Hi All
I started of trying to understand why the sail is almost always close hauled no matter what direction one is sailing relative to the true wind. Obviously this led to discussions on apparent wind direction and speed. So I think I have got my head around most of this but there is one point I would like clarification on.
Is there a formula or at least a rule of thumb (other than feel while your sailing) to find the best point of sail for a given ratio of boat speed vs true wind speed?
I.E. if the best point of sail is 90deg off the wind at a ratio of 1:1 then what would it be at 2:1, 3:1, 4:1, 5:1
I am assuming these figures will plot some sort of curve falling away from the true wind direction and I know you can feel the right point when you’re out there sailing but I’m looking for a rule of thumb that will help me visualize what’s going on?
How can it travel faster than the wind?
Land yachts can travel faster than the wind thanks to a phenomenon known as ?apparent wind?.
For example, you are riding your bicycle on a completely calm day with no wind. However, you can feel wind on your face and it feels stronger as you pedal faster. That is because as you move forward, the motion creates its own wind.
Now imagine you are riding your bicycle but there is a strong breeze coming at you from the right. This natural wind is called "true wind".
When you add this side wind to the cycle ride, the wind the rider feels is now somewhere between the true wind (from the side) and the man made wind (from ahead). This resultant wind is know as the ?apparent wind? and will have a speed and apparent wind angle, measured from the direction of travel to the apparent wind angle.
Some Land yachts are so efficient that it can travel at up to 3 to 5 times the true wind speed on land.
www.greenbird.co.uk/about-the-greenbird/how-it-works
Perhaps the answer is more about air flow around the sail rather than angles to the wind, as speed increases angles change and are not a static thing.
Adjusting the sail / rig to suit the direction you want to head. Are you familiar with the use of tell tails on the sail, and how to get the best out of them?
Here is some more info on sail angles and the use of tell tails.....http://www.wb-sails.fi/Portals/209338/news/95_11_Tellingtales/Tellingtales.html
^^^^ not easily.
People often get confused with airfoil images where as most have riden a bicycle and understand the wind on the face concept.
Apparent wind is the wind that is supposed to show up when I go sailing but apparently did not get the message.
That says it all. We will be at ivanpah end oct. for seven days of fun in the sun. We me freinds there twice year for some sailing and sightseeing. Mostly sailing, hope the apparent wind shows up. That's why we are there for 7 days, a 1,000 miles is along way to drive for no wind. Are you still recouping from the world's heat? I love windsailing but that is to hot for me. Maybe we will see you on the playa and/or sod feild some day.
