Accelerating A Diesel Sailboat: Manual Techniques For Engine Power

Manually accelerating a diesel engine sailboat can be challenging, and most modern sailboat inboard engines cannot be started by hand. However, some engines with manual cranks and decompression levers can be manually started. This process involves placing the throttle in the normal starting position, flipping the decompression levers, and cranking the engine by hand. Once the engine is rotating at maximum speed, the decompression levers are flipped back one by one until the engine runs on all cylinders. This method requires caution, as it can be physically demanding and has potential safety hazards.

Additionally, common issues with diesel engines can impact their acceleration, such as turbo problems, blocked fuel filters, marine growth on the hull or prop, or clogged exhaust elbows. Creative solutions, like using the sails to start the engine, may be required in certain situations.

Check for a blocked fuel filter

A blocked fuel filter is one of the most common causes of a marine diesel engine not starting. If you're experiencing engine problems and have ruled out electrical issues, you should check your fuel system.

Here's a detailed guide on checking for a blocked fuel filter:

Check the Fuel Tank

Firstly, ensure your fuel tank has fuel in it. Don't rely solely on the gauge, as gauges can be faulty. Perform a visual check or dip the tank to confirm.

Check the Fuel Shut-Off Valve

Next, verify if the fuel shut-off valve is open or closed. If the boat has been stored or used by someone else, they might have closed the valve. Make sure it's open.

Inspect the Primary Filter

The primary filter removes large debris and separates water from the fuel. If your primary filter has a glass bowl, check for a line indicating the separation between water and fuel. For metal bowls, drain some fuel to check for water.

Examine the Fine Filter

The fine filter is the final stage of protection before fuel enters the high-pressure pump. If fuel isn't passing through, it could be blocked with contamination or diesel bug. Change the filter, refill it with fuel, and bleed the air out.

Check for Air in the System

Refer to your boat's manual to locate the bleed point. Place a rag, paper towel, or fuel soak under the filter, then unscrew the bleed to release trapped air. Use the manual fuel pump to lift fuel into the filter until clear fuel emerges from the bleed point, free of bubbles.

Address Fuel Contamination

If you have water, debris, or diesel bug in your fuel, consider bypassing your fuel tank. Disconnect the fuel hose between the tank and the primary filter, and connect it to a jerry can of clean fuel.

By following these steps, you can comprehensively check for and address a blocked fuel filter in your diesel engine sailboat, helping to restore its acceleration and performance.

Check for a fouled prop or rope around the shaft

If you notice that your diesel engine sailboat is slow to accelerate, there could be a number of issues at play, one of which is a fouled prop or rope around the shaft. This is a common occurrence irrespective of the type of boat you own. The typical culprits include mooring lines, anchor ropes, fishing lines and nets, and even plastic packets.

Identifying the Issue

Firstly, assess the situation. If you are drifting in safe waters with no immediate danger, you can take your time to address the issue. If there is a possibility of grounding or drifting ashore, it is crucial to act promptly. Consider deploying an anchor to prevent drifting and notify the coastguard or nearby boats for assistance if needed.

Freeing the Fouled Prop

If you are lucky enough to have access to the end of the rope, a simple method is to pull on the free end while another person manually rotates the propeller shaft in the opposite direction from which it was turning when the line was pulled in. This might cause the line to unwind.

If this is not possible, a different approach involves starting the engine in neutral with low revs and briefly pushing into reverse. This action should be momentary, and it is important not to rev the engine hard as it may wrap the line more tightly.

Cutting the Rope

If the above methods are unsuccessful, you may need to resort to cutting the rope. This task can be challenging and even dangerous, depending on the conditions and the type of boat. It often requires donning a wetsuit, dive mask, snorkel, or even scuba diving gear for those trained in its use. Ensure you have a sharp, serrated knife securely attached to a lanyard or pole.

Before entering the water, consider the water temperature, current strength, and the potential for the boat to shift suddenly due to passing wakes. Always have a boarding ladder or another means to get back on board, and tie a rope around the person entering the water as a safety precaution.

Post-Fouling Checks

Once you have successfully freed the prop, engage gear and apply power carefully. It is important to inspect for any potential damage caused by the fouling to the propeller, stern tube, or prop shaft bearings. Be alert for any vibration or water ingress, as these could indicate an issue.

Preventative Measures

To reduce the chances of a fouled prop in the future, consider installing a prop protector or rope stripper. These accessories are available for various types of boats and can be easily retrofitted. Additionally, when manoeuvring or docking, assign a crew member to manage the painter, keeping it short to minimise the risk of entanglement.

