Wet exhaust silencer for Buhk

[davidmh]

I have a Buhk 20 engine in my yacht and the silencer is a stainless steel tube fabrication with a horizontal inlet at one end and similar outlet at the other. in 2002 I had to replace it as it had corroded through on one of the seams. I had a new stainless one made to similar dimensions but the seam was made it the top and not the bottom. It has lasted 16 years until now so I am well pleased, but it is now leaking water again through a weld. My question is should I get another one made in stainless or use a plastic type from the likes of Vetus. My local Buhk/Yanmar dealer says he has fitted many of the plastic ones and they give no trouble unless you have a cooling water failure when they can melt.
What advise would you knowledgeable forum members suggest, stainless or plastic.

David MH

 

[VicS]

I have a Buhk 20 engine in my yacht and the silencer is a stainless steel tube fabrication with a horizontal inlet at one end and similar outlet at the other. in 2002 I had to replace it as it had corroded through on one of the seams. I had a new stainless one made to similar dimensions but the seam was made it the top and not the bottom. It has lasted 16 years until now so I am well pleased, but it is now leaking water again through a weld. My question is should I get another one made in stainless or use a plastic type from the likes of Vetus. My local Buhk/Yanmar dealer says he has fitted many of the plastic ones and they give no trouble unless you have a cooling water failure when they can melt.
What advise would you knowledgeable forum members suggest, stainless or plastic.

David MH

Plastic wont corrode

You can fit an exhaust high temp alarm, or perhaps even better a cooling water flow failure alarm.

 

[Tranona]

Plastic ones, particularly Vetus have been in use for many years and are OE on many new boats. Almost nobody uses stainless now because they are prone to corrosion and expensive to fabricate. An alternative to plastic and commonly used in heavy duty commercial applications is GRP and Halyard Marine have an extensive range available.

However, a Vetus NLP type will be fine with your engine. Details of how to lay out the exhaust system together with a calculator to determine capacity can be found in the Vetus catalogue or on the website.

 

[duncan99210]

I fitted a Vetus plastic one this summer to replace a leaking Volvo stainless one. Job took about 10 minutes, it fitted neatly into the gap left by the old one and has given no problems since. Slightly louder exhaust note than before but if that become too irritating I’ll fit one of their silencers next year. I’m also thinking about fitting an exhaust temperature sensor but it’s not high on the priority list.

 

[vyv_cox]

My boat, built in 1984, came with a Bukh 20 and Vetus plastic trap and silencer. The Bukh was replaced many years ago but the trap and silencer are still going strong. I am not certain that the trap is original but I know the silencer is.

 

[forelle541]

As with Vyv my Sadler 29 has had 2 engines and one plastic exhaust trap and silencer since 1981.

 

[davidmh]

Thanks for your thoughts, will probably go for the Vetus plastic, the GRP ones maybe an overkill for my small engine

David MH

 

[davidmh]

Thanks for all the info I am looking at the simple Vetus water trap not the NLP type and would ask whether the trap needs to be secured to the hull. It is a 45mm dia flex pipe system probably similar to the ones fitted in the Sadler yachts. I see two lugs in the diagrams which look like fixing points ., fixing mine to a bottom surface would be difficult, I could fashion something to attach it to a vertical longitudinal panel but wonder how I would do it. Any thoughts would be helpful.

regards
David MH

 

[peteK]

When I bought my boat the water trap was only held in place by the rubber exhaust hose and it was like that for a few years,but then decided it would be better secured to the hull.I just epoxied a couple of eye plates too the hull and secured the water trap with cable ties to them.

 

[Tranona]

Either cable ties as suggested or you can buy straps with mounting plates. Probably best to insulate from the bulkhead - I used an offcut of neoprene as used in wet suits.

 

[Cockaigne]

Bigheads!