SUBS – Streamlined Sub-Surface Buoyancy

A range of buoyancy modules designed to minimise mooring line oscillations which otherwise can seriously affect current reporting

Product Description

SUBS Product Highlights

  • Improves data via significantly increased stability
  • Virtually eliminates vortex shedding as experienced with spherical buoyancy
  • Substantially reduces mooring excursions and inclinations
  • Ideal for all current measuring and imaging instrumentation
  • Lightweight and accommodates plastic or glass buoyancy

Versions of the SUBS system exist for shallow and deep water applications along with customised models to house most proprietary ADCP/RDCP instruments. It is common for the SUBS to also act as a host for Novatech xenon flash, radio and satellite location beacons to aid equipment recovery on surfacing.

Vortex Shedding in High Currents

It has been known for some years that commercially available electro-mechanical and magnetic type vector averaging current meters were seriously under reporting in many situations. Research in mooring design carried out at the Bedford Institute of Oceanography (Canada) has shown that this is caused by mooring line oscillation. The major cause of this oscillation was shown to be caused by vortex shedding behind the spherical flotation commonly used as mooring buoyancy.
A major data quality improvement was seen when the spherical flotation was enclosed in a streamlined housing. Comparisons of the two types of moorings were made by running a ship-board ADCP above the moorings, and plotting the current meter data against the ADCP data. Excellent correlations existed when both the electro-mechanical and magnetic type vector averaging current meters were moored with streamlined flotation.

Additional information


Ocean Research


Open Seas Instrumentation


A2 & D2 ADCP Buoy Data Sheet

B3 & C2 Flotation Data Sheet

SL Long Ranger Buoy Data Sheet

SUBS Evaluation White Paper – NOAA