cruiser stern

[jonk]

My cruiser stern is large and has two lift up aluminium panels for access to the Vetus engine below. The engine is quite noisy and I would like to reduce the transmitted noise! I have added foam draught-excluder round the bearing edges of the panels and that has helped but I have been considering a large rubber mat to cover the panels (overlapping the edges). I am thinking that this would help in 2 ways - it would stop quite a lot of the rain getting into the engine room (although the draught-excluder has really done that) and it would reduce the noise. Has anyone experience of doing this and does it help? If it does then what is recommended and where do I get it?

 

Thanks in advance,

John

[Phil Ambrose]

Have a look on ASAP's website for sound insulation which you stick to the underside of your deck boards.

Phil

[Stormbringer]

I was considering getting some car under bonnet insulation from a scrap yard and trying that on ours.

I recon it should be cheap enough ... Don't know how effective it would be but hey....

[Phil Ambrose]

I was considering getting some car under bonnet insulation from a scrap yard and trying that on ours.

I recon it should be cheap enough ... Don't know how effective it would be but hey....

I think there is an issue with this stuff and the BSS which was why I suggested trying ASAP or maybe AQUAFAX

Phil

[Stormbringer]

I think there is an issue with this stuff and the BSS which was why I suggested trying ASAP or maybe AQUAFAX

Phil

Ahh..ok, cheers Phil, back to the drawing board then.

Thanks for the heads up ... Much appreciated.

 

And apologies to the op for the bum steer!

[Machpoint005]

_{You need some mass (weight) in the deck boards, and some internal damping, which is why hexaboard (or whatever it's called) is far better -- aluminium chequerplate is just too light to do anything worthwhile.}

Edited April 19, 2014 by Machpoint005

[Phil Ambrose]

_{You need some mass (weight) in the deck boards, and some internal damping, which is why hexaboard (or whatever it's called) is far better -- aluminium chequerplate is just too light to do anything worthwhile.}

Mass is the secret that is why sound insulation board offered by the likes of ASAP and AQUAFAX have lead sheet sandwiched in them.

Phil

[jonk]

Thanks for the replies. The panels (hatches) are aluminium chequerboard and act as sounding boards despite 1" 'padding' stuck on the underneath. The problem with sticking stuff underneath the panels is that it will still leave gaps around the edges for sound to come through. I was thinking that a solid rubber mat might give mass and also cover the gaps round the hatches - that would also stop a lot of rain entering the engine hole when a leaf gets stuck over an exit hole while also providing a warmer surface in Winter.

Thanks again,

John

[cotswoldsman]

A new engine?

[ditchcrawler]

I was considering getting some car under bonnet insulation from a scrap yard and trying that on ours.

I recon it should be cheap enough ... Don't know how effective it would be but hey....

That is designed to stop drumming, you want to stop transmission.

Thanks for the replies. The panels (hatches) are aluminium chequerboard and act as sounding boards despite 1" 'padding' stuck on the underneath. The problem with sticking stuff underneath the panels is that it will still leave gaps around the edges for sound to come through. I was thinking that a solid rubber mat might give mass and also cover the gaps round the hatches - that would also stop a lot of rain entering the engine hole when a leaf gets stuck over an exit hole while also providing a warmer surface in Winter.

Thanks again,

John

I would think it would be nicer to stand on as well. Electrical switchgear rooms use heavy rubber matting.

[Machpoint005]

Still not heavy enough for significant benefit, though.

Mass is the secret that is why sound insulation board offered by the likes of ASAP and AQUAFAX have lead sheet sandwiched in them.
Phil

 

Lead works really well, but is expensive, so heavy board (without lead) plus some absorption is often a good compromise.

[PeterDHS]

Transmitted sound comes in two flavours...airborne sound and structural sound. Airborne sound is higher frequencies travelling through the air in straight lines and can be minimised by lightweight baffles/egg-crate shapes which 'reflect' and absorb the energy. To be even 80% effective there should be no 'holes' such as vents etc that the noise can track through and this is difficult on a cruiser stern with what sounds like two abutting access plates. Strucural sound is the reverberation of the engine resonating through the steelwork and can be minimised by mass (weight) on the simple argument that it takes much more resonance to 'move' a heavy object than a light one.

So the professional insulation panels have a heavy core with a foam bonded on the outer face. Any DIY solution needs to replicate this basic principle.

 

Pete

 

[Machpoint005]

Low-frequency sound from the engine comes straight through the deck boards. This isn't structural. However, the remedy is still to add weight.

Reverberation is by definition airborne!