GRAND ISLE, La. (AP) — The long, slender barriers intended to protect the Gulf Coast from the onslaught of oil haven't been as effective as hoped.

They often float twisted, tangled or sometimes just broken apart, unable to entirely stop the creeping crude.

Since last month's rig explosion and spill of millions of gallons of oil into the Gulf of Mexico — now the largest spill in U.S. history, surpassing the Exxon Valdez — more than 3 million feet of so-called boom has been deployed along the coast.

The boom isn't always sturdy and high winds and waves can send the slime cascading over the barriers.

Experts say while the boom isn't perfect, it provides one necessary line of defense. It also offers a psychological boost to those who feel helpless.