|
|
09-09-2015, 02:27
|
#16
|
Registered User
Join Date: Jun 2015
Posts: 473
|
Re: efficiency of single vs twin engine
thanks all for the reply
still lot of stuff to think about
|
|
|
09-09-2015, 04:52
|
#17
|
cruiser
Join Date: Jun 2015
Posts: 30
|
Re: efficiency of single vs twin engine
Quote:
Originally Posted by stefano_ita
ok don't kill me please
i know the thread has been very widley discussed but...
i was looking at the power vs liter per hour cosumption for a given boat with x shaft horsepower required to reach a y speed.
i calculate i would need about 180 shaft horse power (133kw) for my boat to reach the hull speed (displacement trawler) 46ft 35 ton (70.000lbs) 9 knots hull speed
let's the fight begin
|
If I am in Italy I would buy FNM HPE without any hesitation. I used to have FNM HPEP 250 with bravo 3 x diesel, best ever diesel engine I ever had, and I had a lot.
|
|
|
09-09-2015, 05:16
|
#18
|
Registered User
Join Date: Jun 2015
Posts: 473
|
Re: efficiency of single vs twin engine
Quote:
Originally Posted by blackcrow
If I am in Italy I would buy FNM HPE without any hesitation. I used to have FNM HPEP 250 with bravo 3 x diesel, best ever diesel engine I ever had, and I had a lot.
|
thanks, yes, i'm from italy..never heard before about this engine...i know Fiat power train (also called Iveco) marine engine, being extremely heavy duty and reliable...
but still have to find someone that can give me some price (in italy no one tell you the price via email or so on...you have to go by person and then talk about the price...maybe do 500 miles to know a price...no thanks... )
the nanni diesel are kubota based, so in theory they have common parts to find around the world
|
|
|
09-09-2015, 06:21
|
#19
|
cruiser
Join Date: Jun 2015
Posts: 30
|
Re: efficiency of single vs twin engine
Quote:
Originally Posted by stefano_ita
thanks, yes, i'm from italy..never heard before about this engine...i know Fiat power train (also called Iveco) marine engine, being extremely heavy duty and reliable...
but still have to find someone that can give me some price (in italy no one tell you the price via email or so on...you have to go by person and then talk about the price...maybe do 500 miles to know a price...no thanks... )
the nanni diesel are kubota based, so in theory they have common parts to find around the world
|
then call them on the phone, I do not believe that they do bussiness only in personal, for your eyes only. people from ALASKA are buying FNM engines and I do not believe that Jim Smith are personally jetting off to Italy from Anchorage to enquire about price of certain engine. Must be some dealers or service agents in your local area, that is Italian engine after all.
::..FNM-MARINE....::::: Marine Diesel Engine :::::::::::....................................... ..........
I had a FNM 250 on my boat, have been very happy with it, in the 18 months that I have been running the boat, the engine has paid for itself in fuel savings ( I replaced a 5.7 V8 petrol engine).
The italians invented common rail diesel technology and have a much better handle on it than the japanese or koreans.
FNM Alaska
FNM Alaska
FNM Engine Models
|
|
|
09-09-2015, 06:48
|
#20
|
Registered User
Join Date: Jun 2015
Posts: 473
|
Re: efficiency of single vs twin engine
thanks, i gave a look at the engine range, (over the dealer that i found being very near to me ) they are all very sporty engine...i'm looking something that last 30 years and run at 1800 rpm i saw more than 100hp\liter like your engine surely very nice for sport boat but not for slow displacement trawler
however thanks for the appreciation on our italian engineering
i'll try to be more italian too and ask a dealer for a price for a FPT heavy duty engine...i saw they are widely used world wide, in brasil for example is full of them as generator
----
looking for
http://www.fptindustrial.com/product...s/N45_100.aspx
4.5 liter 4 cyl naturally aspirated 85hp, same rating as the nanni, max 3000 hours /years
too weak, would need at least 130-140 hp..
in the pleasure range
http://www.fptindustrial.com/product...s/S30_230.aspx
3 liter , same rating, 115hp, but at 3500rpm...the nanny has 0.7 liter more (3,7l) , and the same power at 2600rpm...less rpm , less wear...
|
|
|
09-09-2015, 07:32
|
#21
|
Registered User
Join Date: Apr 2012
Location: Illinois
Boat: Rinker 24
Posts: 398
|
Re: efficiency of single vs twin engine
An issue with engines in boats is quite a bit of the time the hull is a bigger variable than the engine. So if you can decide on a hull then move forward from there as to what the power situation will be.
"In general", most any internal combustion engine is most efficient at around 80% of maximum power output. That is why the trend for smaller turbo charged engines is popular, extra power when you need it and some economy too.
Please note, that fuel consumption is only one component in the cost of running an engine, and while I have never had an engine failure during a serious passage I have witnessed 2 that did which is something to think about.
|
|
|
09-09-2015, 08:09
|
#22
|
Registered User
Join Date: Apr 2013
Posts: 11,002
|
Re: efficiency of single vs twin engine
If you concern is primarily the reliability of the motor, a relatively cheap solution (depending on the boat design) is a trolling motor.
