Noisy Exhausts

[kfurbank]

I think my exhaust has got noisier or it may always have been that way, but I would like to see if I can quieten it a little more. Don't get me wrong, it is not Le Boat loud, few are but I'm sure it could be better.

Anyone know whether the silencers go with age? Should mine be mounted the way it is? or should it be more vertical. I am wondering if the exhaust gases and noise are passing over the top of the water rather than through it?

Any advice appreciated.

TIA

[kfurbank]

Pic attached this time hopefully

[ExUserGone]

Try it orientated more upright and see if that helps, is there still the right amount of water coming through?

[ExMemberBobdog]

My exhaust has definitely got noisier with age, or so my missus tells me, especially after a chicken vindaloo.  

[kfurbank]

Leo,

 

Was not sure about moving it, as this is how it has always been mounted. If from new, then the last 21 years, although at least 9 that I know off. Anyone know for sure whether they should be mounted horizontal? vertical? or it doesn't matter?

[Guest]

I'm pretty sure that type should be mounted horizontally, as you have it.

 

You can see the path the exhaust gas and water takes from the indentations. It zig zags to the outlet, all on the same level.

 

I've always ripped out that type and fitted the specific "waterlock" type instead, and found them very quiet, with no increase in noise as the years pass.

 

I've always been nervous of that Vetus plastic construction too, since the melting temperature is lower than dry exhaust gases, if the water intake should eve get blocked.

 

I always replace them with Centek GRP waterlocks and silencers, which can withstand something like four times the over temperature, and won't fail and sink the boat if the exhaust runs dry for any period of time.

 

http://www.asap-supplies.com/green/wet-exhaust-waterlocks

[MBA Marine]

I'm pretty sure that type should be mounted horizontally, as you have it.

 

You can see the path the exhaust gas and water takes from the indentations. It zig zags to the outlet, all on the same level.

 

I've always ripped out that type and fitted the specific "waterlock" type instead, and found them very quiet, with no increase in noise as the years pass.

 

I've always been nervous of that Vetus plastic construction too, since the melting temperature is lower than dry exhaust gases, if the water intake should eve get blocked.

 

I always replace them with Centek GRP waterlocks and silencers, which can withstand something like four times the over temperature, and won't fail and sink the boat if the exhaust runs dry for any period of time.

 

http://www.asap-supplies.com/green/wet-exhaust-waterlocks

Your exhaust hose will not hold up for long with hot exhaust gas, do you change this for steel tube as well? 

[Oddfellow]

Horizontally, as you have it.

 

These are basically plastic units. If they get hot, they will melt, so if your raw water pump has failed in the past, this muffler is likely to be damaged.

[Guest]

Your exhaust hose will not hold up for long with hot exhaust gas, do you change this for steel tube as well? 

 

Rubber exhaust hose will last a lot longer than Vetus plastic silencers.

 

You have a much better chance of surviving a dry exhaust period with a heat resistant GRP silencer.

 

There was quite a bit about it on the YBW forums a few years back when I searched then.

[Oddfellow]

Rubber exhaust hose will last a lot longer than Vetus plastic silencers.

 

You have a much better chance of surviving a dry exhaust period with a heat resistant GRP silencer.

 

There was quite a bit about it on the YBW forums a few years back when I searched then.

 

I wouldn't say "a lot longer". It's not rated as dry hose and will deliminate with alarming speed when subjected to un-cooled exhaust gasses and not always where you can see or feel it bubbling.

[kfurbank]

Looking at my question again I can see that I haven't asked the best question about the way it should be mounted. The silencer is currently horizontal as in the inlet and the outlet are at the same level. My intention when asking whether it should be vertical is not for the inlet to be above or below the outlet, but for the unit to be rotated through approx. 90 degrees such that the inlet and outlet are still level, but the body is vertical. I say approx. 90 degrees because the body isn't currently lying completely horizontal being tilted by approx. 10-15 degrees.

 

I don't think the exhaust system has ever run dry, certainly not in the 9 years I have owned the boat. It is an ex Barnes hire boat and they do tend to engineer things well. The boat has two raw water filters, the first being a piece of gutter downpipe with thousands of small holes painstakeinly drilled in it, followed by the normal bowl filter. This first filter is located within the rather industrial looking pipe between the engine and the hotpot.

