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05-20-2012, 11:38 PM
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#1
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Veteran Member
City: Santa Barbara, California
Vessel Name: Fleur De Lys
Vessel Model: 1988 Nova 36 Sundeck
Join Date: Dec 2011
Posts: 56
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First long passage
We just completed our fist long trip, Dana Pont to Santa Barbara. Did it in two legs. Friday afternoon Dana Point to San Pedro and Saturday San Pedro to Santa Barbara, 121 miles total. A little rough on the first leg heading into about 15 to 20 and a 4 foot 9 second swell. We made a decision to burn diesel rather than daylight on both legs and pushed a little harder than usual. First leg averaged 7.62 knts and 1.18 miles/gal, second leg 8.08 knts and 1.2 miles/gal. Burned more fuel than expected. But i guess that is what you get when you are over hull speed. Everything went well, on the first leg got a little water on the forward bunk from all the water on deck and a hatch that could use some sealing. Santa Barbara is the new home for Fleur De Lys for the next 2 years. Looking forwrad to exploring the islands and doing some surfing and diving.
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05-20-2012, 11:57 PM
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#2
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Guru
City: Walnut Grove Ca
Vessel Name: Cary'D Away
Vessel Model: Hatteras 48 LRC
Join Date: Apr 2012
Posts: 887
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Channel islands are really special
I'm thinking of cruising down from the Delta later this fall. It's been 10 years or so since the last trip out to the islands. Santa Cruz Island is a really special place to visit. It took me two trips to find Painted Cave. When I did it was hard to believe. You should really enjoy yourself.
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05-21-2012, 05:11 AM
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#3
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Guru
Join Date: Oct 2007
Posts: 22,553
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Burned more fuel than expected. But i guess that is what you get when you are over hull speed.
Indeed slow down a K or so and save half of the fuel burn.
SQ rt of LWL x 1.1 is about as fast as you can go cheaply. SL times .9 is even cheaper.
FF
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05-21-2012, 08:41 AM
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#4
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Veteran Member
City: Santa Barbara, California
Vessel Name: Fleur De Lys
Vessel Model: 1988 Nova 36 Sundeck
Join Date: Dec 2011
Posts: 56
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The Admiral wanted to "make sure" we made it into our slip before dark. We normally cruse about a knt slower. 2 if we want to save fuel.
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05-22-2012, 12:36 AM
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#5
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Guru
City: Port Townsend Washington
Vessel Name: " OTTER "
Vessel Model: Ocean Alexander Europa 40
Join Date: Nov 2009
Posts: 2,378
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make sure to eat at up stairs at Brophy Bros in the Harbor in SB, we had our boat there for eight years.. it is still my favorite place in California
HOLLYWOOD
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05-22-2012, 08:26 AM
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#6
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Guru
City: Solomons Island Md
Vessel Name: Fryedaze
Vessel Model: MC 42 (Overseas Co) Monk 42
Join Date: Sep 2011
Posts: 1,721
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I would kill for that kind of fuel economy. My 210 Cummins (twin) burns 3.5 GPH at 8 knts. I have a 25X27 props on 2.66:1 transmissions. I plan on doing WOT sea trials with a good Lazar tach at various RPMs and then get a prop company to evaluate the data. I should be able to get better fuel economy at cruising speed. Not really interested in increasing top end speed, just want to save some $$$$$.
Dave
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05-22-2012, 10:20 AM
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#7
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Senior Member
City: Port Orchard, WA
Vessel Name: Isobel K
Vessel Model: 37' Custom Pilothouse
Join Date: Oct 2007
Posts: 426
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Hi Dave,
I have the same motor cummins B5.9T at 210hp. However, since my boat is a single with a full displacement hull plus having a fairly narrow beam and fairly lightweight(20000 lbs). I cruise at 7.5 knots Rpm of 1500 and use 1.5 gal/hr.
Mathematically, I am using somewhere around 35 hp to move the boat at that speed, so the motor is considerably overpowered for normal duty in my case.
