ASA ASA Sail Trim & Performance 2

Question 1

What is 'twist' in a sail, and why is some twist desirable?

Accepted Answer

The leech falling off to leeward at the top, matching the wind gradient aloft

Answer

Sail twist allows the upper part of the sail to feather slightly, compensating for the wind's natural shift in direction with altitude (wind gradient).

Question 2

What does a wrinkle running from the clew toward the luff indicate about jib trim?

Accepted Answer

The sheet is eased too much and the sail is under-trimmed

Answer

A horizontal wrinkle from the clew toward the luff indicates the sheet is too loose and the sail's foot is not under proper tension, requiring the sheet to be trimmed in.

Question 3

Which sail control primarily affects the mainsail's leech tension?

Accepted Answer

The mainsheet

Answer

The mainsheet is the primary leech tension control on the mainsail; pulling it in tightens the leech and reduces twist, while easing it opens the leech.

Question 4

When does headsail 'backwinding' the mainsail become a problem?

Accepted Answer

When sailing close-hauled and the jib is trimmed too far inboard

Answer

If the jib is sheeted too far inboard when sailing upwind, the air exiting the slot deflects into the mainsail's leeward face, causing it to collapse or backwind.

Question 5

What does moving the jib lead aft accomplish in terms of sail trim?

Accepted Answer

Opens the leech and flattens the upper part of the sail

Answer

Moving the jib lead aft increases tension on the foot and eases the leech, opening the top of the sail and reducing power — useful in stronger winds.

(ASA) American Sailing Association Certifications Practice Test

(ASA) American Sailing Association Certifications Practice Test

ASA ASA Sail Trim & Performance 2