Free tools Windows power users keep installed
One-click scans. No signup required.
For the first search pass, side-scan sonar is usually the better choice. It creates a high-contrast acoustic picture in which a wreck’s hard surfaces and shadows stand out from the seabed. Multibeam sonar is the better measurement system: it produces georeferenced depth soundings, least depth and a three-dimensional bathymetric model. A professional wreck survey normally uses both—side scan to detect and recognize a target, then multibeam to measure and chart it.
What each sonar actually measures
The two instruments are often grouped together because both use sound rather than light, but they answer different questions. Side scan asks, “What is lying to either side of the survey track, and what does its acoustic outline look like?” Multibeam asks, “How deep is every measured point beneath the vessel, and what is the shape of the seabed?”
As an Amazon Associate I earn from qualifying purchases.
Side-scan sonar: an acoustic image of the seabed
A side-scan system sends fan-shaped acoustic pulses to both sides of a towfish or hull-mounted transducer. The receiver records the strength of echoes and renders those returns as a two-dimensional image. A raised, hard object such as a hull, mast or engine component reflects strongly. The object also blocks sound from reaching part of the seabed behind it, creating an acoustic shadow. That combination of bright return and dark shadow can reveal the target’s outline, height and orientation far more clearly than a single depth trace.
NOAA notes that “most side scan systems cannot provide any depth information.” The image is therefore a plan view of reflectivity and shadow, not a depth map. Shadow length can suggest that an object stands proud of the bottom, but it is not a substitute for a calibrated depth measurement.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Multibeam sonar: a swath of depth soundings
A multibeam echosounder (MBES) uses a hull-mounted transducer array to transmit many narrow beams in a swath directly beneath the vessel. The system measures the travel time of each beam’s return and converts it into depth. The result is a georeferenced bathymetric surface: a point cloud or grid showing the seabed and anything rising above it. Multibeam data can also include acoustic backscatter, which describes how strongly the bottom reflects sound, but its primary product is measured depth rather than a photographic-looking wreck image.
NOAA’s Office of Coast Survey says typical multibeam coverage is two to four times the water depth. In deeper water, the angular swath can therefore cover a wider strip, although the usable width still depends on beam geometry, water conditions, vessel motion, bottom slope and the survey’s required accuracy.
Which sonar is best for finding a shipwreck?
Use side scan first when the objective is reconnaissance: locating small contacts, recognizing a wreck-like shape and deciding which targets deserve a closer look. A towed fish can be flown close to the bottom, including in deep water, which increases detail and makes shadows more pronounced. The trade-off is that the fish is underwater and its position is less direct to determine than the position of a hull-mounted sensor.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Use multibeam first when the primary requirement is safe navigation, a precise least-clearance value, a complete depth surface or a three-dimensional terrain model. MBES gives depth coverage beneath the vessel and ties each sounding to the survey reference frame. It is particularly useful when the question is whether a wreck is a navigation hazard or exactly how it sits on an irregular seabed.
Use both when the project includes discovery, identification and chart-quality measurement. NOAA’s operational rule is concise: “If surveyors find a wreck or obstruction using side scan sonar, they will determine the least depth with multibeam sonar.” In practice, side scan supplies the efficient visual-style search and multibeam supplies the defensible dimensions and depth.
