Airmar R111C-LM 2kW CHIRP In-Hull Low/Medium Transducer
Airmar R111C-LM 2kW CHIRP In-Hull Low/Medium Transducer — Product description
Airmar's 2kW CHIRP-ready in-hull transducer in the Low/Medium configuration, built for offshore deep-water fishing where the captain doesn't want to cut a hole in the hull. Shoot-through-fiberglass design with a tank that bonds inside the hull, urethane potted housing, and dual-band coverage from 38 to 75 kHz on the low side and 80 to 130 kHz on the medium side. 87 kHz of total bandwidth from one transducer, with 19-to-10-degree low beam and 13-to-8-degree medium beam.
The R111C-LM is Airmar's CHIRP-ready in-hull transducer in the Low/Medium dual-band configuration. The in-hull approach is what separates this SKU from the thru-hull and pocket-mount variants of similar Airmar elements. Rather than cutting a hole in the hull and bedding a transducer into the water, the in-hull design uses a tank that bonds permanently inside a solid-fiberglass hull. The acoustic signal shoots through the hull material itself, with an epoxy or urethane acoustic window between the transducer face and the hull. The advantage is no hole in the boat, which on a high-value cruising or sport-fishing yacht is worth the small acoustic trade-off. The constraint is that the hull has to be solid fiberglass with no coring, no glass-on-foam construction, and no metal interfering with the signal path.
The L/M dual-band designation tells you what frequency ranges the transducer covers. The low element CHIRPS from 38 to 75 kHz with a 19-degree-to-10-degree beamwidth as the frequency sweeps. That low band is where deep-water tracking lives. Long wavelengths penetrate the thermocline and reach the bottom in 5,000-foot canyon edges where higher frequencies lose the picture. The medium element CHIRPS from 80 to 130 kHz with a 13-degree-to-8-degree beamwidth. Medium frequencies give you better target separation and resolution in moderate depths, and the 80-130 kHz band covers the historically popular 88 kHz and 107 kHz frequencies that older sounders default to. Total usable bandwidth across both elements is 87 kHz, which gives a modern CHIRP-ready sounder enough range to dial the optimal frequency for whatever depth and target you're working.
For comparison, this transducer specifically targets the offshore deep-water fishing profile. Recreational and commercial captains chasing canyon-edge tuna, swordfish at depth, sea-mount tracking, and other applications where the bottom is deeper than what a single-element 1kW transducer can reach. If you're inshore fishing in 200 feet of water and looking for fish-arch detection, this is too much transducer. The CHIRP-ready dual-band design also pays off when you're working at different depths through the day. You can set the sounder to sweep the low band on one channel and the medium band on a second channel, displaying both at once. The low channel gives you the deep-water picture. The medium channel gives you the higher-resolution shallow picture. Most modern 2kW sounder modules support this dual-display configuration natively.
The in-hull tank is included with the transducer in the box, along with all the mounting hardware needed for the install. The tank itself bonds to the inside of the hull with an epoxy fillet and the transducer slides into the tank, suspended in mineral oil or distilled water for acoustic coupling between the transducer and the hull. The fluid coupling is what makes the in-hull design work. Without it, air gaps and uneven hull contact would scatter the signal. The 19.7 kg (43.4 lb) weight is substantial because the tank is heavy enough to hold the fluid coupling and damp acoustic interference. The transducer accommodates hull deadrise angles from 0 to 22 degrees, which covers most modern sportfish and trawler hulls. Steeper deadrise hulls need a different configuration. Patented Xducer ID auto-detect tells compatible chartplotters which transducer is installed so the sounder loads the right calibration tables without manual setup.
One important install note. Because the in-hull tank bonds permanently to the hull interior, the transducer location is more or less permanent once the install is done. Pick the location carefully with consideration for hull geometry, internal access for service, and water flow at the hull skin (turbulent water flow distorts the signal even through the hull). A marine electronics installer with experience on in-hull tanks is the right person for the job, not a DIY weekend install. The fluid coupling also needs occasional service (top-off, replacement) over the years, so plan on access to the tank for routine maintenance. Note from the manufacturer: this product cannot be returned to the original point of purchase. Warranty service goes through the manufacturer directly.
Key Features
- CHIRP-ready dual-band Low/Medium transducer with 2 kW power rating
- Low element: 38-75 kHz with 19-to-10-degree beamwidth
- Medium element: 80-130 kHz with 13-to-8-degree beamwidth
- 87 kHz total usable bandwidth across both elements
- Covers popular fishing frequencies including 38, 50, 88, and 107 kHz
- In-hull (shoot-through) configuration, no hole cut in the hull
- Solid-fiberglass hull only, not compatible with cored or metal hulls
- Hull deadrise compatibility 0 to 22 degrees
- Tank with epoxy/urethane acoustic window included
- All mounting hardware including the tank ships in the box
- Urethane potted transducer housing
- Depth + fast-response water temperature sensing
- Patented Xducer ID auto-detect technology for compatible chartplotters
- Designed for offshore deep-water fishing (canyon, sea-mount, deep-drop)
- 19.7 kg (43.4 lb) housing
Why Buy from NVN Marine
- Authorized Airmar reseller, full manufacturer warranty
- NMEA member and ABYC certified, advice from real boat techs
- Same-day shipping before 3 PM ET on in-stock items
- NY headquarters and Fort Lauderdale flagship retail store
In-hull tank installs are permanent and need a careful location pick before bonding. Tell us your hull layup (solid fiberglass, cored, or metal), the boat make/model, and your planned sounder module. We'll confirm the R111C-LM is the right configuration vs the thru-hull or pocket-mount variants of similar Airmar elements before you order. We can also recommend an installer in your area for the tank bonding work.
