Anyone else boating faster this year?
 

I used to cruise at 28 to 32 MPH, but this year I have been running 35 to 40 MPH, most of the time, during the day. My fuel flow meter shows the MPG difference as very negligible (about .2 MPG more for the higher speeds) and with 9 years and only a little over 450 hours, slightly faster engine wear is not much of a worry. If the engine does wear out, I'll be rebuilding it with upgrades that allow an even faster cruising speed. My boat has a stepped hull and feels a whole lot more planted, the closer I get to 40 too, so there's some incentive beyond simple rebelliousness.

It's in my nature to do this in response to the newly imposed limitations; I've always been a bit rebellious that way. I actually find myself throttling up when I see MP. Anyone else going faster?

Looking forward to meeting you next month Dave. I named my boat FREE SPIRIT. :D

I've hardly been out enough to get on plane. You must be some sort of daredevil by geezum getting up to 40 mph.

Dave R,
I bought a MPG readout a couple of years back but it never seems to get onto my honey do list for some reason. My dream was to generate a curve of mph vs mpg. Your comment has re sparked my interest. I had always assumed that the optimum mpg was very slow and then just on plane. Do you have any mpg numbers for minimum speed. Maximum wake. almost on plane. On plane. faster? Thanks for your comments.

Sure.

idle speed (4 MPH) 4 to 5 MPG
6 MPH 3 MPG
maximum wake 1 to 1.5 MPG
20 to 24 MPH 2 MPG
25 to 27 MPH 2.2 MPG
28 to 32 MPH 2.5 MPG
33 to 40 MPH 2.2 MPG
40+ MPH 2 MPG

Thanks Dave,
Your curve attached here

Having read a lot of Boating magazines while on the ... hmmm ... while sitting and contemplating the nature of mankind, I've generally seen that a small block V8 is most efficient at no wake speed and, more usefully, between 3000 and 3500 RPM. For me that works out to be 30 - 35 MPH (optimally) depending on load and trim due to "sea state". At those speeds enough of the boat is out of the water to minimize the drag. Dave's curve seems about right though I think he has a big block.

Jackass.
 

As a private pilot for the past 27 years, I have always believed -- and was taught -- "safety first." We have a saying in aviation, "There are old pilots and there are bold pilots, but there are no old bold pilots." Playing it safe, not taking unnecessary risks to oneself and others is part of the flying tradition.

It is discouraging to know that some boaters have just the opposite attitude, and act like irresponsible teenagers and have to test every limit just to be rebellious. I hope that no one gets hurt, including the jackasses that can't or won't grow up.

-- Sky

Hyperbole
 

Can you please tell me how going 37.5 MPH vs 30 MPH (to split the ranges mentioned) constitutes such a grave risk to oneself (and others) that you fell the urgent need to insult a forum member ? Just where is your line between safe and unsafe ?

Really?
 

Sky,

I think you need to reevaluate your assessment of who is a jackass here! We have all misread a post before, but I just think you were looking for an excuse to use your old/bold pilot analogy, that everyone has heard 3000 times before. I actually found it somewhat comical that the above posts were discussing being rebellious, while taking into account speed to fuel consumption ratios. I want to thank them for the topic, because it makes me think more about where I will set my cruising speed.
I couldn't disagree more on these individuals being recklass. If anything they are some of the more informed members of this forum.

I think there are a few people here that can't seem to grasp that fuel usage and speed ..are a combination of power..AND Hull FORM. Let's not forget HULL FORM.

Lets take a typical 22 foot bowrider...AND.. a 22 foot by 12 foot Work BARGE. This barge I describe is an exaggeration to make a point. The barge will never get up on plane so will not realize any fuel saving benefit from "planing" that the bowrider will....Given the same power in both...which one do you think will be most fuel efficient..?? BTW: MPG is a farce when used with boats. Gallons Per Hour (GPH) is what is commonly used with boats..

Then there is Pleasure Vs Work. So you can see there are TOO many Variables to yield ANY Meaningful DATA. Just something to think about.

Boating is intended ......To get away from all the "Confines" of day to day living. You don't have to go...you WANT to go. So JUST GO. It's not like you have to comute to work every day in your boat.

