Wednesday, March 20, 2013

Excessive Heeling, Weather Helm, Jibes



Heeling Too Far – Inability To Point High – Strong Weather Helm – Slow Boat Speed – Do These Have Anything In Common?



Yes – All of these conditions could easily be explained by old, “blown out” sails.
It is amazing how often I hear about a new sailboat owner who either did not inspect the sails that came with the “new” boat, or who didn’t know what to look for when inspecting the old sails.  Just finding that there were not any holes, rips or missing stitches… did not mean that the sails were in good shape.  Sails age.  Days on the water, luffing, sunlight, and strong winds ware sails out.  Days on the water, luffing, and strong winds tend to stretch the material that sails are made out of.  As the sails stretch, they become rounder and rounder (deeper and fuller).

Sail-makers talk about the maximum depth of chord – the distance between a straight line from luff to leach and the sail material.  When the wind is light, the sails need a lot of chord depth.  When the wind is stronger, the sail needs less chord depth.  And in strong winds, the flatter the sail the better.  Think about the huge amount of curve there is in a small plane’s wing (like a Cessna 172) and the relatively small amount of curve in a Lear Jet’s wing.  The faster the plane flies, the less curve the wing needs.  The same thing applies for sails.  The lighter the wind, the more curve the sails need.  The stronger the wind, the less curve the sails need. 

Sails can be made flatter by increasing tension along the sides of the sail.  We increase the tension along the sail’s luff by increasing halyard tension or by increasing downhaul tension (sometimes called a Cunningham).  We increase the tension along the sail’s foot with a clew outhaul line on a mainsail or the sheets on a jib.  And we increase the tension on the leach with the main sheet or boom vang for the mainsail, and/or the jib sheet for jib sails.  “Blown out” simply means that increasing the tension on the sail’s sides does not flatten the middle of the sail.  So, as the wind increases and we increase tension along the sides, the sail stays too round and powerful.

“Blown out” sails are probably sail fine in light breezes.  But, as the wind pipes up, the blown out sail cannot be flattened.  The sails are too powerful relative to the wind; and the boat heels over uncomfortably with every gust.  Even though the boat is heeled over uncomfortably, the boat is not moving fast through the water.  Most of the energy from the sail is sideways energy – NOT forward energy.  The keel isn’t gripping the water efficiently either… so, the boat ends up sailing slowly sideways.  Sailing sideways (leeway) means that the boat seems to not be pointing very high.  If you try to point higher, the boat actually slows down.  AND, the excessive heeling makes the boat hard to steer (weather helm).  Ultimately, the weather helm may overwhelm the boat; and the boat rounds up uncontrollably.  As this happens, the wind fills the jib on the wrong side (back-winding the sail) and the boat spins downwind, does an uncontrolled jibe, and rounds back up toward the eye of the wind uncontrollably.  This is about the time the “Admiral” says, “Take those blankety blank sails down and start the engine.”

So, if you have experienced an inability to point with similar boats, excessive heeling, sailing sideways slowly, strong to excessive weather helm, or uncontrolled spins…… the solution may be to buy a new set of sails.  Another option (if the budget isn’t there for new sails) might be to send your sails to a reputable sail loft and ask if the sails can be re-cut to improve their performance.  I did this with my 110% working jib a few years ago and am still amazed at how much better the boat sails with this sail now.  The sail is about 10% smaller but sails much better than before the re-cut.  If your boat really needs new sails – but the budget is tight… Maybe consider looking into one of the less expensive Asian sail lofts like Neil Pryde or looking into a discount warehouse operation like thesailwarehouse.com.  Ultimately, if the budget is really tight, you might consider sewing your own new sails.  Sailrite.com might be just the place to order the materials to make your brand new sail.

You will probably be surprised at how much better your boat sails.  The “Admiral” might be surprised at how much flatter the boat sails.  Both of these are a good thing……


No comments:

Post a Comment