Side-scan and multibeam compared
| Survey question | Side-scan sonar | Multibeam sonar |
|---|---|---|
| Primary output | Two-dimensional acoustic imagery showing reflectivity and shadows | Georeferenced depth soundings and a three-dimensional bathymetric surface |
| Best use in wreck hunting | Broad detection and target recognition | Least depth, dimensions, seabed shape and charting |
| Typical deployment | Towed fish with transmission cable and topside processing unit; some systems are hull-mounted | Hull-mounted transducer array |
| Depth measurement | Most systems provide no direct depth information | Directly measures depth from acoustic travel time |
| Image character | High-contrast, photographic-like plan view with shadows | Measured terrain model; backscatter may add acoustic texture |
| Frequency examples documented by NOAA | 50–100 kHz for broad, lower-resolution coverage; 500 kHz–1 MHz for narrower, higher-detail coverage | Frequency is not stated in the supplied NOAA material |
| Coverage behavior | Search width is selected by frequency, range and tow height | Typical swath is two to four times water depth |
| Positioning | Towfish position must be computed underwater and is less direct than a hull-mounted sensor | Sensor is fixed to the vessel, simplifying georeferencing and motion compensation |
| Least depth | Not established by the image alone | Can be determined from the depth surface, subject to survey quality and coverage |
| Follow-up needs | Often followed by multibeam for depth and by magnetometer, ROV or diver video for identity and condition | May still need side scan, magnetometer, ROV or diver video to identify material and archaeological details |
How frequency changes a side-scan search
Side-scan frequency is a practical choice between area covered and detail resolved. NOAA Ocean Exploration describes 50–100 kHz systems as suitable for broad coverage at lower image resolution. The lower frequency travels efficiently over a larger range, so each line can inspect more seabed, but small fittings and subtle edges are less distinct.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
The 500 kHz–1 MHz range covers a narrower strip while producing much greater detail. High-frequency imagery can separate closely spaced objects, show plating or appendages and make a short, sharp shadow from a small protrusion. Because the usable range is smaller, the vessel must run more lines to search the same area. The best setting depends on the expected wreck size, depth, seabed texture and the probability that a target is small.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsFrequency does not by itself guarantee a good image. Towfish altitude, vessel speed, pulse settings, seabed relief, water-column noise and correct layback calculations all affect whether the wreck is recognizable. A fish flown too high spreads a small target across fewer pixels and weakens its shadow; one flown too low may reduce the search swath and risk contact with the bottom.
Coverage, resolution and survey speed
Side scan: choose a search width deliberately
Side scan inspects a strip on each side of the track. A 50–100 kHz setup can make a large-area reconnaissance practical, while 500 kHz–1 MHz is chosen when the search area has narrowed or the target is expected to be small. The towfish can be brought close to a deep wreck, improving detail without putting the vessel itself directly over every feature.
The apparent speed advantage can disappear if the search requires very high resolution. Narrower high-frequency ranges mean more parallel lines, and every line must maintain suitable tow height and overlap. A broad first pass followed by focused high-frequency lines is often more efficient than running the entire search at maximum detail.
Multibeam: swath width grows with depth, but quality still governs
MBES collects a continuous set of soundings in a swath under the vessel. NOAA’s typical figure of two to four times water depth describes potential seafloor coverage, not a promise that every outer-beam sounding will meet the same accuracy as the center of the swath. Survey planners account for outer-beam geometry, vessel motion, sound-speed changes and seabed slope when selecting line spacing.
A wide swath can map a large area efficiently, and repeated overlapping lines can improve confidence in a wreck’s least depth and shape. However, a depth grid may show the wreck as a mound or depression without the intuitive outline that a side-scan shadow provides. The two data types are complementary rather than interchangeable.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Georeferencing and positioning differences
A hull-mounted MBES is attached to the vessel’s navigation, motion and heading sensors. Each sounding can therefore be placed directly in the survey coordinate frame after applying the vessel’s position, attitude and sound-speed corrections. This makes it practical to compare the wreck with chart datums, define a least depth and build a repeatable three-dimensional model.
A towed side-scan fish is separated from the vessel by a cable. The vessel’s GPS position is not the fish’s position: cable length, catenary, tow speed, water depth and currents can all create layback. The resulting image can still be highly detailed, but the target’s absolute location is less direct unless the survey uses an appropriate acoustic positioning method and carefully models towfish geometry. This is a major consideration when a contact must be revisited, charted or compared with earlier surveys.
A professional shipwreck-survey workflow
The following sequence follows the way the systems complement one another. It is suitable for a planned hydrographic or archaeological survey; local maritime law, protected-site rules and navigation requirements still apply.
Recommended Free Tools
- Define the search area and target. Estimate the likely depth, wreck length, orientation and the smallest feature that would count as a find. Set a coordinate system, line spacing, speed and overlap before launching the survey.
- Plan towfish altitude and frequency. For a broad reconnaissance, consider the 50–100 kHz range described by NOAA. For a smaller area or a need to resolve fittings and edges, use the 500 kHz–1 MHz range. Set altitude so the expected target produces a usable return and shadow without exceeding the instrument’s practical range.