Check for carbon buildup

To check for carbon buildup in a diesel engine, you can use a borescope/endoscope inspection camera. However, it may not fit through the glow plug hole, and you may not want to dismantle a lot of the engine to find another point of entry.

There are only three holes in a diesel engine: the intake, the exhaust, and the fuel injector. The best option will depend on the specific engine and its design.

Carbon buildup is generally more of a problem in diesel engines than in gasoline engines. This is because gasoline has certain detergents added at the refinery, which keeps the injectors cleaner and reduces the carbon load. Diesel fuels do not have this benefit.

Carbon buildup in diesel engines is often caused by:

• Poor fuel quality: Low-quality diesel can contain higher levels of impurities and contaminants that contribute to carbon deposits.
• Short trips and low operating temperatures: If a diesel engine doesn't reach and maintain optimal temperatures, unburned fuel and soot can accumulate.
• Extended idling: Idling causes the engine to operate at lower temperatures, which is not ideal for efficient combustion in diesel engines.
• The EGR (Exhaust Gas Recirculation) System: While crucial for reducing nitrogen oxide emissions, the recirculation of exhaust gases can introduce carbon particles into the engine's combustion chamber.
• Dirty or malfunctioning fuel injectors: These can cause an improper spray pattern or fuel droplet size, leading to incomplete combustion and carbon deposits.
• Low-quality engine oil or infrequent oil changes: High-quality engine oils contain detergents and additives that help minimize deposit formation.
• Turbocharger issues: Any problem causing the turbocharger to perform inefficiently can lead to carbon buildup.
• Overuse of engine braking: Excessive use of engine braking can increase soot production, contributing to carbon buildup.

Check for a turbo problem

If your diesel engine on your sail boat is slow to accelerate, this could be a classic symptom of a turbo problem. To check for a turbo problem, you can start by inspecting the engine room for any oil drips or other fluid under the engine. Look for cracked hoses, loose hose clamps, and cracked fan belts. Feel the inside of the engine room for any oil film and check the areas of the engine that are out of sight for rust or salt trails.

Next, you can inspect the oil by pulling the dipstick and smelling for signs of diesel odor, which could indicate a leaking fuel pump or a failing injection pump. You can also perform a crude viscosity test by pinching a small amount of oil between your fingers and slowly expanding to see how far you can spread it. Compare this to new oil and record the difference.

Another way to check for a turbo problem is to inspect the air inlet. Remove the air filter and check for cleanliness. There should be a light coating of dirty, but not gritty, oil. If there is loose oil or splatter, this could indicate a faulty intake valve or a failing turbo.

If your engine has a turbocharger, you can also perform a turbo pressure test. Find a test port on the intake manifold and install a pressure gauge to check the turbo boost. Compare this to the manual specifications for your engine. A stable pressure that matches the specifications indicates a healthy turbocharger.

If you suspect a turbo problem, it is important to consult a qualified mechanic or marine engineer for further diagnosis and repair.

Check for marine growth

To check for marine growth on your sailboat, start by inspecting the hull and propeller for any signs of buildup. Marine growth can refer to the growth of algae, barnacles, grass, and other marine life on your boat, which is also called biofouling. This can decrease the efficiency of your vessel and reduce its lifespan by corroding key components and causing blockages.

If you find any marine growth, it is important to remove it. You can do this by hiring a diver to clean the hull or by hauling your boat out of the water and scraping off the growth. To prevent marine growth, you can use anti-fouling paint, invest in an anti-fouling system, or use a combination of both. Anti-fouling paint creates a protective layer that prevents marine growth from clinging to your boat. There are several types of anti-fouling systems available, including electrolytic, ultrasonic, chemical dosing, and electro-chlorination systems. These systems use different methods, such as copper ions, high-frequency waves, or chemical dispersants, to prevent marine growth.

In addition to checking the hull and propeller, you should also inspect other underwater metal components such as props, struts, rudders, through-hulls, external strainers, trim tabs, and thrusters. These areas are susceptible to marine growth and should be protected with an effective coat of anti-fouling paint or another type of coating. It is important to note that anti-fouling paint or other preventative measures may not completely eliminate marine growth, especially if your boat is left unused for extended periods. Therefore, regular maintenance and cleaning are crucial to keeping your boat in good condition.

Frequently asked questions