Marine Engineering Projects Gold Coast

Sunseeker 53’ Portifino

FOREVA

FOREVA, a Sunseeker Portofino 53, arrived in the D’Aprix Marine shed for a full mechanical overhaul. After positioning the vessel and coordinating specialist contractors for hull, detailing, and painting works, our engineering team carried out a thorough inspection that uncovered a range of issues, most notably a faulty port transmission reverse solenoid, a starboard engine oil leak, fuel system contamination, and seized raw water impellers. Our team got to work rectifying each fault methodically, servicing both Volvo Penta D12 main engines and the Cummins Onan generator from top to bottom. A replacement HCU control unit had to be sourced and fitted after an additional transmission fault emerged during commissioning, but once installed, both port and starboard transmissions were confirmed fully operational. The fuel system was stripped, cleaned of diesel bug contamination, and reassembled with new filters, while the heavily seized impellers required modified tooling just to extract safely. Propellers were refurbished off-site, reinstalled, and the running gear brought back to full order. A leaking speed sensor through-hull fitting was also found and resealed before final checks. With the engine room thoroughly cleaned, components treated with corrosion protection, and the interior and cockpit restored to a high standard, Foreva was declared ready for relaunch.

A luxurious white yacht on calm water with trees in the background and a person standing on the deck.
Close-up of a boat's hull with a large black opening for a propeller, supported on stands with tools nearby.
Close-up of an industrial engine or generator in a mechanical or utility room, with various pipes, cables, and insulation visible.
Close-up of a white industrial generator or pump with black and silver components, hoses, and wiring inside a metal frame, placed on a concrete floor with a crumpled white cloth nearby.
A luxury yacht on calm water with a person standing on the bow, and another person inside the boat, with trees in the background.
A luxury yacht named Foreva being lifted out of the water by boat hoists at a marina with people taking photos.

560 Cruisers Yacht

AMBIENT

The Ambient came into our workshop and got stuck into a comprehensive program of works to keep her running at her best. We started with a full annual service on both Volvo D12 main engines and the Onan generator, draining and replacing all oils, filters, impellers, anodes, and belts while also overhauling the heat exchanger, replacing both engine wiring loom harnesses, and servicing the Honda tender outboard. Shortly after, we responded to a breakdown at anchor when the port engine starter motor failed, recovering the vessel on one engine, rebuilding the starter, and then returning to carry out further plumbing works including a new freshwater manifold system and NMEA gateway replacement. We then hauled her out of the water for a full antifoul application using JOTUN Seavictor 50 with Jotun Vinygaurd primer, a complete Propspeed treatment across both propellers, shafts, rudders and P-brackets, and a full set of new zinc anodes. During the haul-out we also replaced two through-hull skin fittings, installed four new underwater lights and a targa light, carried out a full injector service on both D12 engines discovering that the port-side injectors had sustained water damage and were over-fuelling and completed the annual tender service. A routine inspection visit in between identified a number of items for attention including minor oil leaks, corroding connections, and audio faults, all of which were addressed in the subsequent works.

Two men walking on a dock near a white and black yacht docked at a marina with other boats in the background.
Four men on a luxurious white yacht named 'Ambient' docked on the water, with two others on the dock nearby, and a calm body of water with other boats in the background.
Three men standing and walking on a dock next to boats on the water, with greenery in the background.

MARITIMO 60’

DISTRACTION

When Distraction came to us, we started with a thorough assessment of both main engines and generators, uncovering a range of issues including loose sump bolts with inconsistent torque, calcium build-up in the coolers, oil leaks from the rocker covers and oil pressure switches, and a coolant leak from the port generator's circulation pump which we replaced along with rebuilding both genset heat exchangers. We serviced the tender outboard, sourced new shift and throttle cables, freed up a heavily corroded tilt lock, and attended to the stern thruster after discovering a log had destroyed one set of blades. Throughout the job we replaced all main engine and generator filters, oils, impellers, anodes, crankcase breathers, and air filters across both port and starboard, while also servicing the ZF 500A transmissions and hydraulic steering filter. We carried out a full bilge clean, investigated a freshwater pressure issue tracing it back to a secondary feed pump and an open tap at the anchor well, and facilitated the tender covers being reupholstered with new pontoon covers in charcoal grey. We coordinated closely with antifouling and paint contractors throughout the haul-out period to keep everything running on schedule, and left the vessel clean, serviced, and ready for the water.

