Gear noise

R

rmenendez

Furuno Fan
Just finished and installation of a new DRS12a and we notice a rather loud gear noise coming when the unit is operating. The noise level is louder when operating at 48 RPM. No prior experience with a Furuno radar before, my previous was Raymarine array that was belt driven and substantially less noisy. Aside from that, image quality on a TZT14 is very good.

Rolando
 
It is normal to hear gear driven units, and the sound will increase at higher speeds for the variable speed units like the DRS units. Normally it isn't excessive unless your mounting causes reverberation and acts as an amp/conduct for the sound. If there was a problem with the scanner, it would be reflected on the radar signal/screen so it does appear to be normal to me. If in doubt, you can always listen to someone else's similar model and compare. The high speed offers better sampling but if you wish to fix the speed to 24rpm, it can changed in the setup. Furuno has seen no problems with the variable speed scanners including the DRS units which started selling in 2008. The units also offer a very good warrantee if you do find something wrong.
 
Thanks Johnny. The radar is mounted on a shell built into the flybridge roof which is hollow and probably helps increase sound transmission. Would you suggest adding sound padding in the cavity underneath? The shell just act to elevate the radar and provides a down firing angle forward for the radar. Photo attached.

Rolando
 

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I am guessing you might have been checking out the new radar at the dock or while running slowly. I have been a bit surprised on the few times when I have operated the radar drifting without the engines running or at the dock. The motor is fairly loud but of course normally with two large Diesel engines under my feet and the wind and water noise, it gets lost in the background while underway. You may be on to something with the hollow mount creating a resonance that could be dampened with some soundproofing.
 
CC32, I listened carefully this morning and indeed it is coming from the cavity and then through the overhead instrument compartment directly underneath. I am pretty sure it can be reduced with some sort of sound absorbing material. At 24RPM its not that bad but at 48RPM its really loud. True that with two big diesels it will be be next to impossible to hear. It was the surprise at first start-up how much louder it was than the previous belt driven unit. But the, the display quality was so much better..... can't wait to see how it does with tracking birds.

Rolando
 
There is a company called Soundown that makes and sells the soundproofing used for engine compartments. You might give them a call and see if you can buy a small section of the "Tuf Mass" . It is a heavy vinyl sandwiched between foam and comes in various thicknesses. You would need to screw or glue it to the underside of that cavity where the radar bolts through.

I suspect after a few runs, you will not really notice the gear noise much, however. That radar is excellent at tracking birds once you get the hang of tuning it. I see small flocks of shearwaters out 4-6 miles routinely if the seas are not too rough.
 
CC32 makes a good suggestion. I do think you should find some sort of sound proofing.

Looking at the photo; I would also suggest (nothing to do with sound) that you coat those bottom bolts that mount the gearbox to the boat with the required sealant. I am sure the installer might still be working on it, but you don't want to leave them exposed like that after the install is completed.
 
Johnny, thanks for the heads up on sealing the bolts. Yes, we are still working on several more new additions in the installation. BTW, I could swear that noise is going down by itself, guess the gears are seating and getting lubrication.
 
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