Tommy Jensen of NRL Stennis maintains daily COAMPS hindcasts for the Indian Ocean (atm 27/9 km; ocn 3.5 km and wave 10 km) with a delay 1-2 day depending on the throughput on gordon. There are two websites with free access.
https://www7320.nrlssc.navy.mil/MISO/
that covers the entire model domain, and
https://www7320.nrlssc.navy.mil/PISTON/
that shows details over the South China Sea area, including the original PISTON area. It contains 10m wind, 850mb wind, significant wave height, surface net heat flux, current and SSH, surface velocity, T 100m, salinity 100m. There is an archive.