A Complete Guide to Marine Hoses

Marine hoses are important for transporting fluids like fuel, water and waste. Each type of marine hose has a specific purpose, ensuring your boat functions well and reducing the risk of leaks, spills and accidents. Whether you own one, take them out fishing or work with them, boats need hoses that work properly and last long. 

We compiled a complete guide to marine hoses to help you identify the type you need to ensure your vessel's safety and efficiency. Choosing the right marine hose that's compatible with your boat's needs includes various considerations, including the use, size, flexibility and durability of the material. Investing in high-quality boating hoses and following recommended maintenance practices can extend the lifespan of these critical components, reducing the frequency of replacements.

Learn about the different types of marine hoses, materials, and installation and maintenance best practices so you can make informed decisions and select the right marine hose for your vessel's needs.

Types of Marine Hoses 

Choosing a marine hose will depend on the specialized application you need it for, such as fuel transfer, water circulation, sanitation and engine cooling. Let's examine some common marine hoses.

Marine Sanitation System Hoses 

Marine sanitation system hoses are tough, flexible and resistant to toilet chemicals. These hoses can be used in boats, yachts, motorhomes and even caravans for sanitary systems. Their purpose is to carry waste throughout your boat's sanitation system, whether from the toilet to the holding tank or from the tank to a disposal system.

Sanitation hoses' most important feature is their odor impermeability. If you use hoses that easily leak or permeate, your boat will quickly give off unpleasant smells. This happens because bacteria break down raw sewage in hose or piping systems, creating anaerobic gases like methane. These gases pass through or absorb into the hose's material. After some time, the hose weakens or starts to form holes and cracks that release these odors.

Smooth bores and heavy built-in barrier layers help to prevent waste trapping and odors compared to corrugated hoses. Most sanitation system hoses last five years or more against odor permeation, after which they need to be replaced.

Marine Fuel Systems 

Marine fuel systems and assembly pieces are specifically engineered to transport fuel on boats safely. They're constructed from high-standard materials that resist degradation from fuels like gasoline and diesel and with low permeability. Many fuel lines are made from metal piping with flexible sections to allow movement in the engine compartment.

Fuel hoses must meet strict safety standards to prevent leaks and fire hazards. They need to be U.S. Coast Guard-approved and marked with J 1527 standards. These hoses are usually marked as A1, A2, B1 or B2 with some variations:

• A1-type hoses: A1 hoses are generally recommended for gasoline uses, especially for fuel lines connecting tanks to engines or generators, due to their reduced permeability and enhanced resistance to fire.
• A2-type hoses: A2 hoses are less common than A1 and are used where slightly lower specifications are acceptable, but still require some level of fuel resistance and safety.
• A1-15 hoses: These hoses are ideal for newer gasoline-powered boat fuel systems due to strict environmental regulations from the U.S. Environmental Protection Agency (EPA). A1-15 hoses provide enhanced resistance to permeation and fire safety measures.
• B1-type hoses: B1 hoses are typically used for diesel applications, including fuel lines for diesel engines and generators.
• B2-type hoses: B2 hoses are less common than B1-types. Since they're less resistant to permeation, they may be used in applications with lower specifications than for B1 hoses.

Engine Cooling Systems 

Whether you're sailing calm seas or through stormy weather, you need an engine cooling system that will last for many years. Engine cooling hoses, or cooling water hoses, are responsible for circulating cooling water or coolant to regulate an engine's temperature. These hoses are made from heat-resistant materials to withstand both high and low temperatures. They're available in various sizes to fit different engine configurations.

Here's how a boat's engine cooling system typically operates:

1. Raw water cooling system: A seacock draws raw water from beneath the boat's hull and pumps it through the engine's water jacket and cooling passages with a mechanical water pump. As it circulates, the water absorbs heat from the engine components.
2. Heat exchanger: The heat exchanger transfers heat from the engine coolant — whether it's freshwater or an antifreeze mixture — to the raw water passing through it.
3. Connection points: Engine cooling hoses connect different components of the cooling system, ensuring a sealed pathway for the coolant.

In an enclosed cooling system, an engine has a tank on top that mixes fresh water and coolant instead of using water from the surrounding environment. This prevents saltwater corrosion in the engine as the raw water only passes through the heat exchanger.

Specialty Marine Hoses

One type of specialty marine hose is the bilge pump hose. Bilge hoses are used to remove water from the bilge area of a boat. They typically consist of flexible and abrasion-resistant materials and may have anti-kink properties to maintain flow under pressure with minimum restriction. These hoses play an important role with the bilge pump to prevent water from accumulating in the hull and maintain a boat's buoyancy and stability.

Bilge pump hoses typically come in two forms:

• Corrugated bilge hose: These boating hoses are easy to run, bend and cut. They are often supplied with bilge pumps but contain a ridged internal structure that restricts flow with extra friction.
• Smooth-bore bilge hose: Smooth-bore pump hoses are better choices since their smoother internal surfaces offer greater flow and efficiency.

Some bilge hoses go lower than where submersible bilge pumps are installed so they can remove more water. However, the hose should have no rises or loops where water can get trapped, adding more resistance for the pump.

Marine Hose Materials

When selecting marine hoses, consider factors such as compatibility with fluids, environmental conditions, flexibility and durability.

Here are some common materials used in marine hoses:

• PVC: Polyvinyl chloride (PVC) hoses are commonly used for sanitation or bilge hoses due to their chemical resistance and durability in water environments. Rigid PVC hoses prevent odors from permeating, but are less flexible and form no direct connections to pumps and thru-hulls.
• EPDM: Ethylene propylene diene monomer (EPDM) rubber is commonly found in marine sanitation hoses and engine cooling hoses because of its excellent flexibility, suction and high temperature, chemical and pressure resistance.
• Nitrile rubber: Nitrile rubber provides excellent resistance to oil and fuel permeation, helping to meet strict fuel safety standards.
• Vinyl: Vinyl hoses are lightweight and flexible, making them suitable for bilge and sanitation systems as smooth-walled hoses.
• Nylon: Nylon is a reinforcement material in many marine hoses to provide strength, flexibility and resistance to harsh chemicals and environmental requirements.
• Stainless steel: Due to their corrosion resistance and durability, stainless steel clamps and spirals are used to secure or reinforce hoses in marine applications.

Marine Hose Installation and Maintenance 

Proper installation practices, regular cleaning procedures and a suitable hose repair kit can help you maintain the integrity and functionality of your marine hoses, ensuring they perform effectively and have an extended life span.

Common issues that could arise from neglecting hose maintenance include:

• Leaks: Deterioration over time can lead to cracks, tears or weakened spots, causing leaks in the system.
• Reduced flow: Accumulation of foreign materials or blockages in neglected hoses can restrict the flow of fluids, affecting cooling, fuel or sanitation systems.
• Overheating: In the case of engine cooling systems, neglected fuel hoses with reduced coolant flow can lead to an engine overheating, potentially causing damage to engine components.
• Safety hazards: Leaking fuel hoses pose a fire hazard, while leaking sanitation hoses create health risks due to exposure to waste.
• Corrosion: Neglected hoses in contact with metal components can cause corrosion due to the buildup of moisture or chemical interactions.
• System failure: A damaged hose in bilge pumps can lead to system failures at crucial times, compromising the safety of the vessel and its occupants.
• Environmental impact: Leaking hoses can discharge harmful substances into the water, leading to environmental pollution and potential regulatory issues.
• Costly repairs: Addressing issues resulting from damaged hoses can be more costly than routine maintenance as it may involve repairing or replacing other damaged components.

Proper installation, cleaning and repairing as needed can prevent these issues and ensure your boat's systems remain safe and reliable.

Hose Installation Guide 

Here are a few hose installation best practices and common mistakes to avoid:

• Follow manufacturer instructions: Always adhere to the manufacturer's installation guidelines specific to the type of hose.
• Proper routing: Route hoses in a way that avoids kinks, sharp bends and chafing against other surfaces.
• Secure connections: Use appropriate fittings and secure connections with hose clamps rated for marine use. Most boats use flexible vinyl or rubber hoses with barbed fittings. You heat these hoses in hot water and use liquid soap as a lubricant for easier installation over barbed fittings.
• Avoid excess length: Cut hoses to the required length to prevent sagging or coiling, which can restrict flow.
• Safety precautions: Use double hose clamps below the waterline for added security and stability. Be sure to connect fittings of the same material within a system to prevent splitting weaker fittings.