I turn a 3 blade 24 x 18 prop, the gear is a Hurth 2:1
Not to restart the argument about whether to run on one engine at a time while cruising issue, but some argue that is one way to help the fuel economy with twins.
I bet if you slow down to 7 knots you will improve your economy noticably
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05-22-2012, 10:23 AM
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#8
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Senior Member
City: Ventura, CA
Vessel Name: Vyndance
Vessel Model: 48 Californian CP
Join Date: Aug 2010
Posts: 153
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Welcome to the neighborhood!!
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05-22-2012, 02:26 PM
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#9
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Member
City: San Francisco
Vessel Name: Paradox
Vessel Model: Hershine 37
Join Date: May 2012
Posts: 9
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I am new to the forum. I am a sailor who is considering a transition to a trawler. My last boat was an Isander Freeport 41 motor sailor. I had a Ford Lehman 80 hp and burned .75 gph at hull speed (7 k) at 1800 rpm. I am looking into a CHB 39 with twin 150's. I don't know the make or model. I expect this will eat my fuel budget and not really gain me much speed at 39 feet, same as my IF 41. I would like to find a 36 footer with a single ford 120. Is the advantage of a second engine (in the event of breakdown) worth the coast of maintenance of a second engine? How many of you guys know of regular engine failure involving a tow or serious endangerment? Plus, at what size/displacement do I really need to consider a second engine to push the boat at hull speed against wind and tide? Is there a formula i.e 37 feet at 34,000 lbs = 160 hp???
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05-22-2012, 05:18 PM
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#10
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Veteran Member
City: Richmond Va
Join Date: Apr 2012
Posts: 98
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Welcome to the forum Bill. My first two boats in the late 80's were twins. After I got away from gas I have had single engine boats ever since. The single v twin debate goes on and on and if you had no problems handling your motorsailor with single then I'd say stick with it. To me its not worth the extra maintence and fuel for the twins. Larryw
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05-22-2012, 05:31 PM
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#11
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Master and Commander
City: Vallejo CA
Vessel Name: Carquinez Coot
Vessel Model: penultimate Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 12,559
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Quote:
Originally Posted by billsteele
... Plus, at what size/displacement do I really need to consider a second engine to push the boat at hull speed against wind and tide? Is there a formula i.e 37 feet at 34,000 lbs = 160 hp???
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There's virtually no limit to the size of a vessel that can be moved at full-displacement speed by a single engine, if so designed. Eighty horsepower should be sufficient (and 120 h.p. way, way more than needed) for the size of the boat described and move it at hull speed of about 7.5 knots, but it wouldn't fully counter a tidal current if that required going over hull speed.
The 80 h.p. diesel engine in my 28,000-pound boat is more than adequate to move it at hull-speed.
__________________
Kar-KEEN-ez Koot
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05-22-2012, 05:49 PM
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#12
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Veteran Member
City: Santa Barbara, California
Vessel Name: Fleur De Lys
Vessel Model: 1988 Nova 36 Sundeck
Join Date: Dec 2011
Posts: 56
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I have twin volvo 150 HP turbo diesels. I figure that i can use about 1/2 the hp they can produce. Using the prop calculator on Boatdiesel.com i believe that i would use about 60-80 of my 300 available HP at hull speed. On my first leg going 9 knts i was probably usign 75 to 100 HP out of each. My normal cruse at 2500 rpm gets me just into the boost range of m turbos where they run cleanand i do about 8 knts. I did have some crazy guy in a sail boat turn right in to me saying "i am out of gas, i am going to the fuel dock (with his outboard at full throttle)!!!!" and my 300 HP got me out of his way. As far as single VS twin, the admiral does feel better having a second engine rather than a nice paddle. A single would need a bow thruster in these california harbors if you wanted to go in and out in the afternoon when the wind is blowing (or if you had bigger ones that me).
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05-22-2012, 10:04 PM
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#13
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TF Site Team
City: California Delta
Vessel Name: FlyWright
Vessel Model: 1977 Marshall Californian 34 LRC
Join Date: Apr 2008
Posts: 13,728
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Quote:
Originally Posted by fryedaze
I would kill for that kind of fuel economy. My 210 Cummins (twin) burns 3.5 GPH at 8 knts.
