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  • How to Choose an Anchor Winch for Your Boat

    Guide

    How to Choose an Anchor Winch for Your Boat

    June 2026 · 7 min read · By Brian Rogers Marine Engineering

    How to Choose an Anchor Winch for Your Boat

    The right winch is sized to the chain and anchor, not to the brochure photo. Here’s how to pick it.

    The line-pull number

    Every anchor winch is rated for a maximum line pull — the force it can continuously apply to the chain. A conservative rule: pick a winch rated at three times the combined weight of anchor plus chain. That gives margin for breakout and for pulling the vessel against wind.

    Horizontal vs vertical

    Horizontal winches sit on deck, chain feeding over the roller. Pros: easy install, easy service. Cons: deck space, exposed motor.

    Vertical winches have the capstan on deck but the motor and gearbox below deck. Pros: tidy deck, protected motor. Cons: chain-locker depth needed.

    12V vs 24V

    Any winch over about 1,000 kg line pull should be 24V — the current draw at 12V becomes unreasonable (300A+). 24V halves the current and lets you use thinner cable.

    Battery and cable

    Winch draws large but short peaks. A dedicated 100 Ah AGM battery close to the winch, cable sized for less than 10% voltage drop at peak amps, breaker in the circuit near the battery. The battery is kept charged by the engine when running.

    Deck reinforcement

    A winch pulls up and backwards hard. The deck under the mounting must be reinforced — a steel or aluminium backing plate, bolted through with 10mm bolts minimum. Don’t rely on self-tappers.

    Chain stopper

    A separate chain stopper takes anchor load when you’re at anchor. The winch isn’t designed to hold ground tackle under sailing-anchor loads — it’s for raising and lowering.

    Need advice on your boat’s stern gear or propeller? Call Brian directly on 0413 771 090 or use the contact form — we respond the same day.

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    Propeller Slip Theory Explained
    Theory

    Propeller Slip Theory Explained

    Slip is the single most misunderstood number in propeller selection. Here’s what it really means — and why 30% slip isn’t a problem for a trawler.

    October 20267 min read

  • Oil-Type vs Grease-Type Shaft Seals

    Materials

    Oil-Type vs Grease-Type Shaft Seals

    June 2026 · 5 min read · By Brian Rogers Marine Engineering

    Oil-Type vs Grease-Type Shaft Seals

    Grease is simple and cheap. Oil runs cleaner and longer. Here’s when each one wins.

    What they do

    Both oil and grease seals form a barrier between the moving shaft and the stationary stern tube. The lubricant lowers friction and keeps the sealing elements running smoothly. Beyond that, they differ.

    Grease-type (traditional)

    A grease cup on deck feeds grease down a line to a sealed stern-tube chamber. Grease the cup periodically; grease pushes out through the shaft seal. Simple and robust, works on any size shaft, but you must remember to grease it.

    Oil-type (Super Seal and similar)

    A sealed reservoir of marine oil feeds the stern tube. Oil runs cleaner than grease, cools better, and lasts longer between services. More components, more cost, but less daily attention.

    Dripless face seals

    A separate category: carbon face against a stainless rotor, water-cooled. No grease or oil in the normal sense. Longest-lasting of the three but needs well-aligned, straight shafts.

    Which to pick

    Casual pleasure boat: grease is fine, cheap, forgiving. Commercial / high-hours: oil-type pays back in less service time. Modern pleasure boat where bilge dryness matters: dripless face seal.

    Need advice on your boat’s stern gear or propeller? Call Brian directly on 0413 771 090 or use the contact form — we respond the same day.

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  • Propeller Nozzles — When They Help, When They Don’t

    Theory

    Propeller Nozzles — When They Help, When They Don’t

    May 2026 · 6 min read · By Brian Rogers Marine Engineering

    Propeller Nozzles — When They Help, When They Don't

    A nozzle can boost bollard pull by 30% — but it costs you top speed. Here’s when to fit one.

    What a nozzle is

    A propeller nozzle (or Kort nozzle) is a short duct around the propeller. By accelerating water onto the blades it increases thrust at low speeds and reduces propeller tip losses. On a trawler or tug, that can mean 20–30% more bollard pull.

    The physics

    At zero or low speed, the nozzle acts as a lifting aerofoil, generating a forward thrust itself. At high speed, drag on the nozzle exceeds any thrust it adds — so the nozzle slows the vessel.

    Who benefits

    • Prawn and demersal trawlers at tow.
    • Harbour tugs.
    • Workboats pulling heavy loads.
    • Push-boats on rivers.

    Who does not benefit

    • Planing hulls at speed.
    • Pleasure cruisers.
    • Any vessel whose top speed is a priority.

    Nozzle fitting

    Nozzles are typically welded steel, mounted to a dedicated foundation welded to the hull. The propeller runs with a tip clearance of about 1% of propeller diameter. Install is a shipwright job on a slipway.

