A salvage tug today, a patrol boat tomorrow...

(and of course self-defense!)

Rgds

AC

Naval salvage tugs are often armed albeit with a pea shooter like the 40mm Bofors shown here as they are warships. Indian warships operate in the Indian Ocean where there is a lot of pirate activity.
The USN fleet tugs (ATF) built during the war had a larger armament (3 inch +20mm) and most kept this armament in post war service. As a matter of fact, some ATFs are still serving in foreign service after 70+ years and are still armed.

May be the armament is for sinking them first and then salvage them ?

Indeed unusual for a salvage tug to have armament albeit in self defence. Thanks for posting this clear picture. Marlon

Do many salvage tugs have guns?

See http://en.wikipedia.org/wiki/Gaj-class_tugboat
Including A-53 INS Matanga Launched 29 October 1977, Commissioned 2 April 1983

The mighty MATANGA - armed & dangerous. A salvage tug with a forward gun !! Great stuff !!