Sound reducing motor cover

c130king · Post by **c130king** » Sun Jun 24, 2007 1:41 pm

I have the 2S 40HP and at WOT it is pretty loud. Was thinking about designing some sort of cover to go over the top of the motor. Some sort of cloth cover with some sort of foam (or something) as a liner. Cut a few holes where the air holes on the motor cover so as not to reduce ventilation. But would hope this would cut a few decibels.

Anyone ever tried this or done anything similar? Found nothing using the search engine or on the mod page. Should this be in the modification section?

Thanks,
Jim

ModEdit: moved to Modifications ~fc

Frank C · Post by **Frank C** » Sun Jun 24, 2007 2:13 pm

Yeah, prolly belongs in Modifications, so now it is~

And I've never seen any threads discussing a top cover. I think you'd be chasing a rainbow to try to cover the top of that motor. Two-stroke motors have double the number of "explosions" per second, and less cast iron overwrapped to muffle them.

IMO a cloth & foam cover would be highly prone to damage, difficult to securely rig, and ineffective anyhow. And the majority of noise is prolly transmitted under your helm seat, anyway. Lots of owners have blanked off the air gap under the helm seat, with pretty notable reductions in motor noise. A snap-fitted canvas tarp would work, but you could test the theory with just some clever cardboard cutting.

However, this mod is probably not good for heavy coastal conditions. You need that underseat gap to drain sea water should the cockpit be overtaken by a wave. Once on SF Bay I had green water flood the lower cockpit, so I was glad there was no obstruction to deter self-draining.

kziadie · Post by **kziadie** » Sun Jun 24, 2007 2:26 pm

BWY has a addon to fit a plate (made out of the same material as the bilge/storage covers under the cushions in the cabin) underneath the transom seat. This reduces engine noise modestly and also helps keep things in the cockpit from sliding out into the engine well. It slides in and out so removal is quick and easy.

I dont remember the cost, but it was inexpensive, so while I dont think this is a total solution to your problem, it might be worth a look.

Kelly

jim nolan · Post by **jim nolan** » Sun Jun 24, 2007 3:09 pm

I have a 40 horse tohatsu. Pretty noisy. I bought a 32 gallon grey rectangular tub from walmart and lined it with sound deadening ceiling tile. It fits right over the motor and does'nt look bad. It works pretty good. jim nolan

Boblee · Post by **Boblee** » Sun Jun 24, 2007 5:47 pm

Don't they have the dedicated motor covers over there, I thought they were also put out by the manufacturers.
They are basically what c130 suggested and tight fitting, I was looking for one as we use our motor as a bxm rest when boarding and it's getting scratched despite care taken.
When I priced them I think they were $250-300 so have been procrastinating.

James V · Post by **James V** » Sun Jun 24, 2007 7:31 pm

I asked about this on a thread some time ago. The Dowser Full Encloseure has a snap in flap that goes infront of the helmsman seat to the floor. Per all reports this keeps the noise down. It will also keep in the stray bottle or sun block form going overboard. This alone would be worth it for me.

Scott · Post by **Scott** » Mon Jun 25, 2007 3:49 am

Even with ventilation I would be cautious about putting any kind of insulating material on the motor cover. What little heat it would hold in could be the diff between running and seized.

Post by **kmclemore** » Mon Jun 25, 2007 1:24 pm

Solution:

Cost:
$US 0.50 ($BB 0.0005 [Boat Bucks])

c130king · Post by **c130king** » Mon Jun 25, 2007 1:57 pm

I had a flap cover for under the helm but on one of my very first times in the boat I forgot about it and it ripped when I lifted the helm...

I should be able to sew it up. But I don't see how that would reduce much noise...but then again what do I know...I will give it a try.

I also have never noticed much heat on my engine cover. I don't think covering it would harm anything...but then again what do I know...could be an expensive oops.

Seems like the cover that Jim Nolan mentioned would be perfect for my situation.

Kevin, your pic did not post properly. (ON EDIT: Never mind...the pic is there now. Those will work and shouldn't cause the engine to overheat...)

Thanks to all. I will continue to investigate in the two weeks I have left in the states. I will probably take it out for 1 day on 4 July (all I have time for) and then again for 2 days on 11 July (hoping to do my first ever overnight trip). Then it gets put away for a while as I move my family to the UK. Probably living in downtown London (Regent's Park area) due to my daughter's school location.

Any UK Mac sailors need any help with their Mac (like sailing it) let me know...

