If you order from Dwyer, you'll want to confirm which mast you have. I almost ordered the wrong thing when I was solving my too-short mast problem by ordering a longer piece for the section below the mast hinge. I looked at the measurements, on this page:
https://www.dwyermast.com/families.asp? ... Name=Mastsand decided I must have a DM-3. The person who took my order pointed out that the DM-284 was commonly used on Daysailers, so that might be what I actually had.
I rechecked, and sure enough, he was right. As EnglishmaninCNY points out, the internal shape of the mast track is different (curved in the case of the DM-284; flat in the DM-3). The outside measurements are extremely close, so it's an easy mistake to make.