Russia's President Vladimir Putin (L) is seen through the glass of C-Explorer 5 submersible after a dive to see the remains of the naval frigate "Oleg", which sank in the 19th century, in the Gulf of Finland in the Baltic Sea July 15, 2013.[Photo/Agencies]

FINLAND, Russia  - Russian President Vladimir Putin took to a red submersible on Monday to dive 50 meters and examine the wreck of a 19th century frigate, his latest stunt in 13 years of power to assert his carefully crafted action man image.

Putin, a 60-year-old former KGB spy more than a year into his third presidential term, is eager to boost his populist appeal to make up for the support lost among Russians following the largest wave of street protests against his rule in 2011-12.

In the past he has submerged in Russia's Lake Baikal, extinguished forest fires and hopped on massive racing trucks.

Wearing a black jacket, blue jeans and white sporting shoes, Putin sat comfortably in the capsule's glassed front and submerged into the Gulf of Finland to look at the wooden wreck.

He resurfaced smiling after some 20 minutes and praised the work of the Russian Geographic Society, which has been studying the sunken vessel, for honoring the memory of Russian sailors who perished in the sea, including during World War Two.

"We didn't really do such work before. I think the time has come now, we can finally do that in terms of financial and technical capabilities. The moral duty towards the Fatherland defenders goes without saying," said Putin, who managed to stay dry.

But in a sign of his changing fortunes, his stunts have increasingly drawn satire and he was ridiculed online as a troubled "alpha-crane" when he flew a deltaplane to lead the rare birds on their migration route last fall.

Putin was forced to admit earlier that a 2011 stunt in which he discovered an ancient amphorae at the bottom of the sea was a set up and he faced accusations that a seemingly wild tiger he tranquilized had been brought in from a zoo.

The disputed stunts echoed in the fresh criticism on Monday with one twitter account saying: "Putin at the Gogland Island will learn about underwater research... Amphorae and tiger cubs have already been delivered."