Since Libyan ruler Muammar Qaddafi, 68, picked Moatassem-Billah, son number four, as his successor, his eldest son, Seif al-Islam, has schemed tirelessly to stay in the limelight and avoid being passed over as future potentate of this oil- and gas-rich nation. Seif's latest dodge, according toDEBKAfile's intelligence sources, is the privately-launched Al-Amal (MV Almathea) for breaking Israel's naval blockade on the Gaza Strip. Awaited by the Israeli Navy Tuesday or Wednesday, Tripoli has officially disavowed the venture.