March 5, 2013 – Another Small Dredge

Dredge and Rainey Report
Another Small Dredge

March 5, 2013

 

This report can be downloaded in PDF file format by clicking the Dredge and Rainey Report, Another Small Dredge hyperlink.

On Tuesday, March 5, Jimmy Delery out of New Orleans set up a demonstration visit to see a small dredge that Windel Curole had brought in to create a protective marsh platform in front of a portion of the flood protection levee around Golden Meadow, La. I drove down from Baton Rouge and Timmy drove over from Vermilion Parish to meet the group on site. There were nine of us in all: Windel, Jimmy, Cathy Norman, Scott Eustis (GRN), Bill Kappel, Gary Rauber (USACE, I think), Thomas Diano (with the dredge), and the two of us. Thomas Diano is with Upperline Equipment Company that handles several types of equipment including the Amphibex 400 dredge that we had come to see.

The small yellow dredge was hard at work when we arrived, pumping mud from the borrow pit inside the levee into the shallow, semi-open water on the outer, exposed side of the levee. Everything about the operation was familiar – just on a bit bigger scale than our “mini” dredge. In fact, when Windel or Jimmy was explaining the operation, we could have written the script.

Figure 1. The small dredge at work in the borrow pit. The 8" discharge hose can be seen crossing the levee behind it.

Figure 1. The small dredge at work in the borrow pit. The 8" discharge hose can be seen crossing the levee behind it.

Figure 2. It all looked strikingly familiar!

Figure 2. It all looked strikingly familiar!

We watched the outfall for a while as Windel or Jimmy described the operation, and took a tour along the levee where Windel showed us previous marsh creation sites that had been done by other methods. He had discovered the same fact that we did – if you put mud into shallow water and broken marsh and bring it up to marsh level, it doesn’t take long for the marsh to colonize it naturally. I’ve always believed that Life on this planet is bursting for a chance to thrive, and that we actually have to work hard to prevent it. Given any chance -a crack in a sidewalk or a newly created mudflat -life of some kind will find a way. It’s up to us, in some cases, as to which kind of life that can be.

We watched the dredge for a while as it worked its way along the borrow pit. I noticed that the basic idea was the same as our dredge. Like ours, the pump was lowered to the substrate off the front of the vessel and pushed material into the hose instead of using a surface suction pump, and two spuds were used as holdfasts at the rear. Segmented hose sported hose-floats to shore, and the discharge could be 3200’ away (ours about 800’) without a booster pump. Both dredges generally worked backwards along a waterway. They both used a diesel engine for power and bio-degradable oil for the hydraulics. They both free-flow dredged material into a shallow receiving basin and are attended by shorebirds as soon as the mud breaks the surface.

The technicalities of dredging were very different from ours though. We raise and lower our pump by cable and swing the entire barge to dredge across a waterway and walk it backwards, using water jets to break up the fill material and the weight of the pump to excavate a series of holes. The Amphibex uses an excavator arm that rotates side to side, reaches out roughly 20 ft away and uses the cutter blades to break up the substrate so it is pumped into the hose by two pumps. It reaches out and slowly draws down and back to remover a strip of material, then rotates and reaches out for the next strip. Their spuds not only raise and lower, but tilt, so that they also “walk” backwards, but in a straight line.

Thomas radioed the operator to bring it to shore for us to get a close up look at the operation and layout. The rear spuds (like ours) were raised and then pivoted out of the way (not like ours). A rear propeller was lowered, the two side stabilizing floats were raised out of the water and the forward excavator arm that supported the pump was raised. The discharge comes off of a fixed port on the side of the vessel (ours is attached directly to the pump), and the dredge towed the hose along with it. It motored over to the bank where we were standing, and used the front arm with the pump to pull itself against the bank while the rear spuds were lowered to hold it in place.

One look at the double pump over cutter-blades on the end of the extendable arm and I was hooked. One of the main problems with our dredging set-up is its limitation in extremely shallow water. I’ve been trying to figure out how to add a swiveling bucket arm to the bow to pull shallow material toward our pump, so that we could work our way into shallow areas. A maneuverable cutterhead like this would be a much better fix! The Amphibex 400 has quite a few other amenities that we coveted, such as the climate controlled, enclosed cab; the pivoting spuds that allow it to walk across shallow areas, across land or self-load to a flatbed; interchangeable excavator arm tools for a variety of uses (cutter bucket, excavator bucket, rake, sprayer, etc.); and the self-propulsion to 8 knots when on water.

I want one. Unfortunately, the guy laughed when I mentioned a donation ($1.3 million!). It was worth a try…

Figure 3. The spuds were raised and tilted, a propeller was dropped into the water and it motored over to us, then the arm was used to pull the dredge against shore and hold it there. The double pump is at the end of the arm on top of the cutterblades.

Figure 3. The spuds were raised and tilted, a propeller was dropped into the water and it motored over to us, then the arm was used to pull the dredge against shore and hold it there. The double pump is at the end of the arm on top of the cutterblades.

Figure 4. All operations of the dredge were handled by one operator in an enclosed, air-conditioned cab (left), and the discharge ran under the cab and to the right side of the dredge.

Figure 4. All operations of the dredge were handled by one operator in an enclosed, air-conditioned cab (left), and the discharge ran under the cab and to the right side of the dredge.

The Amphibex 400 is roughly ten times our dredge in every way but size, from cost to operation to production capacity. It is sleek, well-engineered, and looks comfortable. However, the 8 or 10” hose gave us pause, since we know what it takes to manage a 4” hose. I felt like the driver of an ATV looking at new king-cab truck. I wouldn’t give up my little dredge, but I sure would like to work with this piece of equipment for a while.

Figure 5. This is a comparison of the Amphibex 400 (top) to our little dredge the "John James" (bottom) at roughly the same scale.

Figure 5. This is a comparison of the Amphibex 400 (top) to our little dredge the "John James" (bottom) at roughly the same scale.

Currently, these dredges are manufactured in Canada and have a little problem with the Jones Act working in U.S. navigable waterways. They are setting up a manufacturing facility in Panama City, Florida so that this can soon be overcome. The Amphibex 400 is the smallest dredge in a family of dredges by this Company and they seem to be quite versatile and adaptable. Since it is new to the U.S., the company is still working out their availability and would prefer to sell them, but they think that one like this could be leased out for around $2000/day or $60K/month, not including fuel or labor.

The Amphibex 400 will be working in the Golden Meadow, Louisiana area for a few more weeks, so if you would like to see it for yourself or have any questions, call Thomas Diano, 504-491-9070, or email him at Thomas@upperlineequipment.com.

 

PLEASE NOTE:

This is not an official product endorsement by my employer – the National Audubon Society – but my personal observations and opinions based on my working experience with Audubon’s small dredge. I will be doing other small dredge profiles as opportunity allows, as Audubon does recognize that small dredges such as this are valuable technological tools to be used for coastal restoration in Louisiana and elsewhere.

Karen A Westphal and Timmy J Vincent, National Audubon Society
Louisiana Coastal Initiative and the Paul J Rainey Wildlife Refuge
6160 Perkins Road, Suite 215, Baton Rouge, LA 70808
225-768-0921 office, kwestphal@audubon.org

This entry was posted in Dredge Reports, Marsh Restoration and tagged , , , . Bookmark the permalink.