Amen on the directional changes. I swear there are days when you
could sail a full 360 degree circle around one particular little
island near Big Water and never change tacks. It can get really weird
at times.
Regarding the relative drive potential of main vs jib/genoa, my
Gloucester has a conventional main and 110% jib of exactly equal sail
area, 108 ft/sq each. Even so the jib provides about 70% of the drive.
Regardless of type, the mainsail suffers from having the mast up its
luff. The mast causes significant turbulence over the leading edge of
the sail which reduces its efficiency. One of the main advantages of a
sloop rig is that the overlapping jib/genoa smooths out this turbulence
and accelerates the airflow on the lee side of the mainsail when
everything is trimmed correctly, increasing the overall efficiency and
drive of the main. This is the primary advantage of overlapping
headsails up to about 135% or so. Larger genoas may actually make the
boat slower to windward as they can't be trimmed as close and
effectively as smaller ones. but the extra area has advantages downwind
as long as the sail is light enough to fill properly.
Rigging upgrades for the Gloucester have been geared toward easier
and better control of the mainsail. These include a luff feeder and vang
tackle added last season, and a boomkicker , cunningham line, jiffy reefing
lines, and lazyjacks added this season. Vang , cunningham, and backstay
adjustments on a fractional rig like the Gloucester allow the mainsail
shape to be adjusted to varying wind conditions without reefing until the wind
gets close to a steady 20 knots or more. The difference with just the vang
alone last year was an eye opener. In steady 13-15 knot winds, the vang
could flatten the main enough to prevent the boat from being overpowered.
Better shape allowed the main to provide more forward drive and less heeling
in strong winds. The Cunningham provides downhaul tension on the luff
and flattens the belly of the sail close to the boom, providing another
shaping control. Learning to tweak all this stuff effectively should be
interesting. I am hoping to find crew for some of the club races this year.
The luff feeder prevents the mainsail from jamming in the feed slot
when raising sail. The main goes up much faster , with both hands on the
halyard instead of one hand on the halyard and one feeding the luff rope into
the slot.
The boomkicker is a fiberglass rod spring arrangement mounted behind
the vang tackle that supports the weight of the boom and eliminates the
topping lift. Boom height and tuning are controlled by the vang tackle and
the boomkicker which together act like a rigid vang system does on larger
boats, but at a lower cost. I can't wait to see how this arrangement works.
The lazy jacks will control the mainsail and keep it contained on top of
the boom when raising,lowering, or reefing. When sailing or when the sail
cover is on they stow against the mast.
If I were to buy a Rhodes, the choice between an IMF or conventional
rig would be tough. If bucks were no object I think I would pick a carbon
fiber mast, Doyle stackpack mainsail, fully battened, a 110% jib on a
fractional forestay, and a 185% asymetrical gennaker ( Doyle utility power
sail) flown from the mast head on its own stay with a furler. Well I can dream
can't I? The mast would probably cost more than my current boat!
Razz
29 May 2001
