I have a trailer sailer that was sold to me as a 1980 Spacesailer 18. Other Spacesailers have a boxy coachroof but mine slopes down from the mast. It has been suggested it was a Maxi 20 but a) it's 18 foot long, b) came with Sapacesailer 18 sails and looks like the Swarbrick S boats. Can anyone shed some light on the subject?