A little 5-10hp outboard can often be enough to get you into a slip or anchored till you figure out the issue with the main engine.
And it can do double duty as the dingy motor.
|
|
|
09-09-2015, 09:25
|
#23
|
Registered User
Join Date: Jun 2015
Posts: 473
|
Re: efficiency of single vs twin engine
thanks both
well, i was also looking at a 48v dc 20 kw ac motor..complete with controller ecc 4.000 bucks...i calculated about 4 kts for 3 hours with battery fully charged, and going 2.5 kts just with the 5kw solar...i would need at least a 20kw 48v dc generator...at this price i almost get another nanni 115hp...
..ok the tender with 15 hp outboard...maybe 3 kts at full power...in the middle of the ocean...mh..
maybe a small 30hp diesel to be used as generator with big alternator and a coupling to the propeller shaft...both the electric and this ideas at least will use the main right sized propeller...
any other ideas?
|
|
|
09-09-2015, 13:20
|
#24
|
Registered User
Join Date: Jun 2015
Posts: 473
|
Re: Efficiency of single vs twin engine
p.s.
i've found for pratically the same price
what do you think about this yanmar vs the nanni?
http://www.yanmarmarine.eu/theme/yan...r-4LHA-HTP.pdf
nanni
http://www.nannidiesel.com/downloads....115%20ITA.pdf
the yanmar is 0.4l less displacement, but 45 hp more, espcially..
bore x stroke 100 both bore, and..nanni 120mm stroke vs 110mm of the yanmar...is a lot more long stroke, more efficient for sure!
fuel consumption looks worst for the yanmar, even with the same hp, the only pro is that it has more hp, to be used in bad sea condition...cons..it will turn at higher rpm in stead of the nanni
nanni 60 kw shaft , 1400 rpm 3 liter per hour
yanmar 60 kw shaft 1700 rpm 6 liter per hour
60 kw is the cruise required power....300rpm is 20% more...
nanni option for 160 shaft hp (this one heavy duty, while the other pleasure duty, max 3000 hours year)
http://www.nannidiesel.com/downloads...%20CR2-ENG.pdf
john deer based, bigger, 4,5 liter, 2300 max rpm, very slow..
but take a look at the turque graph...why such a big turque from 1800 to 1900, while the other 2 have a lot more flat curve...it doesn't look linear....and it's the only common rail, while the other 2 are direct igniton and mechanical...so no electronics, more reliability...
nanni n5.160 60 kw shaft 1300 rpm 6liter per hour
looks like i'm a nanni dealer but i still can't look for a better engine except 2x nanni
looking something between the 140-160 hp...40% as reserve power
|
|
|
09-09-2015, 14:50
|
#25
|
Registered User
Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 8,462
|
Re: Efficiency of single vs twin engine
Take a look at the Nordhavn website and see how they do things if you are interested in how a trawler yacht should be set up. Also you will probably get better info on trawler engines on the trawler forum.
|
|
|
10-09-2015, 04:34
|
#26
|
Registered User
Join Date: Aug 2012
Location: Maryland, USA
Boat: 58' Sedan Bridge
Posts: 5,420
|
Re: Efficiency of single vs twin engine
Quote:
Originally Posted by DeepFrz
Also you will probably get better info on trawler engines on the trawler forum.
|
Heh... good point. Seems like some of the guys on trawlerforum.com can discuss fuel efficiency down to the milliliter per minute...
-Chris
__________________
Chesapeake Bay, USA.
|
|
|
10-09-2015, 17:22
|
#27
|
Registered User
Join Date: Aug 2012
Posts: 811
|
Re: Efficiency of single vs twin engine
Quote:
Originally Posted by ranger42c
Heh... good point. Seems like some of the guys on trawlerforum.com can discuss fuel efficiency down to the milliliter per minute...
-Chris
|
That depends on whether the trawl net is full of fish or not.
|
|
|
10-09-2015, 18:17
|
#28
|
Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
|
Re: Efficiency of single vs twin engine
Quote:
Originally Posted by GrahamHO
That depends on whether the trawl net is full of fish or not.
|
Not that sort of trawler
https://en.wikipedia.org/wiki/Recreational_trawler
|
|
|
11-09-2015, 22:52
|
#29
|
Registered User
Join Date: Aug 2012
Posts: 811
|
Re: Efficiency of single vs twin engine
Quote:
Originally Posted by StuM
|
Yeah but I still think dragging a net full of herrings uses less fuel than a net full of snapper
|
|
|
13-09-2015, 04:32
|
#30
|
Registered User
Join Date: Jun 2015
Posts: 473
|
Re: Efficiency of single vs twin engine
thanks all..
yeah i'm coping all the nordhawn except the wing engine
at the end i decided 2x 115 hp nanni
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|