Pack of two B175 D/T Low-High 20° through-hull transducers

The designation "Low-High 20 deg" breaks down as follows:

Low-High: Indicates that the pack contains two separate transducers. One is optimized for low frequencies (Low CHIRP) for better penetration in deep water, and the other for high frequencies (High CHIRP), providing superior resolution for target and structure detection in shallower waters.20 deg: Refers to the internal tilt angle of the transducer. This angle is designed to compensate for the deadrise angle of your boat's hull, specifically for hulls with a deadrise between 16 and 24 degrees. This ensures the transducer beam is directed vertically toward the seabed for optimal performance without requiring an external fairing block.

CHIRP (Compressed High-Intensity Radiated Pulse) technology offers several significant advantages over traditional fixed-frequency fishfinders:

Superior target separation: Enables clearer distinction between individual fish or closely spaced objects.Improved clarity: Echo returns are sharper, providing a more detailed image of the seabed and underwater structures.Increased depth range: Ability to detect the bottom and targets at greater depths.Reduced noise: Minimizes interference and noise for cleaner readings.

The pack includes two transducers for optimal coverage and maximum versatility:

The Low CHIRP transducer operates on a low-frequency band. It is ideal for deep-water detection, providing excellent penetration and the ability to track the seabed even at great depths. It is also highly effective for identifying thermoclines.

The High CHIRP transducer scans a higher-frequency band. It excels in shallow-water detection, delivering superior target resolution, which is crucial for distinguishing individual fish, seabed structures, and wreck details.

These B175 through-hull transducers with a 20-degree tilt angle are specifically designed for boat hulls with a deadrise angle between 16 and 24 degrees. It is crucial to know your hull's deadrise angle to ensure the transducer beam is directed vertically toward the seabed. Installing on a hull with a deadrise outside this range may result in suboptimal fishfinder performance. This information is typically found in your boat's technical specifications or by measuring it.

The "D/T" designation indicates that the sounders can simultaneously measure and transmit two key types of data:

D for Depth: The primary capability of the sounder to measure the distance between the transducer and the seabed.T for Temperature: The ability to measure water temperature at the sounder's location.These data are essential for navigation, fishing, and understanding marine conditions.

These transducers are designed to be compatible with Raymarine sounder systems that support CHIRP technology. This typically includes multifunction displays and latest-generation sounder modules from Raymarine. For specific compatibility, it is recommended to verify that your Raymarine equipment has an integrated or external CHIRP sounder module capable of handling wide-band CHIRP transducers.

Through-hull installation, where the transducer is mounted through the boat's hull, offers several key advantages:

Optimal performance: The transducer is in direct contact with the water, minimizing turbulence and interference for clearer and more accurate readings, even at high speeds.
Signal stability: Less susceptible to air bubbles or water disturbances, which are common with transom-mounted installations.
No external compensation block: The internal 20-degree tilt angle compensates for the hull angle, eliminating the need for a bulky external fairing block.
Durability: Less exposed to shocks or accidental damage than transom-mounted transducers.

The T70075 pack specifically includes two B175 D/T through-hull transducers. One is a Low CHIRP transducer and the other is a High CHIRP transducer, each with an internal 20-degree tilt angle and the ability to measure depth and temperature. The required connection cables to link the transducers to your Raymarine system are integrated into the transducers, and standard mounting hardware for through-hull installation is included.