Join Date: Apr 2002
Location: San Francisco Bay area and West Coast by trailer
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Re: Small Craft Warning
You don't say what kind of 27' masthead sloop you have, but something like a Catalina 27 should do fine with the 2nd reef in the mainsail and the 135% reefed to the -second mark (equivalent to an 85%) up to 25 - 30 kts . But that can vary depending on the stiffness of the boat.
If you sail frequently in steady wind more than 30 kts, you may need get a purpose built 70%, made of heavier cloth than your 135. But switching out an RF sail is a pain in the butt.
A 135% genoa with a luff pad that is not baggy, should reef down to the 20% mark and function similarly to a #4 (85%) quite nicely. That 20% is linear, not area. In terms of area, that's equivalent to .8 *.8 = 64% of the original area. So a properly designed 135% can reef down to the area of .64* 135 = 86%. That's a heavy air jib for your boat.
Think of putting a couple of marks on the foot of the sail at 10,20 and 30% . When you reef down to to the linear 10% mark, you're at 0.9 x 0.9 x 135% = 109% area wise, and slightly flatter. at the 20% reef linear reef mark,, you've got 0.8 x 0.8 x 135% = 85%
You should put a couple of marks on the foot of the sail at 10,20 and 30% of the total foot length. When you reef down to to the linear 10% mark, you're at 0.9 x 0.9 x 135% = 109% area wise, and slightly flatter. at the 20% reef linear reef mark,, you've got 0.8 x 0.8 x 135% = 85%
If your 135% genoa is baggy, or converted from hank on, or doesn't have a luff pad, it will not furl well. It will be too deep and have lots of wrinkles. That will cause heeling and rounding up and poor pointing. If your mainsail is baggy, or designed with a too deep draft, you will heel excessively when sailing upwind under gusty conditions. (Or you need to use all the controls better to depower more)
If you sail frequently in 25-30+ kts, maybe you should consider a 110% jib and then add a couple of free flying light wind sails, for less than 10-15 kts, such as a Cruising Code Zero on a furler for apparent wind angle in front of 90 degrees and an asymm spinnaker for AWA > 90 degrees.
San Francisco Bay and Delta
Last edited by jblumhorst; 04-26-2019 at 11:51 AM.