EDIT: BTW: I have a Donzi Classic (20') with a 350 V-8 Mercruiser and my average fuel consumption is 3.5-4.0 GPH. I keep a log book to document this. When I show up at the gas dock I can estimate how many gallons it will take to fill it up. I have an hour meter. I'm usually within a gallon or two. Every boat....AND operator will yield different numbers. Just sayin. :)

GPH is meaningless unless you know how much distance you have covered. For instance, my boat burns about 15 to 16 GPH at 35 MPH and only 10 GPH at 20 MPH, but I can go futher on a gallon of gas at 35 MPH. I also burn about around .8 to 1 gallon per hour at idle, even if I'm not in gear. That yields 0 MPG. My fuel flow is measure by a device that also measures speed, it can display MPH, MPG or GPH.

My big bock is most efficient right at 3200 RPM, in my boat, which depending on load, can give me 29 to 33 MPH. I've seen it reach 2.7 MPG at 3200 RPM and 33 MPH, but that was with a very light load.

My numbers in a previous post were with a nearly full tank of gas (3/4 or more) and 4 people on board.

Pretty good Dave. I get around 5 gph over the last 3 years. Generally, with no fuel meter to track, I'm in the 25 to 35mph range. Now, 3000 rpm's gets me 30 to 32 mph. There's a math quiz tomorrow on my mpg.

Mine is a very efficient boat, which is paid for in rough water.



Note to Sky:

I think you not only misread the sarcasm in Dave's post, but that you revealed your discomfort level. I know some here are pretty scared, even anal, about even having a boat on plane. So be it. Some of the worst drivers I've ever seen on the road only drive slowly....













and many times, right through a red light.

I'd rather have a thousand Dave's on the water than a single Captain Bonehead. YMMV

Interesting
 

I have an '88 F-223 LS with the original 454 Mercruiser turning a Mirage II 25' prop. The best I can do is 10 GPH and the worst I have seen is 20 GPH. I measure this by dividing the number of gallons used by the hours clocked on the hour meter. I don't have an accurate speedometer.

To maintain 10 GPH. I will go on plane at 3K rpm and throttle back to minimum planing speed at 2200 rpm. If I had a gph meter, I can probably do better.

20 GPH is at WOT at 4500 rpm. Which is 65+ mph. With an 80 gallon tank, that is 4 hours between fill ups.

From what I read in magazines and browsing on the internet, the most accurate way of gathering MPG is with a GPS speedometer. There are GPS speedometers on the market that can calculate MPG and GPH. Expensive. I wonder what the forum members are using for instruments.

I have GPS, a paddle wheel, and a pitot. All three report speed fairly closely on plane.

Good Question
 

I'd wonder what people are using for fuel flow meters. I thought aftermarket items were somewhat pricey. An accurate speedo isn't all that expensive. Even a cheap handheld GPS will have a speedo function. We have a FI Mercruiser 5.7L. I wonder if it has a control bus with a data port that can be read for fuel metering ?

Here's a new 63 foot yacht that burns 5.1 gph at 9 knots and it weighs 108,000 pounds. It was designed by the folks that usually design sailboats - Sparkman and Stephens

http://www.boattest.com/boats/Boat_video.aspx?ID=2022

Bottom Line
 

WHO {CARES} about what Dave is doing with his money or his property. It is his and his alone to do with what he pleases. Why does this liberal ridiculous society believe that everyone must conform. And it is not even conforming to the masses, it is to the small minority which believe that what other people do is their business

GO AWAY!!!! and let people live their lives the way they want to and let them either succeed or fall flat on their faces, their choice

Something about just over 200 years ago there was some sort of a fist fight or some one got tripped up over this matter? I am not sure what that was all about though, Let's all remeber our History and what people die for

Sailboats
 

Back in the '70s I had a 27 foot (5500#) sailboat with a 4 cylinder 30HP "Atomic 4" gas inboard engine. It burned 1.0 GPH @ 6 Kts.

In the '80s, I had a 32 foot (10,500#) sailboat with a 2 cylinder 15HP "Yanmar" diesel inboard. It burned 0.2 GPH @ 6 Kts. That's not a misprint: One Fifth of a GPH.

Sailboats have a much more efficient hull form than planing power boats. They have to, or they won't Sail Well either. Then again, sailors are not in a hurry to get somewhere. :)

I never calculated GPH or MPG VS MPH. I calculated $ per W/E. The formula is complex but I found a shortcut: F/TX2D=E/W+M/O C/C.

My guess
 

Fun / Time x 2 Days = Effort / Work + Meals / Onions x Coolers / Company

Oh ya it was supposed to calculate something about gasoline.