- Run side-scan search lines. Maintain consistent speed and tow height, record navigation and layback information, and inspect the waterfall or mosaicked imagery for strong returns, shadows, linear debris fields and shapes inconsistent with natural geology.
- Classify and rank contacts. Separate likely wrecks from boulders, outcrops, trawl marks and seabed texture. Record the contact’s apparent dimensions, orientation, shadow direction and confidence, but do not assign a precise least depth from the side-scan image alone.
- Re-survey promising contacts with multibeam. Run lines that cross the target and provide enough overlap to model the surrounding seabed. The resulting soundings establish the wreck’s height above bottom, dimensions, orientation and least depth within the quality of the survey.
- Inspect the three-dimensional surface. Look for hull breaks, collapsed sections, masts, cargo piles and scour around the wreck. Compare the bathymetric shape with the side-scan image; disagreement can reveal positioning errors, a partially buried object or an acoustic artefact.
- Add ground truth when identity or condition matters. A magnetometer can test for ferrous material. ROV or diver video can determine construction, cargo, biological growth and archaeological condition. These sensors answer questions sonar alone cannot settle.
- Document and preserve the evidence. Keep raw files, navigation, sound-speed information, tide or datum references, processing settings and contact reports. A reproducible record is essential if the site is protected, revisited or submitted for charting.
Can multibeam sonar identify a wreck?
Multibeam can reveal a wreck’s position, dimensions, height and relationship to the seabed. A coherent raised shape, scour and a distinctive arrangement of projections may make a wreck recognizable, especially when the model is rendered in shaded relief. It is also the correct instrument for determining the least depth used in navigation decisions.
Identification is not guaranteed, however. MBES measures geometry; it does not normally show the same reflectivity-and-shadow detail as high-frequency side scan. A rocky outcrop, debris pile or partially buried hull can produce a similar elevation pattern. Acoustic backscatter may add material contrast, but it is not proof of a vessel’s identity. Side-scan imagery, historical information, magnetometer data and ROV or diver video may be needed to distinguish a shipwreck from a natural feature.
Does side-scan sonar measure depth?
Usually not. NOAA’s wording is explicit: “most side scan systems cannot provide any depth information.” Side scan records echo strength across a swath. Shadow length can indicate that an object rises above the bottom, and overlapping lines can improve interpretation, but neither provides the calibrated least depth required for a navigation chart.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Some integrated survey systems may combine side-scan imagery with other depth sensors, but that does not change what the side-scan channel itself measures. If an exact depth, clearance or three-dimensional seabed model is required, plan a multibeam or other dedicated bathymetric survey.
The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →When side scan should come first
- The search area is large and the target may be small or visually distinctive.
- You need to compare many contacts quickly before committing time to detailed mapping.
- The water is deep enough that a towed fish can run close to the seabed while the vessel remains safely above it.
- Recognizing outline, shadow and texture is more important initially than obtaining chart-quality depths.
- You can support towfish layback and underwater-position calculations when absolute coordinates matter.
When multibeam should come first
- The immediate risk is navigation: you need least clearance or confirmation that an obstruction does not threaten a route.
- The deliverable is a complete depth surface, contour map or three-dimensional terrain model.
- The wreck’s height, buried portions, scour or surrounding seabed relief are central to the decision.
- The vessel already carries a calibrated hull-mounted MBES and the survey area is compact enough that direct bathymetric coverage is efficient.
Why a combined survey is usually the strongest answer
Side scan and multibeam fail in different ways. Side scan can show a compelling target with uncertain absolute position and no direct depth. Multibeam can place a target precisely and measure it while offering less photographic-style recognition. Running both lets the side-scan contact guide where to spend multibeam time, while the bathymetry tests whether the apparent target is actually elevated, how high it stands and where its shallowest point lies.
Additional sensors close remaining gaps. A magnetometer is valuable when the question is whether a contact contains ferrous material, but a magnetic anomaly alone does not prove that the object is a wreck. ROV or diver video supplies visual ground truth and can assess archaeological condition, biological cover and exposed construction. The appropriate combination depends on whether the project is exploratory, navigational, archaeological or a legal investigation.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Planning, equipment and operational limits
Side-scan equipment
A professional side-scan installation consists of a towfish, transmission cable and topside processing unit. The fish carries the acoustic transducers; the cable provides power and data and determines much of the tow geometry; the topside system records, displays and processes the imagery. A hull-mounted side-scan unit avoids some tow complications but cannot always be placed as close to a deep target as a towed fish.
