Join Date: Feb 2000
Location: Annapolis, Md
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In a general sense, at least on bigger boats, mast heights have been increasing not descreasing for a variety of reasons. In general newer designs have a lot more stability than older designs, because they typically have a bit more form stability, carry more ballast relative to their weight, and carry some percentage of their ballast in bulbs. Because of their greater stability they tend to be designed with larger SA/D's and tend to rely less on overlapping headsails, which in turn requires taller masts. Newer designs tend to have fractional riggs or have rigs that proportioned closer to a fractional rig, which also in turn typically results in a taller rig.
I don't know of a 2006 Oday model or why its mast would seem shorter than your 1983 Hunter. I will say in the case of smaller trailerables, the industry has turned to water ballasting for ease of towing, which hurts stability and performance, and with reduced stability they have reduced sail areas and perhaps mast height.