2011 NT32 Pulsating exhaust sound

I recently purchased a 2011 NT 32 and I noticed during cruising at about 8 knots (1,900 rpm if I recall correctly) a rather distinct low frequency pulsating exhaust sound coming from the rear of the boat. I am guessing the frequency is about 5 to 10 Hz. Upon closer examination, the sound seems to be created or emitted in the rear on the starboard side of the boat where the exhaust exists the boat. It seems that the exhaust is somehow interacting with the bolt-on swim platform, causing a resonance condition. The sound (noise) gets worse as the engine speed increases. The sound frequency does not seem to change appreciably with engine speed although I have not confirmed that through actual measurements. Any attempt to quiet this sound by redirecting/adjusting the water flow around the swim platform and adding weight to the swim platform by standing on it, etc. has made no difference.

I am curious if this is normal with this boat model/build year and if anyone else has been experiencing the same issue. I realize that new models use the integrated swim platform. Not sure if the noise issue was a contributor to the design change.

• This topic was modified 7 months ago by Hans Schlamadinger.
• This topic was modified 7 months ago by Hans Schlamadinger.