the currents of air that the walls of the ship

[dfghj]

Hello,everyone

It's quite hard and the first time that I don' t know what the flowing sentence means, please help me, thanks un advance at the bottom of my heart.

ex:
The currents of air that the walls of the ship direct upwards, as well as in the line of its course .


No two sorts of birds practise quite the same sort of flight; the varieties are infinite; but two classes may be roughly seen. Any ship that crosses the Pacific is accompanied for many days by the smaller albatross, which may keep company with the vessel for an hour without visible or more than occasional movement of wing. The currents of air that the walls of the ship direct upwards, as well as in the line of its course, are enough to give the great bird with its immense wings sufficient sustenance and progress.

 

[Edinburgher]

"That the walls of the ship direct upwards, as well as in the line of its course," is a defining relative clause.

The currents of air are enough to <keep the bird gliding without needing to generate its own lift by flapping its wings>.
What currents of air?
Those that the walls of the ship push up and back.

 

[dfghj]

Thanks,Edinburgher ! But in the level of my understanding, the key what puzzles me is the relationship between the currents of air and the walls of the ship,seems to me that both quite different and no verb connects with them, the word that are too diffucult for me to understand. Could you pleased to help me ? Thanks

 

[Edinburgher]

The verb is direct, which in my earlier explanation I paraphrased as push. As the ship moves across the ocean, it has to push the air out of its way. The (mostly forward-facing) "walls" of the ship (parts of the ship's superstructure) create an upward flow of air by directing the air currents upwards. Does that help?

The idea is similar to wind blowing horizontally over some flat terrain, and then being directed upwards when a mountain is in the way. The stream of air flows uphill, and there too birds can soar or glide for a long time without flapping their wings, because they are moving relative to the wind, while remaining approximately stationary relative to the ground.

 

[dfghj]

Hello, Edinburgher ! ! I don't know how to say thanks for your kindly help, you helped me a lot to get over a big problem of my English.

 

[kuronin]

Hello dfghj,

The original text was unclear in its grammar and is difficult to understand...
I think it is interesting, but I am a bit confused, trying to follow Edinburgher's discussion. The verb directs implies human action, like directing a movie, or directing someone to the nearest station. In this situation, deflects seems like a better choice. We can talk about signs directing the flow of traffic, however, so it is a flexible term.
I just want to rewrite the story, in simpler words, to hopefully reveal the true meaning:

No two species of birds perform/exhibit quite the same types of flight patterns; the varieties are infinite, but two general classes can be described. In the case of gliding, any ship crossing the Pacific may be accompanied for several days by smaller albatrosses. These birds can be seen flying alongside a vessel for up to an hour– without any obvious or only occasional movements of their wings. Currents of air are deflected forwards and upwards by the hull of the ship moving along its course. The currents rise upwards around the vessel which also pushes and pulls air along its path at sea. These currents provide enough lift and force, to allow the albatross –with its broad wingspan– to glide alongside or above the ship with minimal effort. Birds can sustain this flight for long periods, without seeming to move or tire.
The other class of flying is ...

I am not a bird scientist, or marine engineer, but I think this is close to what is happening at sea.