Raymarine RV-220 RealVision 3D Bronze Thru-Hull Pair 20°

The Raymarine RV-220 is a PAIR of RealVision 3D bronze thru-hull transducers - one for the port side, one for the starboard side - delivering full 180-degree underwater coverage with all four Raymarine sonar technologies in one professional through-hull installation. For owners of inboard or outboard powerboats 25-40 ft with hull deadrise angles in the 13-20 degree range who want the cleanest possible RealVision 3D sonar performance and don't want the limitations of transom-mount transducers, the RV-220 pair is the right answer.

Why a PAIR of transducers instead of one. Single-transducer through-hull installations work for boats with shallow keels and minimal underwater protrusions - the transducer sees a full 180-degree underwater field of view from a single centerline mount. But for boats with: deep keels (the keel blocks part of the side-scanning view), prop tunnels (the tunnel creates dead zones), strakes or running pads (extensions of the hull surface that block side-scanning views), the single-transducer view has dead zones where you can't see what's below or to the side. The PAIR configuration solves this: the port transducer mounts on the port side of the hull and sees port-and-down, the starboard transducer mounts on the starboard side and sees starboard-and-down. Combined, you get a clean 180-degree view with no dead zones - the keel or other obstructions are out of the sonar's working field of view for each individual transducer. For serious offshore sportfishing where you need complete sonar visibility, the pair configuration delivers what a single transducer can't.

20-degree deadrise compensation - what it means. Boats have a hull 'deadrise' angle - the angle between the hull's bottom and a horizontal plane. Flat-bottomed boats have 0 degrees. Mild V-hull boats have 10-15 degrees. Deep-V offshore boats have 18-24 degrees. For thru-hull transducers to point straight down at the water (regardless of hull angle), the transducer body needs to be angled to compensate for the hull deadrise. The 'RV-220 20-degree' variant has an internal offset that compensates for deadrise angles from 13 to 20 degrees - the typical range for most modern V-hull powerboats. Without proper deadrise compensation, the transducer points at an angle off-vertical, distorting sonar imagery and reducing performance. Verify your hull deadrise before purchase - for boats outside the 13-20 degree range, different RV-200 series variants are available (different deadrise compensations).

Four sonar technologies in one transducer. Each RV-220 transducer is 4-channel - delivers all four Raymarine sonar technologies through a single transducer unit (per side): (1) High-frequency CHIRP traditional 2D sonar (fish arches, thermoclines, bottom hardness, depth contour - the standard sonar view), (2) DownVision down-scanning sonar (photographic-quality detail of bottom and structure directly below the boat - shows individual rocks, brush piles, isolated fish vs the abstract 'fish arch' view of traditional sonar), (3) SideVision side-scanning sonar (wide swath to each side - shows what's off to the sides of the boat as you move, finding structure without driving over it), and (4) RealVision 3D sonar (the breakthrough true-3D underwater imaging that builds a real 3D model of the underwater environment that you can rotate and view from any angle on the chartplotter). All four sonar views simultaneously on compatible Raymarine chartplotters.

RealVision 3D - what's different. Traditional sonar shows 2D images (depth vs time as the boat moves). Side-scanning and down-scanning sonars show 2D images with photographic-quality detail. RealVision 3D builds a true 3D model of the underwater environment - structure, bottom topography, and fish are rendered as 3D objects in space. You can rotate the view on the chartplotter to see structure from any angle, zoom in to inspect detail, and visualize fish position relative to structure in 3D space. For locating fish on isolated structure (a single rock pile in a flat bottom, a submerged tree in a lake, an offshore wreck on flat sand), RealVision 3D shows the structure-fish relationship in ways 2D sonar can't.

Built-in AHRS - critical for 3D imagery. The Attitude and Heading Reference System (AHRS) is a small inertial sensor inside the transducer that constantly monitors the boat's pitch (bow up / down), roll (lean port / starboard), and yaw (heading change). The 3D sonar processing uses the AHRS data to compensate for boat motion - so the 3D imagery stays stable and accurate even as the boat moves in waves, swells, and during maneuvering. Without AHRS, 3D sonar imagery distorts every time the boat moves - you'd see false structure, ghost fish, and unreliable returns. The integrated AHRS is the reason RealVision 3D actually works in real-world boating conditions vs being a marketing gimmick that only works in calm water.

Bronze through-hull body. The transducer body is cast bronze - the standard material for permanent through-hull marine installations. Bronze tolerates the marine environment indefinitely (no corrosion concerns, no UV degradation, no impact damage from minor underwater debris), and it's the material expected by hull insurance and survey requirements for through-hull installations. Suitable for fiberglass and wood hulls (not aluminum - galvanic corrosion concerns between bronze and aluminum require insulating bushings or different transducer material).

Low-profile near-flush design. The RV-220 body extends only minimally below the hull surface - much less than older through-hull transducers that protrude significantly into the water flow. Practical benefits: minimal drag (no measurable boat speed loss from the transducer), no cavitation at speed (the transducer doesn't disturb the smooth water flow under the hull), works fine on trailered boats (low profile means less likelihood of damage during trailering, beach launches, and shallow-water grounding), and no fairing block required (older through-hulls needed a custom-cut wood or epoxy fairing block to compensate for hull deadrise - the RV-220 has the deadrise compensation built in, so no fairing block is needed).

What's in the box. Complete pair kit: RV-220P bronze port transducer with 2-meter pigtail cable, RV-220S bronze starboard transducer with 2-meter pigtail cable, RealVision 3D Y-cable (combines the two transducer feeds into a single chartplotter input), RealVision 3D 8-meter extension cable (extends the combined cable run to the chartplotter), anti-rotation bolts and mounting hardware, and installation instructions. Total cable run from transducer to chartplotter: 10 meters (33 feet) - handles typical helm distances on boats up to 40 ft. Cable plugs into RealVision 3D-compatible Raymarine chartplotters (Axiom, Axiom Pro, Axiom XL series).

Install considerations - through-hull is a serious project. Through-hull transducer installation is isn't a typical DIY project - it requires cutting two holes in the boat's hull below the waterline, accurate transducer alignment, proper sealing with marine bedding compound, anti-rotation features to prevent the transducer from spinning under wave loads, and post-install testing for leaks before launching. For most owners, the install is best done by a marine technician with through-hull experience, typically at haul-out during scheduled bottom work. Plan for $400-800 in installation labor (varies by region and boat type) plus the transducer cost. For owners with hauled-out boats and prior through-hull experience, DIY install is possible - read the installation manual thoroughly, allow plenty of time for proper bedding cure, and test the installation for leaks at least 24 hours before launching. Improper through-hull install can sink a boat - this is one of the rare marine installs where DIY skill level needs to be very high.