Bronze Hose Barbs

Hose fittings and connectors for marine installations

A hose fitting is the part that joins, branches or adapts two or more runs of pipework on board. On boats they are used in fresh and raw water circuits, engine cooling, bilge pumping, grey and black water, fuel and ventilation. At Repuestos Marinos we bring together more than 128 references of fittings and connectors in brass, AISI 316 stainless steel, reinforced nylon and polypropylene.

The wrong fitting is one of the most common causes of leaks and water ingress on board. It comes down to three details: hose diameter, thread type and material compatible with the fluid that will pass through it.

Types of fitting and connector by shape

• T fitting — branches a line off the main run while maintaining flow in both directions
• Y fitting — joins or splits two lines with less pressure drop than a T
• L fitting or 90° elbow — changes the direction of the run in tight spaces
• Straight fitting or joiner — connects two sections of the same diameter
• Reducing fitting — adapts two different diameters without needing extra adapters
• Cross fitting — four outlets for manifolds and distribution points

Connectors, for their part, deal with the threaded side: straight male-female unions, quick-connect couplings, thru-hulls, BSP-to-NPT thread adapters and swivel connectors for runs that move.

How to choose the right fitting

1. Measure the inside diameter of the hose, not the outside. Barbed fittings are designated by the diameter they take: 10, 13, 16, 19, 25, 32, 38 and 51 mm are the most common on leisure boats.

2. Identify the thread. European marine work is dominated by BSP gas thread (1/8", 1/4", 3/8", 1/2", 3/4", 1"). American engines usually use NPT, which is tapered and is not interchangeable with BSP even if the diameter looks the same.

3. Choose the material to suit the fluid. Brass for fresh water and fuel; AISI 316 stainless steel for salt water and exposed installations; nylon and polypropylene for grey water, black water and circuits where you want to avoid a galvanic couple. Never combine brass with aluminium in direct contact with salt water.

4. Always secure with double hose clamps on any connection below the waterline. It is a safety requirement and it prevents most of the flooding incidents caused by a hose coming off.

Fitting and maintenance

Seal tapered threads with PTFE tape or a marine anaerobic sealant, never with ordinary silicone. On parallel threads use an O-ring or a fibre washer. Tighten by hand and give it no more than two turns with a spanner: brass and nylon strip very easily.

Check the connections at least once a season. Replace any fitting showing dezincification (the brass turns pinkish and becomes brittle), pitting or a deformed barb. On installations below the waterline the check should be annual and before every launch.

Genuine, aftermarket and 24-48 h shipping

We work with manufacturers approved for marine use. All the parts meet specifications for salt corrosion resistance and a declared working pressure. Each product page gives the diameter, thread, material and maximum pressure.

Shipping in 24-48 h to mainland Spain and the Balearics, 3-5 days to the Canary Islands and the rest of the EU. Orders placed before 14:00 leave the same day. Returns within 14 calendar days, plus technical support by phone and WhatsApp for questions about fitment or parts diagrams.

Frequently asked questions about marine fittings and connectors

What is a hose fitting in a marine installation?

A hose fitting is the part that joins, branches or adapts two or more runs of pipework within the same system on board. They are used in fresh and raw water circuits, engine cooling, bilge pumping, grey and black water, fuel and ventilation. The most common are T, Y, elbow, straight and reducing fittings.

How do I know what fitting diameter I need?

Measure the inside diameter of the hose, not the outside. Barbed fittings are designated by the diameter they take. The most common on leisure boats are 10, 13, 16, 19, 25, 32, 38 and 51 mm. If the hose has been distorted by use, measure on a straight section with no clamp marks.

What is the difference between BSP and NPT threads?

BSP (gas thread, the European standard) is parallel or tapered with a 55° profile, while NPT (the American standard) is tapered with a 60° profile. They are not interchangeable even when the nominal diameter matches: forcing them damages both parts and causes leaks. Engines of American origin usually use NPT.

Which material should I choose for salt water?

AISI 316 stainless steel or reinforced nylon. Brass works well in fresh water and fuel, but in salt water it can suffer dezincification over time. Never put brass in direct contact with aluminium in a salt water circuit, because that creates a galvanic couple and one of the two parts corrodes.

Do fittings need double hose clamps?

Yes on every connection below the waterline: it is a marine safety requirement and it prevents most of the flooding incidents caused by a hose coming off. Above the waterline a single good-quality clamp is enough, preferably in AISI 316 stainless steel.

How often should I check the fittings on my boat?

At least once a season, and annually or before every launch in the case of connections below the waterline. Replace any part where the brass has gone pink or brittle, or that shows pitting or a deformed barb.