Multibeam equipment
An MBES requires a hull-mounted transducer array, vessel navigation and motion measurements, and sound-speed information so beam travel times can be converted accurately into depths. The installation and calibration burden is higher than simply viewing a side-scan waterfall, but the payoff is a depth-referenced surface that can support engineering and navigation decisions.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Conditions that can degrade either survey
- Incorrect sound-speed assumptions can bend beams and distort positions or depths.
- Vessel heave, pitch, roll and heading errors can smear or misplace features.
- Strong currents can move a towfish away from the predicted layback position.
- Rough seabed relief can hide parts of a wreck in acoustic shadows or create confusing returns.
- Insufficient line overlap can leave gaps or make a contact appear inconsistent between passes.
- Excessive towfish altitude, speed or range can reduce side-scan detail; overly narrow settings can make a large-area search inefficient.
How much seafloor is surveyed?
Scale matters when budgeting a search. NOAA’s Office of Coast Survey reports approximately 4,000 square nautical miles surveyed each year (page accessed in 2026). That figure describes the office’s annual survey activity, not the area a particular vessel or sonar can cover in one mission.
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
For MBES, the commonly cited planning rule is a swath of about two to four times water depth. At a given depth, line spacing must still be chosen for the required data quality and overlap. For side scan, coverage is set by selected frequency and range: the 50–100 kHz examples favor broad, lower-resolution inspection, while 500 kHz–1 MHz favors narrower, high-detail coverage. Treat all of these as planning characteristics, not guaranteed production rates.
Common mistakes and how to avoid them
Calling a bright side-scan spot a confirmed wreck
Bright reflectivity can come from rock, debris or seabed changes. Require a coherent shape and shadow, examine the surrounding geology and, when the identity matters, obtain multibeam and ground truth.
Using a side-scan image as a depth chart
An attractive image does not establish least depth. Schedule MBES or another bathymetric method before making clearance or navigation claims.
Assuming the GPS point is the towfish point
Record cable length and tow conditions and apply an underwater-positioning or layback solution. Otherwise a later multibeam pass may appear misaligned even when both surveys are correct.
Running maximum detail over the entire search area
High-frequency side scan gives more detail but a narrower swath. Start with a frequency and line plan that can cover the area, then focus 500 kHz–1 MHz work on ranked contacts.
Expecting multibeam alone to answer an archaeological question
Bathymetry maps form and elevation. It may not reveal construction details, cargo or material reliably. Add side scan, magnetometer, ROV or diver inspection according to the question.
Decision guide
| Your main question | First choice | Why |
|---|---|---|
| “Is there any wreck-like object in this large area?” | Side scan, generally beginning with a broad-coverage frequency | Efficiently displays reflectivity and shadows across both sides of the track |
| “What is the shallowest point and exact clearance?” | Multibeam | Direct depth soundings produce a georeferenced surface |
| “Is this contact a shipwreck or natural rock?” | Side scan followed by multibeam and, if needed, ground truth | Image, shape and independent inspection provide complementary evidence |
| “How should the wreck be modeled in three dimensions?” | Multibeam, with side scan for interpretation | Bathymetry supplies measurable elevation and side scan helps explain acoustic texture and shadows |
| “Does the target contain iron?” | Magnetometer added to sonar work | Sonar alone does not establish ferrous content |
Bottom line for wreck hunters
There is no single winner for every phase. Side-scan sonar is normally the best reconnaissance instrument because it makes wreck-shaped returns and shadows easy to find and interpret, with frequency choices ranging from broad 50–100 kHz coverage to detailed 500 kHz–1 MHz work. Multibeam sonar is the measurement instrument because it supplies depth, least depth and a three-dimensional, georeferenced seabed model, with typical coverage of two to four times water depth. For a defensible professional result, search with side scan, map the contact with multibeam and add magnetometer or ROV/diver evidence when identity, ferrous content or archaeological condition must be established.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
