*whacks head against the wall*
Fine, I'll post up a new one and give the answer. 2 weeks and not 1 guess...
The answer:
This is the incomplete hull of the SWCM 1, the cancelled leadship of the defunct "Sea Viking" class special warfare craft.
The SWCM program was conceived as a medium-sized multirole patrol craft to transport SEALs, replacing the PB MkIII in the special-forces role. A class of 19 Surface Effect Ships was planned, and the leadship was ordered on in 1984. SWCM 1 suffered major design problems, which caused delays to the program, which in turn lead to the shipyard's bankruptcy. The Navy took possession of the incomplete ship on 7 January 1987 and placed it in a state of preservation, as seen here, for potential future completion. Although there were attempts to get the program back on track, the entire project was ultimately cancelled and replaced by the much more conventional Cyclone (PC 1) class. The incomplete hull, was apparantly scrapped by the Navy afterwords.
Now, for something a whole lot easier: