Checking hoses


As a surveyor, it is my job to inspect hoses for problems as I go about my inspections. It often surprises me just what I find. I frequently see critical hoses that are on the verge of failure, just waiting to let go at the worst time. The vessel owner is usually completely unaware of these ticking time bombs in their bilges. Hoses, hose clamps and other plumbing fittings do not last forever; they all need maintenance or replacement at some point.

A hose or fitting that fails can range from simple to serious; it can be nothing more than a nuisance, or it could potentially sink your boat. Inspecting and servicing or replacing hoses can prevent problems before they happen. Some hose manufactures have stated that hoses should be replaced every five years. Although most will last longer than this, it does point out that hoses do need periodic service.

To avoid problems, owners should do regular inspections of all the hoses in their boats, paying particular attention to those connected to fittings below the waterline. Inspecting hoses for problems is not a popular chore, as it usually requires crawling around in the deep dark recesses of your bilges. That said, it is an important job that should be done at least a couple times a year if you want to avoid problems. If you are not physically able to perform this task, consider hiring someone to do it for you, because — let’s face it — it often requires a contortionist to get into all spaces you should.

It does not take much in the way of equipment: a good flashlight and a headlamp along with a screwdriver and nut driver to tighten any loose clamps you may find. It would also be good to have a supply of spare hose clamps of different sizes handy as well to replace any bad clamps that may be found. You may also want to have a friend aboard or, at minimum, a cellphone just in case you should become stuck somewhere. Do not underestimate this, as it has happened to me. Try to wear clothing that will not easily snag on equipment when crawling into tighter spots, and keep a knife with you as well, just in case. If you do get stuck, remember: Do not panic, stay calm and move slowly. 

This AC pump fitting is poorly supported and can easily be broken or damaged by stored equipment.

Below-the-waterline fittings
So, what do you look for once you have worked your way into the depths of your boat? Of course you want to pay particular attention to any hoses connected to fittings below the waterline, but all hoses deserve a careful inspection to avoid problems. Start with a simple visual inspection: Look for cracks and dry rot or anything else that does not look “right,” and pay particular attention to bends and turns in the hose — these are areas that stress the hose material and often will be where you find cracks or kinking.  For hoses with wire reinforcement, look for signs of rust weeping through the outer jacket. Look for any signs of bulging or swelling, as this can be a sign of internal failure. Check for chafing, particularly near motors, equipment and where the hose passes through a bulkhead or other structure.

Problems are not always with the hose itself but can be with the hose clamps and fittings that the hose is attached to. Carefully inspect the hose where it is attached to any fittings; this is an area where hoses can be damaged by clamps or the fittings themselves. Hoses are sometimes damaged during installation and this may not become apparent until the hose has aged. Look for signs of weeping from any fittings, both around the hose and around any pipe fittings. Check the hose clamps for tightness and rusting, and make sure the hose is the right size for the fittings it is attached to. A hose forced onto a fitting too large or crushed down to a fitting too small is likely to fail sooner rather than later. This is also an area susceptible to corrosion, so check the fittings as well.

While checking the hoses, make sure the right hose is used for the right job. This is particularly true for fuel hoses. Fuels can damage a hose from the inside out, so it is important that the hose be rated for that use. Fuel hoses will be labeled on the outside for their intended use. Any hoses that carry hot fluids for domestic use or cooling on the motor should be rated for high temperatures. Any hoses under pressure should also be rated for that pressure. Waste hoses should likewise be designed for that function as well, in order to prevent odor problems.

Hose clamps can fail
Hose clamps and hose fittings are equally important to the life and success of a hose and its ability to function without problems. Hose clamps can and do fail, causing everything from minor leaks to the sinking of a vessel. Clamps rust and break and, if not applied correctly, they can cause damage to the hose, resulting in failures and leaks. A good hose clamp is all stainless steel, including the adjusting screw, and is made with a solid strap — not one cut for screw threads. I’ve seen a lot of failed clamps during surveys and almost all were broken in the middle where the screw threads are cut into the strap. Good clamps are not cheap, but they are well worth the extra cost for the peace of mind and longer life they provide. Make sure the clamps are snug but not so tight that they are cutting into the hose itself. After installation, hoses tend to compress, which causes the clamp to loosen a bit. A slight tightening is usually all that is needed to keep things working as they should. Over-tightening can damage the hose so be aware of that.

