The latter once belonged to the Royal Squadron of Britain's Queen Elizabeth II, according to Dudi Sudibyo, managing editor of Indonesia's Angkasa aerospace magazine.
World No. 15 Monfils beat Australia's Marinko Matosevic 7-6 (7-5) 6-3 6-3 to earn a tie with Brazil's Thomaz Belluci, who eliminated Israel's Dudi Sela.
The Croatian defeated fourth-seeded Serbian Janko Tipsarevic 6-1 6-3 on Saturday, while Wawrinka beat Israeli fifth seed Dudi Sela 6-4 2-6 7-5 in the other semifinal.