Karthikeyan Prabakaran, 28, Thiruppathi Veerapperumal, 27, and Chellappan Sankar, 29 are alleged to have grievously hurt technician Murugaiya Suresh Kumar on August 23 last year, a crime which carries a jail sentence of 15 years.
The trio allegedly hit Kumar on the head with iron rods multiple times along with Ananthan Seeralan, 25, who is on the run, The Straits Times reported.
Kumar was an employee of Poly NDT in Pandan Loop, which carries out testing and inspections of parts of ships.
The trio was denied the bail. A pre-trial conference is scheduled for November 9, the report said.
If convicted, they could be jailed for up to 15 years and liable to fine or caning.