Think practically
My armchair guess is that masts mostly have been fitted on the centreline for practical reasons.
Since the majority of rigs in the west were stayed, offsetting the mast would result in much steeper shroud angle (and thus loads) on one side than the other. In addition, the shrouds put extra compression on the mast, and since western boats were built around strong keels, it made sense to step the masts on them.
On rigs with freestanding masts, one is freer to offset the mast, if needed. Still, many boats have the deepest bury along the centreline, which is desirable.
Even so, when I look around, at least some (western) mizzens have been stepped more or less off-centre, mainly to avoid the tiller of the transom-hung rudders (Phil Bolger yawls).
On my last two boats, the rudders sit on the transom. On these, it is logic to put the single JR mast on the CL. This results in offset sails with the sheets landing on the side of the rudder, instead of on top of it. Simple and practical.
On a flat-bottomed boat, I would not be afraid of offsetting the un-stayed mainmast a good deal to better make it suit the interior or improve deck space. I am not afraid of awkward handling, and the offset weight can be balanced out with batteries, outboard engine, etc.
However, I don’t seek eccentricity just for the sake of it. The same with the JR itself. I didn’t choose it to stand out from the crowd. The rig ‘chose me’ because it is so good.
Arne