 

The exhaust hose does have a slight uphill run after the silencer which should maintain a water trap as shown in the attached picture, but when listening from the back the water tends to come out in spurts along with the noise which makes me wonder if the silencer is at its best, or mounted the best.

[Guest]

I wouldn't say "a lot longer". It's not rated as dry hose and will deliminate with alarming speed when subjected to un-cooled exhaust gasses and not always where you can see or feel it bubbling.

 

 

Ok, take out the words "a lot", and just leave the word "longer"  

 

Still safer.......

[ExUserGone]

I thought you meant turning 90degrees, thats what I was referring to, although a goose neck setup never hurts to stop back flow.

I have vetus cylindrical water locks and they sap the sound very well and are amazingly adjustable for small spaces, with rubber outlet pipes running up and over it makes up a gooseneck too, used to have straight out pipes and were far too loud, everyone on the gt.ouse know who was coming when throttled up a bit, now I can sneak up while it's still their round.....

[kfurbank]

I think that's going to be my first step. Rotate through 90 degrees, although I think I might need to make some modifications due to how tight it all is to the floor.

 

Anyone know how feasible it is to add a second silencer and any effect that might have on the engine?

 

The reason I ask is that there used to be a raw water cooled generator under the bed in the front cabin. It leaked, made the cabin smell of diesel and was extremely noisy in use. I removed it very quickly but it also had the same style of silencer connected to an outlet on the bow of the boat which I want to remove before too long. The silencer is the same as the one in the rear so my thoughts are to rotate the current silencer. If no better replace with the spare silencer, if still no better put the two in series? 

[sos247]

 

 

Quote "I've always ripped out that type and fitted the specific "waterlock" type instead, and found them very quiet, with no increase in noise as the years pass".

As previously said you have a 'Vetus silencer' fitted, however, these have never really made much difference. I would also fit a GRP waterlock (or any other make) between your engine & the silencer.

You may however struggle fitting a 'waterlock' in the 'correct' position but just swap things around to suit, and just make sure the exhaust water is going down hill until it reaches the water lock (this is basically where the exhaust water is stored when the engine is switched off)

Also a gooseneck can help or a swan neck just before the outlet fitting. 

The length of exhaust pipe determines the water lock capacity (plus engine size) however, on fairly 'level' broads boats its not to vital. The main thing is that the exhaust water gets away from the engine quick enough....similar to a household toilet pipe!

On steel canal boats we angled the outlet fitting 45degrees (facing aft) This made a big difference to noise levels. I believe the new Richardsons boats have this angled outlet?.... 

       

[MBA Marine]

you could also use a water lock followed by a water separator then send the water out the bottom of the boat and cooled dry gas out the back, this would allow a smaller water lock to be used.  down side is most use the water gushing from the exhaust as a tell tail that their impeller is functional.

[650xs]

ahhh make a loop .................

 

make a loop of excess exhaust hose make no bigger than the the hight of the engine water injection point 

 

pin it to the bulk head or hull ie with a large jubliiis clip with a ole bit orf rubber pipe as a sleeeve er back up and a acumilator set up all in one 

 

nice and quite ....now still with plenty of water escape 

 

simples ...............................

 

done it loads and it makes simple silencer utilizing water of the ole engine etc 

 

ie the vetus silencer look inside it should be collasped and not blistered ..if blistered then run on hot exhaust gas at some time ,as said befor look at raw water pump all cooler incl gearbox and engine oild check the ole end caps on header tank etc 

 

change impellar every yera as they die inside and swell etc, use to last  , last a life time it seems .naaaaaaaaaaaaa

water  out and air in, not always a leak to see....??????

 

check them ole pumps 

 

 

check them ole jublee clips yer know ole steel one loose there grip and stainless will die too....

 

weed filter have a seal in top orf lid ................????

 

muscles are blockers tooo with white wine and garlic too....... umm!!!!!!!!

