The victim was identified as Thasan Hilman, a father of one.
The fisherman was on his way back home from the seas while the speeding SL Navy boat hit his minor boat with an outboard engine.
The dead body was taken to Pa'l'la-madu hospital mortuary, the fishermen said.
Vidaththal-theevu, a strategic access route for Sea Tigers during the times of war, is situated in Mannaar mainland and comes under Maanthai West administrative division.
The occupying navy of genocidal Sri Lanka has been at odds with the uprooted people of Vidaththal-theevu as it wants to transform the naval installation at Vidaththal-theevu into a full-fledged naval cantonment amidst opposition from the people.