Tow Tank Seeders

SCITEK Tow Tank Seeder Technical Specifications


SCITEK has been specialising in seeding systems for over twenty years. We offer a number of seeders of varying sizes and across a range of applications, including for use with air flows, in small flow rigs, in combustion rigs, as well as in large wind tunnel facilities.  Recently, we also produced seeding systems that can be used in tow tanks to mix in the water small particles in the path of the vessel to facilitate good quality optical measurements. As all tow tank facilities are different, our device can be customised so that it can be adapted to suit each facility.

Main Features

The intended use of the Tow Tank Seeder System is to deposit hollow glass spheres, approx. 10-micron diameter into a water test tank. It is designed to be mounted at a suitable location on the carriage so that it can seed a small area around the vessel and thus minimise contamination of the tank, thus also minimising the quantity of particles used. The carriage then traverses over the length of the tank with the seeder immersed at the required depth. Once the seeding has been deposited, the seeder is retraced from the water and the carriage commences the measurement run. Flow measurements are not carried out during the seeding phase but shortly afterwards as the seeder will produce undesirable flow disturbance in the water which will adversely affect the flow measurements. The particles are nearly neutrally buoyant and they remain in the water for a generous amount of time to carry out several flow measurement passes

By design the seeder is retractable so that it can be permanently installed on the carriage. It can also be easily removed when not in use. Deployment and retraction is easily facilitated by an electrically operated winch.

The basic components of the SCITEK Tow Tank seeder are shown in the schematic diagram shown above. It comprises of the rake which is essentially five rows of metal tubes with multiple holes drilled on the wall of each tube that are used to discharge water that is premixed with hollow glass spheres. The rake is designed to spread the seeding evenly in the area of interest.

The rake is mounted on a telescopically retractable boom so that it can be immersed in to the water at the desired depth and then fully retracted out of the water when the seeding operation has been completed. At the top of the telescopic boom an automatic hose reel is used to reel or unreel the flexible water hose that feeds seeded water to the rake. The telescopic boom is designed to be strong enough so that it does not bend from the drag it experiences when immersed in the water and towed along the tank. Maximum tow speed for the seeder is 1.2m/s

Seeded water is fed to the seeder from a purpose-built tank (1000 litres) via a submersible water pump. The flow rate of seeded water can be adjusted using a hand operated valve with the flow rate displayed on a rotameter that is situated at the top of the tank. This tank needs to be situated on the carriage and should be close to the retractable boom. In order to ensure that the water within the tank is constantly agitated so that the glass spheres are evenly mixed within the tank, a second submersible pump is used with suitable located outlets which facilitate constant agitation within the tank.

The SCITEK Tow Tank seeder with all its sub-assemblies is shown above. For more information, please download the full Technical Specifications here.

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Rake assembly

The rake assembly can also be custom made to suit customer requirements. The retractable boom can immerse the rake up to a depth of 2.5meters.

Frame mounting assembly

This assembly is normally custom made by SCITEK to suit installation on the customer’s carriage.


It is recommended that installation of the Tow Tank Seeder System and associated equipment is carried out by SCITEK. However, where this is not possible, it can be shipped with appropriate installation instructions.

SCITEK appreciate that each tow tank facility is different and may have specific requirements which we are happy to discuss with you. The operation of the seeder can be customised and automated to suit the operation of your facility.

Contact us now at or by calling +44 (0)1332 365 652 to discuss your requirements with us