I would like to challenge some worthy soul(s) out there with this goal...to make a his/her C36 the quietest vessel, underway motoring, that it can possibly be. And then to write up a detailed article, well-photographed, for the C36IA website.
It's a goal that I would like to undertake, but due to time pressures cannot. Yes, I know we already have an excellent article on silencing the engine box, but I imagine that as only one step in the overall process. It seems to me that there are a multitude of additional steps that could be taken.
For example, the boat has many open cavities and "passages" that must be transmitting engine noise. One example is what I call the "hell hole". (That term isn't intended to deprecate our boat, as it's actually an aviation term referring to the unpressurized uninsulated interior of the empennage, aft of an aircraft's pressure vessel.) The "hell hole" in our boats is the compartment just outboard portside of the center water tank, under the aft cabin floor of a Mk II (I'm not sure about a Mk I). There is a large "sound conduit" or "waveguide" that can carry noise forward from the hell hole, beneath the fridge, into the galley and salon area.
There is a wide variety of sound insulation and sound deadening materials on the market (alas, none of them cheap). These have vastly different characteristics, and the person doing this upgrade would want to research what was best for our boat's sound profile. We're dealing basically with low frequencies, I suspect. Possibly one or more of these materials could be placed at critical points to absorb sound and/or prevent its transmission. Also, there is a lot of open space within our engine compartment, especially just above the stuffing box area...perhaps adding sound deadening there would help silence the engine noise; but that would be a different material, one that could withstand the heat in that compartment.
Ideally, whoever undertook this task could, before beginning the project, at several locations around the boat sample the BEFORE sound level with a sound meter so as to compare with AFTER readings to document a definitive cost/benefit solution. I would be very interested in the sound at three locations: the helm, just above the galley sink, and at some point near the mast.
I am asking a lot, aren't I?
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
Larry:
I will say you write a well detailed setup. I have wondered also about that area in the rear above the center water tank for a long time. It is a source of noise leak. What I am wondering about is if we were to box or close in the engine area so to limit the noise from escaping. What would the heat factor do. I know our motor usually runs 175 degrees. Would this raise the temp any higher?
I am like you in wanting it quieter down below. We are getting ready to take off next June and head to the Bahamas out of the great lakes. So the issue your asking about is a valid concern for me and my wife, more so her. I know there has been a few that have used the leaded insulation from sailors solutions and liked it. But I do not believe they covered the hell hole in question.
Our boat is out of the water for the winter as it is one thing on my list to do was insulated the motor compartment better and to get the sound down. Before I retired some of my work involved vibration analysis and sound so it is not a new thing to me. But it would not be until May that we launch next year. It would be nice to get some other input here also about the heat issue. Maybe that is not a issue at all. Just something I was curious about.
Randy
Randy Sherwood
Mutualfun 1990 # 1057
T/R W/K M35a
Home. Charlotte, Mi.
Boat. St Augustine,Fl.
The first thought is that you need to have some opening sufficient to supply the air the engine needs.
As for heat, in order for the engine to remain close to optimal temperature, the excess heat needs to be removed. This is mostly effected by the internal water cooling system, in my opinion. I just don't see that there can be much air moving over the hot engine to carry away any significant amount of heat.
If any noise reduction mods increased the air temperature surrounding the engine, you might see a small reduction in available peak power due to the reduced air density.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
Larry,
My to do list is much to long to tackle this one. Some quick fixes insulation and seals around the engine cover my get to my list.
It is my belief that much of the racket that eminates from our power plants is from vabration rather than from dirrect noise. I would be interested to know if anyone has installed one of the flexable drive systems available. They are like CV joints on a front wheel drive car allowing the engine to move around on soft mounts and not effect shaft alignment. I have also wondered if a belt drive could be used, notched belts do well on motorcycles that have over 100 HP. I would think belt system would be up to the 25-35 HP of our marine engines and would also isolate the engine from the shaft.
