Rio Damuji class OPV, converted from Spanish-built fishing trawlers:
Early configuration, one twin 57mm adopted from AA tank, two P-15 Termit AShM launchers, two 14.5mm MGs, and two twin 25mm autocannons.
Upgrades, with adopted AA tank turret replaced by naval turret, and 25mm mounts by two AK-630 CIWS with associated fire control radars.
Cubans apparently fly Mi-8 or Mi-14 off the two OPVs of the class.
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It makes me wonder what other ships can be modified this way...... maybe some might even retain their original functions (for examples, cargo or fuel transport) while serving as patrol ships?