Sonar tells you what is under the hull. It cannot tell you which way to steam.
Furuno and Kongsberg build excellent fish-finding sonar, and both publish the numbers to prove it. Neither sees past a few kilometres of water around one vessel, and one of them puts an export licence on its longest ranges.
Our fish detection service is in daily use by fishing fleets, delivered as a mobile application crews download and run at sea rather than a pilot study. It is built by a team of data scientists, GIS analysts and data architects who pioneered data science in fisheries, and the work is supported by the United Nations World Food Programme, the European Space Agency and the World Bank.
Side by side
| Attribute | Represented by UnstratFish Detection | FurunoFSV-85 MARK-2 full-circle colour scanning sonar (80 kHz)12Japan | Kongsberg Discovery (Simrad)Simrad SX90 MKII omnidirectional fishery sonar34Norway |
|---|---|---|---|
| How fish are found134 | Satellite-driven fish detection and fishing-zone advisories, with data from earth and data from space analysed together | 80 kHz full-circle scanning sonar, full digital beam forming, horizontal, S-scan and vertical presentations | Low-frequency omnidirectional sonar, 20 to 30 kHz in 1 kHz steps, central operating frequency 26 kHz, CW and linear FM modulation |
| Search area13A sonar picture and a fishing-zone advisory answer different questions. One shows the school beneath you now, the other decides which grounds are worth the fuel. | Advisories across national waters; the same analytics carry monitoring of unregulated fishing across the EEZ | Around the vessel, at selectable ranges of 60 m to 2,000 m | Around the vessel, operating ranges 25 m to 5,000 m; an optional 6,000 m to 10,000 m extension is listed as requiring an export licence in selected countries |
| Detection range stated for our service13 | Not published | Range scale to 2,000 m | 25 to 5,000 m standard |
| What has to be installed on the boat14 | A mobile application the crew downloads; no hull penetration, no transducer, no sonar room | Control unit 3.8 kg, processor unit 15 kg, transceiver unit 95 kg and a hull unit of 370 kg (800 mm travel) or 390 kg (1,100 mm travel) with tank | Display, processor unit, transceiver unit, hull unit, hoist motor, motor control unit and transducer, with the transceiver in a sonar room and a high-speed Ethernet run to the bridge |
| Power required13Three-phase power and a hoist are the reason omnidirectional sonar sits on purse seiners and trawlers rather than on the small boats that land most of the catch in developing fisheries. | Not published; delivered as a mobile application | Processor unit 12 to 24 VDC, 48 W max; transceiver unit 100 to 230 VAC, 15 A single phase; hull unit 200 to 220 VAC, 4 A three phase | Processing unit 110/220 VAC and 24 VDC on selected systems at 5 A; transceiver unit 750 VA |
| Fleet economics13 | One service across the fleet; guides boats to productive waters, cutting wasted days at sea and improving catch profitability | Per-vessel capital equipment; no price published | Per-vessel capital equipment; upgrade paths require returning a full operating SX90 and a new transceiver and software, no price published |
| Fisheries-management outputs13 | Monitoring, control and tracking of unregulated and unsustainable fishing; bait-to-plate traceability with provenance for seafood buyers | Not published; the brochure covers detection, target lock and fish histogram display on the bridge | Not published as a management output; the catalogue records sonar data storage and recall and user-defined settings |
| Environmental limits published13 | Not published | Processor unit −15 °C to +55 °C, transducer −5 °C to +35 °C, 93 % relative humidity at +40 °C, IEC 60945 Ed.4 vibration | Not published in the fishery catalogue specification table |
| Export and transfer conditions in the vendor document13 | Independent, non-aligned origin with no political exposure to any major-power ecosystem | Not addressed in the brochure | The specification table footnotes the extended 6,000 to 10,000 m range as requiring an export licence in selected countries |
| Institutional backing14 | United Nations World Food Programme, European Space Agency and the World Bank | Commercial vendor; no institutional backing claimed | Kongsberg Discovery, which states worldwide support and training behind the Simrad brand |
| Sustainment model14 | One accountable team from first briefing through delivery and in-region sustainment | National distributor network listed in the brochure | Local dealer supplies software updates and licences and installs them; the vendor recommends staying on the latest release |
Competitor values are quoted from the vendor documents listed under Sources, as published on the date shown. Configurations vary, so treat every row as a starting point for the evaluation rather than a like-for-like test result.
What the table means
These are not substitutes, and pretending otherwise wastes money.
An SX90 MKII will show a school at ranges the catalogue puts at up to 5,000 m, with beam stabilisation and eleven selectable frequencies so two boats working the same ground do not blind each other. Nothing derived from satellite data does that. What sonar cannot do is tell a skipper which ground to run to before the fuel is burned, and it cannot tell a ministry what the fleet as a whole is doing. Our advisories answer the routing question across national waters; the sonar answers the shooting question at the net.
The install decides who can actually use it.
