In an ideal situation, hopefully the escort vessels will carry the Ka31 AEW. (With most destroyers / frigates of Navy capable to have 2 helicopters, this shouldn't be a problem).
The sea may seem calm but may have a swell causing the ship to pitch. Also as part of testing of the ship, we test its stabilisers. In that we delibrately cause pitching and rolling to test out the effectiveness of the stabilisers. Stabilisers are small wing like structures which protude out from the hull below water and counter the rolling and pitching. Such a test is done to see the limits upto which the ship can completely dampen out the rolling and pitching. It is important for a carrier as the pitching and rolling has direct effect on aircraft launch.