A large white motor yacht anchored at a marina with other boats in the background, under a clear blue sky.
Rear view of a white yacht docked at a marina, with a black canopy and railing, and the name 'Destraction' written on the stern, near Sydney.
A white yacht docked in a marina with a city skyline in the background, a man standing on the deck.

RIVIERA 4000

NAUTI BOY

This repower project transformed a stunning Riviera 4000 Offshore, replacing its aging Volvo engines with powerful and efficient Cummins QSB 6.7 480HP engines. The upgrade delivered a noticeably smoother and more responsive performance, significantly enhancing the vessel's handling and reliability.

A custom dash layout was designed to complement the new powertrain, integrating the Cummins system via NMEA2000 for seamless data flow and monitoring. Control was upgraded with Glendinning electronic controls, offering precise throttle response and effortless maneuvering. The result is a modernized, high-performing cruiser that maintains the Riviera’s luxury pedigree while embracing the latest in marine propulsion technology

A white motor yacht anchored in calm blue water with a distant island and another boat in the background.
Marine engine inside a boat engine compartment, white in color with a large air filter and various pipes and cables.
The interior of a boat's control panel showing navigation equipment, gauges, switches, and a person steering.
Two men working on a white motorboat docked at a marina, with tools on the deck and other boats and vehicles visible in the background.
A man in a yellow and black shirt standing on the deck of a boat, working on the white superstructure of a helicopter mounted on the boat within a boat garage or maintenance facility.
Interior of a boat or yacht engine room with two large diesel engines, various parts, tools, and equipment, and a glass-covered compartment at the top with green support.
Two large engines wrapped in plastic in a boat engine compartment, with the boat's steering wheel and dashboard above.
A person working on a large, white machinery part wrapped in plastic, with a crane lifting it, in an industrial setting.
A black and white motor yacht docked in a marina, with other boats and cars in the background under a clear blue sky.
Boat dashboard with gauges, switches, and electronic equipment, including a SIMRAD display and control panel.
The image shows the helm of a boat with a black cushioned captain's seat, a wooden steering wheel, and various navigational equipment, with a large window and a hatch overhead.

Halvorsen 38

AVONE

The Halvorsen 38 vessel Avone underwent a repower, replacing the original 308 Petrol V8 engines with modern Yanmar 4JH80 Common Rail diesel engines, significantly improving efficiency, reliability, and performance. The project included the removal and replacement of overboard valves, modifications to the engine bed, and the installation of a new, custom dash. The boat was pulled out of the water and brought into the D’Aprix Marine workshop facility, where the in-house team also applied fresh anti-fouling. With these upgrades, Avone has been revitalized to offer her owners a cleaner, quieter, and more dependable boating experience, extending her service life for another 50 years of enjoyment.

Top-down view of an empty wooden structure with electronic components, wires, tubing, and metal brackets, possibly part of a project or machinery.
Two boat engines with Yanmar branding installed in a boat, with visible plumbing and wiring.
Sailboats docked at a marina with clear blue sky and trees in the background.
A white and brown motor yacht sailing on calm water in a marina with multiple sailboats docked on both sides and a clear blue sky above.
Close-up of a boat engine with various hoses, pipes, and mechanical parts.
Mechanical or engineering equipment with hydraulic or pneumatic cylinders, hoses, and pipes mounted on a white metal surface.
Close-up of a compact, industrial engine or machine with various metallic and plastic components, pipes, and wiring, mounted on a white platform.
A Yamaha engine installed in a boat with a wooden cabinet nearby.

Voyager 1100

Blue Chip

Our team had the pleasure of caring for Blue Chip, an 1100 Voyager Catamaran. On our first visit, we upgraded the vessel's fuel filtration system by removing the existing 900 series Racor assemblies and installing new Dual 900 Series Racor Fuel/Water Assemblies, before carrying out a full diesel polish of both tanks circulating 3,000 litres in total through 2-micron and water-absorbent filters to ensure the fuel was in pristine condition. We reconnected all fuel lines, cleaned the bilges, checked oils and levels, and ran the engines up to confirm everything was fully operational. On our second visit, we performed a comprehensive 50-hour service on the twin SE Steyr Diesel engines, draining and replacing all engine and transmission oils, installing new oil, fuel, and primary water separator filters, renewing all zinc anodes, replacing the poly V belts, and thoroughly cleaning the sea strainers and bilges. During this service carried out significant additional work including removal of the intake manifold and a complete coolant drain to extract the damaged filter and fully reassemble the engine with new gaskets, seals, and coolant. We left both engines fully operational and Blue Chip in better shape than we found her.

