Na stronie http://www.cmmsc.com/nps_pliki/pdfy/grotrace.pdf wspominają o "cunningham" (kanigam), czyli systemie wypłaszczania liku przedniego (w sumie to działa jak kontrafał grota) i właśnie czymś, co nazywają "flattener" - licho go wie, może to właśnie ta Twoja talia. POniżej jest opis po angielsku:

If you are having to ease the traveler down frequently in the puffs, you should put in the flattening reef. The flattener is a ring in the leech just above the clew. It is independent of the cunningham and will remove a great deal of fullness from the bottom quarter of the sail. It does not have to be entirely taken up, but rather can be tensioned as more flattening is required. Offwind, both outhaul and flattener should be eased to fully open the shelf.