VESSEL REVIEW | Purus Apache & Purus Phantom – Catamaran daughtercraft/crewboats for European windfarm support duties
UK marine services provider Purus has added the catamaran daughtercraft Purus Apache and Purus Phantom to its offshore wind support fleet.
Designed by Chartwell Marine and built by Diverse Marine, the craft can carry technicians from larger commissioning service operation vessels (CSOVs) to offshore inspection and maintenance assignments.
Diverse Marine announced Purus Phantom’s handover on May 19, 2026, and reported that it joined the CSOV Purus Coriolis for the first time on June 15. The first craft, Purus Apache, had been installed aboard Purus Chinook by May 26, 2025.
Diverse Marine also said the vessels can be used for nearshore crew transfer duties.
Low-emission propulsion coupled with comfort-enhancing features
Each aluminium daughtercraft has an overall length of 12.2 metres (40 feet) and a hull length of 12 metres (39 feet). Overall beam is 4.1 metres (13 feet) while depth amidships is only 1.3 metres (4.3 feet).
The lightship displacement is 12.1 tonnes, while maximum laden displacement is 15 tonnes. The maximum draught is 0.8 metres (2.6 feet).
The vessels’ launch and recovery are done using a single-point lifting arrangement that includes a Henriksen HMKRHB-15 hook.
Diverse Marine said the hull was assessed using CFD analysis and scale model tank testing. The design incorporates a high bow and low propulsor arrangement intended to support access at transfer points, together with motion dampening features intended to improve passenger comfort underway.
Twin Volvo Penta D6-IPS500 inboard engines deliver a service speed of 23 knots and a sprint speed of 28 knots. The inboard drives have been proven to generate low noise while exhaust gas aftertreatment ensures compliance with IMO Tier III standards.
Each daughtercraft has 0.85 cubic metres (187 gallons) of MGO capacity and 0.1 cubic metres (22 gallons) of urea capacity. Freshwater and blackwater capacities are also each 0.1 cubic metre.
Each daughtercrat also features 12 Grammer suspension passenger seats and two crew seats. Air conditioning and reverse-cycle heating are included together with heads and an emergency shower.
Protected steps connect the cabin to the flush main deck. The working deck itself is stepless, and deck equipment is mounted beneath it to reduce trip hazards.
Stowage for kit bags and maintenance components is accessible through hatches that sit flush within the deck and are assisted by struts.
At the bow is Buoyant Works cupped fender to minimise the risk of impact damage on the hull during transfers.
Full electronics suite optimised for offshore operations
The vessels each have 24 V DC and 230 V, 50 Hz AC electrical systems supported by a Fischer Panda 5000i 5kVA generator. The deck equipment includes a 25kg delta-type anchor and a Maxwell HRC10-10 anchor winch.
The navigation package includes a Raymarine package consisting of an Axiom 12 multi-function display paired with an 18-inch radar, an AIS, and a DGPS. A Furuno NX900 Navtex receiver and an LH-5000 loudhailer meanwhile support onboard communications.
An Iridium LT3100S satellite telephone provides GMDSS communications. The camera installation comprises four IP67-rated high-definition CCTV cameras with a network video recorder.
