This paper describes a device, the submersible drag gauge (SDG), that can be used for drag measurements in studies of flow‐biota interactions at low (setup A) and high (setup B) load applications. The device is designed so that solely drag forces acting on a test object in a boundary layer now are measured. The SDG can measure drag on organism(s), such as macrophtyes, crayfish or mussels, as well as a combination of such organ...

Previous research, using rigid objects, showed that the magnitude of mean drag on submerged bodies can be influenced by the blockage ratio (ratio of the frontal projection area of an object to the wetted flume cross‐sectional area). In addition, drag measurements, under similar flow conditions, are likely to be affected by other flume characteristics. these factors lead to some uncertainty in drag measurement comparisons betwe...