Dry Stack Exhaust

Idle curiosity:

How do you keep rainwater out?

I see paint buckets, etc, but not all are so protected. Is there some internal drain? Near me in Tacoma is one of the lesser Nordhavns (32?) with a very tall stack. He has an old fender with the bottom cut out, but I'm damned if I can see how he installs it up there.

Mine had 45 degree angle at the top that was about 18 inches with drain slots on the bottom until it came to the vertical portion, never needed a bucket.

AlaskaProf said:

Idle curiosity:

How do you keep rainwater out?

I see paint buckets, etc, but not all are so protected. Is there some internal drain? Near me in Tacoma is one of the lesser Nordhavns (32?) with a very tall stack. He has an old fender with the bottom cut out, but I'm damned if I can see how he installs it up there.

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The guys that use cut fenders and buckets often put it up there and remove it with a boat hook.

My boat has a dry stack, but the pipe turns to a pretty flat angle at the exit. It also has slots across the bottom of the pipe a few inches forward of the exit that drain whatever water finds its way in. I’ve never put a cap on it and haven’t had any evidence of water entry.

Thanx

Many a turbo was lost to rain

I use one of these:

https://turbobarrier.com/

IRENE said:

I use one of these:

https://turbobarrier.com/

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I love it!


Quite the upgrade from a bucket!!


Hollywood

You can install a cap that the exhaust pressure opens.

Although I would never use it in an engine , the gallon can of Mystery Marvel Oil , trimmed to fit the stack worked fine, looked great!

The carrying handle allowed easy tie down in case of high winds.

Lepke said:

You can install a cap that the exhaust pressure opens.

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Have you ever listened to one of those clang incessantly at idle?

Fish53 said:

Have you ever listened to one of those clang incessantly at idle?

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Yes! The clattering from those flappers can be very irritating. But it seems to depend on the weight of the flapper, size of the exhaust, and the engine. I've seen some setups using them that bang and clatter at idle and others where the flapper never hits the pipe with the engine running and there's no noise issue.

rslifkin said:

Yes! The clattering from those flappers can be very irritating. But it seems to depend on the weight of the flapper, size of the exhaust, and the engine. I've seen some setups using them that bang and clatter at idle and others where the flapper never hits the pipe with the engine running and there's no noise issue.

Click to expand...

I've never noticed one on a boat but someone probably has one, I've seen plenty on tractors and other equipment. I suppose it would work but the vast majority of dry stack boats use an angled outlet with a mitered end and drains or an internal pipe, no moving parts and no chance of it being stuck in the open position.

Fish53 said:

I've never noticed one on a boat but someone probably has one, I've seen plenty on tractors and other equipment. I suppose it would work but the vast majority of dry stack boats use an angled outlet with a mitered end and drains or an internal pipe, no moving parts and no chance of it being stuck in the open position.

Click to expand...

Agreed, flappers on boats are a minority. Of the dry stack boats I know of based locally, one has a vertical outlet with a flapper (repurposed 1950s US Army tug), the rest all turn horizontal before the output.

Most have a drain valve at the bottom of the stack in the engine room.

Fish53 said:

Have you ever listened to one of those clang incessantly at idle?

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Yes on construction equipment. I only used dry stacks on commercial boats and tugs. The exhaust was bent and trimmed to keep the rain out.

On ours the external pipe is angled at 45 degrees and drains on the deck roof. Never any water ingress as long as the boat is pointed into the wind. But, when at a dock, we cover the stack with a fender cut in half to keep out blowing rain from aft of the beam.

Fish53 said:

Have you ever listened to one of those clang incessantly at idle?

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Yeah, I drove otr for a while - like everything else, you get used to it
https://boards.straightdope.com/t/truck-exhaust-flappers/223352/3

On a ship the stack is behind the pilothouse so unless you're on deck, you won't hear it.