FULL ROACH MAIN
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J-Composite · Sloop
J-109
Start with a sail plan for how you sail, or choose from profiles already matched to this boat.
Known boat geometry
Rig data,
ready to verify.
Matched sails 6,276
J-109 Sloop rig
Model reference · final dimensions require onboard verification
P 13.15 m Mainsail luff
E 4.72 m Mainsail foot
I 14.16 m Forestay
J 4.05 m Fore triangle
ISP 14.91 m Spinnaker hoist
SPL 1.27 m Spinnaker pole
LOA 10.757 m Length overall
Visual sail selection
See the sail.
Then inspect the data.
Browse sail profiles matched to this boat, then open measured dimensions and observed ranges in the detail panel. Want a complete setup? Plan an inventory around how you sail.
Main sail
STANDARD MAIN
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Headsail · Jib
J1
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J1.5
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J2
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J3
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J4
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Headsail · Genoa
G1
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G2
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G3
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G4
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Code Zero
CODE 0
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Spinnaker
S1
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S2
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Gennaker
A1
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A1.5
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A2
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A2.5
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A3
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A4
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A5
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A6
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Historical sail data
How these numbers are calculated.
Every profile summarizes measurements observed on matching boats. It is useful comparison context, not a production specification.
Example: Standard Main areaPositions use actual measurement values
Min34.7m²
P1036.0m²
Median37.0m²
P9037.5m²
Max39.7m²
Collect matching measurements
Each dimension uses valid records from the same boat model and sail profile.
Keep the typical range
P10–P90 contains the middle 80% of observations. The lowest and highest 10% remain outside the displayed range.
Use the median as centre
The median is the middle observation, so an unusual measurement affects it less than an average.
Final dimensions are confirmed onboard before design review and production.
Model data is context, not a build specification. Rig version, hardware and final onboard measurements are confirmed before production.