Reply
 
Thread Tools Display Modes
 
Old 11-08-2015, 08:33 PM   #261
Guru
 
cappy208's Avatar
 
City: Cape Cod
Country: USA
Vessel Name: Slip Aweigh
Vessel Model: Prairie 29
Join Date: Oct 2013
Posts: 1,131
Simple answer(s) to the question:
My boat gets more speed than your boat.
My boat gets more MPG than your boat.
My boat is more (handsome, cute, pretty, neat, etc etc) than yours.
My boat is roomier than yours.
My boat is beamier than yours.
My boat is longer, shorter, fatter, wider, narrower than yours.
My boat has more head, interior, knee, engine room than yours.
My boat costs less, more or the same as yours.


Those are the correct answers to these and many more questions that are burning through our minds as we contemplate our purchase......

The personal interpretation of any of this info is subject to the readers ability to extrapolate the info, and use it (in)correctly to make their own (un)informed judgement.
__________________
Advertisement

cappy208 is offline   Reply With Quote
Old 11-09-2015, 02:28 AM   #262
Guru
 
Insequent's Avatar
 
City: Brisbane
Country: Australia
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 1,425
Sorry to disrupt the entertainment with some of what the OP was asking......

I normally cruise between 8 - 9 kn. Seems reasonable speed, fuel consumption etc. I really wanted an economical (2 nmpg) 10 kn cruise, but went for more comfort instead. That's another story, but there is some kind of rationale for my cruise speed.

Below is a graph of my sea trial data in a somewhat unusual format: gallons used versus time taken for an arbitrary 100 nm trip. The data points are different rpm and speeds. Fuel use is total for both engines as determined by the John Deere fuel flow instrumentation, which is reputedly very accurate unless at quite low rpm.

The trendline was a fit by excel. Coincidentally, I always operate in the area below the trendline. Normally close to the middle of that area: 8.5 kn plus or minus a bit. If I had a good equation to fit the data and could remember any calculus I'm thinking that point is the maximum rate of change point, likely to be an optimum of fuel use and time taken. I must have figured that out by gut seeing as I cant remember how to do the math!

Trying to go faster than 'fast cruise' just makes a big wake with little time benefit. Going slower than 'slow cruise', apart from being altogether just too slow, doesn't save enough fuel to bother....
Attached Files
File Type: pdf Fuel v time.pdf (89.2 KB, 85 views)
__________________

__________________
Brian
Insequent is offline   Reply With Quote
Old 11-09-2015, 06:39 AM   #263
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Country: USA
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 4,813
Quote:
Originally Posted by Insequent View Post
Sorry to disrupt the entertainment with some of what the OP was asking......

I normally cruise between 8 - 9 kn. Seems reasonable speed, fuel consumption etc. I really wanted an economical (2 nmpg) 10 kn cruise, but went for more comfort instead. That's another story, but there is some kind of rationale for my cruise speed.

Below is a graph of my sea trial data in a somewhat unusual format: gallons used versus time taken for an arbitrary 100 nm trip. The data points are different rpm and speeds. Fuel use is total for both engines as determined by the John Deere fuel flow instrumentation, which is reputedly very accurate unless at quite low rpm.

The trendline was a fit by excel. Coincidentally, I always operate in the area below the trendline. Normally close to the middle of that area: 8.5 kn plus or minus a bit. If I had a good equation to fit the data and could remember any calculus I'm thinking that point is the maximum rate of change point, likely to be an optimum of fuel use and time taken. I must have figured that out by gut seeing as I cant remember how to do the math!

Trying to go faster than 'fast cruise' just makes a big wake with little time benefit. Going slower than 'slow cruise', apart from being altogether just too slow, doesn't save enough fuel to bother....
Brian, that's a great way to graph fuel consumption! I like the idea of an upper limit beyond which fuel consumption goes stupid and a lower point beyond which slower offers no appreciable savings.


Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 11-09-2015, 09:05 AM   #264
TF Site Team
 
Peter B's Avatar
 
City: Brisbane
Country: Australia
Vessel Name: Lotus
Vessel Model: Clipper (CHB) 34 Sedan/Europa style
Join Date: Jun 2008
Posts: 6,669
Send a message via Skype™ to Peter B
Yes, that was good Brian. Even I could understand it. I guess I'm not doing too badly to get 1nmph per litre...but at about 7.5 kn.
__________________
Pete
Peter B is offline   Reply With Quote
Old 11-09-2015, 09:25 AM   #265
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,135
Quote:
Originally Posted by Insequent View Post
Sorry to disrupt the entertainment with some of what the OP was asking......

