A towable and steerable elongated float for a marine seismic source arrangement for use in making a seismic survey at sea, having first attachment means at a lower or bottom part of a float body for allowing at least one seismic source to be suspended from the float, and second attachment means on a fore part of the float body for attachment of a strength taking source towing line or umbilical. The float body comprises first and second elongated steering foils being attached to and spaced from respective port and starboard sides of the fore part of said float body by respective support arrangement. The steering foils have respective longitudinal steering foil axes being oriented in a direction substantially perpendicular to a longitudinal axis of the float body and so as to be substantially perpendicular to a sea surface when in use, the elongated steering foils having respective first and second chord axes. Controlling means control an angle of at least one of the first and second chord axis with respect to the float body longitudinal axis.