The ship is a paddle-boat that the pilots peddle from within. The "mouth" of the ship has three cannons that can create quite some damage. It was stated by Patty that is the ultimate weapon of Baratie.
The Sabagashira I was used against the Krieg Pirates. Patty and Carne tried to use the cannons to strike down Don Krieg, but his Wootz Steel Armor protected him from the blasts, and he lifts the ship like a toy with his great strength, throwing it onto the rooftop of the ocean going restaurant.