Naval Systems

Tripartite class minehunter

Also known as
  • Eridan class minehunter
  • Eridan class
  • Éridan-class minehunter
  • Tripartite-class minehunter
  • Tripartite minehunter
  • CMT
  • Chasseur de mines tripartite
  • Alkmaar class minehunter
  • Alkmaar-class minehunter
  • Flower class minehunter
  • Aster class minehunter

The Tripartite class is a Franco-Belgian-Dutch minehunter family built around low-magnetic composite hulls, precise minehunting propulsion, hull sonar, divers, and remote mine-disposal vehicles. The French Éridan, Dutch Alkmaar, and Belgian Flower/Aster branches gave NATO navies a common Cold War mine-countermeasures design, later exported or transferred to Pakistan, Indonesia, Latvia, Bulgaria, and Ukraine. French ships are documented clearing Iraqi mines off Kuwait in the 1990 Gulf War, while Belgian and Dutch Tripartite-family boats were transferred to Ukraine during the 2014 Russia-Ukraine War for maritime security and future Black Sea mine clearance.

Tripartite class minehunter, Minehunter class, Naval Systems
Image source: File:HNLMS Schiedam M860 3931.jpg - Wikimedia Commons

Role in Conflicts

Mine Countermeasures Fit

French and Dutch source material describe a specialist minehunter built to find, classify, and neutralize submerged mines while limiting the magnetic signature that can trigger influence mines.

Low-signature hull

The French CMT material identifies a glass-reinforced-plastic hull, while Dutch material describes a polyester hull and aluminum superstructure chosen because sea mines can react to magnetic disturbances.

Mine detection

Dutch Alkmaar-class boats use hull-mounted sonar, with a self-propelled variable-depth sonar available when water conditions complicate detection.

Mine disposal

French CMT boats carried PAP 104 vehicles; modernized Dutch boats use SeaFox mine identification and disposal vehicles alongside clearance divers.

Close defense

French and Dutch fits differ by national branch, with French source material listing a 20 mm modèle F2 gun and machine guns and Dutch material listing heavy machine guns after modernization.

Sources: Chasseurs de mines tripartite - Ministère des Armées; Mijnenjagers - Defensie.nl; CHASSEURS DE MINES TRIPARTITES CMT.

Profile / Specs

Profile

Origin
France / Belgium / Netherlands
Type
Minehunter class
Service note
1984-present
Designed
1974
Produced
1977-1995
Number built
35 core French, Belgian, and Dutch ships, plus export and replacement hulls

Specifications

Length
51.5 m
Beam
8.9 m
Draught
3.8 m on Dutch Ministry of Defence Alkmaar-class data
Displacement
543 tonnes for current Dutch Alkmaar-class data; French CMT source lists 684 tonnes
Hull
Glass-reinforced plastic / polyester low-magnetic construction
Speed
13 knots on current Dutch data; French source lists 15 knots
Crew
28-38 on current Dutch data; French CMT source lists 45 mariners including mine-clearance divers
Sensors
Hull-mounted sonar, self-propelled variable-depth sonar on modernized Dutch boats, navigation radar, and mine-countermeasures command system
Mine countermeasures
PAP 104 vehicles on French CMT fit; SeaFox mine identification and disposal vehicles and clearance divers on modernized Dutch fit
Armament
National-branch fit varies; French boats list a 20 mm modèle F2 gun and machine guns, while Dutch material lists three M2 heavy machine guns
National Branches And Ukraine Transfers

The Tripartite design is best read as one shared mine-countermeasures family with national branches rather than a single unchanged ship list. France built the Éridan branch at Lorient, the Netherlands built the Alkmaar branch around Dutch propulsion and later modernization, and Belgium operated Flower/Aster-named boats including Narcis.