Hose Cleaning Methods 

Cleaning marine hoses is an important step to maintain their life span and remove any debris or buildup that may lead to damage or contamination of fluids.

Follow these recommended cleaning practices:

• Water rinse: Flush hoses with clean water to remove debris and residue regularly.
• Mild soap solution: Use a mild soap solution to clean hoses if needed, followed by thorough rinsing.
• Avoid harsh chemicals: Harsh chemicals or solvents may damage the hose's material. Stick with marine-grade boat wash soap that you can use to clean hoses and your boat's surface.
• Prevent standing water: Ensure you install hoses in a way that prevents standing water in sags or loops to avoid premature clogging.
• Dry thoroughly: Allow hoses to dry completely before storage to prevent mold or mildew growth.

Hose Repair Kits 

It's important to inspect marine and boating hoses regularly for wear, leaks and cracks. Additionally, having one or more of the following hose repair kits onboard is beneficial for quick DIY fixes:

• Emergency patch kits: These kits include adhesive patches or tape that can be used to seal small leaks or tears in hoses temporarily.
• Clamp and fitting kits: Various sizes of hose clamps, fittings and connectors in these kits can secure or replace damaged connections on hoses.
• Sealant kits: Sealants and compounds in these kits can be applied to leaks or cracks in hoses to provide a temporary fix until a more permanent repair can be made.
• Patch and plug kits: These kits include rubber plugs, patches or epoxy putty that can seal larger holes or punctures in hoses.
• Emergency hose replacement kits: Included in these comprehensive kits are spare lengths of hose, fittings, clamps and tools to replace a damaged hose.

Choosing the Right Marine Hose 

When choosing the right marine hose, consider the following factors:

• Application: Determine the specific purpose of the hose to select one suitable for the application.
• Material compatibility: Ensure the hose material is compatible with the fluids it will be carrying to prevent degradation or contamination.
• Length: Select the correct length based on your boat's flow requirements and installation needs.
• Temperature range: Consider the temperature range the hose will be exposed to and choose a material that can withstand those conditions without deteriorating.
• Flexibility and bend radius: Ensure the hose is flexible enough to accommodate bends and curves without kinking or restricting flow, especially in tight spaces. This is particularly important for sanitation systems and bilge hoses.
• Reinforcement: Depending on the application, consider hoses with reinforcement layers for added strength and durability, such as PVC or vinyl.
• Resistance to chemicals and UV: Choose hoses resistant to chemicals, UV rays and other environmental factors relevant to your boating environment for longevity.
• Ease of maintenance: Consider how easy it will be to clean, inspect and maintain the hose over time.

Hose Measurement Guide

Hoses are sized by their inside diameter (ID) — measured in inches — with fittings labeled based on the ID of the hoses they fit. To choose the right size hose, they need to match the fittings on pumps, through-hulls, deck fills and tanks. You can use reduction nipples or suitable hose nozzles to adjust different diameters if needed for compatibility. For hose clamps, measure the outer diameters of the hose.

These are popular hose sizes by application:

• Bilge hoses: 3/4 inch, 1 1/8 inch, 1 1/2 inch and 2 inches
• Sanitation hoses: 1 1/2 inch
• Fuel hoses: 1/4 inch to 3/8 inch, depending on the engine's size

Hose Pressure Ratings

Marine hoses come in different pressure ratings, depending on the hose's design and ID. It's best to select a hose with a pressure rating that matches or exceeds the maximum operating pressure of the system to ensure it performs as needed. A slightly higher pressure rating than the system's max provides a margin of safety against unexpected spikes or fluctuations. Smaller hoses and those with reinforcements can handle higher pressures.

Shop Marine Hoses From Fawcett Boat Supplies

If you're a boat owner, marine mechanic or boat maintenance professional, you want to ensure your vessels work safely and efficiently for a long time with limited issues. That's why selecting the right hoses for your specific boating needs is so important.

If you need help narrowing down your choices, Fawcett Boat Supplies can help you find a marine hose for the right application. We provide a 100% money-back guarantee if you're unhappy with your product. Get in touch with our helpful sales team with any assistance you need.