How noisy is your boat?

[Hawgwash]

Interesting comments from another thread:

I travel at 17 knots. I can barely hear the engines.

I have found sound to be a real factor in enjoyment and the most overlooked attribute at time of purchase. When we were looking, we were shocked at some of the differences and how loud some boats that you didn't expect to be were. Also, the huge variations in engines with the worst being CAT.

Ok, so, what is your boat, its age, power and noise level at various speeds?
Does the noise affect your enjoyment?
Anyone ever take dB readings?

I just can't imagine a pair of 3208s under the cabin not being bothersome at 16 knots. On any boat.

 

[GoneFarrell]

Hawgw,
FYI, I have been using an app for my iPad called logSPL. It's an amazingly good and accurate db meter, I've checked it against other equipment and now just use this cause it's always handy. Makes quantifying noise levels easy. Give it a try.

 

[Hawgwash]

Hawgw,
FYI, I have been using an app for my iPad called logSPL. It's an amazingly good and accurate db meter, I've checked it against other equipment and now just use this cause it's always handy. Makes quantifying noise levels easy. Give it a try.

Holy doodle!
I was talking Farrell the other day with an old timer and thought of you. How are you enjoying that thing?
Must be good, never see you on here lookin' fer help.

 

[caltexflanc]

Like many things in boating, I suppose it is a matter of personal tolerance. On my old Hatteras with 2 Detroit 8v92ti's under the sole of the lower helm area, we could carry on conversation without raising our voices, but their presence was very definitely heard. Up on the flying bridge, just a faint distant, pleasant purr. By far the quietest power boat I've ever been on is a Fleming 55, almost like driving a Bentley (and I rode in a Bentley the other day).

 

[N4061]

Sound Proofing

Like many things in boating, I suppose it is a matter of personal tolerance. On my old Hatteras with 2 Detroit 8v92ti's under the sole of the lower helm area, we could carry on conversation without raising our voices, but their presence was very definitely heard. Up on the flying bridge, just a faint distant, pleasant purr. By far the quietest power boat I've ever been on is a Fleming 55, almost like driving a Bentley (and I rode in a Bentley the other day).

Thanks for this post and insight into your positive experience with the Flemming 55 (great boat). While I'm not 100% positive I believe the soundproofing enhancement on the new Helmsman 38E models will use similar materials and construction process to achieve a superior level of comfort. I'm glade to hear you view point and excited to see the level of improvement on our boat compared to earlier models which I already thought very quiet boats.

John T.
Helmsman 38E - Under Construction

 

[Hawgwash]

Interesting comments from another thread:Ok, so, what is your boat, its age, power and noise level at various speeds?
Does the noise affect your enjoyment?
Anyone ever take dB readings?

I just can't imagine a pair of 3208s under the cabin not being bothersome at 16 knots. On any boat.

Can we go back there now?

 

[GoneFarrell]

Holy doodle!
I was talking Farrell the other day with an old timer and thought of you. How are you enjoying that thing?
Must be good, never see you on here lookin' fer help.

I'm really liking the boat, I think it's great fun. The thing is great in chop, B Farrell knew what he was doing hull-wise. I'm just going through stuff on the boat, fixing, sanding/painting, repairs, chasing down leaks, upgrading the electrical for modern electronics, getting to know all the systems, how to find boat stuff/parts, burning through $$ like its an all-expense paid trip to Las Vegas, the usual boat stuff. Having thrusters both ends has ruined my docking/spring line skills!

I'd be on it today but I'm far away on a mountain top in southern Oregon. Should be on board next week.

Barry Farrell is still kicking last I'd heard, maybe I can track him down later this summer, we'll see. And so is the long time origional owner.

I've been lurking through a lot of threads here, tons of useful info and opinions. Trawler folk are A-OK in my log book.

Anyways, I used to mess around with noise as engineer, mainly figuring out how to design noise out of equipment that had to be really quiet. That is more effective than trying to dampen something that is noisy, but dampening/isolator design is something I fooled with too...laser measurement systems that could see the noise in the air, I remember we had to whisper when we were near it as our voices would show up on the scope, adding a few nanometers to measurement error.

Still messing with that on the galley table; recently layed out an isolation system for a 2KW generator that should reduce the drumming of the flybridge/house roof when we're below.

 

[Brooksie]

On the bridge, no noise at all, just like being on a sailboat without the creaking & groaning of the standing & running rigging. In the cabin also very quite carry on conversation in normal voice. At idle, in the cabin, a few rattles.
Of course, no great trick with only 50hp @ 2000rpm and crusing speed 15hp @ 1300rpm

 

[healhustler]

About the same as Brooksie...nearly silent on the bridge. Just enough vibration to let you know if things are right. Yesterday, I was fortunate to be on the bridge in Mango Mama (another Krogen Manatee) while using the decimeter App on an I phone. In windy conditions at 7 knots with doors open, 69 decibels. Conversation in the pilothouse was normal. Of course, the hull, decks and walls are cored. Besides the obvious space and economy, quiet cruising may be the best single asset.