BranchSource-backed contextUkraine relevance
ÉridanFrench CMT/Éridan boats are documented with low-magnetic hulls, PAP 104 mine-disposal vehicles, and French Navy service from the 1980s.The existing direct conflict-use evidence for this branch is the 1991 Kuwaiti-coast mine-clearance mission.
AlkmaarDutch Ministry of Defence material identifies the Alkmaar class as the Dutch name for the internationally known Tripartite class.HNLMS Vlaardingen became Melitopol, and HNLMS Makkum became Henichesk after transfer to Ukraine.
Flower / AsterBelgian Tripartite boats include BNS Narcis, a minehunter visible in open-license Lithuanian Ministry of Defence imagery.BNS Narcis was transferred to Ukraine as Mariupol alongside the Dutch Vlaardingen transfer.

Sources: Mijnenjagers - Defensie.nl; Belgium and Netherlands donate first minehunters to Ukraine - Defensie.nl; Ukraine receives ex-Dutch Alkmaar-class minehunter Henichesk - Naval News; Belgian minehunter Narcis - Wikimedia Commons.

Variants

Tripartite names vary by navy: Éridan for the French branch, Alkmaar for the Dutch branch, and Flower/Aster names for Belgian boats.

VariantConfigurationDesignation notes
Éridan classFrench national branch

French material identifies the CMT/Éridan boats as the French Navy's Tripartite minehunters, with 13 ships entering service between 1984 and 1988.

Sources: CHASSEURS DE MINES TRIPARTITES CMT, Projet de loi de finances pour 2003 : Défense - Marine - Sénat

Alkmaar classDutch national branch

Dutch Ministry of Defence material says the Alkmaar class was jointly designed by the Netherlands, Belgium, and France and is internationally known as the Tripartite class.

Sources: Mijnenjagers - Defensie.nl

Flower / Aster classBelgian national branch

Belgian Tripartite boats include the former BNS Narcis, a minehunter transferred to Ukraine as Mariupol.

Sources: Belgium and Netherlands donate first minehunters to Ukraine - Defensie.nl, Belgian minehunter Narcis - Wikimedia Commons

Self-Defense Gun

Éridan class minehunters are documented with a single 20 mm modèle F2 gun for close-range defense.

AmmunitionAmmunition typeFiring evidence
20mm GIAT M693 autocannon, French 20 mm autocannon chambered for 20x139mm NATO rounds, Infantry Weapons20mm GIAT M693 autocannon20 mm naval autocannon

ODIN documents the Éridan class with one 20 mm modèle F2 gun.

Sources: Éridan class minehunter - ODIN

Timeline

Tripartite class minehunter Key Events

  1. Tripartite program ratified

    France, Belgium, and the Netherlands ratified the Tripartite minehunter program, with the French share covering 10 ships at the outset.

    Sources: CHASSEURS DE MINES TRIPARTITES CMT

  2. French CMT enter active service

    French Senate reporting later described 13 CMT as having entered active service between 1984 and 1988.

    Sources: Projet de loi de finances pour 2003 : Défense - Marine - Sénat

  3. Dutch Alkmaar-class production completes

    Dutch Ministry of Defence material says the Royal Netherlands Navy ultimately received 15 Alkmaar-class minehunters and identifies the class as the international Tripartite design.

    Sources: Mijnenjagers - Defensie.nl

  4. Kuwait mine-clearance mission begins

    French minehunters began clearing Iraqi mines off the Kuwaiti coast during the 1990 Gulf War.

    Sources: The French Naval Campaign off the Kuwaiti Coasts - Global Studies Center

  5. Modernization program launched

    The French Navy launched a modernization program for the 13 CMT, with work scheduled through 2005.

    Sources: Projet de loi de finances pour 2000 : Marine - Sénat

  6. Ukrainian crews train on Makkum

    Dutch reporting said 35 Ukrainian sailors completed training aboard HNLMS Makkum, while Vlaardingen and Makkum were both planned for donation to Ukraine.

    Sources: Ukrainian crew trained aboard Zr.Ms. Makkum - Defensie.nl

  7. Narcis and Vlaardingen transferred to Ukraine

    The Dutch Ministry of Defence announced that Belgian BNS Narcis and Dutch Zr.Ms. Vlaardingen had been transferred to Ukraine at Zeebrugge.

    Sources: Belgium and Netherlands donate first minehunters to Ukraine - Defensie.nl

  8. Henichesk enters Ukrainian service

    Naval News reported that the former HNLMS Makkum had entered Ukrainian Navy service as Henichesk.

