Shauna asked:
How does the thrust operatea and how does the boat respond to sailing into the wind and with the wind?
Not for schoolwork; just wonderin’
How does the thrust operatea and how does the boat respond to sailing into the wind and with the wind?
Not for schoolwork; just wonderin’
TEN POINTS FOR BEST ANSWERRR!
Please answer quickk!
Jose
The only thing I can come up with is that the sail is the only aerodynamic factor. It’s used to turn everyday wind into directional motion with the help of rudder and tacking etc..
Comment by done wrenching — January 9, 2008 @ 2:39 pm
A sail is like a wing. It creates lift which is converted into forward motion. Sailing downwind the sails catch the wind and the boat is pushed along with the wind.
Comment by mark t — January 10, 2008 @ 12:21 pm
Sailing into the wind, the wind hits the sail at an angle creating a center of effort, working against the keel that becomes the center of resistance pushing the boat forward where there is the least resistance.Sails are held tight along the centerline of the boat.
Sailing with the wind the boat is being pushed by the wind with little resistance against it. The sails are let out to the side of the boat.
Comment by science teacher — January 13, 2008 @ 11:52 am
Sails propel the boat in one of two ways. When the boat is going in the direction of the wind (i.e. downwind - see Points of sail), the sails may be set merely to trap the air as it flows by. Sails acting in this way are aerodynamically stalled. In stronger winds, turbulence created behind stalled sails can lead to aerodynamic instability, which in turn can manifest as increased downwind rolling of the boat. Spinnakers and square-rigged sails are often trimmed so that their upper edges become leading edges and they operate as airfoils again, but with airflow directed more or less vertically downwards. This mode of trim also provides the boat with some actual lift and may reduce both wetted area and the risk of ‘digging in’ to waves.
The other way sails propel the boat occurs when the boat is traveling across or into the wind. In these situations, the sails propel the boat by redirecting the wind coming in from the side towards the rear. In accordance with the law of conservation of momentum, air is redirected backwards, making the boat go forward. This driving force is called lift although it acts largely horizontally.
The lift generated by a sail can be resolved into two main components; forward force and sideways force (see vector space for an explanation of this principle). These forces act against opposing forces generated by the hull and the keel
On a sailing boat, a keel or centreboard helps to convert the lateral force into forward movement of the boat with some sideways leaning, or ‘heel’. The forward motion is created because the shape of the keel has a much smaller cross section in the fore and aft axis and a very large cross section on the athwart axis (across the beam of the boat). The resistance to motion along the smallest cross section is “easy” while motion across the large cross section is “hard”. Forces across the boat are resolved by balancing the sideways force by the mass of the ballast in the keel being raised against gravity by the boat heeling, while forward forces are balanced by velocity through the water and friction between the hull, keel and the water. In other words it is easier for the sail to push the boat forward rather than sideways.
Comment by Lupo Cattivo — January 14, 2008 @ 9:26 am
Two words……..Bernoulli’s principle.
Comment by mcd_48230 — January 17, 2008 @ 3:17 pm
mcd_48230 has it. Look it up…
Comment by dpooch — January 19, 2008 @ 9:34 pm