Exhaust pipe instead of hose pro cons

[Cyrus Safdari]

I have a length of UL-rated fiberglass 2" exhaust pipe, and was wondering if there would be any pro con to using it instead of exhaust hose for the final run from the gooseneck to the exhaust thruhull
I plan on epoxying in a bit of it as an exhaust thruhull, as a barb for the exhaust hose, so I was wondering why not extend it some more and use the whole pipe length
Now that I have gutted the boat, either now or never situation
I would guess it would be louder but once installed there's no worry about chafe etc at least for that run of exhaust

[ItDepends]

There is no intrinsic reason not to use it, although there are design issues, mostly around its lack of flexibility. When you say UL rated, I assume that is for fire resistance. In the event of losing cooling water, you do not want to set your exhaust system to burning!

You'll need a loop of hose between the engine and the pipe to absorb motion and vibration. If one end of a long pipe is glassed to the hull, you'll need to be really sure you can not apply any leverage on the other end. I'd suggest a flexible coupling there as well.

Otherwise, as far as I can see, it's just being sure you follow all the well known good practices for slopes, heights, drainage, etc. None of those change with solid piping.

[sailormed]

The gooseneck is on the engine and vibrating with the engine. I do not comprehend how you are going to compensate the movement of the engine relatif to the hull structure with this setup.

[team karst]

no muffler?

[skipperpete]

Is the gooseneck at or near the thru hull or on the engine? I’m not fond of glassed in pipe for exhaust overboards. Many power boats use long lengths of GRP pipe for their exhaust systems, older Hatteras’s used 25’ of 10” tube with silicone hump hose and elbows to make the connections so a short length of 2”Grp pipe should work provided that it’s supported and the end connections are flexible enough. You can get silicone pipe from most auto parts supply shops, 2” is used on turbo boost hoses ( my 4wd has 4 of em)
The size of superyacht wet exhausts .... yes , some do have them can be quite large but still Grp[ATTACH]265785
Incidentally, a loss of cooling water usually melts the closest plastic thing in the system and this is usually the Aqualock, as soon as that melts, the exhaust gas takes the short path to freedom not the long path to the transom. It’s not unreasonable to carry a bit of hose and an elbow to bypass a melted Vetus in anticipation of an overheat.

[Cyrus Safdari]

Thanks all. This is an option to consider then

[Cyrus Safdari]

Originally Posted by sailormed

The gooseneck is on the engine and vibrating with the engine. I do not comprehend how you are going to compensate the movement of the engine relatif to the hull structure with this setup.

Sorry, to be clearer I'm referring to the exhaust run from the exhaust vented loop (which itself follows the muffler) to exhaust thruhull. There's a bit of exhaust hose elbow connection to absorb vibration at the vented loop end, should I go this route.

Come to think of it I can use some more of this fiberglass exhaust tubing to make a U-shaped vented loop too with a barb glassed-in for the vent hose...would save a couple pounds weight, too bad I already bought the bronze vented loop