CYG1413 — Underwater Free-Field Pressure Transmitter

CYG1413 Underwater Free-Field Pressure Transmitter: Underwater Explosion Measurement

Sealed underwater transmitter for low-distortion shock-wave capture in underwater explosion (UNDEX) testing. 20 to 100 MPa range, 450–1000 kHz natural frequency, 0.2–0.3 µs rise time. Cavity-less flush diaphragm, waterproof housing and sealed cable, amplified 0–5 V output. Anti-IR optical option.

100 MPa
Top of Range
1000 kHz
Natural Freq Peak
0.2 µs
Rise Time
Φ8 mm
Probe Head Diameter
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CYG1413 underwater free-field pressure transmitter for underwater explosion shock-wave measurement

What an Underwater Free-Field Transmitter Is

A free-field transmitter reads a pressure wave as it travels through the surrounding medium, with nothing nearby for it to bounce off. Suspended in open water on its cable, the CYG1413 lets the underwater shock wave wash over a flush diaphragm, so you read the incident pulse rather than a version reshaped by a tank wall, the bottom, or the free surface.

The CYG1413 is the underwater member of the CYG400 piezoresistive dynamic pressure family. It seals the cavity-less MEMS sensing element and its amplifier into a waterproof 195 × 132 mm housing with a sealed cable, so the unit survives immersion while keeping the diaphragm flush to the water. There is no trapped cavity to ring and smear the rising edge of the shock.

Four ranges, 20 to 100 MPa, cover underwater explosion work: charge tests in ponds and tanks, ship-shock trials, and underwater shaped-charge research. For free-field blast in air rather than water, use the CYG412 high-pressure free-field sensor, which shares these ranges in a teardrop probe form.

CYG1413 Technical Specifications

GroupParameterValue
SensingTechnologyMEMS piezoresistive silicon strain bridge
DiaphragmStainless steel, fully flush, cavity-less
Anti-light interferenceAnti-IR optical coating (option F4)
Range & SpeedRange span20 / 40 / 60 / 100 MPa
Natural frequency450 / 600 / 800 / 1000 kHz (range-matched)
Rise time0.3 µs (20–40 MPa); 0.2 µs (60–100 MPa)
AccuracyTransmitter accuracy0.5% / 1.0% FS (selectable)
Non-linearity±0.5% … ±1% FS
Temperature driftZero 0.02–0.05 %FS/°C; sensitivity 0.02–0.05 %FS/°C
Power & OutputPower±15 VDC
OutputAmplified 0–5 V
MechanicalHousing formSealed underwater housing 195 mm × 132 mm, with waterproof cable
DeploymentCable-suspended; sealed gland, waterproof cable
Wetted materialWater (silicon + stainless steel diaphragm)
EnvironmentOperating temp0 to +50°C (in water)
Compensated temp0 to +50°C

Range Selection: Four Ranges, One Underwater Housing

The CYG1413 ships in four ranges. The housing, cable, and rise time stay the same across all of them; only the sensing element changes with range. Pick the one whose full scale sits about 30 to 50% above your expected peak. That leaves headroom without throwing away bridge sensitivity.

RangeNatural frequencyRise timeTypical event
0–20 MPa450 kHz0.3 µsNear-field shock in water, small underwater charge
0–40 MPa600 kHz0.3 µsClose-in underwater detonation, ship-shock trials
0–60 MPa800 kHz0.2 µsStrong underwater reflected shock, hull loading
0–100 MPa1000 kHz0.2 µsPeak underwater explosion, mine and torpedo testing

At 60 and 100 MPa the natural frequency climbs to 800 and 1000 kHz and the rise time tightens to 0.2 µs, so even the fastest underwater shock transients still register on the rising edge. For blast in air rather than water, the CYG412 free-field sensor shares these ranges in a teardrop probe form.

Where the CYG1413 Is Used

The 20–100 MPa band is built for one job: near-field, high-energy detonation. Peak pressure runs into the tens of MPa, and the rising edge lands somewhere between a few tenths of a microsecond and a microsecond.

Underwater Explosion (UNDEX)

Free-field shock-wave profiles from underwater charges in ponds, tanks, and open water, where the unit reads the incident pressure pulse before bottom or surface reflection arrives.

Ship-Shock & Naval Trials

Hull and onboard-equipment shock qualification against underwater detonation, where peak pressures reach tens of MPa with sub-microsecond rise.

