Category Archives: Assessment

Subhub Project Awarded FORESEA Funding to Test at EMEC

QED Naval are excited to announce that they have been awarded funding for the open sea testing at the EMEC tidal test sites. This provides access to both the scale tidal test site along with the grid connected Falls of Warness site.

QED Naval have engaged in pre-commercial discussions for a contract at EMEC to carry marine operations at their test site that aims to validate claims of the Subhub tidal platform. These include:

  • Reduction in the cost of deployment of tidal turbines using a single marine operation to install the turbines ready for operation on the seabed within a broad range and tidal states and wave conditions.
  • Enhanced power output and site capacity factors.
  • Retrieval of the system for maintenance in a single marine  operation using a low cost multicat vessel over a broad range of conditions.
EMEC Falls of Warness tidal test stie.
EMEC Falls of Warness tidal test stie.

Significant site feasibility work has already been carried out by QED Naval as part of the FORESEA application which will ultimately see them connect tidal turbines to the grid for verification of the enhanced performance characteristics provided by the Subhub foundation solution.

GIS mapping tool containing all the flow data, berth positions and bathymetry of the Falls of Warness tidal test site.

GIS mapping tool containing all the flow data, berth positions and bathymetry of the Falls of Warness tidal test site.

Subhub Completes High Flow Installation Trials

Successful Installation & Retrieval Trials in Real Tidal Conditions

Subhub TUC Tocardo Dummy Turbines
Subhub in transit condition whilst moored up in real tidal conditions after a passing squall brought waves up the channel. The white blade profiles simulate the rotors of the turbines during installation/retrieval.

Recent testing of the Subhub operations model in high tidal flow conditions proved its ballast system capabilities and installation and retrieval methodology with great success. QED Naval were able to install the model on the seabed safely and in a controlled manner within minutes. The model was then secured on the seabed overnight before being recovered to the surface gracefully within an equally short time period and control.


Despite onerous wind, wave and current conditions experienced during testing, the Subhub coped admirably during the installation and retrieval trials.  Scaling these extreme conditions to the prototype size, based on a 4.0m diameter turbine, would be equivalent to over 2m/s or 4 knots with a significant wave heights over 1.0m


Frontal profiles of turbine blades were added to the cross beam to simulate three turbines being installed on the Subhub; the blades acting against the current presented no issues.

Subhub Testing Commences

Subhub Operations model being launched for the shakedown tests.
Subhub Operations model being launched for the shakedown tests.

QED Naval launched the Subhub Operational model last week at Forth Estuary Engineering’s (FEE) dock in Leith. The last few weeks has been a hive of activity finalising the setup of the ballast systems, instrumentation, and the dock access and testing arrangements.

FEE have provided outstanding support during the preparation and will to be on hand through the testing phase. The Subhub will now be put through its passes to test the stability during installation, ballast system control and installation/retrieval methods.

The Director of QED Naval was on site to witness the launch and initial testing and has stated, “A lot of  hard work has gone into getting the Subhub project to this point which is a credit to the team and supporting companies. The Operations model represents a big step forward for the Subhub project de-risking the ballast system and installation/retrieval methods which is a key selling point used to reduce the cost of deployment and overall the cost of energy”.

Subhub Operations model fully instrumented with pressure and tank level gauges and air ballast system.
Subhub Operations model fully instrumented with pressure and tank level gauges with air ballast system.


Subhub Ops Model Weighs In

The Subhub Operations Model continues it fit-out and setup for the testing at Forth Estuaries Engineering’s (FEE’s) dock in Leith. An essential part of that was the “weigh-in” to check against our design calculations to ensure she is correctly ballasted for her initial trials.

The operations model is based on a 1.0m tidal turbine rotor diameter. It is designed to accommodate 3 of the heaviest tidal turbines on the market. The Operations Model has been built to the same mass proportions of the prototype so its motions will be accurately modeled.