 

[Nomad Willy]

Brooksie,
That's it.
The smaller they are the less noise ... but that's assuming all other things are equal and they never are.
Most of the noise comes from things like a bulkhead being like a drum. The engine shakes the hull and everything on the boat shakes. Many things on a boat will be excited (vibration wise) and shake the air and everything attached to it.

Low frequency vibrations from big and low rpm engines may be better at shaking big things like bulkheads. More noise. Noise is made up of vibration in the air consisting on intensity (as in amplitude) and frequeny or frequencies. The bigger the moving engine parts the bigger the amplitude. And the fewer the # of cylinders in the engine the lower the frequency. Think big 4 cyl engines. Worse yet a big 4cyl at idle. One could say low frequency noise is more pleasing and not so bothersome .. but have you been next to a boom box at a stoplight lately?

My engine makes a lot of noise but unlike a PU truck the engine is mostly sealed in it's compartment belowdecks and w some sound insulation it's not objectionable below 2500rpm, and we cruise at 2300. Also the engine is small (40hp) so noise wise life aboard Willy is rather pleasant .... for diesel power. The prechamber type of combustion chamber also helps.

 

[101TUG]

report from builder on all cabines 58 decibel at cruising RPM and 61 decibel on master who the the one with bulkhead with engine room

 

[Nomad Willy]

Tug,
Is that the sound of you and your friends breathing on the bridge?

 

[GFC]

When on the flybridge and running on plane all I hear is the sound of the water coming off the hull. At hull speed, almost no sound at all. Conversation is easy at a normal tone.


In the salon (OK, Marin....saloon) you can definitely hear the Cats when we're on plane, but I wouldn't describe it as loud. More of a "louder than gentle hum". At hull speed in the cockpit I can feel the engines more than hear them. Until I open the hatch to the engine room. Then they're much louder.

 

[Capt. Jon]

Quote...."I just can't imagine a pair of 3208s under the cabin not being bothersome at 16 knots. On any boat."

Well, we can't run at 16 knots as 14 is about max cruise. Noise in the cabin is not bad. Of course we have over an inch of lead foam backed insulationin the engine room. It helps lots!

 

[Ski in NC]

Hull speed 950rpm 7.7kts: Lower helm a gentle purr, no need to raise voices, stereo does not need to be turned up to hear. Upper helm, can't really hear the engine at all, just water and wind noises.

Moderate cruise 1900rpm 19kts: Lower helm pretty loud, mostly prop noise, some engine noise. Have to raise voices and turn up stereo. Basically standing on engine. Upper helm, hard to hear engine at all, but plenty of wind and water noise.

Fast cruise 2200rpm 23kts: Lower helm just plain loud, mostly prop noise ringing through hull. Flybridge still no engine noise, just wind and water, but even that is pretty loud.

I'm jones'n to try a modern 4b DQX wheel instead of the old skool Michigan 3b wheel I've got now. Most of the noise I have is prop noise, and a modern prop may fix that.

Or if fuel prices go up, then I go slow and that will solve the noise problem!!

 

[Bruce B]

Hawgw,
FYI, I have been using an app for my iPad called logSPL. It's an amazingly good and accurate db meter, I've checked it against other equipment and now just use this cause it's always handy. Makes quantifying noise levels easy. Give it a try.

As I instructed, I just downloaded the logSPL app to my iPad. This is a great tool! As the people at American Tug were kind enough to send along some data for the boats we are considering I already had some numbers but...what to equate them to???

Well, I happen to own a Ram 2500 with the latest Cummins 6.7 diesel, the same family of engines that American Tug happens to use in both the 365 and the 395...
So I ran the calibration on the logSPL app and went for a drive.

What did I find in my little 3 mile loop? My truck at 40 mph makes about the same noise as the 395 does at about 8 knots. Under moderate acceleration the noise from the truck is about the same as the 395 at 15 knots...

Go figure! I'll do some more tests when I can get the truck out at speed but I'm guessing that I know what I will find.

Great app!
Thanks,
Bruce

 

[dhays]

I haven't brought my decibel meter out to the boat. I will say that at 7 knots, 1400rpm the water noise if the pilothouse doors are open is more than the engine. In the cabin at that speed you don't have to speak any louder than normal.

The original owner spec'd 2" sound insulation in the ER instead of the standard 1".

Looking at it another way, at 7knots the NP43 is quieter than my sailboat ever was at 7 knots under power or sail.

 

[Bruce B]

I haven't brought my decibel meter out to the boat. I will say that at 7 knots, 1400rpm the water noise if the pilothouse doors are open is more than the engine. In the cabin at that speed you don't have to speak any louder than normal.

The original owner spec'd 2" sound insulation in the ER instead of the standard 1".

Looking at it another way, at 7knots the NP43 is quieter than my sailboat ever was at 7 knots under power or sail.

That is pretty quiet!
Now forgive me but what is an NP 43?
Bruce

 

[dhays]

North Pacific 43

Think of the amount of wind and wave noise present to get a 40' monohull sailboat to 7 knots.

 

[Hawgwash]

I'm jones'n to try a modern 4b DQX wheel instead of the old skool Michigan 3b wheel I've got now. Most of the noise I have is prop noise, and a modern prop may fix that.

