exhaust noise

[Capt Ratty]

I have a 1968 tc with twin 6 / 53 Detroits. The exhaust noise is very loud, almost to the point that you can't carry on a conversation without shouting. The rpm is at 1200 to 1500. Are other boats this loud or do I need mufflers?
Is it a design flaw? If I need mufflers, where is a good source?
There are no apparent exhaust leaks. The starboard exhaust hose was recently replaced.
Thanks

[J's Dream]

Are they naturals? My 892N's are really loud. People tell me they I wake them up and they live 4 houses away! I think they are just that loud.

[Boatsb]

Welcome to the "garbage truck club" I have 8v53's and yes they are loud. naturals don't do well with mufflers and to be honest we got used to it.

[Brian Degulis]

Naturals will be louder than turbos. Metal or fiberglass exaust lines will be louder than rubber. A lack of water flow will increase noise. The most efective muffler is the lift type a larger version of what's on your generator. My last boat had 671 naturals Centec 6" lift mufflers made it as quite as a church mouse.

Brian

[neosin]

My hatt is loud with 8v71s... But i like it, has that oldschool hotrod boat sound... everyone knows it's my hatt... I've had other hatt guys come up and ask if i did something... lol i even have rubber pipes... I think it's the 871s that have that really deep sound... I like it, sometimes it can bother you in the wrong rpms my 1200rpm is really bad, the drone will make it so you can't speak with out yelling, but my 10kts rpm does very well you can talk normally... Maybe play with your rpms and see if you can find something that works well without eating up to much fuel.

Even 50 - 100 rpms can make a major change the way is drones in the lower helm. My flyingbridge doesn't drone on us at all... You hear it but isn't not loud at all up there.

Today with my engine tech we ran the boat with all of my floors up checking rpm, heat, oil leaks after a tuneup. It helped. Temps are 185 and 183 at 1950rpms doing 14kts. 190 on both at 2050 rpms doing 15.3kts, Didn't test wot as i know it will climb to 200 after about 30 mins. Will be doing some fuel flow tests soon i'll post them up later...

oh yea, running at them rpms with no floors, WOW now thats loud, sounded like i was in the middle of a tug with full load on my lower helm. I can't believe how well my floors deaden the sound.

...out

I have a 1968 tc with twin 6 / 53 Detroits. The exhaust noise is very loud, almost to the point that you can't carry on a conversation without shouting. The rpm is at 1200 to 1500. Are other boats this loud or do I need mufflers?
Is it a design flaw? If I need mufflers, where is a good source?
There are no apparent exhaust leaks. The starboard exhaust hose was recently replaced.
Thanks

[Dustoff44]

Is there a source or website for Centec ?

[Capt Ratty]

Ok, they are naturally loud. How can I tell if the mufflers are shot. A 40 year old boat with probably the original mufflers? What else can be done without the expense and hassle of replacing them? Access is very limited. Did Hatteras forget something when they put together a luxury yacht? Would it be quieter at a higher rpm? Unlikely. Do you have to wear earplugs? I can't emagine cruising all day with that much noise.

[Capt Ratty]

neosin
I will try some rpm variations.
Thanks

[neosin]

The only real rpm that just kills me is 1200 - 1240 ish for me. Just DRONES like mad... But about 1320 is almost quiet I can cruise for 8 hours without problem. Mine doesn't have mufflers on the engines. Remember this was the 1970s, mine being a 1972, Big blocks and deep engine sound was very "in"... To me it still is as i used to race drag... So really i like it lol.

Play with your rpm, When i'm at cruise rpm, 1950 - 2050 doing 14 - 15kts i get no drone and it lowers down, you get more water noise than anything else really.


...wanted to add, Inside the salon, forget about it... engine nose at 14kts is nuts. However my wife sleeps in the rear cabin at 8-10kts all the time. My buds watch tv in the salon granted it's turned up when I'm at 8-10kts.

neosin
I will try some rpm variations.
Thanks

[Brian Degulis]

Is there a source or website for Centec ?

Yes there should be either search centec or vernatone

Brian