Underwater Shaped-Charge

Close-in underwater shaped-charge and warhead characterization, where confined peak pressures reach 40–100 MPa over sub-microsecond rise times.

Mine & Torpedo Testing

Pressure-field mapping around underwater ordnance detonation for lethality, standoff, and protective-design studies.

Bubble-Pulse & Cavitation

Capturing the primary shock and the bubble-pulse train from an underwater explosion for energy-partition and cavitation analysis.

Subsea Structure Loading

Reflected and diffracted underwater blast loading on subsea structures, platforms, and protective barriers in the 20–100 MPa range.

Deployment: Underwater Placement and Sealing

An underwater transmitter only reads cleanly if you place, seal, and reference it right. Three rules cover most UNDEX test setups.

Face orientation. Point the diaphragm face toward the charge. The sealed housing takes the wavefront square on the diaphragm with the body trailing, which keeps diffraction and reflection off the face. Past about 15° off-axis, peak amplitude starts to read low by an angle-dependent amount.

Sealed deployment. Suspend the unit on its waterproof cable from a rigid frame, boom, or buoy at the test depth, and stop it swinging. Check the cable gland and housing seal before every immersion. Route the cable clear of the line between the unit and the charge so cable motion does not read back as noise.

Standoff and depth. Fix the radial standoff and the water depth precisely and log both with the shot. Underwater peak pressure falls off steeply with distance, so a 10% error in standoff turns into a 20-30% error in pressure. Take a hydrostatic zero at depth before the event so the dynamic record sits on a known baseline.

CYG1413 Ordering Code

Standard order format:

CYG1413 <range> <accuracy> <cable> <anti-IR> <custom>

SegmentCodeMeaning
Range20 / 40 / 60 / 100Full-scale value in MPa
AccuracyP4 / P50.5% / 1.0% FS
CableC1 / CSWaterproof direct cable / double-shielded waterproof anti-interference cable
Anti-IRF4Anti-IR optical coating (for line-of-sight to the detonation flash)
CustomQCustom cable length, sealing depth, or housing configuration

Worked example: CYG1413 60 P4 CS F4 Q — 0–60 MPa range, 0.5% accuracy, double-shielded waterproof cable, anti-IR optical coating, custom 25 m cable length per attached sheet.

CYG1413 FAQ

Free-field underwater measurement captures the shock wave as it moves through the water, with nothing nearby for it to bounce off. The sealed unit hangs in the wave path on its cable and the wave passes over a flush diaphragm, so you read the incident pulse rather than a version reshaped by the tank wall, the bottom, or the surface.

The cavity-less MEMS element and its amplifier sit inside a waterproof 195 × 132 mm housing, and the cable enters through a sealed gland. Only the flush stainless diaphragm meets the water. Check the gland and seal before every immersion; the housing keeps the electronics dry while the diaphragm reads the shock directly.

Estimate your event’s peak, then choose the range whose full scale sits about 30 to 50% above it. That leaves headroom for shot-to-shot variation without giving up bridge sensitivity. When the peak straddles two ranges across a test matrix, oversize slightly rather than risk clipping.

Water absorbs the infrared flash quickly, so for most underwater shots the IR pulse fades before it reaches the diaphragm. If the unit sits close to the charge with a near-direct line to the detonation flash, add the F4 anti-IR option. Its chip-level optical coating stops the IR pulse before it can saturate the silicon junction and clip the rising edge.

Suspend it on its waterproof cable from a rigid frame or boom at the test depth, stop it swinging, and point the diaphragm face at the charge within about 15°. Verify the cable gland and seal before immersion, and keep the cable clear of the unit-to-charge line so cable motion does not read back as noise.

Use the CYG412 when the blast is in air rather than water. It shares the CYG1413 ranges (20–100 MPa, 450–1000 kHz, 0.2–0.3 µs) in a teardrop probe form for free-field air blast. The CYG1413 is the sealed underwater version for the same pressures in water. For lower underwater pressures, ask about the matching low- and medium-pressure free-field members.

Technical Support

Three background guides for engineers specifying or commissioning a CYG1413 underwater transmitter. Open in a new tab; the deep-dives complement the spec-and-selection focus of this page.

Ready to Specify a CYG1413?

Send us the expected peak amplitude, the standoff distance and water depth, and the cable length you need. Our pressure-instrument engineers will reply with a CYG1413 range, ordering code, and lead time.

Our engineers usually reply within 12 business hours.

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