Abraham put Ishamel on Hagar's Shoulder? She later flung Ishmael under a bush

[Peter]

Gen 21:14 And Abraham rose up early in the morning, and took bread, and a bottle of water, and gave [it] unto Hagar, putting [it] on her shoulder, and the child, and sent her away: and she departed, and wandered in the wilderness of Beersheba. 15 And the water was spent in the bottle, and she cast the child under one of the shrubs.

Some folks like Ayamen1 http://islamchristianforum.com/index.php?topic=1256.0 try to insist that because of this English language translation that this means that Ishmael must have been an infant, insisting Hagar was carrying him on her shoulder (and presumably wandered 1200 kilometers across harsh desert to Mecca on a single skin of water!), in efforts to make the bible a lie, or suggest this is a contradiction, rather than trying to understand it. (Ishmael was in his mid-teens).
That's the difficulty when the spirit of antichrist causes folks to put so much effort into MISunderstanding.

Indeed it could have simply meant that Abraham was transferring his burden of Ishmael for Hagar to shoulder.

However checking a Hebrew interlinear we find
http://www.scripture4all.org/OnlineInterlinear/OTpdf/gen21.pdf

and-he-is-rising-early Abraham in-the-morning and-he-is-taking bread and-flask-of waters and-he-is-giving to Hagar placing on shoulder-of-her and the-boy and-he-is-sending-away-her

It's obvious that the bread, and the water, is placed on the shoulders of both Hagar and Ishmael.

and-she-is-flinging the-boy under the-shrubs

and she cast
Old Testament Hebrew Definition:
07993 shalak {shaw-lak}
a primitive root; TWOT - 2398; v
AV - cast 77, cast out 15, cast away 11, cast down 11, cast forth 4,
cast off 2, adventured 1, hurl 1, misc 3; 125
1) to throw, cast, hurl, fling
1a) (Hiphil)
1a1) to throw, cast, throw away, cast off, shed, cast down
1a2) to cast (lots) (fig)
1b) (Hophal)
1b1) to be thrown, be cast
1b2) to be cast forth or out
1b3) to be cast down
1b4) to be cast (metaph)

Whether it simply means she effectively discarded Ishmael, or he was collapsing against her, and she slung him around and down into the shade under shrubs, or even if she was carrying the boy as he was thirsting to death (she was after all Sarah's servant, so she would have likely been muscular from the work) there are lots of ways to reasonably envision this account. Even simply casting him out of her sight, or casting him away.