20th May 2012, 22:04
In order for a carrier to head into the wind (or any ship for that matter) for the purposes of aircraft operations, what do they use to tell the wind direction? Apparently, a carrier can sail at 30 - 35 knots which causes a pretty decent "wind" relative to the deck. What device is used to separate the natural wind direction and speed relative to the direction and speed of the ship? I doubt that putting a wrought iron rooster up on the mast with an arrow and NSEW arms will work!
21st May 2012, 02:08
An ASR helicopter can hover over a given point regardless of wind so presumably the equipment involved can read surface to 100' wind? Probably not the method they use though, I'm just guessing!
21st May 2012, 06:36
Just like in flying machines.
21st May 2012, 07:01
Part of he high tech solution might be to have some kind of banner/pennant/flag/windsock mounted on a short mast near the front end of the ship which would indicate the relative direction of the wind over the deck.
Hang on - they may have thought of that already.
21st May 2012, 08:06
On sailing yachts they have an anemometer and windvane which connects electronically to a suite of instruments which include wind direction, wind speed, speed through water, depth etc. The wind indicator is capable of displaying both the apparent wind direction and true wind direction. I am sure that would work quite well on something bit bigger!
21st May 2012, 11:02
And that's exactly what they use during deck operations and will pass to the pilots - apparent wind.
21st May 2012, 11:46
Many seagoing vessels are fitted with anemometer/wind vane for weather reporting purposes i.e. 6 hour OBS message transmission plus ship handling & log entry purposes.
21st May 2012, 13:27
Relative wind - ship speed = true wind (vector math).
21st May 2012, 13:39
One of the first bits of navigational math taught in nautical science is vector math. An angle deck carrier will have a fixed anemometer forward of the island to measure the relative wind, but will also use other equipment (as below) to determine the relative wind.
The vector 'ER' represents the ship's motion.
The vector 'RW' represents the relative wind.
The vector 'EW' represents the true wind.
Given any two, you can graphically solve for the third.
Back in the old pre-GPS days, a similar equation utilizing ER, RM, and EM was first utilized to determine the ship's motion first taking into account set & drift (direction and speed of the underlying sea current).
Sea room permitting, the ship's course and speed is normally set to provide the relative wind down the angle deck at 30+ knots.