    Need advice on your boat’s stern gear or propeller? Call Brian directly on 0413 771 090 or use the contact form — we respond the same day.

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    Anode Selection for Marine Vessels
    Theory

    Anode Selection for Marine Vessels

    Choose the wrong anode and your prop and shaft pay for it. Zinc, aluminium or magnesium — here’s how to decide.

    August 20266 min read

  • Diagnosing Boat Vibration Problems

    Troubleshooting

    Diagnosing Boat Vibration Problems

    May 2026 · 7 min read · By Brian Rogers Marine Engineering

    Diagnosing Boat Vibration Problems

    If the boat vibrates at a specific RPM, there’s a reason — and it’s usually fixable. Here’s where to start.

    Does the vibration tie to RPM?

    First question: at what RPM does the vibration appear? That tells you a lot. Vibration proportional to engine RPM — engine- or coupling-side. Vibration at a specific RPM, going away either side — resonance, often shaft or hull.

    Propeller as the usual suspect

    A bent blade, a lost tip, a chipped edge, or growth on the blades will cause vibration at propeller RPM (engine RPM ÷ gearbox ratio). Remove the propeller, inspect, measure. 1° pitch variation blade-to-blade = noticeable vibration.

    Shaft issues

    Bent shaft, loose coupling, worn cutless bearing letting the shaft whip — each shows at propeller RPM. Run-out gauge on the shaft near the coupling is the test.

    Alignment

    Poor engine-to-shaft alignment causes vibration that gets worse under load. A feeler-gauge check at the coupling will show it.

    Engine mounts

    Old or saturated engine mounts transfer vibration to the hull. Press down on each mount with the engine running at idle — a soft mount compresses noticeably. Replace at manufacturer intervals (typically 7–10 years).

    Hull resonance

    A vibration that occurs at just one RPM and nowhere else is often hull resonance — the propeller is forcing a frequency at which the hull plates ring. Changing propeller blade count can shift the forcing frequency away from the resonance.

    Need advice on your boat’s stern gear or propeller? Call Brian directly on 0413 771 090 or use the contact form — we respond the same day.

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  • A Brief History of Marine Engineering in Australia

    History

    A Brief History of Marine Engineering in Australia

    April 2026 · 8 min read · By Brian Rogers Marine Engineering

    A Brief History of Marine Engineering in Australia

    A short history of our trade — from pulley blocks and tar to CAD-designed propellers.

    The sail era

    Marine engineering in colonial Australia began as blacksmithing. The first marine shops in Brisbane, Sydney and Hobart made iron fittings, chain, rudder stocks, and (eventually) rigging screws for schooners. The sail era handed off slowly — well into the 20th century, many fishing boats still carried a working sail rig alongside the engine.

    Steam and the early engine era

    Steam engines came late to Australia and left early. The real revolution was the arrival of marine diesel in the 1920s. Suddenly a 40 ft fishing boat could carry a reliable 30 hp engine, work farther from port, and skip the sail. The marine engineering trade shifted to shaft lines, propellers and gearboxes.

    The post-war boom

    After 1945, boat building and marine engineering grew with the Australian prawn fishing industry. Trawlers north of Brisbane and in the Gulf of Carpentaria needed propellers, shafts and winches. Brian Rogers started his trade in 1950, serving Brisbane and the growing Queensland fleet.

    The CAD era

    By the 1990s, propeller design moved from pattern-and-tradition to CAD. Blade shapes could be modelled, performance curves predicted. Brian Rogers Marine Engineering adopted CAD design in that era — allowing propellers to be matched exactly to the engine and hull, with measurable fuel savings.

    Today

    Today the workshop combines traditional precision machining with modern 3D design and CNC-ready drawings. The business is the same — stern gear for vessels across Australia — but the tools have evolved. Decades of accumulated knowledge about hull-prop-engine interaction remain the single most valuable asset.

    The next decade

    Marine engineering faces the same transitions as the broader marine trade: electrification of pleasure craft, hybrid propulsion on commercial vessels, and continued pressure on fuel economy. Propellers for electric drives are already a growing part of the design workbook, and the trade will continue to adapt.

    Need advice on your boat’s stern gear or propeller? Call Brian directly on 0413 771 090 or use the contact form — we respond the same day.

    Read Next

    More from our workshop

    Diagnosing Boat Vibration Problems
    Troubleshooting

    Diagnosing Boat Vibration Problems

    If the boat vibrates at a specific RPM, there’s a reason — and it’s usually fixable. Here’s where to start.

    May 20267 min read
    How Your Propeller Affects Fuel Burn
    Theory

    How Your Propeller Affects Fuel Burn

    If your boat is wearing the wrong propeller, you’re burning diesel for no return. Here’s how to see it in numbers.

    June 20266 min read