Trojan Boat Forum

In an ongoing effort to replace things that I think should just be replaced that are 30 years old on our 10 meter, I am now at the hump hose connection between my elbows and swivel on each engine. At this point, every other rubber hose has been replaced. Last year, we had one blow out at a very inopportune time. I was able to find a replacement piece of 4" Sheilds wet exhaust hardwall to get me through the weekend (and remaining summer). My occasional mechanic (when I come across things that I can't do my self) said that they quit messing with hump hose sections years ago and use the hardwall all of the time.
I get what the hump hose does and how it's able to flex with engine vibration. Probably a great transition between two fixed objects with one vibrating. Really, the entire exhaust from the swivel to the muffler on our boats is pretty flexible. I don't see the necessity for the 3" long $25 hoses.
I'm planning on replacing all 4 hump hoses with new 4" Sheilds (w/wire) hardwall and new t-bolts. I don't see the hard wall hose blowing out the side like the softer hump hose might.
In all fairness....It did blow out for a reason. The 3" hardwall main exhaust line below got hot at some point and eventually prolapsed causing enough blockage to blow out the weaker hump hose.
Anybody have any thoughts on why the hard wall may be a bad idea as an elbow/swivel connector?

Was wire-reinforced hose available when they built your boat? Was hump hose just cheaper? Ask yourself why Trojan spec'd hump hose and not wire-reinforced for this application as you decide whether you should do something different.

Wire reinforced hose had been around for a long time pre 10 meter for sure. . IMO You would be better off with the " hump hose " . You need to have some flex and you won't get much with a 4" section . If the hose was longer you would have more flex .

Do you have any photos of the exhaust ?

For a 3" long section, unless the two points of contact (elbows and swivels) line up perfectly to each other, you must use the hump hose. They are meant to allow for slight misalignment at that short of a distance. Using anything else may experience enough strain to put it over its design spec. Even if the sections are aligned now, using a wire wound hose will not allow for engine alignment adjustments should one be required in the future without adding strain to that joint.

Let me add 2 thoughts if the hose blew out look for a cause like bad risers or other causes of poor water flow . Also watch your engine going from forward to reverse , you will see why its a good idea to have some flex . Again photos of the exhaust would help I could change my opinion to not needed or MUST have LOL . I am just going from of my interpretation of your description .