Thank you Hugh for the info.

The beauty of sailing is the movement though the silence at sea. The Duck would be "perfect" if the engine noise could be completely eliminated.

Have anyone experimented with marine electric motors (hybrid propulsion systems) such as the one offered by Solomon Technologies, http://www.solomontechnologies.com/sti_electric_drive.htm .

Regards,

The sound insulation on the SeaHorse 462 is quite good....they actually buy lead sheet and lay it up between two layers of foil backed foam then line the engineroom with perforated metal sheet with a synthetic sandwich....so the limited time I have had onboard steaming suggests it is very quiet...

To improve on this I will be fitting a Racor "SILENCER-Air Filter" as a considerable amount of engine noise comes from the air filter....if you also mount this Silencer on a "Trident" 90 degree elbow you can reduce the noise even more....this noise saving is at the top end of the reading ....not sure of the actual numbers but say you had 125DB standing inside the engine room, the air silencer and elbow may cut about 10% say 12DB to 123DB....big deal you might say as it will cost about $500 to set up....well if you are outside the engine room with a reading of say 70DB before fitting the Silencer, you take off 12db and you are back to 58db...a benefit of nearly 17% and that is 24hours a day if you are steaming for the rest of the time you have the boat!! how could you not fit one!

Claudius,

Happy New Year. On your first point, I don't understand your comment. Yes, a silent duck would be wonderful, but its a power boat. I might be missing some context.

On your second point, hybrid propulsion is primarily for sail boats to have a limited motoring capacity off batteries charged when you are sailing much like a hybrid car charges battery when braking but you need a ton of batteries (literally). Because you aren't sailing in a duck, it wouldn't really work. What you could do though, is consider diesel/electric propulsion which would run an electric motor from a generator. There might be noise, vibration and fuel efficiency advantages to this but its more expensive and is controlled by lots of electronic "stuff". Worth looking into but with eyes wide open.

Claudius,
Comming from an engineering background (mechanical) I believe in the advantages of Diesel-Electric Drive Systems and am making preliminary enquiries,but will need more than an Engineering Degree to sort through the two main systems AC & DC, both complex, not easy to fix at sea & very expensive. Possibly if a person were a multi millionaire who wishes to own a "Marina Queen" OK.
Check out these sites
AC system: Siemans- www2.sea.siemans.com
www.feys.org
DC System: Ossa Powerlite- www.ossapowerlite.com
Solomon Technologies system does not seem to have the gunt although they say there systems are for vessels up to 55', have a look at there examples, river and lake vessels, small hp motors.
Phill

Hi

Just saw your post Nordhavn is doing a expedition type 72 feet with electrical drives

Now Pacific Asian Enterprises has taken the lead in adopting an advanced Siemens-developed version of this proven propulsion system to large yachts in the form of a proof-of-concept diesel-electric Nordhavn 72. “We’re really excited to be connected to the Siemens group,” says Dan Streech, president of PAE. “They’re using us to introduce the technology into the trawler-yacht market.”


luck

Diesel/Electric only has fuel efficiency advantages when used with old tech diesel engines that are lightly loaded. For example a diesel that could produce 100hp at 1500rpm but where the prop can only absorb say 35hp at 1500 rpm.

New Tier II / electronic / Common Rail diesels are more efficient when lighted load and negate any efficiency advantage that diesel electric may have.

Some don’t like electronic diesels... I would assume the same persons would note like the complexity of diesel/electric either.

Have a look at issues 107 to 109 of
http://pbb.proboat.com/
for Nigel Calder’s articles on this issue.


Cheers
John
Seahorse 52

Hi

Not sure about the article can not have access to it .

But " Siemens " offers the Diesel Electric drive
I sent then a email asking about the saving if you use one , will see what is the answer is

http://www2.sea.siemens.com/Industry+Solutions/Marine/i....htm?languagecode=en

quote:

Originally posted by Red_Trosky:
Hi

Not sure about the article can not have access to it .

But " Siemens " offers the Diesel Electric drive
[/URL]

Hi Red Trosky
Go to the link i gave below, enter Nigel Calder into the search function, you will get four pages of articles, go to page four and you will see the artciles im refering to towards the bottom of the page. You can read for free, no passwords required.

John

hi

Just found it


http://www.proboat-digital.com/proboat/20071011/

will try to read it and see

Thanks

Forgot to mention that I finally did some steaming time on ICE and found a couple of small areas in the engine room around the micro wave recess where there was a small amount of sound insulation missing , so refilled that...and I have bought some lead/foam stickyback sound insulation sheet to cut up and fit into the engine room air inlet enclosure as there is a 12inch fan hole at the bottom, that lets a little noise out into the pilot house, so I will line that as well...Brian on his 382 "traveller" suggested that and it is a good idea...every bit counts...(my two english seaglaze water tight doors into the engine room also have sound insulation fitted inside)....I will use the same stuff to line the steering gear/auto pilot enclosure under the aft Queen bed to hold back any pilot pump noise.....but if you do this you must make sure you have set the sensitivity of your pilot drive correctly as you will not hear it working and it may be over working and burn out !