    Sources: Ukraine receives ex-Dutch Alkmaar-class minehunter Henichesk - Naval News

Media

Tripartite class minehunter Videos

Tripartite class minehunter Images

Tripartite class minehunter, Minehunter class, Naval Systems - view 1
Source: Belgian minehunter Narcis - Wikimedia Commons
Tripartite class minehunter, Minehunter class, Naval Systems - view 2
Source: File:FS Eridan M641 (Dublin April 2017)-126675.jpg - Wikimedia Commons
Tripartite class minehunter, Minehunter class, Naval Systems - view 3
Source: File:M641 Eridan and Serenissima in Tallinn Bay 28 May 2015.JPG - Wikimedia Commons
Tripartite class minehunter, Minehunter class, Naval Systems - view 4
Source: File:Eridan Minesweepers.JPG - Wikimedia Commons
Related Weapon Systems
Hunt class, Mine countermeasures vessel class, Naval SystemsNaval SystemsHunt classMine countermeasures vessel classThe Hunt class is a British mine countermeasures vessel class built by Vosper Thornycroft and Yarrow Shipbuilders for low-signature minehunting, route clearance, and coastal patrol work. Royal Navy and Ministry of Defence sources document HMS Brocklesby clearing mined approaches in the Gulf, Iraq, and Libya, while the remaining Royal Navy ships use sonar, clearance divers, glass-reinforced plastic hulls, and SeaFox mine-disposal vehicles to find and neutralize mines.
Sandown class, Single-role minehunter, Naval SystemsNaval SystemsSandown classSingle-role minehunterThe Sandown class is a British single-role minehunter family built by Vosper Thornycroft around a low-signature hull, Type 2093 sonar, remote mine-disposal vehicles, and light self-defense armament. Royal Navy and export ships have served in mine-countermeasures roles with the United Kingdom, Saudi Arabia, Estonia, Ukraine, and Romania; a 2025 House of Commons Library briefing described HMS Bangor as the last Sandown-class vessel in Royal Navy service. Direct conflict sourcing places HMS Sandown in NATO Adriatic ordnance clearance after Operation Allied Force and Sandown-class vessels in coalition route-clearance work around Umm Qasr during the 2003 Iraq War.
Hunt class mine countermeasure vessel, Mine countermeasures vessel class, Naval SystemsNaval SystemsHunt class mine countermeasure vesselMine countermeasures vessel classThe Hunt class is a British mine countermeasures vessel class built primarily by Vosper Thornycroft, with some hulls built by Yarrow Shipbuilders, for low-signature mine-hunting and clearance work. Royal Navy and Ministry of Defence sources document HMS Brocklesby clearing a mined channel into Umm Qasr during the 2003 Iraq War and destroying a mine near Misurata during the 2011 Libya campaign with sonar and the SeaFox mine disposal system.
Frankenthal class minehunter, Minehunter class, Naval SystemsNaval SystemsFrankenthal class minehunterMinehunter classThe Frankenthal class is the German Navy's Type/Class 332 minehunter family, built from a Hameln-derived common platform by Lürssen, Abeking & Rasmussen, and Krögerwerft. Bundeswehr data describe ten MJ332 boats with non-magnetic steel hulls, Seefuchs/SeaFox mine-disposal drones, mine rails, diver facilities, and MJ332B, MJ332C, and MJ332CL mission fits, while former German hulls also served the UAE as Al Murjan-class mine-countermeasure vessels.

