SDT Sherlog TA - Ultrasound Detector for Hatch Tightness Testing (Discontinued)

Overview

The SDT Sherlog TA was a stand-alone ultrasound detector and multi-transmitter that SDT International launched in 2000 as the world's first class-society-certified solution for ultrasonic tightness testing of ship hatch covers. Sherlog wasn't a piece of software or a later rebrand — it was a separate instrument line (Sherlog S, Sherlog TA) that predates today's combination of "SDT270/SDT340 detector + HATCHecker sensor + SHERLOGReporter software."

This model has been discontinued. Type approvals for SDT-manufactured Sherlog units remained valid through June 2011, after which the manufacturer formally retired the Sherlog 200/270 line (a transitional version built on the SDT270 platform). The current replacement is the HATCHecker kit (a dedicated hatch-cover sensor) built on either the SDT270 or SDT340 detector, with reporting handled by SHERLOGReporter.

Key features

A self-contained kit

• Sherlog TA detector — a handheld unit with an LCD, a built-in ultrasound sensor and a connector for external sensors
• SDT 8 multi-transmitter — 8 emitters at 125 mW each, stabilized at 39.2/39.6 kHz (bi-sonic mode), generating a reference ultrasound signal inside the cargo hold
• 820 mm flexible sensor — access to hard-to-reach spots around the hatch perimeter

Tightness testing

• Source-receiver method — the transmitter is placed inside the closed hold, the detector scans the perimeter seam from outside
• Tamper-proof routes — a predefined sequence of inspection points with a timestamped, non-editable result
• 1,000-location memory — 4 storage positions per point, for ultrasonic and non-ultrasonic readings

Data and certification

• RS232 — data transfer to PC
• Certification — the instrument shipped with class society type approvals (DNV, Lloyd's Register) for use during surveys

Technical specifications

Parameter	Description
Function	Multifunction detector + multi-transmitter
Display	Backlit graphic LCD
Keyboard	8 function keys
Built-in ultrasound sensor	Open type, 40 kHz ± 1 kHz, sensitivity -65 dB/V/µBar
Flexible sensor	820 mm, 40 kHz ± 1 kHz, sensitivity -70 dB/V/µBar
External sensors	7-pin Lemo connector, ultrasonic and non-ultrasonic
Memory	1,000 points × 4 positions, tamper-proof hatch-round software
Communication	RS232, 19.2 kBaud
Battery	NiMH, 7.2 V, 1500 mAh, 8-10 hours, 500-1,000 charge cycles
Housing	Extruded aluminium
Weight	750 g (with battery and holster)
Dimensions	225 × 90 × 40 mm
Headphones	130 dB, noise isolating
SDT 8 multi-transmitter	8 emitters × 125 mW, 39.2/39.6 kHz, 240° dispersion
Operating temperature	-15°C to +60°C

Why the model was discontinued

SDT moved the Sherlog function onto its shared detector platform: instead of a dedicated stand-alone instrument, today's setup uses a general-purpose detector — SDT270 or SDT340 — that also covers mechanical diagnostics, leaks, electrical faults, steam traps and other predictive-maintenance tasks, paired with the HATCHecker sensor tailored to hatch-cover geometry. Reporting and class-society compliance are handled by SHERLOGReporter, which inherited the original Sherlog's name and purpose.

What to choose instead of Sherlog TA

• HATCHecker — a dedicated sensor for hatch cover and cargo hold tightness testing, the direct functional successor
• SDT270 / SDT340 — general-purpose detector platforms that HATCHecker connects to (replacing the stand-alone Sherlog TA detector)
• SHERLOGReporter — reporting software for hatch tightness testing in class-society formats (replacing the tamper-proof software and RS232 transfer)

Support for this discontinued model

• Repair and calibration of previously purchased Sherlog TA units remains available through SDT's authorized service centres
• Type approvals for Sherlog units manufactured through June 2011 are on record in the manufacturer's certificate archive
• For new purchases and to continue a survey programme, migrating to the SDT270/SDT340 + HATCHecker + SHERLOGReporter combination is recommended