A lieutenant of the Free French Navy will describe his work on the world's largest submarine at a meeting of the Naval Society tonight at 8 o'clock in the Dunster House small Common Room.

Lieutenant Michaut is an officer on the Surcouf, a giant submersible which is now in Portsmouth Harbor, being refitted for further operations on behalf of the DeGaulle forces.

The Surcouf carries a complement of 150 men, boasts of 10 torpedo tubes, and displaces 4000 tons--an average submarine figure is about 750 tons. The Surcouf was built at Cherbourg recently, has seen considerable service, and was visited by DeGaulle before it came here.