Sources

Chasseurs de mines tripartite - Ministère des ArméesPublisher: Ministère des Armées et des Anciens combattants | Note: Supports the class mission, current French Navy context, length, beam, speed, crew, sonar, PAP 104 fit, and armament details. | Accessed: 2026-06-25Mijnenjagers - Defensie.nlPublisher: Ministerie van Defensie | Note: Supports Dutch Alkmaar-class specifications, minehunting role, sonar and SeaFox fit, low-magnetic hull explanation, Tripartite international name, and 2014 Russia-Ukraine War direct transfer context: Vlaardingen and Makkum were to be donated to Ukraine. | Accessed: 2026-07-07Belgium and Netherlands donate first minehunters to Ukraine - Defensie.nlPublisher: Ministerie van Defensie | Note: Supports 2014 Russia-Ukraine War direct transfer context: Belgian BNS Narcis and Dutch Zr.Ms. Vlaardingen were transferred to Ukraine, Vlaardingen was renamed Melitopol, and Makkum was planned to follow as Henichesk. | Accessed: 2026-07-07Ukrainian crew trained aboard Zr.Ms. Makkum - Defensie.nlPublisher: Ministerie van Defensie | Note: Supports 2014 Russia-Ukraine War direct training and donation context: Ukrainian sailors trained aboard Makkum before Dutch Tripartite-family minehunters were transferred to Ukraine. | Accessed: 2026-07-07Ukraine receives ex-Dutch Alkmaar-class minehunter Henichesk - Naval NewsPublisher: Naval News | Note: Supports 2014 Russia-Ukraine War direct transfer context: former HNLMS Makkum entered Ukrainian Navy service as Henichesk, after Mariupol and Melitopol had already been transferred. | Accessed: 2026-07-07SIPRI Arms Transfers DatabasePublisher: Stockholm International Peace Research Institute | Note: Supports the transfer-research lane and database context for major conventional arms transfers through the most recent annual update. | Accessed: 2026-07-07Category:Eridan class minehunters - Wikimedia CommonsPublisher: Wikimedia Commons | Note: Supports the class identity as a French subclass of the Tripartite-class minehunters, the French Navy operator context, inception in 1984, and Arsenal de Lorient builder metadata. | Accessed: 2026-06-25Éridan class minehunter - ODINPublisher: U.S. Army ODIN | Note: Supports the Éridan class fit with one 20 mm modèle F2 gun for close-range self-defense. | Accessed: 2026-06-27The French Naval Campaign off the Kuwaiti Coasts - Global Studies CenterPublisher: Gulf University for Science and Technology | Note: Supports the 1990 Gulf War mine-clearance context, including French minehunters operating off the Kuwaiti coast from 30 January 1991. | Accessed: 2026-06-25CHASSEURS DE MINES TRIPARTITES CMTPublisher: CAIA | Note: Supports the December 1974 tripartite agreement, the French CMT class identity, the 13-ship French service period, the glass-reinforced-plastic hull, and the mine-countermeasures fit around sonar and PAP 104 vehicles. | Accessed: 2026-06-27Projet de loi de finances pour 2003 : Défense - Marine - SénatPublisher: Sénat | Note: Supports the French Navy's 13 CMT in active service between 1984 and 1988 and the 2002-2005 modernization calendar. | Accessed: 2026-06-27Projet de loi de finances pour 2000 : Marine - SénatPublisher: Sénat | Note: Supports the October 1999 modernization launch for the 13 CMT and the modernization-cost context. | Accessed: 2026-06-27File:FS Eridan M641 (Dublin April 2017)-126675.jpg - Wikimedia CommonsPublisher: Wikimedia Commons | Note: Supports image provenance and licensing context for the primary Éridan-class image. | Accessed: 2026-06-25File:HNLMS Schiedam M860 3931.jpg - Wikimedia CommonsPublisher: Wikimedia Commons | Note: Supports image provenance and licensing context for a Dutch Alkmaar/Tripartite-class primary image. | Accessed: 2026-07-07Belgian minehunter Narcis - Wikimedia CommonsPublisher: Wikimedia Commons | Note: Supports image provenance for BNS Narcis, a Belgian Tripartite-family minehunter later transferred to Ukraine as Mariupol. | Accessed: 2026-07-07File:M641 Eridan and Serenissima in Tallinn Bay 28 May 2015.JPG - Wikimedia CommonsPublisher: Wikimedia Commons | Note: Supports gallery image provenance and licensing context for a second Éridan-class image. | Accessed: 2026-06-25File:Eridan Minesweepers.JPG - Wikimedia CommonsPublisher: Wikimedia Commons | Note: Supports gallery image provenance and licensing context for a third Éridan-class image. | Accessed: 2026-06-25