I knew a music critic who bought a new high-end turntable and amp and passed me his expensive headphones to demonstrate. I listened and after a while cautiously said, "Joe, I gotta tell you, I hear a hiss." He replied: "If you do, that's your problem."
How much noise should a diesel make? How much is normal? How much is too much? Beats me. Entirely subjective, no? I did remember how much I was able to quiet down the Universal 5432 offshore by stuffing blankets under the companionway ladder, which made for better sleeping with an engine on. Thereafter I made a custom cover for the engine box out of sound-deadening blankets. They're like furniture blankets, just denser and more expensive. That helped a lot.
...
So I decided to add new insulation, too. The existing sound deadening material on the engine box was "Mylar" tape covering a spongy mass. I didn't know how spongy until I opened it up.
From West Marine I obtained a $150 kit of 1-inch engine room insulation and figured to make a ten-minute job of it on the boat. As usual, not so. The insulation is quite heavy, the size of each applied piece needs to be exact, and removing the old insulation was a mess waiting to happen. Better to cart everything home to the garage.
The insulation has a sticky back, but we're advised to also use fasteners that come with it. It's fairly easy to cut with a utility knife or shears. The exposed sides need to be sealed with the shiny tape included, which the manufacturer calls "aluminumized" tape. I had a devil of a time scraping off the old glue by which the former owner had applied some sort of acoustic foam long since deteriorated. The sticky-back product does require a smooth surface for adhesion.
The kit comes with pins to aid the adhesive. The manufacturer suggests epoxying the pins on, but I just attached them with a few small screws. Handy finish caps are provided.
Well, an easy enough job--most of the time spent was confirming that the thick, heavy insulation would fit snug, but not interfere with the seating of the panels.
How much difference is there? Well, "more than you can hear." I do think the overall engine noise is reduced by maybe 10 percent* (*see comments below). But it feels like more than that, since certain frequencies are dulled. The insulation seems to work best on low frequencies. The blanket has more effect on the pinging and clicking elements of normal diesel operating sound.
Pretty subjective, but it does take the edge off the din in the cabin at 2300 rpms. Here's a video that proves, if nothing else, that all our ears and needs are different.
How much noise should a diesel make? How much is normal? How much is too much? Beats me. Entirely subjective, no? I did remember how much I was able to quiet down the Universal 5432 offshore by stuffing blankets under the companionway ladder, which made for better sleeping with an engine on. Thereafter I made a custom cover for the engine box out of sound-deadening blankets. They're like furniture blankets, just denser and more expensive. That helped a lot.
...
So I decided to add new insulation, too. The existing sound deadening material on the engine box was "Mylar" tape covering a spongy mass. I didn't know how spongy until I opened it up.
From West Marine I obtained a $150 kit of 1-inch engine room insulation and figured to make a ten-minute job of it on the boat. As usual, not so. The insulation is quite heavy, the size of each applied piece needs to be exact, and removing the old insulation was a mess waiting to happen. Better to cart everything home to the garage.
The insulation has a sticky back, but we're advised to also use fasteners that come with it. It's fairly easy to cut with a utility knife or shears. The exposed sides need to be sealed with the shiny tape included, which the manufacturer calls "aluminumized" tape. I had a devil of a time scraping off the old glue by which the former owner had applied some sort of acoustic foam long since deteriorated. The sticky-back product does require a smooth surface for adhesion.
The kit comes with pins to aid the adhesive. The manufacturer suggests epoxying the pins on, but I just attached them with a few small screws. Handy finish caps are provided.
Well, an easy enough job--most of the time spent was confirming that the thick, heavy insulation would fit snug, but not interfere with the seating of the panels.
How much difference is there? Well, "more than you can hear." I do think the overall engine noise is reduced by maybe 10 percent* (*see comments below). But it feels like more than that, since certain frequencies are dulled. The insulation seems to work best on low frequencies. The blanket has more effect on the pinging and clicking elements of normal diesel operating sound.
Pretty subjective, but it does take the edge off the din in the cabin at 2300 rpms. Here's a video that proves, if nothing else, that all our ears and needs are different.