This hose setup has a broken clamp that isn’t doing anything to keep the hose in place, plus it’s connected to a badly corroded fitting.

The use of improper fittings will likewise result in problems, and this is a common issue with aftermarket installations. Hoses should be connected with properly sized barb fittings or fittings designed to be used with hose. The standard fitting is a barbed tail threaded to a pipe fitting to make the transition from hose to pipe. The barb should be properly sized to the hose and have sufficient length for the hose to seal tightly. Generally speaking, you will be able to get at least two clamps firmly over the barbed section. The hose should be pushed onto the barb so that it fully covers the barb without any exposed material left.  The barb itself should be of the correct material, meaning you should never use brass below the waterline. A hose should never be attached to a threaded pipe fitting, as this will result in leaks as the fluid follows the threads. A hose should also not be fitted to a smooth pipe or copper tube as it could slide off with surprisingly little force and cause leaks to be more likely. 

Run them clear
Hoses should be well supported and run clear of any wires and/or moving parts. As with wires, neatly run hoses are not only safer but also easier to inspect and service. When securing hoses, use clamps or straps that will support the hose without damaging it. Metal straps should only be used if they are protected with rubber. For small hoses, wire ties can work well; however, with larger hoses, clamps and hangers designed for supporting hoses are better. Make sure no hoses are run over hot equipment such as exhaust pipes. This is particularly true for oil and fuel hoses, as leaks can cause fires with these fluids. When running hoses, try to avoid hard turns since these can stress the hose material and will shorten its life. Make sure the hose is not in contact with any sharp edges or vibrating equipment as well.

Should you find any bad hoses that need replacing, do not just automatically replace the hose with the same type. Very often the wrong hose was used in the first place, or there may be something newer that will work better for the application. For any below-waterline use, make sure the hose is rated for that use. As mentioned above, fuel lines must be rated for use with fuel, and this includes any fuel fill hoses as well as supply lines. Make sure any hose used for suction, such as intake hoses, are reinforced with either wire or hard plastic to prevent collapsing. Sanitation hoses should be rated for waste to help reduce odors; there are several new hoses designed for this, so a little research would be well worth the effort. Any hoses used for potable water should similarly be rated for this use.

Removing and installing hoses is not always the easiest job on a boat, but there are a few tips and tricks that can help make the job easier. Before trying to remove a hose, first remove the clamps and then try to rotate it on the fitting to break loose any bond that has developed. I’ve found that a heat gun can be the best tool for this. Warm the hose before removal or installation. Take your time and allow the heat to fully penetrate the hose material to fully soften it. For hoses that are very stiff or just do not want to let go, you can try prying it off the fitting with a screwdriver or hose-removal tool from an auto parts store. Shoot a bit of WD-40 or other petroleum lubricant between the hose and its fitting. Work it up and down while pulling it off the fitting. It also helps to wear work gloves to avoid those war wounds. When installing a new hose, once again, some heat applied to the hose end along with a bit of liquid dish soap will make life easier. Do not use petroleum lubricants with a new hose as it may damage the hose material.

A hose setup that initially looks good, but closer inspection reveals a broken clamp. 

While checking the boat’s fluid hoses, do not forget about air hoses as well. Blower and air conditioning hoses should be checked, since air hoses tend to be made with a thinner material and can be damaged easily. Make sure there are no dips or loops that could fill with outside water or condensation and block air flow. Small leaks can add up in air conditioner hoses and reduce your unit’s efficiency, so repair any leaks with — you guessed it — duct tape.

Hose failure is probably the most common reason for a boat sinking either at sea or at dock, and let’s not even get into the misery involved in the failure of a waste hose. Although it may not be the easiest task on your boat, it may be one of the more important and often overlooked maintenance jobs. It is well worth the effort to know all your hoses are in good condition and it may just save your boat from serious problems.

Capt. Wayne Canning lives on his Irwin 40 Vayu, in Cape Coral, Fla. A marine professional for more than 40 years, he is now a full time marine surveyor, freelance writer, and consultant. Visit and for more information.

By Ocean Navigator