[C.Ricko]

you could also use a water lock followed by a water separator then send the water out the bottom of the boat and cooled dry gas out the back, this would allow a smaller water lock to be used.  down side is most use the water gushing from the exhaust as a tell tail that their impeller is functional

you can get exhaust temp senders which will alarm you before the engine overheats...

http://www.defender.com/pdf/vetusmufflerinfo.pdf

[MBA Marine]

you can get exhaust temp senders which will alarm you before the engine overheats...

http://www.defender.com/pdf/vetusmufflerinfo.pdf

yes you can and if the engine has a electric solenoid you can yet the engine to shut down as soon as the sensor has no water. 

[littlesprite]

Would having the engine cut out halve way under Wroxham bridge be a little tricky.

[MBA Marine]

Would having the engine cut out halve way under Wroxham bridge be a little tricky.

not really, if it got half way under then momentum should carry it through!

[sos247]

Would having the engine cut out halve way under Wroxham bridge be a little tricky.

 

Yes, generally the old Lloyds standard preferred ALL marine engines to be shut down by the captain of the vessel (person in charge) i.e. energise to stop. This would allow them to keep the engine running to the bitter end!

This is why so many of the early engines had stop cables or external stop solenoids.  Gensets & most car engines were generally wired the opposite way, so they would shut down on their own if they overheated etc.

On the Norfolk broads its not too much of a problem however, if it was a ship/boat coming into harbour it would be dangerous if the engine decided to stop. Its only recently that things have changed. Barnes now use a shut down system.

I would guess that so many engines in the early years would have been saved they didn't need to wait for the hirer to switch them off! Thats why several hire companies used large red warning lights & alarms!!  

A mallet swinging out from the headlining may have been more use!  

 

   

[MBA Marine]

I think if you were punching the tide up through Yarmouth then you wouldn't want the engine cutting out just because it was running a bit hot. Could be a bit scary! I believe a few owners of ex-Brinks craft on here have removed the system.

people always look to unlikely scenarios, do you get much weed to block your intake across Breydon or are you more likely to to suck some up in a little used dyke like many peoples boats more in? and if you value your boat you will replace your impeller as part of your annual service therefor its very unlikely to fail. 

[kfurbank]

Thanks guys for all the advice. Lots to think about there.

 

Yes mine is ex-Barnes and when I re-wired her I disconnected the solenoid and replaced it with a very loud buzzer and lamp. I can see the possible benefits of the system on a hire boat but being the owner of the engine and being based on the Southern Broads and therefore used on the more tidal rivers I decided that I wanted the chance to make the decision, rather than it being made for me. Impellor is changed annually or at approx. 200 engine hours. The boat is also used all year round so the impellor never gets a chance to sit in the same spot for more than 3 weeks or so. I believe that if laying  the engine up for the Winter for a few months then ideally the impellor should be removed else they tend to stay flat on the compressed side. Being ex-Barnes there are two water filters, one rather industrial and the normal bowl type. Both are regularly checked and cleaned and I have never had a problem with water flow. Rarely finding much weed at all in the second bowl filter. I don't think I would go down the separation route as I want to just enhance what I already have, as opposed to re-engineering too much and I do like the reassurance of seeing water flow out the back. Apart from the issues of a blocked water filter potentially going undetected, there is also the issue of a leak causing water to be pumped into the bilge and again it not being detected until the bilge pumps start working overtime. I do a fair bit of night nav as well and the dash nav light switch has two positions. The first to power up the nav lights, the second to additionally power the dash gauges which are fitted with 24V bulbs so good enough to see, but dim enough not to wreck night vision. So I'm fairly confident the engine has never overheated since I've had her and is monitored well. Fortunately she was re-engined with a new Nanni two years before I bought her. 

 

I like the look and the idea of the water locks, but am dubious about how much space I have under the floor. Will need to look at this again. The link to the Vetus PDF does confirm that I need at the very least to rotate the muffler some more. I am also thinking that if I insert the second redundant generator muffler I would gain enough spare hose to try and make a goose neck towards the outlet.

 

Plenty of work planned for next year and some time ashore after four years in the water so all the floor will be up then and hopefully a quieter boat when it goes back in. 

[ExUserGone]

I have flow switches in my raw water system and a bi-colour led on the helm, turn on ignition it goes red (so you know it's working), start engine it quickly goes green, water flow stops it gows red, simple and saved me a few problems often where I've just stopped the engine and restarted to clear something sucked against the inlet.