I normally cruise between 8 - 9 kn. Seems reasonable speed, fuel consumption etc. I really wanted an economical (2 nmpg) 10 kn cruise, but went for more comfort instead. That's another story, but there is some kind of rationale for my cruise speed.

Below is a graph of my sea trial data in a somewhat unusual format: gallons used versus time taken for an arbitrary 100 nm trip. The data points are different rpm and speeds. Fuel use is total for both engines as determined by the John Deere fuel flow instrumentation, which is reputedly very accurate unless at quite low rpm.

The trendline was a fit by excel. Coincidentally, I always operate in the area below the trendline. Normally close to the middle of that area: 8.5 kn plus or minus a bit. If I had a good equation to fit the data and could remember any calculus I'm thinking that point is the maximum rate of change point, likely to be an optimum of fuel use and time taken. I must have figured that out by gut seeing as I cant remember how to do the math!

Trying to go faster than 'fast cruise' just makes a big wake with little time benefit. Going slower than 'slow cruise', apart from being altogether just too slow, doesn't save enough fuel to bother....
Actually, without actually charting it in that manner, we do often look at the day ahead in that manner. We had two legs at the start of our current trip. Miami to Key West 170 nm., so our goal was average 17 knots, 10 hours. However, the next leg was Key West to Naples, 214 nm. With the time in and out at 10 knots, we figured 20 knots on the majority of that leg. Then Naples to Ft. Myers Beach 50 nm. For that, leisurely pace allowing 4 hours was just fine. About half the gpnm.
BandB is offline   Reply With Quote
Old 11-09-2015, 09:38 AM   #266
Guru
 
City: Northport
Country: USA
Join Date: Aug 2015
Posts: 813
I like the chart as it is for many considerations but we also often need to figure tides around here. Just a few weeks ago heading up the Hudson it was much better and almost the same fuel cost to place the rpms for 17 knots (in neutral seas) then running at what would have been 8 knots without tides.
Figuring your SOG and where you will be in a few hours and the new SOG will often lead you away from the standard calculations.
smitty477 is offline   Reply With Quote
Old 11-09-2015, 01:07 PM   #267
Guru
 
Scary's Avatar
 
City: Walnut Grove Ca
Country: USA
Vessel Name: Cary'D Away
Vessel Model: Hatteras 48 LRC
Join Date: Apr 2012
Posts: 884
6 knts max speed 10knts. Reduction almost triples range. Since my boat is so damn slow , no point getting in a hurry. There are plenty of times I miss thespeed of past boats. That's why you need a fast small boat as well. Ideal would be a twenty foot aluminum with a good sized four stroke outboard.
Scary is offline   Reply With Quote
Old 11-12-2015, 11:06 PM   #268
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,262
I travel between 35 and 65 miles per hour going to/from the boat. That satisfies my need for speed. Makes me appreciate 6.3 knots on the water.

This last Tuesday had several episodes with tugs-with-barges heading directly toward me. Slow-going gave time to react. (Altered course; they did not.)
__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 11-12-2015, 11:36 PM   #269
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,135
Quote:
Originally Posted by markpierce View Post
I travel between 35 and 65 miles per hour going to/from the boat. That satisfies my need for speed. Makes me appreciate 6.3 knots on the water.

This last Tuesday had several episodes with tugs-with-barges heading directly toward me. Slow-going gave time to react. (Altered course; they did not.)
Did they see yellow and target you?
BandB is offline   Reply With Quote
Old 11-13-2015, 09:00 AM   #270
Member
 
mdhervey's Avatar
 
City: Fort Myers, FL
Country: US
Vessel Name: Carousel
Vessel Model: Grand Banks 42 Europa
Join Date: Nov 2014
Posts: 12
Our GB 42 Europa idles at about 5.2 knots and will run all day at 15 knots. The optimum $/mile, which I believe is raw right measure, is at 9.3knts. Our plans use that speed but when running in waves, the better ride is usually around 13 knots.
mdhervey is offline   Reply With Quote
Old 11-13-2015, 10:13 AM   #271
Guru
 
Codger2's Avatar
 
City: San Diego
Country: US
Vessel Name: "Sandpiper"
Vessel Model: 2006 42' Ocean Alexander Sedan
Join Date: Oct 2007
Posts: 5,420
Quote:
Originally Posted by mdhervey View Post
Our GB 42 Europa idles at about 5.2 knots and will run all day at 15 knots. The optimum $/mile, which I believe is raw right measure, is at 9.3knts. Our plans use that speed but when running in waves, the better ride is usually around 13 knots.
__________________
Codger2

My passion for improving my boat(s) exceeds my desire to constantly cruise them.
Codger2 is offline   Reply With Quote
Old 11-13-2015, 10:49 AM   #272
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,709
Speed is highly related but this is about the cost of fuel. There's been many hundreds of posts about fuel burn down through the years. Many threads. People here obviously have the boats they want but can't afford. And the answer is to buy smaller boats. All our lives we've beed upsizing not downsizing so it's hard to do.

