Every hose on your boat has a predicted life, from air conditioning systems to water systems to exhaust hose. Some hoses have shorter life span than others and some are more important than others. One of the things that cause a shortened lifespan on a hose is exhaust gases. Although the hoses are built for this application, a failure in your exhaust hose will cause exhaust gases to enter the boat and will create a deadly environment.
Small hoses are a piece of cake to replace, but on most of the boats we service, 8″ or 10″ hoses are the norm. Large hoses are tough to work with. Most of the time hoses run behind cabinetry and through inaccessible places in the engine room.
In addition to the hose itself, there are other parts that go with the system that need to be investigated. We often find exhaust elbows that are cracked due to overtightening of clamps. Cracked elbows will cause leaking of both gases and water. We avoid this problem by using stainless steel crush rings. The crush rings fit inside the tubing and are substantial enough to keep the ends from cracking, even if the clamp is overtightened.
We also find that some elbows are oddly angled to make the required connections to the engine. You can buy 90 degree and 45 degree elbow from any marine supplier, but if you need other angles you will need to special order. But since the elbows are the exact same materials as fiberglass exhaust tube, we can cut the angle we need from tubing and fiberglass it to create any elbow we need.
And speaking of clamps, we never use regular hose clamps or reuse clamps. The only type of clamps we will use are T-bolt or Torque clamps. The benefit of t-bolt clamps is that they provide constant pressure around the clamp and can be tightened sufficiently without stressing the clamp or the fitting they are being used with.
Also important are the mufflers, which will need a good inspection whenever you are changing exhaust hoses. Most mufflers are primarily fiberglass and are subject to heat stress and other problems. But also, since they are fiberglass they can usually be repaired if necessary. We make that determination based on the size and replacement cost of a new muffler. If it is substantially costlier to replace, we will repair the mufflers.
Running the hose is almost always a two man job due to the weight, length and rigidity of the hose and where it needs to be placed. Of course, using the best hose available is a given unless you want to be doing the job again sooner rather than later. It is also important to have the hose runs be as level as possible – with no uphill runs or sags. To keep things that way, some support has to be added occasionally. Also, anywhere it needs to run through a bulkhead, the edges of the hole it runs through should be padded. We often just slice a piece of water hose and slip it on the raw edges of the bulkhead.
A properly reworked exhaust system should give years of service. But still, don’t think it is a one-time job. If you keep your boat for over 20 years or so, you may be looking at another one at some point in the future. If you use the best parts and installation methods you can expect to delay the next job as long as possible.