Dave
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Dave, he's getting about 1.2 MPG and you're getting about 2.3 MPG.
I'd say you're doing just fine for efficiency.
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05-23-2012, 04:45 AM
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#14
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Guru
Join Date: Oct 2007
Posts: 22,553
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Is there a formula i.e 37 feet at 34,000 lbs = 160 hp???
There is a "Rule of Thumb" that works fairly well.
The displacement in tons (2240lbs) times 3 is about all the HP a displacement boat should need.
That might give a 7.5 K speed , smooth water no wind.
So your boat would be about 15-16 tons and require 45 HP .
On a well setup boat you will see 15-18HP for each gal of diesel.
3GPH
The sq rt of 37 is about 6 and somewhere between 6 x.9 and 6 x 1.15 will be your LRC , long range cruise speed , which should go to 2 GPH or less.
No displacement boat needs tons times 5 in HP.
Single or twin , That's RELIGION . reality need not apply.
See the anchor threads,,,more religion
My opinion a twin is 5% better at docking in hard conditions ,
If you usually dock someplace like the East River with 4K current great.
Otherwise its an industrial single for me.
FF
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05-23-2012, 07:12 AM
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#15
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Guru
City: Solomons Island Md
Vessel Name: Fryedaze
Vessel Model: MC 42 (Overseas Co) Monk 42
Join Date: Sep 2011
Posts: 1,721
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Thanks for pointing out my error Flywright. I read MPG and my brain saw GPH.
Dave
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05-23-2012, 11:27 PM
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#16
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Member
City: San Francisco
Vessel Name: Paradox
Vessel Model: Hershine 37
Join Date: May 2012
Posts: 9
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I noticed a for sale for a mainship with a trubo perkins 160 that burned 5GPH with a note "good fuel effecience". Am I understanding this correctly that in one hour the boat will burn 5 gallons of fuel???
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05-23-2012, 11:39 PM
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#17
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Guru
City: PNW
Vessel Model: 1976 Californian Tricabin LRC
Join Date: May 2011
Posts: 1,860
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Quote:
Originally Posted by billsteele
I noticed a for sale for a mainship with a trubo perkins 160 that burned 5GPH with a note "good fuel effecience". Am I understanding this correctly that in one hour the boat will burn 5 gallons of fuel???
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If it were twins and running 2500+ rpm's in a 40 foot boat, that would be about right at 10k. Each engine should burn about 2.5 to 3.0 gph in my 6.354 experience. For a single 160 hp. If it is measured at WOT 2800 rpm maybe so?? But that's blowing diesel out the exhaust though.
Larry B.
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05-24-2012, 12:04 AM
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#18
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Guru
City: Vallejo, California
Vessel Name: Mahalo Moi
Vessel Model: 1986 Grand Banks 42 Classic
Join Date: Jun 2008
Posts: 2,093
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Quote:
Originally Posted by billsteele
Am I understanding this correctly that in one hour the boat will burn 5 gallons of fuel???
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Yep, about the same as I burn when I'm driving my pickup down the interstate. The difference is I travel about 75 miles in my truck and only about eight or nine miles in the boat. But I have WAY more fun in the boat during that one hour . Now, if you can convince your better half that my logic makes sense, then you'll be a happy boat owner...
__________________
Ray
"Mahalo Moi"
1986 GB-42 Classic
ΜΟΛΩΝ ΛΑβΕ
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05-24-2012, 04:46 AM
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#19
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Guru
Join Date: Oct 2007
Posts: 22,553
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5GPH is only 70 - 80HP delivered to the water about what it takes to ctuise below hull speed on a 40 ft LWL boat.
Go slow , and you can cut the fuel burn rate in half.
But even below SL .9 it still takes fuel for skin friction , just not wave making.
FF
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06-01-2012, 09:23 AM
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#20
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Guru
City: Pensacola
Join Date: May 2012
Posts: 748
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Nice Boat. I have a 40ft.
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