Furuno publishes a hull unit of 370 kg or 390 kg with tank, a 95 kg transceiver and three-phase power for the hoist. That is a purse seiner or a large trawler, fitted in a yard period. Most vessels in the fisheries that matter to a coastal state are far smaller and will never carry that equipment. A mobile application on a phone reaches those crews on the day it is issued, which is why the same platform can serve fleet profitability and national monitoring at once.
One line in the Simrad specification table is worth reading twice.
The extended 6,000 to 10,000 m range is footnoted as requiring an export licence in selected countries. That is Kongsberg being straight with buyers, and it is also the shape of the problem: the best performance in the catalogue is the part a foreign ministry gets to approve. Our service carries no such condition. Independent, non-aligned origin means the review that matters happens between the parties on the contract.
Where our page is thinner than theirs.
Furuno and Kongsberg publish range scales, beam widths, power draw and temperature limits. We publish outputs and delivery, not detection performance figures, and this table says so in every cell where that is true. A buyer comparing precision should ask us in writing for advisory resolution, update cadence and the validation record behind them, and should expect a document rather than a claim.
Questions buyers ask
What is the best alternative to a Furuno or Simrad fishery sonar for a government trying to raise national catch value?
It depends on what the money is meant to buy. A sonar fit improves one vessel: Furuno's FSV-85 MARK-2 works to a 2,000 m range scale, the Simrad SX90 MKII to 5,000 m, and both need a hull unit, a transceiver and a yard period. If the goal is fleet-wide, our satellite fish-detection service reaches every boat with a phone and directs them to productive waters, which is the intervention that changes fuel spend and days at sea across a whole fleet. Ministries that fund both usually put the sonar on the large vessels and the advisories on everyone.
Can satellite fish detection replace a fish-finding sonar on board?
No, and we do not claim it does. Sonar sees the school under the hull in real time and lets the skipper decide when to shoot the net. Our advisories tell the skipper where the productive water is before the trip. Kongsberg's own catalogue makes the honest point that sonar performance changes with weather, temperature layers, salinity, bottom hardness and ships' noise, so the picture is never identical between two vessels. Satellite advisories and sonar answer different questions on different timescales.
How do the export conditions compare between Simrad, Furuno and an independent supplier?
Kongsberg's fishery catalogue footnotes the optional 6,000 to 10,000 m range extension on the SX90 and SU90 as requiring an export licence in selected countries. Furuno's brochure does not address export conditions at all, which is not the same as there being none. Our fish detection service comes from an independent, non-aligned source with no political exposure to a major-power ecosystem, and it is supported by the UN World Food Programme, the European Space Agency and the World Bank.
How does cost of ownership compare between fitting sonar and subscribing to satellite advisories?
Nobody in this comparison publishes prices, so treat any quoted figure with suspicion. What is documented is structure. A sonar fit is capital equipment per vessel: control unit, 15 kg processor, 95 kg transceiver, a hull unit of 370 to 390 kg with tank, three-phase power, plus dealer-installed software updates and, for a Simrad upgrade, returning a full operating sonar. Our service is delivered as a mobile application with sustainment through one accountable team, so the cost scales with fleet size rather than with steelwork.
Which figures does Unstrat not publish for its fish detection service?
Detection range, advisory spatial resolution, update cadence and forecast accuracy are not in our published catalogue, and this page marks them as not published rather than filling the cells. They are available under a signed enquiry. Where Furuno and Kongsberg publish a number and we do not, the honest answer is that they have a datasheet culture built on hardware and we have not yet matched it in public.
Sources
- 1. Furuno, 360-Degree Omni Scanning Sonar FSV-85 MARK-2, full-circle colour scanning sonar brochure (copy held on this site)Retrieved: 2026-07-31 · Specifications page gives 80 kHz frequency, range scales to 2,000 m, beam widths, tilt angle, hull unit travel and raise/lower times, power supply and environmental conditions; dimension drawings give unit weights.
- 2. Furuno, FSV-35/FSV-85 Full-Circle Color Scanning Sonar brochure (Catalogue No. E-413) (copy held on this site)Retrieved: 2026-07-31 · Side-by-side specification columns for the 24 kHz FSV-35 and the 80 kHz FSV-85, including hull unit types, travel and equipment lists.
- 3. Kongsberg Discovery (Simrad), SIMRAD General Catalogue, Fishery Products (copy held on this site)Retrieved: 2026-07-31 · Sonar specifications table gives SX90 operating ranges 25 to 5,000 m with the export-licence footnote on the 6,000 to 10,000 m option, 20 to 30 kHz in 1 kHz steps, 256 transceiver channels, 750 VA transceiver consumption and the opening-angle table.
- 4. Kongsberg Discovery, Simrad SX90 product page, long-range 20-30 kHz fish-finding omnidirectional sonarRetrieved: 2026-07-31 · States the 26 kHz central frequency, electronic tilt from -10 to +60 degrees in 1 degree steps, the system unit list including hull unit and hoist motor, and dealer-installed software updates.