Engines and Repowering

Repowering an older sailboat or trawler involves much more than simply replacing the engine. The projects below cover the complete diesel repower and repair process, including troubleshooting and repairing existing equipment, selecting a replacement marine diesel, engine removal, engine-room planning, rebuilding engine beds, shaft and coupling work, exhaust, cooling, fuel filtration, electrical and charging systems, controls, instrumentation and final installation. The process also includes diesel fuel tank removal and repair, including cleaning, inspection, corrosion repair and preparing an older aluminum tank for continued service. Together, these projects cover the engine, fuel system and supporting mechanical systems involved in repairing and repowering an older boat.

Ultimate Pocket Trawler Diesel Engine Repower

Follow my complete Albin 27 pocket trawler diesel engine repower series, as I document every step required to replace an aging marine diesel with a new engine in an older fiberglass boat. This series covers the entire marine diesel repower process, including engine selection, measuring the engine compartment, comparing specifications, ordering and actual costs, removing the old engine, preparing the engine room, installing the new diesel, engine mounts, transmission, propeller shaft and drivetrain alignment, cooling, exhaust, fuel, electrical and charging systems, controls, testing and final installation.

The goal is to create a practical, real-world guide for anyone considering a DIY diesel engine replacement or repower in an older sailboat, trawler or cruising boat.

Join the Werkers for additional notes and behind-the-scenes content from the Albin 27 repower and restoration.

Go to the WERKERS

How to Choose a Diesel Engine for a Boat Repower

Choosing the right diesel engine is one of the biggest decisions in a boat restoration or repower. In this video, I walk through the process of selecting a new marine diesel engine for my 1986 Albin 27 pocket trawler, including why I removed the original Nissan LD28, how I determined the appropriate horsepower for a displacement hull, and the small marine diesel engine options available in the U.S. I explain why I chose a Beta Marine 43 HP diesel and cover the practical considerations for a DIY boat repower, including engine size, installation, engine beds and mounts, serviceability and long-term maintenance.

How to Determine if a Marine Diesel Engine Will Fit Your Boat

Before choosing a new marine diesel engine, you need to determine whether the engine will physically fit your existing engine compartment, engine beds and hull. In this video, I show the measurement and mockup process I use when planning a DIY boat repower, including checking engine dimensions, oil-pan clearance, engine-bed spacing and the effects of an asymmetrical fiberglass hull. Using a Beta Marine 43 installation as the real-world example, I compare deep-sump and shallow-sump configurations and show why careful engine fitment needs to happen before ordering components or beginning a marine diesel repower.

Mechanical vs. Common Rail Marine Diesel Engines for a Boat Repower

When repowering an older sailboat or trawler, the choice between a mechanical diesel and a modern common rail engine can affect reliability, serviceability and long-term maintenance. In this video, I use my new Beta Marine 43 as a real-world example and explain why I chose mechanical fuel injection over a common rail Yanmar for a long-range cruising boat. I also walk through the complete repower package, including a 275-amp high-output alternator, dual alternator charging, hydraulic transmission, shallow oil sump, custom engine mounts, heat exchanger plumbing, shaft coupling and lithium battery charging system.

How to Build a Fiberglass Sailboat Engine Well Plug

This Skipper 20 engine well restoration shows how to improve an open sailboat outboard engine well by fabricating a removable fiberglass plug that closes the large opening in the bottom of the hull when the outboard is not being used. The project covers measuring and patterning the engine well, shaping closed-cell foam, laminating a custom fiberglass plug, sanding and fairing the finished part, and adding rubber gasket material and a split boot to control water intrusion. The result demonstrates a practical DIY solution for improving the engine well on a small sailboat while retaining access to the outboard when needed.

Removing, Inspecting and Restoring an Aluminum Diesel Fuel Tank

Old diesel fuel tanks can hide corrosion, leaks, sludge and decades of contamination—while being extremely difficult to remove from a sailboat or trawler. In this video, I show the complete process of removing a large aluminum diesel fuel tank through a restricted cabin opening, disconnecting the fuel and fill lines, and inspecting the tank for corrosion, pinholes and chafing. I also cover cleaning accumulated diesel sludge, fabricating DIY aluminum inspection ports, restoring the existing tank and pressure-testing it before putting it back into service.

Planning a Boat Engine Room for a Diesel Repower

A well-planned engine room makes a major difference when repowering or rebuilding an older sailboat or trawler. In this video, I show how I planned a compact engine compartment to make the best use of limited space while maintaining access for installation, service and future maintenance. I cover diesel engine placement, freshwater and holding tanks, marine electrical and plumbing systems, sound insulation, bulkhead organization, through-hull fittings, scuppers and steering components, using my Albin 27 restoration as the real-world example.

