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Surveyors at RLDA Surveying & Mapping are experienced at working in deep water. Established in 1954 in the Commonwealth of Puerto Rico, the firm has successfully completed thousands of projects for clients in both the private and public sector, and hydrographic surveys are a mainstay of its business. But when an engineering and architectural firm contracted the company in 2010 to perform pre- and post-construction hydrographic surveys for a new maritime police pier, RDLA surveyors encountered a new challenge. Would their traditional methods work in shallow water?
Renán López de Azúa, PLS, president and owner of RLDA, knew the answer. “Conventional survey vessels, usually 20 to 30 feet long, are not an option in small rivers, creeks and lagoons,” he says. “To provide our clients with the most reliable hydrographic data in extremely shallow and soft-bottom water, we recognized that we needed to enhance our traditional surveying platform.”
Using a kayak was appealing for a number of reasons, explains de Azúa. These sleek, inexpensive and environmentally friendly vessels are easy to maneuver in a variety of water depths, cost little to maintain and can be deployed quickly.
RLDA chose a 13-foot 10-inch Torque Ocean Kayak with a Minn Kota saltwater trolling motor, stabilizing pontoons and a capacity of up to 475 pounds. On this platform, the surveyors installed two Hemisphere GPS VS101 Series GP Compass systems, which are designed to provide a highly accurate GPS heading that takes into account the pitch, roll, and speed of vessels. To obtain accurate depth data, the team added a Teledyne Odom hydrographic echosounder.
The team shielded the GPS receiver and echosounder components from the elements by placing them within an insulated case that is positioned on a desk-like support just in front of the area reserved for a laptop computer, which would run the standard HYPACK hydrographic survey and processing software.
Squeezing all of this equipment onto a low-profile kayak was no easy task. A great deal of customization was required to accommodate all of the positioning, sounding, data integration and power components without compromising the kayak’s weight limitations and balance, while ensuring that all of the equipment would be easily accessible from the operator’s constrained position. Fortunately, everyone involved had a positive attitude. “Our team’s enthusiasm, combined with the eagerness to succeed and create a reliable and safe shallow water survey platform made the process enjoyable,” de Azúa says.
RLDA has since been able to use the kayak for several other projects. de Azúa is confident that the new platform will become an increasingly valuable asset in the future. “The use of the kayak surveyor has opened opportunities for work not possible when using traditional survey platforms,” he says. “Quick, light and efficient, this survey package will provide our clients with survey data from areas that were previously unreachable, and in a more efficient manner. Shallow bodies of water are no longer a match when working from the kayak surveyor. Additionally, using only one operator/surveyor, it frees company’s asset to be utilized in other projects--a crucial benefit that allows us to be more competitive in pricing our work.”
• RLDA Surveying & Mapping extends its appreciation to Tony Melendez, PLS, and Instant Print Corp. for their support.
Kayak Surveyor ComponentsVessel – 13'10" Torque Ocean Kayak
• Includes a battery box and kill switch.
• 100% sealed connections prevent corrosion and short circuits.
• Extra-large rudder designed to optimize steering.
• Infinitely variable speed control.
• Large covered bow hatch.
• Weedless wedge prop offers weed-free cruising.
• Durable Minn Kota saltwater trolling motor delivers 33 pounds of quiet power.
Echo Sounder – Teledyne Odom Hydrographic System
• Designed for inshore and near-coast hydrographic marine surveys up to 800 meters of water depth.
• Its ease of use, portability and cost efficiency make this device a perfect choice for shallow water surveys.
• The sensor unit is compact, interfaces directly to a standard laptop PC and comes complete with power and data cables for data acquisition.
• The dual-frequency transducer operates at 210 kHz, 8 degrees.
Data Integration Software – HYPACK
• Designed for hydrographic data collection and processing with single-beam, multibeam, side scan sonar, etc.
• Full navigation with AIS integration.
• S57 chart update and real-time verification.
• Real-time 3D terrain modeling with AVI recording.
• Real-time altitude for keel clearance.
• Provides reports for sections, volumes, TIN models, plots and side scan mosaics.
Positioning Equipment – Hemisphere GPS VS101 Series GP Compass
• Professional heading and positioning unit.
• Affordable solution delivers 2D GPS heading accuracy better than 0.1 degree rms.
• Differential positioning accuracy of less than 60 cm, 95% of the time.
• Integrated gyro and tilt sensors deliver fast startup times and provide heading updates during temporary loss of GPS.
• Fast heading and positioning output rates up to 20 Hz.