I know a guy who ripped his windlass off his catamaran because his anchor got caught on the bottom.  That’s a bad day.   Maybe a fluke anchor from Revolution Anchors may have helped. 
These newly introduced anchors feature a double shank with the chain running from the crown to the chain between the shanks and through a machined stainless box that houses a release mechanism.  This mechanism at the end of the shank is designed to let go once you drive over the anchor (at 90 degrees).  The chain pops off the shank end and is then only connected to the crown and the anchor is lifted free of the obstruction be it a rock, kelp or underwater cable.

The three models in the Revolution Anchors line are designed for boat from 16-36 feet and even the company makes sure you know that these are best used as lunch hooks, not overnight situations in a blow.  Sure, the snag release mechanism can be overridden by adding a bolt to the box but it strikes me that small fishing craft that anchor for a short time in the afternoon are better targets for these anchors than a cruising sailboat. 

The three models retail from $285-434 and weigh between 12 and 18 pounds.  They can be used with most rollers.  Shanks are replaceable and the anchors are made of 316 stainless steel.  Use with caution until you get the hang of it.