Propeller Scour

Vangnes, Norway

Both Filter Point and Constant Thickness mattresses have been used as bed scour protection increasingly over the last 35 years. Concrete mattresses provide extremely good protection to propeller scour jets as they provide continuos concrete slab protection.

Bagamoyo, Tanzania

The critical design aspect is resistance against propeller suction uplift. Uplift suctions around propellers can vary greatly, depending mainly on the clearance distance from the bed to the propeller. Suction forces are determined from experimental test data produced for Proserve by Southampton University Marine Research Department.

Matt Types Used

Mattress thickness can be provided, for dead-weight stability, or driven anchors can be used with thinner mattress with equal effictiveness. Constant Thickness matts CT150 - CT350 mm thickness are widely used where only light suction forces apply. FP150 Filter Point mattress is also often used in this application.

Edge Detail

Mattress edges should be protected from underscour by mattresses turned down into edge protection trenches. A reactive protection detail can also be incorporated using stone placed on a mattress fabric extension.