You can tell by looking at the side view and number of gun ports. The 1813 Wasp was somewhat bigger than the 1807 Wasp. She carried 4 more 32-pounder carronades and a larger crew. Learning from the advantage of having of having big frigates, the United States built the new sloops during the War of 1812 to be bigger and better gunned than enemy sloops and able to outrun anything bigger than them.