Many or perhaps even most of us have from youth (a long time ago) have had a play world centered around mechanized toys dominated by those that burn oil in one form or another. How many engines do you own? Count them. Most will be shocked to realize how many there are. BandB was right. One should boat according to the conditions and the conditions now are high fuel costs and too many people on the water. Smaller boats are the way to go. Or even finding something else to do like bicycleing that dosn't burn much fuel. Not in our natural catergory of likes as we'd rather ride a big motorcycle or truck that makes lots of noise. It's making a bold statement saying I'm not going to go quietly ... as in protest. It's our way of life (at least playing and many for working too) but I hear a lot more whining than stories about adapting to present and future assumed to be conditions. Actually the abundance of big pickups and motorcycles that make a lot of noise are directly related to this. Little pickups and motorcycles were very popular a short time ago ... but now almost extinct. I'll bet very soon little pickups and motorcycles will become popular again. Styled in of course in a different way to achieve the necessary vougeness.
__________________
Eric

North Western Washington State USA
Nomad Willy is online now   Reply With Quote
Old 11-13-2015, 11:13 AM   #273
Guru
 
tpbrady's Avatar
 
City: Anchorage/Wrangell
Country: USA
Vessel Name: Silver Bay
Vessel Model: Nordic Tug 42-002
Join Date: Sep 2012
Posts: 506
For us it has never been so much the money, but being able to cover the distance between fuel stops. I started with a 22ft C-Dory and had some trips of multiple days covering 220 miles with 50 gals of gas. At that point it was a trade off between speed and fuel but the C-Dory did pretty well at 15 knots and toward the end of the trip after burning off fuel and reducing the amount of water, booze, food, etc it got a lot better. Today fuel is not so much an issue since the Nordic can make just about any run in SE AK at max sustained cruise 11 knots and have a little left over. However I can operate at less than 1 nmpg or at 3+ nmpg (7.5 kts). In 300 miles that is a lot of money. Since we cover around 2000 miles over the boating season, the difference between 1 and 3 nmpg is a whole lot of money.

Tom
tpbrady is online now   Reply With Quote
Old 11-13-2015, 11:25 AM   #274
Guru
 
MYTraveler's Avatar
 
City: West Coast
Country: USA
Join Date: Apr 2014
Posts: 850
In my experience, the bigger the boat, the less significant fuel costs become. If you can't afford the boat, scrimping on fuel burn won't make the difference.
MYTraveler is offline   Reply With Quote
Old 11-13-2015, 11:34 AM   #275
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,135
Quote:
Originally Posted by manyboats View Post
People here obviously have the boats they want but can't afford.

and the conditions now are high fuel costs and too many people on the water.

Smaller boats are the way to go. Or even finding something else to do like bicycleing that dosn't burn much fuel.
The arguments one uses to try to support their own likes and dislikes. I sure don't get the impression there are a lot of people here who have boats they can't afford. Do you mean can't afford to run wot 100% of the time? Or is it prefer not to, prefer to save some money to use for other things. I do not agree all the discussions of fuel costs mean people can't afford it. I, like most, can afford many things I choose not to spend on.

Conditions are high fuel costs and too many people on the water? Fuel costs are at a historic low. As to people on the water, I don't know where you decided it was too many. Is that when you're not the only one? Is two company and three too many? All I've heard for years is the reduction in people actively boating. Go boat on any inland lake in the Southeast and you'll find out what too many people feels like and yet it's still down from ten years ago.

Now we get to the point you'll use any possible means to make even with statements such as above that smaller boats are the way to go. Or bicycles. Damn, I tried riding my bicycle across the water and we sunk. Pedal boats maybe?

I respect that you've found the type boat and boating you enjoy other than that there are too many of us on the water. You don't need to use contrived arguments to support it. Just say "I believe" or "I like" and that's all it takes. We have 9 people on board at the moment and will have three more guests tomorrow. We'll have 12 or 13 for Thanksgiving. Please don't say I need a smaller boat.

There are certain topics that are always popular. Fuel consumption gets discussed on road and water regardless of current prices. I honestly heard in passing someone ask the other day what fuel mileage a Rolls Royce gets. That's like the restaurant where if you have to ask you can't afford it. I had no idea, but I did look it up. A Phantom gets 19 hwy, 11 city, 14 overall.

