Pure foams offer many advantages over macrosphere composite foam systems including robustness, ease of repair and modification in the event of damage or design changes, and extremely low water ingress rates. It should be noted, however, that these are ‘premium products’ and are therefore typically selected for more demanding service conditions such as extreme operating depths and/or service criticality such as manned service.
Two ranges of pure syntactic foam are available, differing primarily in core density. Both the “Standard Range” and the “Ultra-Low Density Range” are normally produced in pre-cast blocks. These blocks may be supplied for client assembly or can be factory assembled into finished buoyancy modules.
The buoyancy performance of the ultra-low density material is understood to be unique amongst ROV buoyancy foams in that the buoyancy does not progressively reduce due to hydrostatic compression as the ROV flies into deeper water. This is because the bulk modulus - ie, the compressibility under hydrostatic pressure - of the foams is marginally less than sea water
