Exhaust silencers.

miket

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21 Jun 2001
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N Hampshire
Broom 37, 306hp TAMD61A's.
Currently on straight through exhausts to semi submerged outlet.

Contacted "Halyard" who claim between 40% and 70% in exhaust noise, dependant on system used. Price appears to be about £700 per side.

Has anyone any info' on actual success of these silencers?
Alternative suppliers also sought.

Views welcome.
 

david_bagshaw

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Dont know about that size, but we have their products in our onan generator exhaust, & THEY REALLY WORK,, and I meant to shout., unlike the generator which whispers.



David
www.yachtman.co.uk
 

hlb

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But, But!

You cant put silencers on a boat.

What would the yachties think?

And no veruuuuummmmmfff. Up onto plane.

No more grumfs and growles whilst backing round the marina.

Come to your senses man.

Its all that bloody turkey thats doing it.

Save him some body. help S.O.S Mayday Mayday!!

Haydn
 

Gludy

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Brecon, Wales
Itnteresting ... I have a 6kw generator in the lazerette and it is very noisy. As my heating/airconditioning runs off mains, it would ber very handy to have the generator going - I had planned to put some sound proofing in the lazerette but this idea of a silencer may make more sense - is it really that much more silent or is it best to spend the bucks on sound proofing? Advice needed.


Paul
 

Gludy

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Mike - I have TAMD61A's - does the exhaust solution do away with the problematic volvo ehaust elbows? At about £700 per engine for your suggested solution, this works at about the same price as replacing the exhaust elbows with the modified volvo versions.


Paul
 
G

Guest

Guest
Re: Genny silencing.

I would bet that a silencer itself, cutting noise at source, will be a good idea. As for soundproofing, our genny came with a plastic box, soundproofed on the inside, two halves connected by little latches and straps, that entirely covered the generator. Does yours not have the same?
 

ChrisP

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21 Aug 2001
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South East England
Got them on the Humber. Difficult to say how much noiser it would be without them. The boat still has the throaty roar around the marina but when underway the exhausts spend much of the time under water. Might be worth contacting Volvo as the increased back pressure may affect performance and more importantly fuel consumption. The configuration of the exhaust piping can affect the burn and scouring of the in the cylinders. Even minimal increases in back pressure can cause smoking exhaust and fouling of the injectors. When you talk to the manufacturers give them details of the exhaust pipe sizes and the number of bends etc. From this they can estimate the total pressure drop accross the exhaust and tell you if the system is within the limits of the engine.
Best you get a move on and do the job because when the EU laws get going any work of this kind will require testing to revalidate the CE mark.
Best of luck and happy new year.

See you soon
Chris.
 

david_bagshaw

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Your 6 Kva , how fast does it run , the onan is 7.5Kva and runs at 1500rpm.

Engine is quiet any way but the halyard equpement does remove the exhaust noise completely, particularly as we have their "exhaust dryer" installed, so the´re is no splosh etc.


David
www.yachtman.co.uk
 
D

Deleted User YDKXO

Guest
Mike, funnily enough I'm looking at the exact same thing on my Broom 37 which has Sabre 275hp engines. My boat has in-line silencers (black rubber-like tubes) made by Elastomuffle with the exhausts exiting the side of the hull just above the waterline. I take it yours are similar? Noisy, is'nt it?
I talked to Broom, first, who were'nt very helpful. They dont know of any retro-fit mods. Basically, the problem is three-fold; firstly, the exhausts exit the side of the hull and not the transom, secondly, the exits are above the waterline not below and thirdly the Elastomuffle silencer does'nt work nearly as well as a water-trap type (such as Halyard)
I talked to Halyard at the Southampton Show this year and showed them a sketch of my exhaust layout. They reccomended one of their grp dual chamber silencers at about £700 a side as you say. Great, I thought, lets have a couple of those but thats where the problems start.
Dimensionally, you can squeeze a couple of these Halyard chambers into the engine space (at least on my boat) but they are relatively high and the only place I could see for them was above the stern glands making it even more difficult to adjust the stern glands (have you got the ones with those sodding great big adjuster nuts?) and block any access to the engine space from those little doors in the aft cabin. The second problem is that the diameter of the exit pipe from the Halyard chambers is 150mm; my existing exhaust pipe diameter is 125mm. Halyard say that using 125mm pipe would cause back pressure reducing engine efficiency; I certainly did'nt want to lose any boat speed. Fitting 150mm pipe would mean substantial modification of the exhaust exit flanges in the hull and probably some hacking about of the shower tray on the port side (behind which the port exhaust runs)
To cut a long story short, once I realised the amount of additional work required to fit the Halyard silencers, I gave up. I'm told the performance of the existing Elastomuffle silencers can deteriorate with age as the baffles inside can loosen so I'm having those checked out first.
BTW the Broom 41/415 has below waterline transom exhausts with proper silencers so I'm now hankering after a new boat but a set of ear defenders might be cheaper
If you get anywhere further with your investigations I'm really interested in hearing
 

Gludy

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Re: Genny silencing.

No, do not have the same Matts. I think it mat be worth me appraoching the problem by having one made though, seems a better way to do it than sticking bits of sound proofing all over the place.

So with that and a silencer, I may well lick the generator sound problem. My boat has its heating, cooking, hot water etc all from mains, so I really do need to shut the generator up and make it practical to use.


Paul
 

hlb

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Re: Genny silencing.

Gludy. Why not just go back to gas cooker and engines for heating water, like the rest of us. Then hardly ever need generator. Theres only about two nights a year when I've ever missed one. Usually tied to a buoy in Salcolmbe on a cold night when heating system is draining the batteries.
But then turn oven on for heat.

Haydn
 
G

Guest

Guest
Mike, I have worked on a lot of Brooms, Princesses, Fairlines etc with 61 A volvos, now my Princess 388 has no silencers, mates 385 has, now at tickover mine is a bit louder but on the move I would say that they are the same levels.
Another thing to consider is that one year mates impeller went, causing exhaust to collapse and catch fire, melted his silencer hence more cost.

I have recently carried out a lot of work on a Broom 37 with 306's and in my opinion it is no quieter with the silencers on than my Princess without them, all comments IMHO I guess.

Paul js.
 

miket

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N Hampshire
Thanks for all your thoughts/ advice.

Spoke to a very helpful chap on the Halyard stand at LIB yesterday, and it all sounded quite bullish.

Deleted User's comments very helpful as I hadn't done proper measurements of the space available, and as access, other than at the back of the engine, is severely restricted, I certainly don't wish to make it any worse. (yes. mike, I do have those same stern glands)

Pricing at £700 also seems a bit optimistic. I suspect by the time I have had them fitted it will be well over £1k per side.

Will probably leave it until end of 2002 season, when we hope to cruise further afield, then if I want to change the boat (again !) it's a good excuse to give the lady!!! Sneaky eh?
 
D

Deleted User YDKXO

Guest
I picked up the Vetus catalogue at the LBS. Page 111 shows a type MV exhaust suitable for high powered engines and which Vetus claim gives a 'tremendous reduction in noise'. I'm going to investigate this one further as it looks to be about the same size as my existing silencers and fitting should be much easier. Its also a lot less money at £250 a side
 
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