It was to do with the anchor design Martin. Most ship anchors of the period were of the "fisherman" type as shown in Proteus' helpful pictures above. As you can see, the flukes and the stock are set at right angles to each other to ensure that the anchor would dig in when dropped. But this made it impossible to draw up into a hawsehole or to stow flat on deck. In the days of the sailing navy the anchors would be lashed to a cathead projecting over the side of the ship (as on HMS Victory). Early steamships continued this practice but later the anchor design evolved to that shown by Proteus above. As you will notice, one of the arms of the stock has a right angled bend at the end with a ball on it. The centre of the stock was secured to the shank of the anchor with a pin. When the pin was withdrawn, the stock could be slid through an eye at the top of the shank and turned so that it would lie parallel with the shank which enabled the anchor to be stowed flat on deck. It still wouldn't fit up the hawsehole though so you had to have a davit to hoist it on board.
Anchor design is quite a scientific business as different types are best for different sea bottom conditions, sand, rock, mud etc. Generally, the fisherman type is considered to be rather inefficient these days and all large vessels are fitted with a stockless type where the shank can be drawn up into the hawsepipe. Smaller vessels like yachts may have a variety of types but most are either based on the Danforth or the Plough designs.
Colin