Ok, now educate me on modern vs old skool and why it's quieter.

 

[BandB]

Ok, on the boat we're on right now with Twin Man 1200's. At 900 RPM, 62 decibels, at 1400 RPM, 66 decibels, at 1900 RPM, 71 decibels, at 2400 RPM, 76 decibels.

Our noisiest boat is a sport boat so open and at 1000 RPM, 71 decibels, at 1500 RPM, 74 decibels, at 2300 RPM, 80 decibels.

Our quietest boat at 750 RPM, 51 decibels, at 1500 RPM, 59 decibels, at 2450 RPM, 60 decibels.

I consider quiet to be a boat that never tops 70 decibels and noisy to be one that hits 80 decibels.

And, yes, we have a decibel meter. I've found the numbers on the testing sites to be within 2 or 3 decibels of real, however.

 

[Insequent]

My engines, JD 6068's, are under the saloon floor. I was curious about how much the wall to wall carpet helped with noise reduction. Numbers below, at 1750 rpm (8.5 kn) which is typical running speed:

Carpet in place - lower helm 70 dB Saloon 75 dB
Carpet removed - lower helm 80 dB Saloon 82 dB
Entrance to ER, door open - 99 dB

I was a little surprised at modest noise level variation between 1500 and 2000rpm. With carpet, 1500 rpm gave 73 dB at the helm, but was unchanged at 75 dB in the saloon. At 2000 rpm, helm was 72 dB and saloon was 78 dB.

Without carpet sound levels were the same throughout that rpm range at the helm but in the saloon increased to 86 dB at 2000 rpm.

I have subsequently put a mat on the saloon floor but have not re-measured the noise. It won't be as quiet as with the carpet which also had a a rubber underlay.

I should also note that the saloon floor has a number of hatches to the ER that provide a 6' x 6' opening. With better attention to sealing the bedding of the hatch (at present wood on wood) sound levels would be reduced.

On the bridge of course there is little engine noise, but I did not measure it.

 

[markpierce]

Definitely can hear the engine here. That's good because it gives a clue on the engine's state. Not loud enough, fortunately, to drown normal-volume conversations.

 

[BandB]

My engines, JD 6068's, are under the saloon floor. I was curious about how much the wall to wall carpet helped with noise reduction. Numbers below, at 1750 rpm (8.5 kn) which is typical running speed:

Carpet in place - lower helm 70 dB Saloon 75 dB
Carpet removed - lower helm 80 dB Saloon 82 dB
Entrance to ER, door open - 99 dB

I was a little surprised at modest noise level variation between 1500 and 2000rpm. With carpet, 1500 rpm gave 73 dB at the helm, but was unchanged at 75 dB in the saloon. At 2000 rpm, helm was 72 dB and saloon was 78 dB.

Without carpet sound levels were the same throughout that rpm range at the helm but in the saloon increased to 86 dB at 2000 rpm.

I have subsequently put a mat on the saloon floor but have not re-measured the noise. It won't be as quiet as with the carpet which also had a a rubber underlay.

On the bridge of course there is little engine noise, but I did not measure it.

Sometimes it doesn't take a lot to make a big change as shown by your carpet.

On the lake we owned a 30' Cobalt Bowrider with twin 430 hp gas volvo I/O's. It was over 70 decibels at 1000 RPM or so, over 80 at moderate running speeds, and it topped 90 decibels at WOT. The dealer went to work trying to reduce the sound with some under cover insulation, with some sealing around the engine cover, and with some soundproofing under the seats that were over the engines, part of the engine hatch. It was a very powerful sounding boat, but wanting to keep our hearing plus be able to carry conversations on, we wanted it quieter. Lowered it 5 to 10 decibels depending on speed. Biggest difference was at cruise and WOT where it was very throaty.

 

[101TUG]

Tug,
Is that the sound of you and your friends breathing on the bridge?

on bridge and pilot house can't hear engine only noise from water on hull

 

[dhays]

The carpet is a good point. My boat came with carpet sections cut and edged for the saloon floor. The carpet sits on top of that mesh non-skid stuff. I hadn't though about it, but that has to add a lot of sound insulation to the saloon. I love the look of the teak and holly floor, but I have to say the carpet is fantastic.

 

[ksanders]

twin 330 cummins

In the pilothouse at displacement speeds there is a low rumble. In the salon you can hear them but not so loud that watching a movie is bothersom.

At 2400 RPM cruise you can hold a conversation in the salon but watching a movie is not as plesant. From the pilothouse you can hear the engines but not so bad that normal quiet conversation is difficult.

 

[O C Diver]

With the new 4 cylinder John Deere turning 1,400 rpm at cruise, the boat especially the pilothouse is very pleasant. It's so quiet I can easily here the engine room exhaust blower running.

Ted

 

[Hawgwash]

Mrs. Sanders climbs the steps to the pilothouse with a coffee for the skipper.
Kevin?
Kevin?
KEVIN!

Yeah hon, I'm down here watching Pretty Woman. Come join me.

 

[Old deckhand]

Each year, as I get older, the engine gets quieter.