A white yacht named 'Blue Chip' docked at a marina, with other boats and a cloudy sky in the background.
Oil water separator machine connected to pipes, with a pressure gauge and electrical components nearby.
A small engine with a red valve cover, air filter, vacuum hoses, and electrical components in a confined space, likely inside a boat or vehicle engine compartment.
A white motor yacht named BLU CHIP docked at a marina with other boats, under a partly cloudy sky.
Boat control panel with steering wheel, GPS, and navigation instruments, overlooking a marina with numerous boats docked.
Close-up of a small boat engine with various hoses, filters, and wiring in a confined engine compartment.

Bowman 49

Lai Mantana

The Bowman 49 Lai Mantana underwent a full repower and systems refit at the D’Aprix Marine workshop facility, replacing the original Perkins engine with a modern Yanmar 4JH80 Common Rail engine. The upgrade included new Polyflex flexible couplings, Tides dripless shaft seals, a Racor turbine water/fuel separator, custom engine feet, and engine bed modifications. A new Gori propeller and running gear were installed, along with a custom dash and replacement of overboard valves. This comprehensive overhaul has delivered a cleaner, quieter, and more reliable performance—ensuring Lai Mantana is ready for another 50 years of safe and enjoyable cruising.

Marine engine installed on a boat with various hoses and wiring, inside a wooden cabin.
An industrial diesel engine on a wooden pallet outdoors.
Two workers install or service a boat engine through an open access point in the boat's deck. One worker is wearing an orange and black shirt and brown boots, the other a black cap and black shirt. Tools and a black cover are visible nearby.
Person on a boat using a crane to lift equipment during maintenance or repair.
People sitting inside a boat on a sunny day, with a large wooden steering wheel and various navigational instruments at the front, parked at a marina with other boats in the background.
A sailboat being lifted out of the water by a boat hoist at a marina on a clear day with blue sky and scattered clouds.

Custom Allot Cat 54'

SEA-R‍ ‍

Sea-R underwent a major repower and systems overhaul, replacing the old Caterpillar engines with new John Deere 4045SFM85 engines. This upgrade more than doubled her top speed—from 12 to 22 knots. The project, managed by D’Aprix Marine Services, included coordination of multiple trades, a complete vessel re-wire, installation of a new battery system, and in-house anti-fouling. All works were carried out at the Gold Coast City Marina, with ongoing after-sales support and maintenance provided to ensure long-term performance and reliability.

A large yellow Caterpillar industrial engine with pipes and filters, placed on a table in a workshop.
Two workers installing a large industrial engine in a construction site with a concrete floor and structure.
A large industrial engine being lowered with a crane at a marina. The crane is labeled "GCCM" and "BIG LIFT," and part of a boat is visible in the background.
A white motor yacht cruising on calm water with a clear blue sky in the background.
Close-up view of machinery inside an aircraft with insulation, wiring, and metal components, including a protective wire cage covering part of the equipment.
A white engine installed in a boat hull with visible pulleys, belts, and hoses, surrounded by boat components.

SCIMITAR CAT

Yanmar 4LV’s ‍

The Scimitar Cat underwent a full repower and dash refit, transforming both its performance and user experience. D’Aprix Marine Services replaced the original twin petrol Volvo engines with two brand-new Yanmar 4LV diesel engines, significantly enhancing power and efficiency. To complement the engine upgrade, a state-of-the-art dash was custom-fitted, integrating the latest technology from Yanmar and Simrad. Originally reaching a top speed of just 15 knots, the vessel now effortlessly achieves 27 knots, delivering a smoother, quieter, and cleaner ride for its owners.

A boat's control console with a steering wheel, electronic panel, and wires, with some parts missing or disconnected.
A person working on two large, red and gray marine engines inside a boat's engine compartment.
A large boat is being lifted by a boat lift at a marina on a sunny day with a bright blue sky and scattered clouds.
Marine engine with Yamaha branding installed in a boat engine compartment surrounded by white surfaces and various hoses and pipes.
View of a boat's cockpit with navigational controls, steering wheel, and electronic displays, overlooking a marina with docked boats and a yacht in the background.
A man standing on a white motor yacht docked at a marina during daytime with clear blue skies.
Boat dashboard with Yanmar navigation screens, analog gauges, and control switches, with a marina and other boats in the background.
The image shows the interior of a partially disassembled white machine or device, exposing various wires, tubes, and internal components.