Nope. The formula F/TX2D=E/W+M/O C/C is:

Full Tank X 2 days = empty wallet + maxed out credit card.;)

Okey Dokey: TODAY....These days... A sence of humor can take you a long way. I'm all for it. The more we can smile the better. :D:D:D:D

So, at a capacity of 2,105 gallons, @2.70/gallon, and assuming 20 hours of run-time fun each week from April to October, you only have to put in $5,683 worth of gas once per year!

The only problem is that this boat is built in Zhuhai, China, and I'm not sure I want my money to go to the Chinese like this.

WOW! I have a VDO speedometer with a pitot. It's reading is all over the place compared to my hand held GPS. At 25 mph the GPS reads 30 mph. At 45 mph my GPS read 40. At WOT it is 60 mph versus 68 mph on the GPS.

My on plane speed is 30 mph on the GPS compares to 20 mph on my speedometer. Last night I was out after dark and use my GPS to maintain 25 mph. My boat won't plane and put out one heck of a wake!

The pitot is in my Bravo 3 drive leg and feeds the OEM Faria speedometer. It's suprisingly accurate. The GPS is a Standard Horizon CP155C. The paddle wheel is connected via an NMEA2000 bus to my Lowrance LMF-200 multi-purpose gauge (my GPS is NMEA183 compliant, not NMEA2000, hence the paddle wheel for speed). Adding speed information and fuel flow sensor to the LMF-200 allows it to display MPG and range.

I use my tach like NASCAR
 

My Speedometer is OME and has a plastic pitot and doesn't even start to register until 20 MPH. So to avoid any late night encounters with the MP. I brought my portable car GPS aboard and found out where my tach was at 25 MPH. It interestingly enough was around 2600 RPM with SS prop and a half a tank of gas. Of course to plane the trim tabs are all the way down and I am throwing a great wake boarder wave.

Speedo accuracy
 

Same here except for the accurate part. To be fair the speedo agrees with the GPS +/- 1 MPH at 35 MPH. Last Sat night we were out and I got the boat into the minimum state I would call "on plane". The speedo said 22 and the GPS read 25. Trim all the way in and full tabs except for port/starboard level. Lesser speed got the GPS down to 20 MPH but it was a quasi mush-plane state.

FWIW the speedo on the SeaDoo is dead nuts on (per GPS) anywhere between 20 - 50 MPH.

I have been cruising at 35-40mph this year, since gas is so much cheaper than last year :D

If there are alot of boats around-specifically those MP boats, I obey the 45mph limit all day...if no boats are around and we are in the broads..I drop the hammer often :devil:

That sounds like a logical plan. Have fun and be safe.

I did 30 mph (GPS) one night just to say I did. I don't go out at night too often and most times this year the conditions don't warrant planing speeds.

Can't break the daytime speed limit, tried once this year. Best I could do was 38 mph, I'll try again next spring. With a freshly cleaned bottom, empty tanks, and no passengers, I might get close. All the magazine boat tests, say my boat should do 41 mph.

Get rid of the GPS, and your boat will do OVER 41 :D

Prop change
 

Do a little experiment with your prop. Most boat mfg would use the standard prop that came with the engine package from the engine builder. It is not necessarily the best prop to use. For instance: My boat came with a 23" Mirage prop. At WOT the engine was hitting the rev limiter. I replace the prop with a 25" Mirage II. At WOT the rev was down 200 rpm but it was not limited electronically. I gain about 6 mph. I also notice my fuel use is down. :D

Some marinas have used props that you can experiment with. You can also buy/sell props on Craigslist and or EBay. :cool:

Since my boat does not have a speedo, VtSteve is right, if I get rid of the GPS I can brag about any speed I want.

BH, I have four props, (twin Volvo duoprops) plus my boat is always in the water, so experimenting with pitch is more work than I'm willing to do. I perfectly happy with the boats speed, it goes plenty fast. Besides I think I need the lower pitch to get the boat out of the hole, it weighs 16,000 pounds.

Ok what am I doing wrong?
 

I am new to this forum but not new to boating. I am totally baffled by this GPH. I am reading 2.5-30 GPH. I take this as you are burning between 2.5 and 3 gallons per hour. This seems incomprehensible to me.

I have a 21 foot bow rider with a small block all stock. At best I burn 8 GPH. I run the boat anywhere between 2200 rpm – 3500rpm. Ok maybe once this year I passed Mee-N-Mac’s place at 4800. But only once. I usually cruise around 28 MPH @ 2700 RPM

What am I doing wrong I would love to get 2.5 – 3 GPH.