Enjoy your boat, your style, your dislike of hp and love of economic. I admire your choices. I just don't share them.
BandB is offline   Reply With Quote
Old 11-13-2015, 02:00 PM   #276
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,709
Many truths Mr B,
I think you're right but I don't think you've explaned all this fuel burn talk away. you forgot about the running twins on one talk that's been going on almost forever and never seems to die. The obvious answer is a mix of 4-5 ussues.

Every boat has a target design speed (fairly narrow range) that the boat was meant to run at and few here seem to be doing that. Another reason that may draw quite a few is that a lot of trawler skippers view passagemakers to be the ultramate trawler. And a low burn rate is a very high priority w passagemakers. But trawlers are a quite different boat from them. So perhaps a lot of trawler skippers are just trying to imitate the passagemakers. When I first got into this I read every word of PMM and still have about 30 of those mags plus the book Voyaging Under Power. Haven't read either for years.

Also most of us had faster boats when we were younger and miss the speed. I do. not only getting places faster but the feel of a planing boat underneath w nice banked turns.
__________________
Eric

North Western Washington State USA
Nomad Willy is online now   Reply With Quote
Old 11-13-2015, 04:02 PM   #277
Guru
 
BandB's Avatar
 
City: Fort Lauderdale
Country: USA
Join Date: Jan 2014
Posts: 13,135
Quote:
Originally Posted by manyboats View Post
Many truths Mr B,
I think you're right but I don't think you've explaned all this fuel burn talk away. you forgot about the running twins on one talk that's been going on almost forever and never seems to die. The obvious answer is a mix of 4-5 ussues.

.
The last time I got fuel, I saw a man in a new Mercedes pull up to the pumps, get out to pump gas, and then stop. He turned to me and said, "It's 2 cents cheaper down the road." He told me where. He seemed bothered I didn't stop pumping then. So everyone has their areas in which they become very cost conscious, just different for us all. You're right though about twins on one for whatever reason, not wanting to run the boat as it was designed. However, one thing you see here is a huge amount of semi-displacement and even planing boats being used as displacement because they were more affordable or had better layouts than boats designed for slower speeds.

However, most naval architects and most builders take the dual function into consideration now. A tremendous percentage of new boats are advertised with WOT, Cruise, and Economy Cruise. It's this is a nice cruise for this boat, a good point, typically cruise being around 70-80% load and this is a very comfortable slower speed to be more economical and increase your range. You see fast megayachts that have speed and range to cross oceans, but not both at the same time. I just pulled up a production 164' Westport to see how they put it. Max Speed: 24 kts. Cruise 20 kts. Range at 16 kts 2900 nm. Range at 12 kts 5200 nm. Grand Banks certainly doesn't expect their boats to primarily be run at cruise. Even Fleming quotes multiple "sweet spots". So designers do take into consideration the need for comfort at various speeds.
BandB is offline   Reply With Quote
Old 11-13-2015, 05:21 PM   #278
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,709
BandB,
I thought you're Mercedes guy was a joke at first. Can't relate to that as being anywhere near mainstream. But I've seen guys like that. Very expensive cars are common at the cut rate gas outlet ARCO. Perhaps they are scared to death of loosing their money.

Speaking of money, views on this speed and fuel burn issue will be all over the place on this forum as we are so diverse in what we have availible to spend on boats and other toys. I feel like a really poor Joe here but I'm a rich guy compared to Janice. And there are people here that I consider really well off that are average schmucks to many others.
__________________
Eric

North Western Washington State USA
Nomad Willy is online now   Reply With Quote
Old 11-13-2015, 09:40 PM   #279
Guru
 
City: Venice Louisiana
Country: United States
Join Date: Dec 2013
Posts: 1,097
I think Janice is richer than all of us put together.
kulas44 is offline   Reply With Quote
Old 11-14-2015, 12:32 PM   #280
Art
Guru
 
Art's Avatar
 
City: SF Bay Area
Country: USA
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 7,979
Quote:
Originally Posted by kulas44 View Post
I think Janice is richer than all of us put together.
Agreed!

But - Eric is pretty darn "rich" too... just makes comments sometimes that don't show just how "rich" he really is. Richness exists in many levels and forms. Both Janice and Eric are two of the forms!

Happy Personality Daze! - Art
__________________

Art is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hull speed duckcaptainbill Marlow - Mainship 4 03-02-2012 12:08 AM
Your speed at idle markpierce Power Systems 34 10-28-2011 08:19 PM
speed seal skipperdude General Discussion 23 08-04-2010 04:25 PM
Spray at Speed Marin Grand Banks 1 11-24-2008 12:32 PM




All times are GMT -5. The time now is 12:09 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012