JibCap’s Scuttlebutt #1 – Ready to Reef your Furling Jib
Sailors were quick to realize another benefit of the furling jib – reefing. A reefed furling jib improved sailing performance and crew safety by reducing the time to reduce sail and keeps everyone in the cockpit as the winds increased. However, reefing the furling jib can come at a cost. Reefing, if not done correctly, will increase the frequency of sail repairs. Torn fabric and ‘blown-out’ / ‘baggy’ jibs are the usual result.
Discussions with sailmakers about the ‘dos and donts’ of jib reefing gave us new insights on reefing.
A. If you reef the jib by taking in 2 to 4 feet of sail without ‘Luff Foam’ or a ‘Rope’ attached in the middle of the jib’s luff, you have a high potential of creating a ‘bag’ at the middle area of the luff. Note: an improperly tensioned head stay increases the ‘bag’ as well. This ‘bag’ not only reduces sail shape and sailing performance but moves the wind pressure strain to the new head and tack locations on the leech and foot. These new leech head and foot tack locations are not designed for this additional stress and will result in fabric stretching and damage. The final result will be the failure of the fabric and stitching.
There are three solutions to this situation:
1) Install Luff Foam on your jib. The Luff Foam provides the ability for the sail to furl evenly on the headstay foil, keeping the wind pressure strain spread uniformly on the luff. The new leech head and foot tack locations will not be subjected to stress beyond the design of the fabric. The Luff Foam will also eliminate the ‘bag’, improving sail shape and performance.
2) Install Luff Foam and leech and foot reinforcement patches. The installment of reinforcement patches on the leech and foot will guarantee the safety of sail fabric, but will restrict the reefing options, limiting the reef points to the locations of the reinforcement patches. Luff foam is still required to eliminate the ‘bag’.
3) Take-in more sail to the point where the jib roll looks uniform and there is no sail bag. This normally occurs when the clew is taken forward of the mast. Reefing the jib to this extent has the same effect as installing ‘Luff Foam’.
B. Jib Sheet Angles have a huge impact on the stress transmitted to the new leech head and foot tack locations…with or without Luff Foam and reinforcement patches. The sheeting angles need adjustment as soon as the jib is furled. Incorrect sheet angles result in poor sail shape, trim (leech or foot luffing), performance, and either the new leech head or new foot tack locations will be overly stressed. Often the jib sheet blocks are not adjusted properly because of the degree of difficulty and safety. With the winds increasing and the crew working on the leeward side, the sheet blocks probably are difficult to move. Depending on block and track design, there are several actions to take to make it easier to adjust the jib sheet angles when reefing and under load. The time to devise a strategy on how best to adjust your jib sheet angles is when sailing in a moderate breeze under controlled conditions.
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