Table:
text: Mighty Ships
Season 4
Season 4
No_in_series No_in_season Title Vessel_Type Vessel_Operator Narrated_by Original_air_date
20 1 MV Beluga Bremen Cargo Ship Beluga Shipping Anthony Green 2011
21 2  USNS Robert E. Peary  Cargo Ship US Navy Anthony Green 2011
22 3 DSV Skandi Arctic Diving Support Vessel DOF Subsea Barbara Budd 2011
23 4  MS Stena Britannica  ROPAX Ferry Stena Line Anthony Green 2011
24 5  USCGC Bertholf  National Security Cutter US Coast Guard Barbara Budd 2011

Question: Name the ship type for mighty ships in beluga shipping?

Question: Name the ship type for Dof Subsea under Mighty Ships?

Question: Among the powerful ships, name the most in the season?

Question: Name the lore for Beluga shipping under Mighty Ships?

Question: Can you name the season number for beluga shipping for Mighty Ships?