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Old 06-01-2018, 12:35 PM
Surcouf 23 Surcouf 23 is offline
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Dead exhaust - how to change flex hose

Hello Community.

based on what I have seen in the most recent threads, I am not the only small sailor facing rusty exhaust at the beginning of the season...

Recap: I was given that boat 2 years ago. A 1977 Catalina 27, gas A4, likely original to the boat. My beloved engine is a first class rust bucket, with 2 plugs that have resisted the yearly change for the past few years...

So transfer from dry marina to the wet one last week, it was quite smokey inside. Afraid that it was oil cooking or similar from the engine, I dive inside and start looking for the source of that light smoke. Quickly realized that this was a nice smell of exhaust gases including a good share of CO. After a few minutes of happily breathing it, I ended up feeling a warm flow of gases coming out of the "insulation tape" on the exhaust pipe. Once back at the marina, I take a cutter to remove it (I hope it is not abestos...), and start cutting it out. And there surprise, the blade goes right through the tape, directly INSIDE the pipe. The insulation was holding the 2 pieces of pipe together!

Anyway, i am not the first nor the last one to suffer that. After a couple hours of forum navigation and reading previous people experience, I get to the marina fully geared with tool boxes to try to remove that, praying that no bolt would break in the block... luckily, the last owner to touch that system had stainless bolts used. They agreed to come out after some time and convincing arguments. There is a God for small boat owners

So that thing was really dead

Then, only after all pieces come out nicely, I call Ken at MM and buy the pre-made piece. I just do not have the time to run after the different pieces at the hardware store...

So this is where I need your help guys: from the exhaust manifold to the end of the previous exhaust piece (where now my flex hose (the one going to the transom) is waiting for a new male friend, I have around 30 inches. Ken confirmed me that their new piece is around 18 inches long... so I am short 10+ inches on that big flex hose pipe.

If I want to do that repair properly, I need to change that flex hose for a longer one: I am not fat, but I am 6'3, and there is no way I can squeeze myself through the small hatches, rotate 90° and be able to get to the end of that pipe on the transom. So here is my question how the f***** is one supposed to change that flex hose? My only solution is to send my 7 yo daughter, as I tried to convince my 40 yo wife, who is the same size, who told me there was no way she would go/creep in that dirty oily place...
Any other solution?

the back-up solution is to insert a 10" long piece of flex-hose with a middle nipple...

Thank you!!!
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Last edited by Surcouf 23; 06-01-2018 at 12:46 PM.
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Old 06-01-2018, 02:01 PM
Dave Neptune Dave Neptune is online now
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Surcouf, I have had success by using a long chisel or saw to cut the clamp on the hose. Once cut try twisting the hose to see if it will loosen, if not remove the screws from the exhaust flange and apply more twist and some spray lube into the gap.

With some flanges the base is large enough to open the hole in the transom a bit and pull the whole thing out. A small hole around the flange can also be used to chisel the clamp or clamps. Just be sure to reseal the transom.

There may be another flange available if the one on yours won't cover the larger opening.

Dave Neptune
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Old 06-01-2018, 03:26 PM
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marginal marginal is offline
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Looks like the Moyer Catalina style exhaust (if that's the one you're looking at) has NPT threads on the output of the black water mixer section.
If true you could extend it by a foot with a piece of black iron pipe.
You'd need to check your hose would go over the OD of the pipe, but that is also true for the exhaust assembly un-modified.
I suppose there could be a corrosion concern with black iron after the mixer but easy to change every few years.

Note that the separate brass water mixer from Moyer does not have NPT on both ends like the black one in the link above appears to. It has NPT on one end and a hose barb on the other - I fitted one last year.

Good luck
1981 C&C 30 MK1 "Starlight" #657
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Old 06-01-2018, 03:31 PM
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Of course you could disassemble the Moyer unit and add the extension before the mixer...
1981 C&C 30 MK1 "Starlight" #657
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Old 06-01-2018, 04:13 PM
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ndutton ndutton is offline
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Reading the first post my thoughts went immediately to Dave's solution. Modifying the MMI system to reach the existing hose will buy you some time as will splicing in a short hose to reach but someday the entire hose will need to be replaced. What are you going to do then?

A variation to Dave's advice is you can pretty easily modify the transom attachment with a stainless doughnut plate. The ID has to fit the exhaust hose clamp, the OD has to be a little larger than the hole in the transom after you've enlarged the transom hole to extract the thru-hull with the hose and clamp attached, approximately the same size as the ID of the new doughnut. In use you'll fasten the thru-hull to the doughnut, attach the new hose to the thru-hull with the clamp (2 clamps?), slide the entire assembly through the transom from the outside and fasten the doughnut to the transom with caulking and sheet metal screws. For a nice yacht quality finish the doughnut must be polished to a bright mirror finish.

If you have adventure in your heart and your marriage can survive it, tell the wife you're sure there's a smallish honey at the local nudie bar who would do it for a price. Of course remind the wife you asked her first. Fair is fair.
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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Old 06-01-2018, 05:54 PM
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Old 06-04-2018, 02:15 PM
Surcouf 23 Surcouf 23 is offline
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So, a few goods news:
- ordered the parts from MM Wednesday at 3PM, at the cheapest delivery option, and I got it 48 hours later. Just amazing!
- I went to the easy and cheap option, went to Home Depot and got a union and a 12" nipple (plus a couple fitting for the water side). Put all that together Sunday after the kids Lacrosse game. Had to change the water flex hose pipe downstream of the anti-siphon valve, that was now too short. Tightened everything, and started. It works just great. Only mistake (there has to be), I forgot to put sealant/teflon tape between the union and the nipple, and I have water dripping (1 drop per second) when running... stupid mistake, but that will not prevent me to sail this summer. Hopefully rust will plug it before the end of the season, if not I will correct that next winter... when changing the flex hose pipe... because:
- I just realized that in the port storage there is in fact a hatch on the back side, that will likely allow me to access the back of the transom, too loosen the hose clamps, and change the hose pipe. Welcome to the world of the sailboat owner that does not know his boat. I feel ashamed.

I have the impression that I have the exact same water flow as before, no change in noise (the "damper" on the old pipe was 100% filled with rust anyway..)

in the picture, the pipe looks tilted, but just a wrong visual effect, it is rather horizontal
thank you for your advices!!
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Old 06-04-2018, 10:29 PM
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Al Schober Al Schober is offline
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Last week, delivered our Tartan 30 from New London to Rockland, ME. Exhaust failed by Gong 10 in Buzzards Bay, and the first tow operator wanted to take us into New Bedford. I held out for a tow to Marion (Burr Bros). Didn't really want a fishing boat fix (soup can and hose clamps).
Mechanic was aboard at 0730 the next morning. They tore out the entire exhaust and replaced the shaky stuff with stainless. We were underway at 1630 and completed the trip without further incident. First photo shows repaired piping ready to install.
Second photo shows our welcoming committee to the Gulf of Maine. Greeted by a pod of Atlantic white sided dolphin - first there was one, then three, then about 15 or 20. Leaping on both sides of the boat, crossing under the boat, and some doing back flips - incredible!
Third photo shows what's left of the bilge blower - we're very lucky we didn't have a fire on board. There was some serious heat due to the failed exhaust!
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