Effects of Apparent Wind Not So Apparent

[Melody Miller]

Hello All:As most of you know, I had some issues with reefing - when to do it and how to do it. Well, I had an experience yesterday that somewhat intrigued me and I *think* I know the answer to the question but here goes anyway. Seems to me that experiencing apparent wind of about 18 knots while sailing at a *beam reach* is a much different thing than experiencing 18 knots apparent sailing *close* to the wind. Yesterday I sailed for some time at 90 degrees to the wind at 18 knots apparent and the boat stayed around 15 degrees of heel. Perfect.But I know that 18 knots apparent sailing *close* to the wind generally causes me to reef because the boat wants to heel at about 20 to 25 degrees.Methinks the difference is due to the orientation of the boat to the wind. Close to wind, the boat is experiencing more of the lifting effect of the wind,thus the greater tendancy to heel.Would someone please comment on my speculation?Most sincerely,Melody Miller

 

[Hayden Watson]

Methinks you be right

Hi Melody:Boy!, (opps Girl!) you are sounding like a sailor.You got it just right. The reason is in the angle of the sails to the boat. If your sails are tirmed correctly the forces generated by the sails should be very simular at both headings (ie a little bit of lift and a lot of drag). Sails going up wind generate 2 forces generaly called lift and drag. When close hauled lift (the smaller of the two) pulles you forward and drag causes you to heel. At a broad reach the sails have a much wider sheeting angle. this means that the drag on the sail is helping to pull the boat forward and the lift may even be reducing heel. Hayden WatsonS/V Papillon'88 C30Spokane, WA

 

[Charlie]

A lot of wind

Melody, Methinks that you are having a problem with Sail Trim 101. First, for maximum aerodynamic force, the ideal sail angle is about 30 degrees to the apparent wind no matter what the boats heading. Without going into a lot of technical jargin, a boat heel excessively when you allow it to become overpowered by the wind. Under these conditions, side force becomes severe. If you must sail close to the wind when the true wind speed is 10kts or more. then feather up to weather and flatten the sails.After which you can ease both sheets and move the traveler block to leeward. all three operations spill wind from the sails reducing the side force. As the boat rights itself the center of lateral resistance and the center of effort will fall into line, righting the boat. Remember that the apperant wind is always stronger then the true wind when a boat sails close-hauled. The blending processof the two winds shifts the apparent wind forward of the true wind, so the boast sails closer (points)to its actual power source.Try It! you will like it!!! and you won't be sailing on your head