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NMCB 74 Surveyors, Making the Unknown Known

Navy NewsStand

Story Number: NNS091130-12
Release Date: 11/30/2009 4:57:00 PM

By Mass Communication Specialist 1st Class (SW/AW) Ryan G. Wilber, Naval Mobile Construction Battalion 74 Public Affairs

HELMAND PROVINCE, Afghanistan (NNS) -- Naval Mobile Construction Battalion (NMCB) 74 recently received support from Navy engineering aides, who trekked across the sand in the Helmand Province, Afghanistan, to provide NMCB 74 with an accurate representation of the topography of Camp Leatherneck's expansion site.

Without vital information provided through the topographical survey, NMCB 74 wouldn't be able to correctly form the foundations for the facilities or roads that will comprise NMCB 74's new working space.

The new Seabee camp at Camp Leatherneck will occupy 21 acres, with a main road that's more than 7,000 feet long.

The elevations for the foundations, referred to as pads, the slope of the area for drainage and the shape of the road were all determined by NMCB 74's operations department before the survey began. Surveying the expansion site was the first step in the actual building process after the planning phase was completed.

"[The Operations Department] decides what elevation everything will be, the slope or what the pad elevation will be, and then we take it from there. That way the equipment operators know how much to cut or fill," said Army Spc. Joel Quintanilla, a survey team member, assigned to the 655th Concrete Team, 19th Engineer Battalion.

Preparation for the survey begins with setting up electronics in the office. With a minimum of two known points and the camp layout diagram, coordinates are entered into the Trimble S-6 controller.

"We plug the numbers into the S-6 geodometer, and we know where to go from there and put in stakes," said Engineering Aide 2nd Class Adolfo Valdez, NMCB 74 lead surveyor.

The process may sound simple, but the fact is that these Seabees were introduced to the Trimble S-6, a rather sophisticated piece of surveying equipment, just two months ago during turnover.

"More advanced equipment makes it a lot easier as opposed to doing it manually where you just have a transit and telescope - using a tape measure rather than a computer," said Quintanilla.

At the expansion site, the survey begins by connecting the base to the controller of the S-6 via Bluetooth. Once connected, the controller is moved to each of the two known points and their elevations entered. This process, called a resection, allows the base to know its elevation and coordinate. Now the surveyors are set to find the elevations of unknown points.

"Once we've entered the coordinates of each point into the controller and [synchronized] it to the base, the controller will lead us to the desired point using line-of-sight technology. I'll set the pole, level it out and press the button, and the base tells the controller the elevation," said Valdez.

"All you have to do is click and measure whatever points you want into the machine, and it will actually take you right where it's supposed to be, and it's pretty accurate," added Quintanilla.

Using line-of-sight technology in the desert where frequent and unannounced sand storms blow through is sometimes challenging, but Valdez and his crew gather the information after a number of long walks across the uneven sand.

Before the survey is complete and the information is ready to be uploaded, the team will have walked nearly every foot of the 21 acre site, not to mention placing 500 stakes to mark off the main road along the way.

Once back in the office, the S-6 is connected to a sophisticated computer program, which provides a visual representation of the site once the coordinates and elevations from the survey points are uploaded.

"The software is made specifically to complement the controller," said Engineering Aide 2nd Class Asdru Arana, leading petty officer. "The Terramodel program shows elevations and depressions, which show us how much dirt we need to bring in or cut, to achieve proper drainage for our roads and plot."

With the print out from the program, called a site plan, NMCB 74's Alfa Company, who operates earth-moving equipment, is provided with an accurate representation of the site's topography. They know how much dirt must be removed or added to construct the camp site and road according to the site plan.

Even after the site plan is provided to Alfa Company, the team's work is not complete however. It is vitally necessary for surveyors to be on site to take elevations as the work progresses to ensure the final pad or slope of the road are constructed according to specifications.

"It's a lot of going back out there to make sure they are where they need to be," said Quintanilla.

The importance of surveying, as the first step in the building process is immense. An accurate survey leads to a sure foundation and a new functioning camp for NMCB 74.