Catalina 30 Muffler

[ndutton]

It is entirely possible your boat never had the check valve. Earlier models did (both Shawn and I have 1977 models) and I understand Catalina dropped them in later model years because they were a constant failure point that caused excessive exhaust backpressure when they failed. Maybe if they used a higher quality valve the failures would not have occurred, the reason I replaced my failed original brass valve with steel flapper pin with an all 316 alloy stainless version. When mine finally quit it was stuck open so I did not have any debilitating symptoms.

What was the point?
For starters, let's accept that Catalina engineer Gerry Douglas knows his stuff. He's not infallible (see lower chainplate failures, plywood shoe in the keel stump, engine harness wiring plugs that dissolve over time) but with the incredible number of boats produced his successes far outnumber the klinkers.

I believe but cannot say for certain the intent of the exhaust check valve was to guard against flooding the waterlift muffler when sailing hard on stbd tack when the entire exhaust line can be below the waterline. Ideally an engine exhaust system is as close to the centerline of the boat as possible so heeling makes little change in the elevations but the Catalina 30's exhaust runs along the port side. This may not mean much to those who sail in light conditions but in my neck of the woods it does. A sail in a 20~25 knot blow may be an exhilarating ride that memories are made of but in Los Angeles outer harbor it might be called Tuesday. It blows like stink every afternoon so a rails under stbd tack is commonplace.

With the external flapper on my exhaust outlet I could probably have done away with the check valve but while I may pontificate on this forum excessively, I'm not about to think I know better than Gerry Douglas. Without good reasoning or experience otherwise, if he thought it was important that's good enough for me. It was installed on my boat from the factory and my engine has never had a water incursion in 41 years so it's my preference to maintain it as originally designed. Note again, that's in my case and sailing in my local conditions.

[rkohl44]

So my boat falls into the "not factory installed" category. I'll decide later whether to put one in or not. I also discovered it does not have a raw water strainer. That, I will put in.

Yep, she ruptured alright. And I'm going to replace it with the Centek model Neil has.

[rkohl44]

And it was going so well...

As you can see, the exhaust flange is in two pieces and one bolt is broken off. Other than soaking it in PB Blaster for a lot more time, tapping with the Steel Persuader, and applying heat, any other suggestions for getting the stubborn bolt and frozen half flange off?

[sastanley]

rkohl, I know you don't want to hear this but what I did was buy the $$ exhaust manifold flange from Moyer, and then sourced local 1.25" NPT pipe to make a new riser. I actually have two sets..I have two Moyer manifold flanges and two Moyer mixers (down there by the hose clamps), so that I can take my time rebuilding the failed one while the working one is in the boat. My first one lasted about 7 years, and looked much like your failed one in that pic. Unfortunately, the rust is an awesome glue, and it is hard to get the broken parts off and the new parts on in a short period of time.

I have recently moved and do not have my archive file server running at the new house yet to provide pictures, but I basically made as tall of an upside down "U" as possible underneath the galley to give me a bit more leeway on the 'overcrank/water incursion' problem that sometimes happens in our C-30's.

That broken piece in the middle of your blue rag is the Moyer manifold piece you should probably call Ken to get replaced...you may very likely be able to clean up the "mixer" that is surrounded by hose clamps and re-use it.
P.S.> I also recommend making (or buying from MMI) stainless studs that attach the manifold flange to the manifold.

[JOHN COOKSON]

Try standing the manifold upright so the PB blaster will migrate down along the threads by gravity as you tap on the bolt head.
No promise this will work but it should increase your odds of success.

Is there any way to get a bit more leverage by tapping on the remaining flange piece so the bolt is moved with it? I've done this before with a cleat I wanted to remove that was mounted on an aluminum spar that was held in place with two stainless screws. I cut section out of the middle of the cleat then tapped on the horns. The screws came loose pronto. No more cleat.

TRUE GRIT

[ndutton]

If PB Blaster does not perform like you hope try a 50-50 mix of automatic transmission fluid and acetone. Testing has shown it to be more effective than any commercial concoction available.

