Agree
Mary,I've got to agree with Jack on this one. It would be very difficult to do this without actual access to the mattress. Unless possibly you can contact someone at Catalina and get dimensions, angles, etc. from them. I have done standard size sheet modifications before on our previous boat. It was really not fun, so this time we ordered the custom sheets from Catalina. They are very nice quality and fit perfectly. For us, it was well worth the price, which was approximately the price of department store sheets (high end). $200ish? for both front and back cabin, fitted and flat, with 4 pillow cases. Good luck either way and enjoy your new boat!!