in the process of making a hard top and I am aware that this will give me a bit more windage. I have the wind speed/PSI figures but I need also the conversion for HP to lbs pull - I know on occasion the mags do ouboard comparison tests and one of their comparators is a bollard pull test bbut I have not managed to find this. Specifically the connection between 30HP and lbs pull. I can relate the engine power to sail power to get a feel for the additional wind resistance particularly from the nose as that is where I will have max additional frontal area.