SpiderFLOAT closer to a prototype stage.  The research team is developing innovative control strategies, which involve both turbine and substructure, to reduce loads on the platform thereby keeping its mass and footprint small. One critical step in the commercialization of the SpiderFLOAT is the assessment of its costs. The team’s first estimates confirm the very competitive LCOE targets that we set out at the beginning of this project.

Stay tuned for more updates.


We are grateful for working with Colorado School of Mines (CSM) on this project that Dr. Rick Damiani had led while at NREL.

With CSM, we are optimizing the structural design of the SpiderFLOAT, an innovative substructure invented by Dr. R. Damiani (FWTC), Mr. S. Sirnivas (NREL), and Mr. F. Wendt (Ramboll).

The project is part of ARPA-e's ATLANTIS program, is led by NREL and Colorado School of Mines, and seeks to use control-co-design techniques to minimize costs in the OWT floating substructure.  Other partners include the University of Colorado at Boulder, the University of Virginia, and the American Bureau of Shipping.

Tasks include optimization of concrete structures and aero-hydro-servo-elastic simulations of the entire OWT.