What a Difference a J
Makes.
Now it's possible to sail fast with just a friend or two as crew.
After all, isn't this how we sail most of the time on a day's sail or when cruising?
Rarely is the gang aboard to hold the boat down or fly a chute.
Considering the realities of how we sail, the measure of a good sailboat should
be how well it sails upwind and downwind with only 2-3 people aboard. The goal is VMG,
Velocity-Made-Good, straight into the wind or away from the wind, considering both speed
and sailing angle. Many of the modern integrated instrumentation systems can display this
data, or you can use a set way-point to windward on a GPS to come up with the number.
Good short-handed VMGs are when a "50-something" husband & wife
jibe a J/105 (34.5 ft.) with asymmetrical through Woods Hole against the current, while
others motor. Or, if you can beat upwind in steep waves doing 6.8 knots with a VMG of 5
knots in 18 knots of wind!
Safe, Fast & Easy
Flying one of these new asymmetrical chutes from a retractable, carbon-fiber bow sprit is
a one person job. By using a cockpit-operated snuffer, no one has to be on deck when the
spinnaker is flying, being jibed or doused. To jibe, simply let off one sheet and pull in
the other. Downwind VMG is doubled. Result? Less motoring and more sailing.
It's safer. One corner of the spinnaker (the "tack") is always secured
to the bowsprit, eliminating wild oscillations. The sail has more slope to its leading
edge with a center-of-effort located further forward and lower. Wind gusts lift the bow,
propelling the boat forward with finger-tip control. No more "white-knuckled"
round-up broaches.
Speed from the asymmetrical's greater power pushes the apparent wind 30-50
degrees forward of the true wind direction. In light air and lumpy seas, the sail's added
power steadies the boat. Deep sailing angles (160-170 degrees True Wind Angle) are
achieved in a breeze. The luff, which is 8% longer than the straight line distance from
tip of the sprit to halyard exit on the mast, rotates to windward as the sheet is eased -
projecting area to the wind like a conventional spinnaker when pulled back by a pole.
That Feel
The new Js instill a sense of confidence, freeing one from anxieties. Even when planing at
10+ knots, one feels in total control. There's less work. Guests aren't pressured into
unfamiliar tasks. Fewer orders are needed. It's more fun! Like a good sports-car, turning
as if it were part of you. Not with sluggish delay. But with a smooth, even response -
around crests, down waves and through crowded harbors.
Mainsail Only
The new J's sail well flying any sail combination you feel comfortable with. For
harbor-cruising or heavy winds, an unreefed main is the answer. If the boat sails 6+ knots
under main alone, why bother with large overlapping jibs? Visibility is improved. The big
main is a bonus for "cruising canvas" races. And, it takes one person to sail
the boat. High wind mode is a flattened mainsail with open leech, achieved by tightening
backstay, cunningham, vang and outhaul. These adjustments are quicker and easier than
reefing. The jib can be rolled up and forgotten.
34% Upwind VMG Gain?
Hull design, rig, sailing length and weight location greatly affect VMG. You see many
cruising boats motoring upwind in both light and heavy air. Why? Not enough sailpower
for light air or stability for a breeze. For example, the J/120 (40 ft.), sailing upwind
at 7.2 knots, 38 degrees from the true wind (25 degrees apparent) will have a VMG of 5.7
knots. This is 15% faster than other production 40 footers sailing 7 degrees further from
the wind at 7 knots with a VMG of 4.7 knots. And, it's 34% faster than a classic cruiser
doing 6 knots with an upwind VMG of only 4.2 knots. These differences are inescapably
locked in by design and construction.
Low Center of Gravity
Good upwind VMGs are only possible with a low, vertical center of gravity (VCG). Top-heavy
boats roll and pitch. This motion disturbs water flow around the boat and airflow past the
sails, not to mention equilibrium of the crew on deck. The lower the weight of the boat
relative to its waterplane, the greater the stability, the more sail that can be carried
and the smoother the motion. This explains a J's smooth, stable ride through waves. The
VCG is well below the waterplane.
