DPC Waterlock & silencer leak
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URL: https://www.myhanse.com/forum_posts.asp?TID=11245
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Topic: DPC Waterlock & silencer leak
Posted By: Mark_J1
Subject: DPC Waterlock & silencer leak
Date Posted: 25 February 2019 at 15:00
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Hi all - anyone found a leak from the DPC Waterlock silencer and found the cause? I’ve got one on my Yanmar 3JH equipped hull from 2005. I get a small leak when the engine isn’t running. Seems to be coming from underneath but I haven’t extracted it just yet. I gather these Waterlock are basically just 2 stainless end can pieces joined and covered by a neoprene sleeve. So my guess is the neoprene has given out? Anyone found a replacement available? If the DPC one is toast I might fit a Vetus NLP3 which promises a quieter exhaust note but I'd rather not fork out the £300 if I can avoid it. Interestingly thanks to prevailing winds I’ve found the engine bay sides are not sealed to the floor. So any leak from the aft of the engine bay exhaust area neatly pools under the soul board of the cabin with nowhere to go. Panels now sealed so the drip is directed to the bulge pump!
Mark ------------- Hanse 400e "Grey Goose" Hull #31 |
Replies:
Posted By: Rock
Date Posted: 25 February 2019 at 20:32
 Mark,Not an answer to your question, but a comment. I think a quiet exhaust on the Hanse with 3JH4 remains a dream. I had an extra (think is Vetus) muffler added when I installed my SD60. Barely hear a difference, still somewhat annoyingly loud. Regards, Peter
------------- Hanse 400e "M-square2" #0241 |
Posted By: Mark_J1
Date Posted: 25 February 2019 at 21:08
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Neatly done job there so a shame if the results aren’t forthcoming. There’s another thread on the forum where someone reduced the exhaust diameter to change the note with apparently some useful results. If I end up replacing the Waterlock I’ll drop in with the result.
Mark ------------- Hanse 400e "Grey Goose" Hull #31 |
Posted By: hawkeye
Date Posted: 25 February 2019 at 23:18
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I installed an NLP3 to try and reduce the noise. Did not make much difference. In my view, the exhaust diameter is too large for the amount of water and consequently the waterlock (oversize) does not properly seal each chamber. No other 40hp marine engine I have looked at has such a large diameter exhaust. Most are about half the diameter. I suggested to the diesel mechanic that I might reduce the exhaust diameter, but he opposed changing from the Yanmar standard size claiming it could lead to back pressure and overheating. Good to know that the silencer has minimal effect as that was an option I was considering. John
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Posted By: Mark_J1
Date Posted: 03 March 2019 at 19:14
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I finally extracted my DPC Waterlock Silencer. Source of the small leak was a) some numpty at the Grefswald put it in back-to-front b) stainless end can rusted to the point of being porous (at least in part) as a result. I've included some shots below. These DPC waterlocks are just a pair of end cans joined by a neoprene sleeve. | thought the leak was most likely from rotting neoprene. Was very surprised to see the state of the downstream end can. |f you have this make of waterlock worth checking (as others have mentioned on the forum) it is the right way round. Also don't be tempted to disregard a minor leak from it. A few more engine hours and I would have had a 40HP pump releasing water into the bilge :-) New waterlock Vetus NLP3 on order! Mark    ------------- Hanse 400e "Grey Goose" Hull #31 |
Posted By: Axel
Date Posted: 03 March 2019 at 21:32
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Hi Mark, my former boat was a Dehler 34. it had also the same system. Every few years the V2 stainless steel was rotten and my engine was pumping lots of water into the bilge. You should get the end pieces out of a better material. Axel ------------- Hanse 385 #434 Nyanga 2 |
Posted By: Mark_J1
Date Posted: 03 March 2019 at 23:13
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New one from Vetus is mostly of plastic construction. No idea what the life span will be. As I’ve gathered it’s a reasonably easy fit with at least a little promise of reduced noise it seems the best choice for now. Only found one source of the original DPC version but no pricing. I could probably have got another end can made locally but at this point, time is more my driver. Mark ------------- Hanse 400e "Grey Goose" Hull #31 |
Posted By: Mark_J1
Date Posted: 23 March 2019 at 22:56
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To end this thread, the Vetus NLP3 Waterlock turned up after a 3 week wait. Custom order apparently so not something to order at the last minute. It’s approx 20cm longer than the original DPC item but I didn’t want to shorten the existing hoses until all was tested. It is tight but does fit. The trick is to use the option to twist the NLP3 inlet & outlet pipes and to rotate one of the chambers 30 degrees. That keeps the aft end low enough. With a waterlock the right way round the exhaust water flow is smoother and I have a dry bilge again now the leak is resolved :-) As noted earlier in the thread, I’d say the multi-chamber NLP3 makes some difference to the exhaust note but not a lot. It’s a little more mooted however I wouldn’t recommend replacing the original Waterlock just for noise reduction purposes. The difference isn’t worth the cost. Mark ------------- Hanse 400e "Grey Goose" Hull #31 |