Thanks

The pumps at the fuel dock have to be calibrated every once in awhile by law, so the readings there are most likely quite accurate. That leaves your "Hour Meter". I suspect your Hour Meter is running only intermittently, causing you to get bad GPH figures when you do the math at fillup.

I am not using an hour meter and my previous boat (50hp less) had about the same GPH.

I have always thought 8-15 GPH was normal.

Normal
 

Depends on the boat size and weight but that range is about right. Consider that 2.5 MPG at 30 MPH is 12 GPH. People can get much better GPH if it's a small light boat, like a 10 HP on the back of a rowboat or with the auxiliary in a sailboat going 5 MPH. Not sure who you thought was burning 2.5 - 3.0 GPH in something larger ????

If you don't use an Hour Meter, HOW are you keeping track of time. Because of the human element, just looking at your watch every now and then is not going to suffice for accuracy.

As I mentioned earlier, my 20 foot Donzi with a 5.7 liter Mercruiser (350 Cubic Inches/260 HP) burns about 3.5 to a little over 4 GPH overall, from putting around the docks @ 5 MPH to cruise at about 32 MPH....with an occasional goose up to 60. Looking at the boating magazines, it looks like a 350 @ wide open throttle would burn 21 GPH... IF... the engine would last an hour at WOT.

BTW: A Two Stroke outboard will burn more gas than todays more fuel efficient Four Strokes. The reason for this is that a two stroke "Fires" on every revolution of the crankshaft, whereas a Four Stroke fires on Every Other revolution.

EDIT: Lets not forget: GPH stands for Gallons Per Hour.

Then I must be doing something wrong
 

The boat weighs 3600 + 3 occupants. One is the wife and one is the 5 year old so that is like 3600 + 2 occupants. (just in case the wife reads this).

Anyways the engine is 5.0 MPI. 250HP.

I must be calculating wrong.

..yeesirreee...yup...yup...up...goes the speed on my sailing....was able in the last two weeks to sell off my 25 year old Echo 12' sailboat, 'Tink A Belle', for about 925 dollars and replace it with a new 25 year old Wingstar 13' sailboat for about the same money....fiberglass and aluminum basically lasts forever....just clean off the mold and either wax or paint it up,,,,,,rope lines get demolded by soaking in bleach & water....and am thinking about naming it 'McChicken'.....after the sandwich on the dollar menu......bigger sails...more dynamic hull...along with two oars and oar locks for a way to get back when the wind dies out... if you see someone standing on top of an upside-down, turtled sailboat.....clinging to the center board and waving an oar.....that will be me :)

Here's how it's done. Get an Hour Meter and have it wired to the ignition switch..or however the meter manufacturer tells you to do it. Whenever the KEY is ON..ie Engine running, the clock is running...measured in Hours and Tenths of hours.

Go to the gas dock and FILL it up. Write down the reading from the Hour Meter in a little logbook. Next time you need gas, go back to any gas dock and fill it up Again..AND write down the hour reading again. I always write down the Gallons pumped each time as well. Divide the gallons pumped to FILL up the gas tank... by the Hours and Tenths of hours on the hour meter. This will give you Average GPH used since you last filled the tank....which will cover all types of driving during THAT fillup.

After a few Fill Ups you will see a trend which will reflect your overall average and you will be suprised that the GPH used will become pretty consistant from tank to tank. Don't worry about Who was on board at any given time because it will all average out.

I have a 40 gallon tank and when my gas guage gets down to half full I start thinking about another fillup. Gas guages are notoriously inacurate. The Hours used is much more acurate in determining how much gas is left in the tank, after you become used to the routine. You must AWAYS Fill Up for this procedure to work.

Thanks NoBozo,

I will get one this week.

I must be putting around more than thought :D

Perhaps you read MPG as GPH.

I think they are going faster.

I was headed out of Meredith this afternoon doing about 33/35mph and there were several boat overtaking me a lot faster than 5-7mph more than me.


Go for it if MP is not going to enforce it!

Depends on the boat. Mine is pretty efficient hull design, and lighter. My overall average is 4.5 gph and change. I'm not that light on the throttle, but lately, I get better mileage at 30 mph.

I have the 5.0 V8 MPI 260 HP Merc driving a 22' cuddy.

Average for boats of my size is around 7-8 gph. They ride better, and are heavier.

My friend has a 28' Rinker cuddy, and he gets around 9 gph as his average. The weight is double.