Do I need a muffler

[GILow]

Originally Posted by El Pinguino

I think there is a reason the noise no longer bothers Jim.......

Westerlys were built with straight through exhausts... just a gooseneck at the transom... never bothered me..... neighbours? Not so happy.. Crew ditto..

Fitted a Vetus like this last year https://www.vetus.com/en/exhaust-sys...-5-litres.html

Bugger of a job shoehorning it in...

Crew happy... I can't tell the difference... dunno why....

Thanks EP.

Aside from trolling Jim, which is always fun, you’ve reassured me. Westerlys are a boat builder I seriously respect. If it’s good enough for them then it’s good enough for me.

And, of course, if it is too noisey I can always add one later.


But if Westerly were not worried about the technical side then I am very reassured.

[GILow]

Originally Posted by Jim Cate

Matt, the water pump">raw water pump is more or less a constant displacement pump. It will push the same amount of water per rev whether or not you have a water lift thingy. I can't see that much of a cooling difference happens when you add the water lift.

Anyhow, theories aside, we have had no issues with our lift-less exhaust. There is an down pointing elbow at the exhaust manifold outlet, an injection point a few inches downstream, and then down to a flat run along the hull to the lazerette where there is a loop up to deck level and down again to a sea level exhaust pipe. As you know the boat has done a lot of miles, and experienced fairly harsh conditions over the past 30 years and nearly 6000 hours... and no issues with cooling, hose melting, backing up or were-sharks swimming up the pipe.

There is a low "growl" from the exhaust, louder than many boats, much quieter than any dry stack. An advantage for this is that on those rare occasions where we've lost coolant flow due to jelly fish or plastic bag ingestion, the exhaust note changes markedly and gives one a warning that something is agley.

On Insatiable II the exhaust port is slightly above sea level and the run of the hose to the stern is slightly below sea level. I dunno if this makes any difference... yours is likely deeper than mine.

Jim

Jim, your extensive positive experience on a custom one-off marries well with EP’s mainstream builder experience.

I’m not overly concerned with noise, though from what I am hearing here, it’s not a big issue.

What you describe in exhaust layout is very much what I’d expect mine to look like after a conversion to the Beta 50.

A downwards dip from the mixer is proscribed by the Beta exhaust, and I can see how this would probably accomodate any water that flows back after engine shutdown. I’ll just make sure it is a generous dip.

[GordMay]

FWIW:

The Beta Marine ‘Installation Guide & Operators Manual’ states:
“... Always fit a waterlock/silencer to stop any water in the exhaust system back filling the engine...”
'Cooling' begins page 24 ➥ https://www.betamarinenc.com/wp-cont...tion_Guide.pdf

[mvweebles]

Originally Posted by GILow

Thanks EP.

Aside from trolling Jim, which is always fun, you’ve reassured me. Westerlys are a boat builder I seriously respect. If it’s good enough for them then it’s good enough for me.

And, of course, if it is too noisey I can always add one later.


But if Westerly were not worried about the technical side then I am very reassured.

You cannot compare installation from one builder to another. Builders will follow the engine manufacturers requirements for installation and cooling - if Beta requires a lift muffler and Westerly were to have installed one, the boat would be fitted with a lift muffler if for no other reason than to not void the warranty.

Sailboats are more prone to back filling of engine and hydra lock of engine because of the heel angles they experience. If your engine will be deep in the bilge such that the exhaust manifold is below waterline, the installation requires a vented loop. Possible your old engine, given its larger size, sat higher in the mounts than your new beta.

Careful here. There's more than meets the eye.

[DougR]

Several points bear examining....

- "the waterlift cools the exhaust"-- Not really. The vast amount of cooling occurs when the water is injected into the exhaust stream at the exhaust elbow/riser, before the lift muffler. There are bazillions of power boats running around with rubber hose connected directly to the exhaust elbow and then running directly to the transom, with out mufflers of any sort. No heat, no problem... except a bit of noise.

- The purpose of the lift muffler is to (wait for it) "lift" the exhaust water high enough to exit the hull and not back flood the engine. It normally accomplishes this by its internal standpipe design which allows pressure to build up when engine RPMs are low and then blow the water up over a goose neck where it then drains. When the engine is running at higher revs, such as cruise speed, there is practically no water remaining in the muffler. The exhaust gas velocity and turbulence evacuate the canister and everything flows thru in a continual stream.

- "The muffler should be sized to contain as much volume as the down stream exhaust pipe volume" .... You can do this, but it's not necessary because the downstream pipe is never full of water when the engine is running. The waterlift has to have enough volume to hold that amount of engine water downstream of the vacuum valve, as well as the drain back from the exhaust hose which is past the muffler. This normally is a surprisingly small amount relative to the hose run volume. Then it needs some extra capacity for cushion. The best plan is to take off the inlet hose and measure the amount of water remaining in the muffler after allowing the engine to idle for awhile and achieve equilibrium. Seldom will there be more than two inches of water remaining in the canister.