I noted at one of my sons football games years ago they use the same Kubota engine to power some portable lights at the field. The enclosure had a some foam insulation inside the unit but, more notably the engine was on very soft mounts and you could stand quite near the generator and the bulk of the noise was just the exhaust. Our engines a quite shaky and I think being able to isolate them from the boat would do far more than simple insulation.
Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas
Good input, Steve.
You cause me to mention another "Your mission, should you choose..." that occurred to me, but that I am NOT going to propose, and that was converting the boat to electric drive, a "hybrid" in other words. Now THAT would truly be a fringe project for a technician/engineer/amateur radio/brain surgeon/plumber type person. No doubt the boat would quietly hum along after such a conversion, but it's so far out of the realm of practicality that I doubt anyone would do it. It would be interesting, though.
As to vibration, you may be correct. But no matter the source of a noise, if there are passages that convey the sound throughout the boat, it isn't contained. Essentially what I envision is better containment, a la the lighting generator you describe at the ball field.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
Larry,
With your mention of hybrid/fuel cell technology, it got me thinking to what ever happened to the fuel cell project with HaveBlue and the Catalina 42 retro fit in 2004...
[url]http://www.evworld.com/article.cfm?storyid=686[/url]
HaveBlue site is closed but it would be interesting to see if Catalina had any updated information.
Jack
Solstice
Hull #1598
1996 MKII/TR/FK - M35AC - 3 Blade MaxProp
Lake Texoma
www.texomasailing.org
Jack:
Here s a nice article on it. But it is old. [URL="http://www.landfallnavigation.com/fuelcells.html"]http://www.landfallnavigation.com/fuelcells.html[/URL]
Randy Sherwood
Mutualfun 1990 # 1057
T/R W/K M35a
Home. Charlotte, Mi.
Boat. St Augustine,Fl.
The engine noise has always been a concern of mine too and I have given this subject a lot of thought and have wondered about the following two ideas:
1. I have recently read somewhere that by changing the motor mounts this will in fact qiet the sympathetic vibrations form the engine.
2. If the engine compartment were closed off more that would lead to a higher temperature, but how about using our blower that is built in to (I believe) all of our boats to expel the hot air. Just a few thoughts....
Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B
Glenn,
I recall that one of our members uses the blower with the thought of keeping the engine compartment cooler and leaves it running after shutdown to remove as much heat as possible from the boat interior. I cannot vouch for how well that works.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
Just a FYI:
In a paper I got from Boat US. They had talked about this subject. If you use a blower as this. Make sure it is labeled continuous duty so it will not over heat and start a fire.
Randy
Randy Sherwood
Mutualfun 1990 # 1057
T/R W/K M35a
Home. Charlotte, Mi.
Boat. St Augustine,Fl.
That's a VERY good point, Randy. Thanks.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
Larry and Glenn,
Changing the motor mounts significantly helps in reducing engine noise. A number of years ago I swapped out the OEM mounts in Julandra for a set of Vetus K75 mounts. They are softer than the OEMs, and therefor transmit less noise thru to the hull. I never took any readings, so I can't give any percentages, but I did notice the difference.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
While reading the Dec. 2009 Sailing magazine I noted this add for an electric motor. There are some videos as well using a Catalina 27. Looks like a 36' boat could be refit for $5500 plus the costs of additional batteries and whatever it would take to keep them charged. Reads well but I question the distance and the available power (battery performance) should there be storm conditions. For a diehard sailor with deep pockets this surely would be a way to go. Imagine no oil, deisal or gas, antifreeze, rust, fumes, noise, etc., what away to go! Think of the storage possibilities where the fuel tank is but then the concerns of boat balance? Enjoy [url]http://www.electricyacht.com/[/url]
Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine
Gary,
Because the subject of your comment is so interesting, I have begun a new thread and copied your thoughts into it as the starter posting. This will properly acknowledge the new topic, and will reserve this present thread for the sound reduction topic that was intended.
Anyone wishing to comment on C36 'hybridization' is asked to use the new thread dedicated to the topic.
Thank you.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B