On Friday, July 26, 2024, the GROM Military Unit (JW GROM) announced that it had awarded a contract worth 676,500 PLN (approximately 174,672 USD) to Griffin Group Defence from Warsaw for the delivery of two towed side-scan sonars.
Sonar holowany ARC Explorer Mk II / Zdjęcie: Marine Sonic Technology
According to the tender documentation, an open procedure for this matter was announced on May 17, 2024. The only selection criterion for the offer was price (100%). The bids were opened on June 13. Griffin Group Defence was the sole bidder, and its offer met the requirements, scoring 100 points, which led to its selection on July 8. The corresponding contract was signed on July 23. The delivery must be completed within 90 days from the contract date but no later than October 31 of this year (JW GROM has also commissioned PZL Mielec for the maintenance of Black Hawks).
According to the technical specifications of the order, the towed side-scan sonar is designed to provide real-time imaging of the seabed structure at depths of up to 70 meters to detect and identify small underwater objects lying on the seabed. The sonar is adapted for use with a RIB-type combat boat by a maximum of two crew members and can be easily mounted or transferred to another boat.
The equipment set includes:
- Laptop with software;
- External GPS/GLONASS antenna;
- Towed sonar weighing up to 25 kg, operating in CHIRP or Adaptive CHIRP technology, dual-frequency (Low Frequency LF – 600-900 kHz with an imaging range of at least 80 m; High Frequency HF – 1200-1800 kHz with an imaging range of at least 25 m);
- Tow cable (two sections – a longer one with a minimum length of 100 m and a shorter one with a length of 25 m);
- Electric winch with a control device;
- User manual.
Griffin Group Defence offers the ARC Explorer Mk II towed sonars from the American company Marine Sonic Technology (Atlas North America), based in Yorktown, Virginia.
The ARC Explorer Mk II is the latest generation of towed side-scan sonar designed for searching and surveying bodies of water during search, rescue, and recovery operations. The Adaptive CHIRP technology used in this sonar provides high-quality imaging. Its high-resolution imaging and simultaneous operation at two frequencies, combined with a durable construction and the ability to operate at depths of up to 300 meters in a portable system operated by just one person, make it an ideal tool for search and rescue services as well as security agencies.
The Sea Scan ARC Explorer Mk II system consists of a sonar (TowFish) with a stainless steel hull, Kevlar-reinforced tow cable, waterproof processor unit, and a rugged portable computer. Depending on the needs and tasks of the user, two standard dual-frequency options are available. The 600kHz/1200kHz option offers an ideal compromise between long-range and high-resolution sonar capabilities, while the 900kHz/1800kHz option is optimized for applications requiring ultra-high-resolution images and the detection of very small objects in the first pass, minimizing both operational time and costs.
The ARC Explorer Mk II uses simultaneous dual-frequency scanning with a user-selectable maximum range defined for each frequency. The integrated adjustable tow point and the ability to adjust the transducer’s tilt angle are particularly important for conducting surveys of bridges, piers, port quay walls, and offshore platforms, as well as assessing the condition of the underwater sections of vessel hulls. The ARC Explorer Mk II is equipped with a built-in safety system that includes a mechanism to prevent the loss of the towed sonar if it becomes obstructed by an underwater obstacle.