About this tender
The Williams DieselJet 625 is the build we ask Williams for when an owner's programme calls for a proper diesel-powered tender at the larger end of the RIB category. At 6.32m LOA with a 230hp Yanmar 4LV engine driving a jet unit, it carries eleven passengers without asking the hull to do anything it was not designed for. Williams quotes a typical fitment yacht of 40m and above, which puts it squarely in the range where garage volume is real and the tender needs to earn its berth.
The jet-drive configuration is the defining characteristic here. No propeller below the keel means shallow-water access, predictable behaviour alongside a swim platform, and a propulsion system that is genuinely low-maintenance in the context of a working superyacht tender. The 4LV is a well-proven Yanmar unit; captains who have run it across a season report that the service intervals are straightforward and parts availability is not a concern in any of the main Mediterranean or Caribbean charter bases.
Standard equipment is comprehensive for the class. A Raymarine Axiom 7-inch MFD with integrated depth sounder and chartplotter is fitted as standard, the helm console folds to reduce air draft for tight garage clearances, and the Hypalon tube construction is what we would expect on any tender going to sea for extended periods. The options list covers MCA compliance patches, AIS, a Fusion audio system, and underwater lighting - the items captains typically need to specify before handover.
Highlights
The four details we'd point out first to a captain who hasn't seen one on the water yet.
The 230hp Yanmar 4LV is a four-cylinder common-rail diesel unit mated to a jet pump, giving the 625 a quoted top speed of 46mph (74kph) and the shallow-water access that a propeller-driven tender cannot match. Diesel fuel compatibility with the mothership is a practical operational benefit across a full season.
The helm console and windscreen fold to bring overall height down from 1.6m to 1.18m in low-profile configuration. Combined with the optional single-point lift, this gives captains and deck crew a genuine solution for tight tender garage fitments without structural modification to the boat.
Williams rates the 625 for eleven persons, which is a meaningful number for a 6.32m tender. The beam of 2.41m and centrally mounted engine layout give sufficient deck volume to seat that complement without the hull sitting deep in the water or the ride becoming uncomfortable in a short chop.
A Raymarine Axiom 7-inch multifunction display with depth sounder and chartplotter is included in the base specification. Navigation lights are plug-in, and the options list extends to AIS and an additional chartplotter for owners who want full situational awareness from the tender helm.
The removable tube is handmade in Hypalon, the synthetic rubber compound that holds up to UV, fuel, and abrasion better than PVC alternatives. Twelve standard colour schemes are available, with custom colours, upholstery, and moulding options offered for owners who want the tender matched to the mothership's livery.
Gallery
The full specification
Specifications, prices, availability, and performance figures are supplied for guidance only and remain subject to confirmation by the yard, seller, broker, survey, contract, and final specification.
Questions, answered
Last call · Available
Williams · Oxfordshire, UK
Tell us about your yacht, your programme, and the missions DieselJet 625 needs to handle. We come back within 48 hours with a written assessment - fit for the brief, lead time, and trade-offs against alternatives in the same band.
Prefer to talk? +44 (0) 77180 88055 · other ways to reach us
From the library
