Polymeric or Lead?

[Gixer]

My current engine soundproofing is falling apart so I’m going to replace. Question is, is it worth paying the extra and adding the weight of lead?
I get the physics of it and the decibel reduction differences but would like some real world experience’s.

Engine is 1GM10 in a 27f yacht.

 

[Turnnidge]

I have used both, on a couple of boats. The polymeric one is good on flat areas, but doesn’t conform to any uneven substrate where the lead one is easier to shape over lumps and bumps. A good spray contact adhesive is the way forward.

 

[B27]

1GMs don't qualify for soundproofing, they don't emit sound, they are a continuous seismic event.

The soundproofing foam may reduce the sound which travels from the engine through the air to the engine box, but it won't attenuate the engine shaking the whole damned boat. The 'sound' mostly travels through engine mountings, prop shaft etc.

 

[johnalison]

I put lead round a Volvo 2002 on our then Sadler 29. Although not a cure, it was pretty effective and worth the effort.

 

[wombat88]

I've just used some stuff (on a car) that appears to be made from a layer of adhesive material, then a layer of what looks like bitumen, then a layer of this foil. It is consequently heavy but quite thin. It has proved to be very effective in damping the racket from a small, water cooled, rear engine.

On reflection I think that sound proofing does make an improvement but we tend to convince ourselves that it is more effective than it is in reality. As B27 says, it is the transmission of sound that is the real culprit.

 

[Tranona]

My current engine soundproofing is falling apart so I’m going to replace. Question is, is it worth paying the extra and adding the weight of lead?
I get the physics of it and the decibel reduction differences but would like some real world experience’s.

Engine is 1GM10 in a 27f yacht.

According to the specifications the reduction in sound transmission is the same (23dB) for 23mm that I used. Sound transmission is mainly through the gaps so more important to seal the engine box as much as possible and baffle the air intakes. Lead may be better when it is used for dampening resonance on flexible panels such as cockpit floors.

TBH not sure any of it makes much difference with a 1GM in a small boat and doubt you could tell any difference between the 2 types.

 

[Gixer]

TBH not sure any of it makes much difference with a 1GM in a small boat and doubt you could tell any difference between the 2 types.

This is exactly what I thought.

The soundproofing is mounted onto mostly wood and all flat panels.

Thanks guys.