About this tender
The DieselJet 505 is the build we ask Williams for when a programme needs a proper diesel jet-drive tender at the 5.0-metre mark. Nine persons aboard, a Yanmar 4JH producing 110hp, a top speed of 40mph, and the low-draught jet-drive characteristic that lets you slide onto a shallow beach or manoeuvre in a tight tender garage without the anxiety that comes with a propeller-driven boat. Typical fitment is yachts of 30 metres and above, which tells you exactly where Williams positions this hull in the range.
The 2021 redesign brought a meaningfully improved helm: a centrally mounted Raymarine display, a folding helm and windscreen for low-profile stowage, and revised slash-cut tubes that clean up the visual line and the boarding experience simultaneously. Larger bathing platforms and additional grab handles are details that matter at the mothership, where guests are boarding in swell or at pace. Silvertex upholstery and leg bolsters round out a cockpit that is built for repeated daily use rather than occasional ferry runs.
Standard equipment is comprehensive: FlexiTeek decking, a Raymarine Axiom 7-inch MFD with depth sounder and chartplotter, automatic fire extinguisher, four-point lifting pad-eyes, and a removable handmade Hypalon tube. The optional single-point lift is worth specifying on any vessel where the davit arrangement makes four-point rigging slow or awkward. We would also add the MCA-compliant high-visibility patches if the vessel operates under flag-state workboat code.
Highlights
The four details we'd point out first to a captain who hasn't seen one on the water yet.
The Yanmar 4JH 110hp diesel driving a jet pump gives the 505 the shallow-water access and propeller-free safety margin that petrol outboard alternatives cannot match at this length. Williams quotes a top speed of 40mph alongside the low-draught handling advantage at the beach or in a congested tender garage.
The folding helm and windscreen reduce overall height from 1.39m to 1.06m, which resolves the clearance problem in tight davit or garage arrangements. An optional single-point lift complements the fold-down system and speeds turnaround when the mothership is on anchor.
The 505 seats eight plus one, with the layout engineered around under-seat storage, a removable ski pole, bow U-bolt, and multiple boarding points. The centrally mounted engine keeps the tubes lower in the water and the cockpit floor clear, which is the right trade-off at this passenger count.
A Raymarine Axiom 7-inch multifunction display with integrated depth sounder and chartplotter is fitted as standard, not as an option. The optional upgrade to a 9-inch unit with AIS is available for vessels where the tender operates at greater range from the mothership.
Williams fits removable handmade Hypalon tubes with grab handles and boarding step pads as standard. Hypalon resists UV degradation and fuel contamination more effectively than PVC, which is the right material choice for a tender living on a davit in a Mediterranean or tropical programme.
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 505 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
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