BUDGET NOISE SOLUTION SCHEME

Being realistic, its quite possible that some owners have all the above noise issues and fear a very costly remedy, but there is a simple scheme that can allow you to budget and spread you costs over time - starting with the cheapest solution and then working towards the most expensive.  The result will be a complete cure, but over time.  The first and cheapest noise solution is Sound Insulation and is something that could be done anytime of the year as a DIY project.  The next, mid-budget item/s is the exhaust silencer and separator unit, and a good time for this when the boat's out of the water during winter lay-up since you may have to fit a water drain through the hull.  Finally, the top end budget item is the Aquadrive, complimented by the soft engine mounts.  Practically minded owners have installed these Aquadrive units themselves, and their experiences and guidance has been well documented in the marine journals.

Rattling Cabin Doors?
Can't talk in the cockpit? 
Can't hear the radio?
Rattling Galley Stove?
Noisy Exhaust Splosh?  
Can't hear yourself think in the Saloon? 
Generator exhaust disturbing you - or nearby boats?

If you have any one or more of these issues than you have a noise problem!

Diesel engines vibrate and create noise. This unwanted noise and vibration is not only wasted energy, but its also a pollution which can reduce the pleasure of boating, and it can be cured!

Curing noise and vibration means understanding it.  Once you understand the source, you can establish the remedy.  Noise divides simply into three types:-  airborne noise, structure borne noise and exhaust noise.  Three simple tests will take you (and a helper) around ten minutes:

Test 1.
Go to the fore-cabin and press your ear against the port hole window.   Block your other ear.  With the engine in neutral, ask you helper to change engine revs back and forth, and if you can 'hear' engine changing revs through the glass, then you have a STRUCTURE BORNE NOISE issue.  You may also 'feel' the change in engine speed through your ear.

Solution
First we need to mount this engine on much softer engine mounts so that they absorb as much of the engine's vibrations as possible.  If the engine is vibrating really badly it might be worth consulting your dealer or agent any way.  However, these softer engine mounts will only work if the coupling between the engine and the propeller shaft allows free movement with no vibration transmission down the shaft.  This means that a set of Halyard soft engine mounts needs to be complimented by an Aquadrive so that they work in conjunction with each other.  An Aquadrive is the only shaft coupling system in the world that will allow a full inch of movement for the engine to vibrate on super soft mounts, up and down, side to side and fore and aft.  The Aquadrive also removes the propeller thrust from the  engine mounts, allowing them to function properly without being strained by the forward thrust of the propeller.  As an added bonus, an Aquadrive also completely removes the need for accurate shaft alignment.  On some engines the Aquadrive will do the trick without changing the engine mounts, so talk to Halyard first.

Test 2.....

Test 3.....

Noise Finder