How to Remove an Old Marine Diesel Engine From a Boat

Removing a heavy diesel engine from an older sailboat or trawler can be one of the biggest challenges in a boat repower. In this video, I show how I removed the old marine diesel from my boat using a crane and discuss DIY alternatives for lifting and extracting an engine when professional equipment isn’t available. I cover planning the lift, dealing with limited engine-room access, safely moving the engine through the boat, and practical options for getting an old diesel engine out before installing a replacement.

How to Paint a Boat Bilge and Engine Room with Epoxy Bilge Paint

Painting the bilge and engine room is an important part of restoring an older sailboat or trawler, but the coating needs to withstand water, oil, fuel and other chemicals found around marine engines and bilges. In this video, I show the complete preparation and application process using Total Boat epoxy bilge paint, including surface preparation, painting techniques and the finished coating. I also give an unsponsored review of the epoxy bilge paint and discuss its durability and suitability for a DIY fiberglass boat restoration.

Repairing Fiberglass Engine Room Hatches & Replacing Soundown Insulation

Engine room hatches on older sailboats and trawlers can develop flexing, cracked fiberglass and water intrusion, particularly around soundproofing installations. In this video, I remove failed Soundown marine sound insulation, diagnose water damage and repair a deteriorated fiberglass hatch lip using epoxy and fiberglass reinforcement. I also cover engine-room hatch construction, soundproofing, water intrusion and why proper project sequencing matters when restoring or repowering an older boat.

Removing a Rusted Propeller Shaft Coupling During a Boat Repower

A rusted or seized propeller shaft coupling can be difficult to remove when repowering an older sailboat or trawler. In this video, I show how I removed an old marine shaft coupler as part of a diesel repower, including why the coupling needed to come off, the tools used to cut and remove it, and the precautions required when working around the propeller shaft. I also discuss engine placement, shaft alignment and marine transmission choices that need to be considered before installing the new diesel engine.

Using iPhone LiDAR and CAD to Measure a Boat for an Engine Repower

Accurate measurements are critical when fitting a new diesel engine into the confined engine compartment of an older sailboat or trawler. In this video, I show how to use an iPhone LiDAR scanner to capture a 3D model of a boat’s engine compartment and import the scan into CAD software for engine-placement planning. I compare LiDAR scanning with traditional tape measurements and templates, demonstrate scanning and exporting with iPhone apps and Onshape, and cover common scanning mistakes. This technique can help DIY boat restorers plan engine fit, clearances and component placement before installation begins.

Using Foam Mockups to Plan Water Tanks, Batteries and Engine-Room Layout

Before ordering expensive tanks or installing major components, a simple foam mockup can help determine whether everything will fit inside a tight sailboat or trawler engine compartment. In this video, I show how I use EPS foam to build full-size mockups of freshwater and waste tanks, batteries and other marine components before installation. I also cover engine-room layout, tank sizing and fittings, space planning for pumps and electrical systems, and common mistakes that can be avoided by testing component placement before committing to the final installation.

How to Stop Water Entering Boat Engine Room Vents

Engine-room ventilation needs to provide adequate airflow without allowing rain, spray or boarding water into the engine compartment. In this video, I show how I upgraded the engine-room vents on an older trawler by replacing the original plastic vent covers and fabricating custom fiberglass dorade boxes to help separate water from incoming air. The project covers marine engine-room ventilation, preventing water intrusion, fiberglass fabrication with epoxy and WEST SYSTEM products, and improving vent protection while maintaining airflow for the diesel engine and onboard systems.

Where to Find Rare, Vintage and Obsolete Boat Parts

Finding rare or discontinued boat parts can stop a classic boat restoration when the original hardware, engine component or replacement part is no longer manufactured. In this video, I visit Marine Sales & Repair near Detroit and meet Earl “the Pearl” Stilson, one of the remaining old-school boat-parts dealers specializing in used, vintage and hard-to-find marine components. His inventory includes vintage Chris-Craft parts, Hercules marine engine components, rare engine gaskets, bronze hardware, teak handrails and decades of used marine equipment. He has a lifetime of engine repower knowledge. For anyone restoring an antique powerboat, classic fiberglass sailboat or older trawler, marine salvage yards and longtime used-parts dealers can be an important source for obsolete marine engine parts and boat hardware that conventional suppliers no longer carry.