Why is my boat engine so noisy?

[Slipstream 34]

Active noise reduction technology is very effective in aircraft intercom systems. I have pondered getting a cheap pair of ANR headphones and wiring them to a speaker in the engine compartment. I have no idea how effective it would be and there are much important jobs need doing first. I have searched the Web and can't see any off the shelf systems... probably because it is a daft idea and wouldn't work.

I wonder if I could tempt Professor Mcdoon to make a "yapp" of it.

 

[Rivers & creeks]

Active noise reduction technology is very effective in aircraft intercom systems. I have pondered getting a cheap pair of ANR headphones and wiring them to a speaker in the engine compartment. I have no idea how effective it would be and there are much important jobs need doing first. I have searched the Web and can't see any off the shelf systems... probably because it is a daft idea and wouldn't work.

I wonder if I could tempt Professor Mcdoon to make a "yapp" of it.

A very interesting idea, does it work by amplifying a frequency with a sort of opposite phase?

 

[Avocet]

Yes, that's how they work. Unfortunately, they tend to only work on constant frequency noises and can only really "kill" the noise in a fairly small area. As you move around the boat, I think you'll find areas where the two wave-forms ADD to each other, rather than cancel each other out.

 

[Slipstream 34]

You would only need it to be effective at cruising rpm. If the speaker is mounted in the engine bay that's relatively small. If you could attenuate the noise before it gets out it would make a difference.
Might a good excuse to get a bad ass speaker system on the boat!