Update/change/add silencer to 46 Post

I want to follow this thread.

The only way I know to reduce the noise of a DD is to use ear plugs.

there is a reason that they call them "screaming jimmys"

I always loved the sound of Detroits! I was out on my buddy's 46' last Saturday and enjoyed those "screaming Jimmys".

Muffler exhaust solutions run the full price spectrum, but I have had good luck working with Bruce Browning at Centek for engines in this power range- Centek Industries - wet exhaust systems, genset pollution control

They have been able to reduce the exhaust note to acceptable levels on CAT C18's, which is no small feat.

They may have a solution where you do not have to go to underwater exhaust. You may also want to put some type of carpet underlayment treatment to quite the salon.

Know nothing about DDs but I inserted some silencers from GGB Exhausts in my two FL SP225s and it made a world of difference. The ones I bought slip into a 4" ID exhaust hose.

They also have other solutions.

Bob

I think you have to be concerned with reducing back pressure

They list HP ratings on their site. Again, I don't know about DDs, but on the FLs they reduced the higher frequency noise which was so annoying. They are by no means quiet, but it is a much more pleasant noise.

I have no connection to the company, just a satisfied user. I did a lot of searching and there are quite a few different solutions out there. For our setup the inserts were the simplest, and also cheapest, solution.

Bob

I would also contact and ask D'Angelo's marine exhaust in Fort Lauderdale. All they do (pretty much) is exhaust and they also do great work and are good people to deal with.

The Sea Deuce with a set of 16-92's is quiet enough to have a conversation at all rpm's in the cockpit and flybridge. It's exhaust is similar to the third diagram from your quote- only the first section after collection which empties into the surge tube is different. Going to an underwater exhaust is asking for issues IMHO. Call up MES in Riviera Beach and ask for advice.

We have 10" exhaust in the transom. I took a rubber 90 degree Elbows, pointed down and clamped it on. First rev sprayed & splashed water everywhere. Drilled 2" holes in the sides for idle relief. Next time I'll drill these holes facing inward (under the swim platform). The bottom edge was shapes like a thruster tube lip.
This did greatly reduce the 1000 rpm howell and lowered the sound level. At speed, the exhaust is unrestricted as it dumps into the void behind the transom. Still quieter than original. At idle it blub-blubs but you can give & receive docking instructions without yelling.

I found them at Sailors Exchange in Liquordale (Surplus store). I had looked at them for months and made an offer. I'm anchored out this weekend, despite one heck of a front pounding in from the NW (We had to get off the dock). I'll get some pics up next week.

Started a new thread @;
http://www.yachtforums.com/index.php?threads/poor-mans-exhaust-silencer.23691/

Could yo place a picture of how it looks?.. we all will appreciate it.