Technical specifications
| Title | Airmar R111C-LM 2kW CHIRP In-Hull Low/Medium Transducer |
|---|---|
| Manufacturer Part Number | R111C-LM |
| Brand | Airmar |
| UPC | Not assigned |
| Type | In-hull (shoot-through) CHIRP-ready dual-band transducer |
| Frequency Band | Low + Medium |
| Low Frequency | 38 to 75 kHz |
| Low Frequency Beamwidth | 19 to 10 degrees |
| Medium Frequency | 80 to 130 kHz |
| Medium Frequency Beamwidth | 13 to 8 degrees |
| Total Bandwidth | 87 kHz |
| Power Rating | 2 kilowatts |
| Hull Type | Solid fiberglass only |
| Hull Deadrise | 0 to 22 degrees |
| Acoustic Window | Epoxy or urethane |
| Housing | Urethane potted |
| Mounting Hardware | Tank and mounting hardware included |
| Additional Sensing | Depth and fast-response water temperature |
| Auto-Detect | Patented Xducer ID technology |
| Common Use | Offshore deep-water fishing (canyon, sea-mount, deep-drop) |
| Weight | 43.4 pounds (19.7 kg) |
| Returns | Not returnable to original point of purchase per manufacturer |
Frequently asked questions
What does in-hull mean and how does it differ from thru-hull?
An in-hull (sometimes called shoot-through) transducer bonds permanently inside the hull. The acoustic signal travels through the hull material itself to reach the water. There's no hole cut through the hull. A thru-hull transducer punches through the hull and sits in direct contact with the water outside the boat. In-hull is what you pick when you can't or don't want to cut a hole. Thru-hull is what you pick for the best acoustic performance and the most flexibility on hull material.
What hull types work with this transducer?
Solid fiberglass only. The signal path needs uniform hull material for clean acoustic transmission. Cored fiberglass (with foam, balsa, or other core material), aluminum, or steel hulls won't work because the core or metal will scatter and absorb the signal. For cored or metal hulls, the thru-hull or pocket-mount variants of similar Airmar elements are the right alternatives.
What's the L/M designation mean?
Low and Medium frequency bands. The low element CHIRPS from 38 to 75 kHz, optimized for deep-water work down to canyon edges and sea-mounts. The medium element CHIRPS from 80 to 130 kHz, optimized for moderate-depth resolution and fish-arch detection. Pairing both in one transducer lets you cover deep and mid-range applications without swapping hardware. For shallow-water work and very high-frequency imaging, the L/H (Low/High) variants of similar elements are the right alternatives.
What sounder module do I need?
A 2 kW (or higher) CHIRP-capable sounder module from one of the major marine electronics brands. The transducer's bandwidth covers 38-130 kHz across both elements, so the sounder module needs to support that band. Most current commercial-grade 2-3 kW black-box sounder modules from the leading marine electronics brands will pair correctly. Tell us your sounder model and we'll confirm before you order.
How deep can it actually see?
Practical depth depends on bottom hardness, hull condition, thermocline, and sounder module power. On a clean install over hard bottom with a 2 kW sounder, the low band typically holds the picture out to 4,000-5,000 feet. The medium band holds resolution past 1,500-2,000 feet. In-hull installs typically lose 10-15 percent of effective depth compared to a thru-hull of the same element because the signal passes through hull material, so factor that into expectations.
How permanent is the install?
Effectively permanent. The tank bonds to the hull interior with an epoxy fillet. Removing it later requires grinding the epoxy bond off the hull, which damages the gelcoat or interior finish. Pick the install location carefully because once it's bonded, it stays. A marine electronics installer with in-hull tank experience is the right person for the install.
Does the tank need maintenance?
Yes, occasionally. The fluid coupling (mineral oil or distilled water) between the transducer and the tank can evaporate slowly over the years and may need topping off. Some installers also replace the fluid every 5-10 years to keep the acoustic coupling fresh. Plan on tank access for routine service. The original installer will typically include a service note about access and fluid type.
What boat size is it sized for?
Offshore sport-fishing and cruising boats, typically 35 feet and larger, where the deep-water fishing profile matches the transducer's capability. Smaller boats usually don't need (or have helm room for) the 2 kW sounder module that drives this transducer.
Is the temperature sensor included?
Yes. Built-in fast-response water temperature sensor reads through the hull and reports to the sounder module through the same transducer cable. Most modern sounder modules and chartplotters will pick up the temperature reading automatically.
What's the warranty?
Standard manufacturer transducer warranty. Coverage details are in the documentation. Note from the manufacturer: this product cannot be returned to the original point of purchase. Warranty service goes through the manufacturer directly. We'll help coordinate warranty issues if needed.