Another point that I like to check for is if the muffler is mounted offset from the centerline of the engine exhaust elbow, I place the entry into the muffler on the side of the pot away from the engine. This way if the vessel takes a knock down and the muffler is above the engine, the water remaining in the pot will be trapped inside. If you build your own muffler it's easy to place baffles to prevent this water exit during a knockdown.

DougR

[rslifkin]

I'd personally keep a muffler in the system, but you can most likely swap your existing one for something much smaller to free up some space.

[captlloyd]

For what it’s worth I had a smaller Kabota engine on a zero turn mower and marveled at how little heat that engine generated. I would be tempted to run a Kabota dry stack with insulating material and little or no muffler. I ran a 5.9 Cummins in my steel boat with no muffler and dry stack with no problem at all. If I were trying it on your type of boat I would run a 12 volt cooling fan through the engine compartment.

[sainted]

One of the primary purposes of a water lift muffler is to pump the exhaust water up to a point significantly advice the water line, typically in a loop that goes straight up from the lift to a “u” and then down to whatever path gets the exhaust to the transom. The loop prevents water from getting in the engine from following seas or water blown against the exhaust outlet by a brisk breeze. I’ve seen multiple engines flooded this way.

The other job of the water lift is to store any water left in the exhaust system when the engine shuts down. Vetus says to use 40 or 60% of the volume of the exhaust system that could potentially contain water that will flow into the lift. That is, you should exclude the volume of the exhaust system after the loop.

Vetus does make horizontal water locks that are intended to serve an exhaust system that slopes up to the transom. In those systems you are supposed to put a loop above the water line at the transom. Vetus makes a “j” trap for that purpose.

Anywho, I wouldn’t build an exhaust system without a water lift or lock. I’ve seen too many ruined engines.

Scott

[GILow]

Thanks all. I can see now how the “muffler” is serving a very different role to what I had expected.

I’ll do some measuring but I think I’ll probably have to factor in a muffler/water lift just to keep the warranty issues clear.

A pity, it would have been nice to get that space back.

[GILow]

Originally Posted by captlloyd

...
If I were trying it on your type of boat I would run a 12 volt cooling fan through the engine compartment.

Actually, I’ve got that already. Having such a stinky old engine has made me work very hard on the engine-space ventilation.

[Uncle G]

I think that engine only has a 2" exhaust, so maybe you could get a smaller waterlock - and use new 2" hose up to the highest point in your exhaust run (and leave the remaining length in 90mm). I would worry that an engine with a 2" exhaust may not have sufficient puff to lift the cooling water up in a 90mm diameter exhaust. Probably best to speak with Beta.

[Stu Jackson]

Originally Posted by GILow

Thanks EP.

Aside from trolling Jim, which is always fun, you’ve reassured me. Westerlys are a boat builder I seriously respect. If it’s good enough for them then it’s good enough for me.

And, of course, if it is too noisey I can always add one later.


But if Westerly were not worried about the technical side then I am very reassured.

Matt, it would seem to me that you might consider asking Beta, if you haven't already. In addition to the boat builder, the engine guys, NEW engine guys, would be worthwhile to chat up.


A few years ago, I replaced my muffler with one I received from a VERY generous fellow sailor on another boating forum (for the cost of shipping only from CT to CA!!!). He was repowering his Catalina 30 with a Beta engine, which Beta said required a 2" exhaust, his (and mine) are 1-5/8", into and out of the waterlock muffler. Same HP engine, maybe even a few HP SMALLER!


As noted by a previous contributor, Vetus makes smaller mufflers with various inlet/outlet sizes.


PS - The HX cools the water somewhat before it enters the muffler.



And, while we're trolling Jim (!!!), remember, he only SAILS!!! Noise? What noise?!? Ann's gonna remove his earmuffs any day now.......

[GILow]

Originally Posted by Stu Jackson

Matt, it would seem to me that you might consider asking Beta, if you haven't already.

Yes, definitely on the cards. Not least because they have to approve whatever I do to get the warranty.

[StoneCrab]

Unless I am misunderstanding some of these posts, I am very surprised to learn that there are boats out there running dry exhaust through rubber hoses.

That would be incredibly hot and seems unsafe.

[captlloyd]

Originally Posted by StoneCrab

Unless I am misunderstanding some of these posts, I am very surprised to learn that there are boats out there running dry exhaust through rubber hoses.

That would be incredibly hot and seems unsafe.

You don’t need to run a dry exhaust through any rubber hoses. You need to be aware that if your piping is going to run near or through bulkheads, decks or any other part of a boat that is wood or fiberglass that you need to make sure it is either insulated or the temperature at that point is not excessive. A heat measuring device would be employed at any critical point. Of course my boat was steel so no issue. But many commercial fishing boats run dry stacks, even smaller ones. It sure simplifies things.