Foam Luff

[wflowe2]

Opinions on how much a foam luff improves sail shape on a partially furled head sail?

 

[RichH]

Best obtainable sail area reduction for a jib on a furler, even with a foam luff, is only about 30% SA reduction. Once you go beyond ~30% sail area reduction the SHAPE of the sail will be BAD.

There are special 'shapes' that can be designed for the leading edge profile of a jib on a furler ... and the combo of foam luff, special shape, and precise/advanced furler design 'may' get you to 40% sail area reduction ... before the shape 'goes all to hell'.

Reason for all this: A sail usually has it maximum amount of 'curve' at about 30-40% back from the luff ... and if you roll up beyond this you now only have a board-flat, but severely wrinkled along the rolled up luff, part of the sail exposed. A sail is a quasi-spherical shape, and furler foil is a cylindrical pipe-shape.

Without a foam luff you 'may' get 15% roll-up before the shape becomes BAD: with a foam luff you 'may' get 30% before the shape goes BAD.

 

[Warren Milberg]

While I don't disagree with what Rich has to say about sail shape theory, my personal experience with a number of boats/sails is that (1) I would never again buy a headsail with a foam luff as I don't think it improves performance measurably (I have a 150 with a foam luff, and a 120 without), and (2) I've found I can roll up any amount of headsail on my furler and, even with an ugly luff, still do hull speed if the wind is howling. Read some of around-the-world-sailor Webb Chiles' books for a similar opinion.

 

[Cayennita]

If the wind is so strong that you need to do a partial furl, then the shape is not very important. In my ex 51 footer I had a North 135 with 3 lines sewn in the luff instead of foam. They vary in length depending on the amount of furling desired. I used it for 7 years before I sold the boat and it kept a decent shape. The boat went up wind very well with the main also reefed 25-28 apparent and doing 7 knots.

 

[Gunni]

Opinions on how much a foam luff improves sail shape on a partially furled head sail?

What size genoa are we talking about? On my 130 the foam inserts allow for good shape down to 100 size. But I wouldn't want that 130 blowing out and I don't want to haul it down in a breeze.

Interesting that Warren mentions Webb Chiles. I share Chiles evolving perspective: With the advent of furling Asyms the big genoas make less sense. My next headsail will likely be a furling 100 blade, and my Asym will go onto a continuous line furler and retracting sprit. It is getting easier and easier to singlehand a spinnaker. And that is a good thing.

 

[wflowe2]

Thanks for the opinions. I have a 125 genoa on a Catalina 320. It has been pretty windy so far this season so I have been sailing reefed often. I agree with Warren that I have had no trouble hitting and even exceeding hull speed (new clean bottom) with my current sails so maybe an investment in a foam luff isn't such a great idea.

Bill

 

[robertsapp]

Speed's great, but what about your ability to point? We've noticed when the wind tops about 22 to 25 knots, with our 100% jib rolled up a third of the way and a double reef in the main, we can sail just fine and plenty fast, but no closer than about 80 degrees apparent, which is a pain when that's the way home lies.

 

[wflowe2]

I agree that pointing suffers when the genoa is reefed. So back to the original post ,would a foam luff help with pointing?

 

[BobM]

I have a foam luff and the shape is much better, but perhaps some of the difference I discern is due to the furler not the foam. My point is that a furler without a top swivel, such as a CDI ( which I had on my old boat without a foam luff) is likely a big part of having a decent furled shape.