But first I have a two-week course in DC (NATO Staff Officer Course) from 15 - 25 July. Any DC area Mac sailors need a partner on the weekend of 20 Jul let me know...

Thanks,
Jim

Boblee · Post by **Boblee** » Mon Jun 25, 2007 5:50 pm

Don't THINK insulating the motor should cause any heat problems providing the thermostat is ok and the air vent is not covered.
Will have to find some details on the ones I looked at some time ago.

bastonjock · Post by **bastonjock** » Tue Jun 26, 2007 12:37 pm

c130king wrote:I had a flap cover for under the helm but on one of my very first times in the boat I forgot about it and it ripped when I lifted the helm...

I should be able to sew it up. But I don't see how that would reduce much noise...but then again what do I know...I will give it a try.

I also have never noticed much heat on my engine cover. I don't think covering it would harm anything...but then again what do I know...could be an expensive oops.

Seems like the cover that Jim Nolan mentioned would be perfect for my situation.

Kevin, your pic did not post properly. (ON EDIT: Never mind...the pic is there now. Those will work and shouldn't cause the engine to overheat...)

Thanks to all. I will continue to investigate in the two weeks I have left in the states. I will probably take it out for 1 day on 4 July (all I have time for) and then again for 2 days on 11 July (hoping to do my first ever overnight trip). Then it gets put away for a while as I move my family to the UK. Probably living in downtown London (Regent's Park area) due to my daughter's school location.

Any UK Mac sailors need any help with their Mac (like sailing it) let me know...

But first I have a two-week course in DC (NATO Staff Officer Course) from 15 - 25 July. Any DC area Mac sailors need a partner on the weekend of 20 Jul let me know...

Thanks,
Jim

when i finally get one ill let you know,there is a MAC sailors UK club,the price difference between the states and the UK will have you stunned,remember to double the number in the UK for a US price conversion.

Are you going to be based in London?
i live in Peterborough,nearest Yank base is Alconberry

Rich Smith · Post by **Rich Smith** » Tue Jun 26, 2007 3:38 pm

My wonderful wife and dog bought me noise-cancelling headphones for my birthday one year. They work quite well...they don't make it entirely quiet but they take a good chunk of the sound away...

Cheers,
Rich.

Jack Sparrow · Post by **Jack Sparrow** » Tue Jun 26, 2007 7:53 pm

I too had concerns about blocking off the area under the helm seat not allowing water to be displace from the cockpit during large seas (we blue water sail sometimes) hence I was reluctant to infill this area. What I came up with was by using the aft berth panels that are flexible enough to be dislodged when a small amount of pressure is applied. This is achieved by mounting it in thin locating channels positioned around the outside edges of the panel. To test this effect I threw a 5 gallon bucket of water (trying to simulate wave force) firstly from the rear and then from the front each time the panel dislodged and water drained freely. A small lanyard was fitted on the outside of the panel to avoid it being lost overboard. I feel the result as an engine noise suppressor without the lost in safety has been achieved. There is a down side during the coarse of the season I found myself resting my heel against this panel dislodging it unwillingly. We also had an engine cover made to stop scratching, fading and as a sound suppressor lastly we power it with 4 stroke.

Jack Sparrow

to view infill
http://macgregorsailors.com/cgi-bin/mod ... record=831
to view engine cover
http://macgregorsailors.com/cgi-bin/mod ... record=829

c130king · Post by **c130king** » Wed Jun 27, 2007 4:46 am

Bastonjock,

I will be at a NATO facility in Northwood (NW London). Alconbury is not to far away as I understand things.

We will be living pretty much downtown. Our daughter will go to the American School in London (ASL) in St. John's Wood and they offer busing service to the nearby communities. So we will live nearby for that service and I will do the bus/tube commute to Northwood everyday.

My

will stay in Jacksonville FL. Hopefully I will get back to see it once or twice a year. I will get most of my sailing fix from reading about everyone elses great experiences. That and my Sail magazine.

Would love an opportunity to sail in the UK. Let me know if you ever want to get together.

Thanks,
Jim

c130king · Post by **c130king** » Wed Jun 27, 2007 4:51 am

Jack Sparrow,

You are a mod master. Your mods are very nice. I agree with your last sentence...4-stroke is a great sound reducer. I might go that route if/when I ever re-engine.

I don't have much experience with outboards. But at the marina in Norfolk I watched the marina guys take out one of their rental fishing boats with a 90 HP 4-stroke and they gunned it to get it on the trailer. I could barely hear it.

Jim

MacGregorSailors.com

MacGregorSailors.com

Sound reducing motor cover

Sound reducing motor cover