PerryCat 44.5

PURRFECT ‍

The PerryCat 44.5 vessel Purrfect underwent a comprehensive repower and upgrade, replacing its original Yanmar 4JH4-TE mechanical injection engines with advanced Yanmar 4LV250 Common Rail engines. The upgrade resulted in a cleaner, quieter, and more fuel-efficient performance with multi-stage injection technology. Managed by top shipwrights and painters, the project included custom dash installation, engine bed modifications, a full vessel respray, and in-house antifouling at The Boat Works Marina. Post-repower, Purrfect achieved impressive performance — 25 knots at 3500 RPM and a cruising speed of 15 knots at 2500 RPM.

A large white yacht docked at a marina with other boats in the background under cloudy skies.
The image shows the captain's control panel on a boat, featuring a steering wheel, two Simrad navigation screens, and various gauges and controls, with boat docks visible outside the windows.
Two men on a boat, one showing the other a smartphone with a sonar or fish finder display, near a steering wheel and electronic equipment, on a body of water.
A used car engine with visible belts, pulleys, hoses, and metal components, placed inside a garage or workshop.
A white sailboat named 'Purrfect' inside a large industrial warehouse, elevated on supports for maintenance or storage.
A mechanic working inside a vehicle's engine compartment, wearing a black shirt and cap.
Engine installed in a boat’s engine compartment with the Yamaha logo visible.
View of an engine installed inside a small, confined space in a boat or RV, with wiring and a mirror reflecting a bathroom or shower area.

LARSON 370' YANMAR 6LPA-STP

Moorea ‍

When the big project kicked off, we brought the Moorea into the D’Aprix shed for a complete re-power and refit, starting with routine maintenance to keep her systems in check and her bilges clean. We stripped her right down, pulling both petrol engines, the Westerbeke generator, and all the old plumbing, exhaust systems, and wiring, then gave the bilge a full sand, clean, and fresh coat of flow-coat and marine paint until it looked brand new. From there, we lifted in twin Yanmar diesel engines, fitted new PSS shaft seals, installed a MASE generator, and ran all-new fuel, exhaust, and raw water systems, upgrading just about everything along the way; new skin fittings, ball valves, sea strainers, a Sani Marine toilet, a macerator pump, bilge pumps, a Garmin autopilot system with rudder feedback, and a Bennett TPI trim tab kit. We also had the props scanned, re-pitched, and balanced before turning our attention to the finishing touches, wiring the dash, calibrating the Garmin fuel senders for both 500-litre tanks, and installing navigation lights, a Fusion stereo, a shore power lead, and bonding all through-hulls throughout the bilge area. With everything tested and operational, we took her out on a sea trial and she handled magnificently.

A boat docked in a boat lift at a marina with other boats visible in the background.
A white and black motorboat docked at a marina alongside a concrete pier, with other boats and yachts in the background.
Person working inside a white boat, kneeling and using tools near the interior.

MARINER 3400

KORA ‍

A D’Aprix Marine Services repower project brought new life to a classic 1989 Mariner 3400 by integrating two modern Steyr Diesel SE286E40 engines. This repower combined cutting-edge performance and efficiency with timeless design, delivering both power and reliability without compromising the vessel's original charm. The Steyr SE286E40 engines are known for their compact size, low emissions, and smooth operation, making them ideal for refits where space and performance are both critical. The result is a vessel that not only maintains the elegance and classic appeal of the Mariner 3400 but also benefits from improved fuel efficiency, reduced noise, and enhanced maneuverability — a seamless blend of heritage and innovation.

A person working under the floor of a boat, inspecting or repairing the boat's engines.
A close-up view of a Tesla electric engine with visible red and silver components, wires, and mechanical parts.
A white motorboat docked at a marina with several other boats surrounding it under a cloudy sky.

Have a Marine Engineering Project in Mind?

From complete engine repowers and major mechanical works to complex vessel refits, D’Aprix Marine Services brings specialist experience, precision workmanship and manufacturer-backed expertise to every project.

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