This addition is custom designed and not practically used on a semi displacement vessel of this type. It would be argued the bulb bow would be innefective due to the light weight and smaller size of the vessel, which would be rocked and rolled anyway. However, this has been designed to work in coilition with the added keels and fins at the base of the centre starboard and port of the ship. This enhances the hydrodynamics of the hull to properly utilise a bulb bow here.
That being said, as the diagram below will show, this addition can only have full affect between two knots of the trawlers speeds. With this particular trawler, capable of 20 knots, I can guess it will be at an optimum cruising speed between 12 and 14 knots. A proper sea trial is required before an actual optimum speed can be quoted.