This document discusses the major components of hydrographic surveying including marine vessels, positioning instruments, and depth sounding instruments. For marine vessels, it describes the different types and equipment needed for small, medium, and regional scale surveys. Positioning instruments have transitioned from traditional methods like transits to modern techniques like GPS. Depth sounding is performed using echo-sounders, with single beam echo-sounders providing depth at a single point while multi-beam echo-sounders can map a swath of sea floor.

1. HYDROGRAPHIC
SURVEYING
LECTURE 2:
BASIC MEASUREMENTS AND EQUIPMENTS
BY: AHMED YASSER AHMED MOHAMED NASSAR
SECTION: 1 ID:20

2. HYDROGRAPHIC
SURVEYING
MAJOR
COMPONENTS
Marine Vessel
Small Scale
Medium Scale
Regional Scale
Positioning Instrument
Depth Measurement (sounding)
Instrument

3. 1 - Marine Vessel Surveys
Small Scale Medium Scale Regional Scale
Vessel • Oars
• Life Jackets
• Gas Tanks
• Extra Oil
• 10 HP Engine
• 25-65 ft. vessel
• licensed operator
• 65 ft. and larger research vessel
• with competent crew and equipment
Depth and
Position
• 50’ leadline
• Range poles
• Plans
• Total station
• Prism pole with extension rods
• fathometer and transducer (for deep
water)
• Echo sounder
• tool box
• Transducers
• GPS or TSI
• motion reference units (MRU).
• Multi-beam transducer
• GPS
Miscellaneous
(Others)
• Radio
• 300 ft. tape
• Navigation Chart
• Staff sheets
• 2 Batteries
• Repair kits
• Tool box
• A small vessel for the near-shore
shallow water survey system
• Cameras for stereo imaging
• Integrated multi-disciplinary data collection systems
• requires accurate in-ship surveys for sensor integration,
calibration, and synchronization.

4. Different Sizes of Vessels
Small vessel Medium Vessel Large research vessel

5. Comparison Between Lead-line and Range
Pole
Ranging

6. Echo-Sounders

7. 2 – Positioning Instrument
• Modern methods
• Land-based electronic ranging
• Space-based positioning
Basic positioning method is Resection.
Positioning method is changing with the
change in project specifications and site
conditions
Preferred method for positioning offshore
surveys is GPS
• Traditional instruments
• Sextant
• Transit
• Stadia
• EDM

8. GPS
POSITIONING

9. 3 – Depth Sounding Instrument
1. Transducer send a sonic pulse to sea floor.
2. Sonic pulse (sound wave) propagates, hits the
sea floor and starts to reflect.
3. Receiver detect the returned pulses (waves)
Note that the pulse take the distance forth-and-
back, so with known the time of the pulse and the
sound speed we can calculate the Depth by the
relation:
2 ∗ 𝐷𝑒𝑝𝑡ℎ = 𝑡𝑖𝑚𝑒 ∗ 𝑠𝑝𝑒𝑒𝑑

10. 3 – Depth Sounding Instrument
Single beam echo-sounder Multi beam echo-sounder

11. THANKS