The “Operations Model” is the 3rd in a series of models with very specific objectives. It has been developed to test the ballasting system and conduct installation/retrieval trials.

Subhub operations model combined with X-Beam being weighed and checked against design weight.
Subhub operations model combined with X-Beam being weighed and checked against design weight.

ANSYS Boosts Productivity on Subhub Project

QED Naval selected ANSYS Spaceclaim as their advanced CAD design tool after a review of other products on the market. Spaceclaim is a direct modeler which means any line, curve surface or solid element of the CAD geometry can be modified and updated in an instant using simple tools.

Spaceclaim integrates seamlessly with the rest of the ANSYS suite through Workbench into Fluent and Mechanical. It can import geometry from the majority of CAD  formats. It is particularly good at fixing errors in geometry really quickly and intuitively by using the main pull tools. This is particularly useful for CFD fluid modelling and FEA structural analysis.

Spaceclaim provides a significant increase in performance in producing manufacturing outputs drawings which has allowed us to transfer our design to our suppliers and subcontractors quickly and easily.

Baseline Subhub model within Spaceclaim.
Baseline Subhub model within Spaceclaim.


Aris Zavvos Joins QED Naval Team

QED Naval is proud to welcome a new member of staff into the ranks. Aris Zavvos who has recently joined us has a Sustainable Energy Systems Master degree and a PhD in Electrical Engineering from the University of Edinburgh. Aris has been recruited as the Electrical Systems and Turbine Integration Engineer to manage the electrical design and development of the Subhub tidal turbine foundation as well as validating the instrumentation and data acquisition system during the testing stages of our first prototype.


New Recruit Maintains QED Predictive Flow Capability

Javier Sanmartin joined QED Naval and in so doing builds on the fluid modelling capabilities. Javier is an accomplished ANSYS Fluent user having completed his Masters thesis on modelling wind turbines. With this latest recruit QED Naval maintains its capability to model the fluid and wave loading on marine structures such as offshore wind, wave and tidal turbines. Javier brings the additional capability of blade modelling so the thrust & torque and power coefficients of the turbines can be predicted.

Full ‘Stream’ Ahead on the Subhub Tidal Turbine Foundation

QED Naval is delighted to announce that they have received the financial backing from Kelvin Capital and the Scottish Investment Bank this week to support the continued development of the Subhub, the tidal turbine foundation structure.

This 1st tranche of money will allow QED Naval to conduct the tank testing of 2 models of increasing scale within the world class, FloWave TT facility. These experiments will allow them to validate the current Subhub design against 3 principle objectives that include:

  • Verification of the design process and tools;
  • Provide evidence of the performance claims increased power output and;
  • Define the limitations from extreme loading events from combined wave and tidal forces.
Subhub validation model nearing completion.
Subhub validation model nearing completion.

Subhub Scale Testing

QED Naval have submitted an application to MARINET FP7 to complete scale testing of the Subhub foundation platform at IFREMER in France. The intent is to test  a scale model in their circulation tank in the first quarter of 2014 to experience both wave and tidal conditions.

The objectives are to:

  • Validate the Subhub design and ballast calculations required to secure the turbines to the seabed;
  • To assess the accelerations in the flow field in way of the turbine rotor blades;
  • To assess the increased power outputs capable by using the Subhub foundation structure;
  • To assess upstream and downstream effects such as scour and wake recovery;
  • To determine the extreme loading effects on the turbines and Subhub caused by the interaction of waves and currents.
IFREMER laboratory test facilities.

QED Naval Opens the Door to Collaboration with Tidal Developers

QED Naval now has the full capability to deliver the Subhub Feasibility Study including hydrostatic stability characteristics using Paramarine, structural response and fluid loading analysis using ANSYS Mechanical and Fluent, respectively.

We now have the technical team in place to allow us to fully utilise these tools and are keen to work with tidal developers to optimise their turbines using the Subhub foundation structure and assess its abilities to enhance the power output and the potential to reduce turbulent gusts.