Yaquina
Dredging is accomplished by progressive traverses around the harbor mouth like a giant underwater vacuum. During operations, drag-arms (suction pipes) are hinged on each side of the Yaquina with the intake drag-head (intake) extending downward and back towards the stern. The vessel moves slowly-1 to 3 knots - as the drag-head is moved along the channel bottom. Slurry (debris material) is sucked up the pipes and deposited into the hopper (container). When fully loaded, it sails to the disposal site.

"Most often we fill the hoppers by pumping past overflow. The mixture that comes into the ship is usually 15 percent sand and 85 percent water. By allowing water in the hoppers to overflow, we keep ‘richening’ the mixture as sand settles until about 1,000 cubic yards is present for dumping," Captain Hunt, Captain of the Yaquina is quoted as saying.

The Yaquina is operated by the Corp of Army Engineers and is one of two similar dredges assigned to the West Coast.  The dredge is not exclusively dedicated to the West Coast and can be called to any part of the World if need by our Armed Forces.   The ship is described as a self-propelled, hopper dredge and is equipped for 24-hour operation.

In talking to some of the long-term locals, the appearance of the Yaquina isn’t all that unusual.  The dredge shows up every once in a while (maybe yearly) to open the harbor mouth.  Without the periodic dredging, most the West Coast ocean harbors would turn into lakes and all marine activity would come to a halt.  

Several years ago, California underwent a period of beach erosion.  The levels of the beaches, for hundreds of miles, were lowered by several feet.  I specifically remember that both Malibu and Watsonville were in danger of losing hundred of ocean side home.  I bring this up only to illustrate that the ocean is quite capable of moving millions of cubic feet of sand around in a short period of time.  Anyone who has seen the towering sand dunes at Pismo Beach and Oregon Dunes National Recreation Area can’t help but be amazed by the power of the sea.
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Our window to the world has a great view of Morro Rock but also includes a vantage point to the harbor entrance.  Watching the various ships and boats coming and going into Morro Bay may not be the most exciting form of recreation but one of those quiet pleasures that form a memory to be summoned up in the future’s idle moments.  By comparison to the normal activities the appearance of a ship called Yaquina has made the harbor entrance a focus of attention for not only the tourist but the locals as well.

The Yaquina is 200-foot long, ocean-going ship that looks like a coastal freighter of some kind.  What’s unusual is that it’s camped right in the mouth of the harbor entrance and has been there for weeks.  The ship does move about the harbor mouth and periodically heads out to sea – but soon return.  The ship sometimes moves perilously close to the breakwaters but seems to know what it’s doing.

The Yaquina is a dredge and its job is to remove the accumulated sand that builds up at the mouth of the harbor.  The sand contributes to the “dangerous bar” ((link)) described in one our earlier reports.  The sand build-up makes the bar shallow, which in turn makes the waves higher, which makes the harbor entrance dangerous.  Obviously the risk of dragging the bottom is also increased.
The self-powered, Sea-going Dredge Yaquina