Are Suzuki 50 HP Motors Unusually Loud?

Has anyone used a db meter to take a reading in the cabin of a 16' C-Dory. My guess is it's about 80-85 dbs at WOT and if thats right, see below for a scale and the expected result.
My goal would be to see a noise level of no more than 70dbs. Remember dbs is a log scale to the power of 10--although our ears are not running on the suggested intensity of the log scale-- we seem to adjust.

85 dbs
Upper limit for any comfort, which is limited. Ear muffs suggested for log exposure

80
1 meter from ringing alarm clock. Conversation is difficult. After a 1-hour exposure, thought is difficult and the stomach contracts.

75
Railroad carriage. Normal conversation not possible. Consensus of experts is that sound levels below 75 dBA "are unlikely to cause permanent hearing damage."

70
Small car at 30 mph; 3 meters from a vacuum cleaner.
 
From a technical point of view, the multi-layered approach mentioned by Thataaway is interesting. Sounds like something developed to enclose equipment on a submarine! Bob- do you know anything about the history of the development of this technology?

Does the same noise problem exist in the 18, 19, and open bulkhead 22 Sport Cruiser? Could be there's something specific about the resonant frerquency of the 16's cabin size and engine rpm matchup?

I still think earplugs may win the economic side of the war!

In desparation, one could always invite Byrdman along with his 8-track player and tape of Iron Butterfly's Inagaddavida played at 10 or more db over the engine noise!

Joe.
 
This is a great discussion.

The noise level in the cabin of my 19 is not uncomfortable for me. But, it is uncomfortable for my husband. Irony; he has some hearing loss. I would love to get a db reading in the cockpit, with the drop curtain in place and without. The curtain does dampen the level of noise. I think that you can rent a db meter, I am going to look into that. I would recommend to anyone who notices the noise "more this year than last", and "head ringing" that has not been experienced before, to check out the engine, and to get your hearing checked. I am sure that someone out there knows much more about the many types of hearing loss, tinnitus, etc. than I do. I do know that one type of hearing loss can cause discomfort around certain noise frequencies. A bit counter intuitive.

As far as quieting an engine, would a plexiglass or lexan deflector mounted in front of the engine, canted towards the stern, deflect some of the noise? Or maybe just go fast enough to leave the noise behind? Zoom Zoom.

I am off to catch a crab! Robbi
 
Robbi":2g1year4 said:
Or maybe just go fast enough to leave the noise behind? Zoom Zoom. Robbi
Click to expand...

Robbi,
Your "zoom zoom" remedy is the best resolution so far! It has simplicity, is easy on the wallet, and makes me laugh... :lol:
 
No to answer your post question.... The 50 hp Suzi is not a "loud" motor. You go sit in the pews of some old churches... Yep, that cathedral shaped alter area is that way for a reason.....to bounce the sound "AT" the congregation.... In a 16...and even the 19.... YOU ARE THE CONGREGATION... Robbie is right on target. It is really wild how little it takes to "bounce the sound" in another direction. Go to HomeDepot, buy a roll of duct tape, and a piece of that insulation board in 4x8' sheets. And.. get some goo stuff to remove the tape gunk when you finish this test... Now, simply cut a 4 sided box shape with a box cutter razor blade to fit the shape you need.... forward edge, two sides... and the top piece....leaving the aft facing side open to allow the sound to "bounce" aft of the boat. Duct tape it to your hull... This is a proto-type design...that you can try for less than $20 to see if it works... if it does... Then simply cover the "box" in some 1/4" AC plywood.... after you paint it up good to match the paint design of your boat and...to keep the water out of the wood...and you can trim it all up nice and pretty with some type of trim strips... :smiled and go ahead and enjoy a conversation on your boat.
 
On my buddys' little Arima we built a removable hinged table that goes over the motor well out of starboard. Sorry I don't have a picture handy but it is similar to the one the Arima factory sells for their boats. It does seem to block a lot of the noise. Also provides some nice usable space that is otherwise wasted.
Norm
 
Opps.... upon re-read..... I forgot our 18 anglers (all 14 of them)... have the same effect. Norm... I will have to take a look at their site...

Norm.. I should go pick up C-Byrd this week...going with a jackplate of 10 or 12"... so.... I need to get my thoughts going a bit on the aft section of her.... and this sounds good....no pun intended.

Byrdman
 
No Patrick, Mine does not have that effect. Remember mine has the bulkhead and door like her big sisters. Definitely the way to go IMHO.
Norm
 
If would seem to me that something similar to what Ray Macke did on his cabin skiff is what you guys need.

w28box.jpg


BTW: If you haven't read his website about building it I think you will find it very interesting. http://www.egyptian.net/~raymacke/index.html
 
Yea.... kinda what Ray did... Thanks.. :thup


...... :note don't ya know I'll always be truuuuua. :note

Thanks Don. I needed that flashback. :smiled
Byrdman
 
Yeah, I thought the same thing Pat!

His engine cowl is functional but I think I would change it to make it more useful by getting rid of the angle on the front and just go straight up to make room for a fish cleaning station/table area.

Or incorporate a cooler mount along with the cowling. Although that might be putting too much weight up high.
 
Patrick, I'm not sure how high your new motor will be but my Etec is low enough that the table top could be just about level with the top of the motor well. It would need to be hinged to allow the motor to tilt up but that may be even less of a factor with the 12" jackplate you are putting on.
Norm
 
You are target on with the height Norm.... To the point that after looking at some of the stearing cable issues with manual stearing.... that I am forgoing the jackplate at this time... Gonna put her in the water and run her a bit ....and just use her for a while and adjust fire from there... she is shinny now... will post newest pic on C-Byrd thread.

Yes... that looks like a nice set up back there. Good point about too much weight getting too high...and it has been a while since I have spent a lot of time on a mono hull.... got some oh yeah stuff to work back thru....that can only happen on the boat, in the water, in all the differant circumstances that occur.

Byrdman
 
I just received my Quitecar paint. It is really a paste. I have decided the only way to give it a true test is to :
Build a water tank for the engine so I can run it on the back of the boat on land while stopped.
That way I will not have any wind or water noise influencing the results.
I will run the engine at different RPM’s and get noise readings at different points on the boat using a db meter.
I will then paint the inside of the engine cover and repeat the test.
I will then apply a second coating and repeat the test.
I will then do the same after a third coating. (supposedly three coatings give the maximum noise reduction)
I will post the results here at the conclusion of the test.
Don’t hold your breath waiting for the results. I start haying tomorrow and do not expect to finish until Saturday or Sunday. I then may take a few days off and go cruising on Hood Canal so it may be after the first of July before I have completed my test.

I hope it makes a significant difference.
 
Hay{sic} Oldgrowth,
Glad to hear your going to run a test with a db meter and the sonic control paint. If it works you will get a Gold Star for research
Blue
 
We could talk about it until the cows come home and never accomplish anything or I could spend $125 to $150 and try something. If it helps it will be worth it, if it does not, I have blown more than that on dumber things. Besides it’s the challenge as much as anything else.
 
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