Enter the electric halyard winch...
There is one factor, which I think has pushed the size limit for a single sail upwards, and that is the electric capstan. These need not be of the hi-range electric genoa-winches, but can be simpler electric capstans meant for hauling up the anchor. They are surprisingly affordable, and surely much cheaper than splitting the sail area into two sails.
The biggest single-sail JR I know about is the 80sqm rig of Peregrine (JRA NL 48). They added an electric winch after 2-3 years, and just kept the manual winch as back-up.
I bought an electric winch handle for my 48sqm sail of my Johanna, after 8 years ‘in manual’, and I now frequently use that handle on the 35sqm sail of my Ingeborg.
I find that the energy consumption needed to raise the sail is quite low, so will not drain a battery. The internal battery in my Winchrite appears to last ‘for ever’. I just topped up the battery once this summer, just to be on the safe side.
A little theory:
The energy needed to hoist 50kg 10 m up is...
E = force [N] x distance[m] = (50 x 9.81)[N] x 10[m]
= 4905Joule = 4905Ws
If we assume that we lose 50% in friction, the energy needed is roughly 10.000Ws
If that winch is to bring that weight up within 100seconds, the motors’s power must be
P = 10000Ws : 100s = 100 W
In a 12Volt system , the current flowing through the winch motor would be
Current = 100W : 12V = 8.33A
The current consumption is the current x time
= 8.33A x 100s = 833As
Since our 12V batteries are rated in Amp-hours, the current consumption needed to raise 50 kg 10 metres (with 50% loss) is.
Current consumption[Ah] = 833[As] : 3600 = 0.23Ah
( = 0.23 x 12 = 2.8Wh).
That is a little less than it takes to have a 3W lightbulb on for one hour.
Conclusion: Electric halyard winches are definitely not ‘battery hogs’.
Arne