If an anchor is heavy enough to hold the ship down, how do they store it on the ship?

the anchor is not heavy enough "to hold the ship down"

the anchor is heavy enough so that that it sinks down.. then they let out extra chain so that when the current or wind pulls and drags the anchor it is at an angle and not straight up and down from the ship.. so digs into the bottom enough so that the ship will not drift

it is kind of like this...

Imagine holding a grappling hook.. you are strong enough to lift it straigt up. right. that should not be a problem...

But if you let about 30 feet of rope out then try dragging it...you will find it usually digs in or catches on something and it is much more difficult to move than lifting it strait up.

it is the same principal

It's not the weight holding down the ship, it that was the case then dropping anchor in too deep of water would sink the ship as the anchor would pull the boat down. It simple gives the boat an attachment point to keep it from floating away with the waves/current/wind. Sometime the anchor will catch onto rocks, and that helps, but its not required as it can still hold a ship in place when dropped in sand. It's just enough weight to counteract the forces from the ocean currents.

The anchor usually hooks into something, usually rocks, so that the ship can't drag it and the weight of the chain away from the anchor point. Being heavy enough does NOT mean it weighs more than the ship.

It's not the weight! An anchor is designed to dig into the bottom and that's what holds the ship.

anchors are amazing pieces of engineering. A forty pound anchor has held my twenty thousand pounds boat in near hurricane conditions more than once.

http://www.schoolofsailing.net/anchors-and-how-the...

So simple change it