Here is a reprint of a post from six years ago:

Penetrating oils
A friend sent this to me the other day and I thought it worth sharing. I'm sure we all have a “scientifically rusted” environment somewhere on our boats.

Machinist’s Workshop Magazine™ recently published some information on various penetrating oils that I found very interesting. Some of you might appreciate this. The magazine reports they tested penetrates for break out torque on rusted nuts. They are below, as forwarded by an ex-student and professional machinist. They arranged a subjective test of all the popular penetrates with the control being the torque required to remove the nut from a “scientifically rusted” environment.

*Penetrating oil .......... Break out torque*
None ........................... 516 pounds
WD-40 ..................... ... 238 pounds
PB Blaster .................... 214 pounds
Liquid Wrench ............... 127 pounds
Kano Kroil .................... 106 pounds
ATF-Acetone mix...............53 pounds

The ATF-Acetone mix was a “home brew” mix of 50 - 50 automatic transmission fluid and acetone. Note the “home brew” was better than any commercial product in this one particular test and you can also use ATF- lacquer thinner 50 - 50 mix. Note also that “Liquid Wrench” is almost as good as “Kroil” for about 20% of the price.

[Al Schober]

I keep two squirt cans on my shelf. One is just 30W oil. The other is a 50/50 mix of ATF and kerosene. The latter works well for me as a penetrant, without the volatility of acetone.

[rkohl44]

I thought it was going to be a valve, but after getting the drain hose off, I think it's a vented loop. Either way, the drain hose is kinked and the anti-siphon hole is completely blocked. The drain hose simply ran to the bilge.

Can any sharp eyes tell me which this is?

The new one will follow Neil's suggestion for a vented loop. Can it simply drain to the bilge, or is it preferable to tap it in to the galley sink thru hull?

The stubborn 1/2 exhaust flange is soaking in penetrating oil for Thanksgiving weekend. Hopefully, that'll be enough time.

[ndutton]

You have a vented loop with a hose that's way too big. When it was kinked you had no vent at all and therefore no anti-siphon protection. There are a couple of ways to avoid the kink: 1)add two brass elbows so the hose connection points down or 2)get the proper size hose with reinforcing braided layers. I use heavy wall fuel grade hose and it does not kink.

About bilge or sink drain discharge, that's up to you but in my case I prefer a dry bilge so I would either connect the vent hose to the sink drain or replace the small hose connection on the loop with an anti-siphon valve and do away with the hose. As you've read I prefer a vented loop over an anti-siphon valve so I'm plumbed to the galley sink drain. Running my engine requires both the engine intake and sink drain thru-hulls to be opened.

[rkohl44]

If I plumb to the galley sink, does it matter where it connects (above waterline or below)?

[ndutton]

If I plumb to the galley sink, does it matter where it connects (above waterline or below)?

No. Mine is inside the galley cabinet which makes it slightly above the static waterline. It's easier to work in there as opposed to lower. If it helps I can provide a picture on Saturday.

[Peter]

Agree that it does not matter above/below the waterline from a functionality perspective, but perhaps with an eye to safety, would it not be better to minimize connections below the waterline?

Peter

[ndutton]

Agree that it does not matter above/below the waterline from a functionality perspective, but perhaps with an eye to safety, would it not be better to minimize connections below the waterline?

Well, yeah but I think more important is the integrity of the installation whether above or below the waterline. Proper materials, good design and consideration of all factors make for a safe boat.

[rkohl44]

Neil: yes, please: pictures of your entire vented loop system would be fantastic. In fact, pictures of your entire exhaust system would be great too. The muffler I ordered a month-and-a-half ago has been on back order, but should ship next week.

Which brings up the next subject...gunk on the manifold. How do I get it off? The mating surfaces are not flush and I don't know how much leeway I have using the manifold and flange gaskets. How much tolerance do I have?

[ndutton]

Here are a few pictures of some of my exhaust system components. The vented loop has no anti-siphon valve, it is truly vented. The second picture shows how the hose from the top of the loop attaches to the galley sink drain plumbing. The stainless check valve is located high in the port cockpit sail locker. The pictured external flapper is not my boat but I have the same thing.