Netherlands Rotterdamsche Droogdok Maatschappij (RDM)
Walrus class
The Royal Netherlands Navy's diesel-electric attack submarine class, known for its distinctive X-form stern rudders and quiet operation in the shallow, congested waters of the North Sea and Baltic approaches. Due to be replaced by new-build submarines under the Dutch Walrus Replacement Program, selecting the French Naval Group Barracuda design.
In service since 1990 · 1 operator countries
Compiled from public sources ·primary reference ↗ ·last verified 2026-07-02
300
m depth
21
kn
9,989
nmi
1,900
t
50
crew
Pricing: Unit cost not publicly disclosed
Procurement snapshot
Availability & export
National export licensing
Subject to Netherlands export-control approval; verify eligibility with the manufacturer.
Channel: Direct commercial / G2G
Fielded & proven
Limited · 1 operator
In service since 1990. Status: active · ~4 built.
Lifecycle cost (est.)
No public unit price to model from. Why so few systems publish one →
Interoperability
No standardised NATO calibre / datalink detected in public specs.
Derived guidance from public data, export regime by country of origin, lifecycle from the GAO ~30% acquisition rule. Verify eligibility, pricing and offsets with the manufacturer and your acquisition authority.
Full specifications
Firepower
Armament, payload and guidance.
| Torpedo tubes Number of torpedo tubes (submarines and some surface ships). | 4 |
|---|
Physical
Dimensions, weight and crew.
| Length Overall length including gun/probe where applicable. | 67.73 m |
|---|
Propulsion
Engine, power and fuel.
| Engine Powerplant model and type. | 3x SEMT Pielstick PA4 200 VG diesel engines with 1x HOLEC electric motor and 420-cell VARTA batteries |
|---|---|
| Engine power Engine output power. Higher moves more weight faster. | 6,300 hp |
| Propulsion type Turbofan, turboshaft, diesel, gas turbine, solid-fuel rocket, ramjet… | Diesel-electric |
Sensors & avionics
Radar, sensor suite and datalinks.
| Radar Primary radar. AESA (active electronically scanned array) is the current state of the art. | Signaal/Decca 1229 navigation radar |
|---|---|
| Sensors IRST, EO/IR turrets, laser designators, sniper pods, thermal sights. | Signaal ZW-07 radar, Argo Phoenix I electronic support measures, Thomson Sintra TSM 2272 Eledone Octopus sonar, GEC Avionics Type 2026 towed array sonar, Thomson Sintra DUUX 5 passive ranging and intercept sonar |
Program
Cost, production scale and operators.
| Units built Total production run. Higher means proven manufacturing, mature logistics and spares availability. | 4 |
|---|---|
| Operator countries Number of countries operating the system. More operators means broader support ecosystem. | 1 |
Specifications compiled from public Rotterdamsche Droogdok Maatschappij (RDM) and reference sources ↗. Published defense figures are approximations, treat comparisons as directional. Last verified 2026-07-02.
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Type 212A Frequently asked questions
What engine does the Rotterdamsche Droogdok Maatschappij (RDM) Walrus class use? +
The Rotterdamsche Droogdok Maatschappij (RDM) Walrus class is powered by the 3x SEMT Pielstick PA4 200 VG diesel engines with 1x HOLEC electric motor and 420-cell VARTA batteries.
What is the Rotterdamsche Droogdok Maatschappij (RDM) Walrus class used for? +
The Rotterdamsche Droogdok Maatschappij (RDM) Walrus class is a submarine typically used for isr.
How many countries operate the Rotterdamsche Droogdok Maatschappij (RDM) Walrus class? +
The Rotterdamsche Droogdok Maatschappij (RDM) Walrus class is operated by 1 countries.
How much does the Rotterdamsche Droogdok Maatschappij (RDM) Walrus class cost? +
Rotterdamsche Droogdok Maatschappij (RDM) Walrus class: Unit cost not publicly disclosed. Defense program costs are rarely fully public and vary by contract and configuration.