Resin Infusion Process
You get what you pay for. Low VCG is achieved by light, strong construction of what's
above the water. Starting with J/80. J/80 One
Designs (26.25 ft.) and J/120s, and all successive new J/Boats benefit from
the
innovative SCRIMP resin-infusion process. End-grained, aircraft-grade balsa-core laminates
have structural GRP skins with 65-70% glass content, or the equivalent of custom
high-tech, oven-baked pre-pregs.
Carbon-Fiber Rig
The best place to reduce weight is aloft. J/Sprit boats have Hall spars - the best
engineered, tapered, aluminum racing spars available. They are custom-designed for J
Boats, race-tested and abused to insure reliability with a good safety margin built-in.
Running backstays aren't required. Checkstays, where provided, are for sail shaping or an
extra margin of safety in extreme offshore conditions. For the J/120, one may select
a carbon-fiber mast to further optimize upwind VMGs for short-handed
cruising. These white, custom-engineered, one-piece, autoclaved spars have a luff track
designed for low-profile and low-friction slides. The 120 pound weight saving aloft is
equivalent to having two invisible 200 pound genies sitting on the weather rail to improve
performance.
Ballast Ratio & Shoal Draft
The best place to add weight is in the keel. The closer that is to 50% of the boats total
weight (DSPL) the better. A lead keel, fixed under a deep, structural molded sump, having
much of the weight in a bulb at the bottom, is better yet. The J/120's ratio is 6,000
lbs/12,900 lbs or 47%. A high ballast ratio and quality construction are even more
important, if you decide on our shoal draft option. A "J" with a shoal draft
keel will outperform most deeper cruising boats. Before deciding on this option, consider
that the need for shoal draft may be a function of speed. A fast boat, that easily sails
50 miles in a day, puts more deep harbors in range than can be visited in a year.
Righting Moment (RMC)
Good upwind VMG requires good stability. A measure of this stability is RMC, the foot
pounds needed to heel the boat 1 degree. Keel weight, form stability and construction
quality are captured by this number. Among similar boat types, the higher the RMC relative
to DSPL, the more likely that two people can sail her upwind to her capabilities. J/120's
RMC is 9.4% of her DSPL.
Horsepower
Sails are the horses. A light boat with clean lines and good stability can carry the sail
power needed for lively performance. There's no need for tall, scary rigs with heavy sheet
loads and winches. Sail Area to displacement (SA/[DSPL/64]^.67) is a good indicator of how
much horsepower the design can handle and what its speed potential might be. Look for
ratios over 20. The J/120 is at 22%.
Low Resistance
Too much weight usually means too much wetted surface (WS). Like brake shoes. The more WS
there is relative to sail area, the quicker you stop. A good SA/WS ratio is critical for
performance in North America's light air. Among 40 footers, J/120's ratio of 2.7 is fast.
A boat with a 2.0 would be "glued".
Then there's form drag. It's usually faster to be long and narrow. But only when
combined with greater stability and sail power. A length (LWL) to beam (BWL) ratio greater
than 3 is desirable for good directional tracking in waves. Then, oversized keel, skeg or
rudder surfaces aren't necessary. A long canoe tracks, a pram spins. J/120 has a healthy
3.7:1 ratio with flared topsides. Flare slaps waves down and keeps the crew dry.
Vertical-sided hulls bounce waves up on the crew.
Speed Rating
The rated speed of most sailboats is published. Order a copy of PHRF Handicaps from US
SAILING (401-683-0800). It's how we know the projected speed of a J/120 with genoa will be
30 seconds per mile faster than a Sabre 42 - more than the length a football field after 8
minutes of sailing! Or, that her all-round speed will equal boats which are nearly 20 feet
longer, such as a Swan 57, Hinckley 59 or Deerfoot 62. An often overlooked benefit of such
speed is the help it gives you in route-planning when dealing with weather systems.
Your Next Boat
Now more than ever before, differences between sailboats are greater than differences
between golf clubs, tennis rackets, skis or cars! Performance is the reason you don't see
wooden or solid fiberglass tennis rackets, skis or golf clubs anymore. A fast new
"J" can make a beginner look very good, leaving the experts far astern with
little solace that slow is easier or more comfortable. It could take years, owning and
sailing all types of boats, to learn that good design and high quality composite
construction makes so large a difference. Or, you can make the most of your time and
dollars by acquiring what we've learned and are building into the seven new award-winning
J/Sprit designs from 26 to 53 feet in length.
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