Questions about efficiency
 

Been shopping Formulas and have a question about fuel efficiency. Began looking at some 271 SR1 boats with either the 454 or 502 magnum, but for the same money I can get a little bit older 311. So my question is, how much more fuel would I burn in a 311 with say 454 magnum carb engines with Bravos versus a 271 with a EFI magnum engine? I like to cruise at 45-50 mph.

One 454 or 502 MPI engine vs (2) carbed 454's. The carb'ed engines should be slightly less fuel efficient based on that alone.

I've seen where people claim the 2 engines will not have to work as hard and therefore not burn as much fuel each....but that has not been my experience. A 454 running 3,500 rpms burns a certain amount of fuel regardless, having another beside it seems to burn exactly twice IMO.

your gonna burn double, regardless, and if it was slightly less it is so slight you won't know, to cruise at 50 on a 271 you will be runnning around 4200's you can buy mine but its carbed some view that as a good thing

I have looked at your boat actually in pictures you posted on previous threads and I do like it. You think it will burn double? I know it will burn more, I am just curious exactly how much. I would love the larger 311, but also want to be able to afford to run it how and where I want.

That old school 311 is a great boat....but expect it to burn about 1.1-1.3 mpg at cruise vs about 2.2-2.4 mpg in the 271. 88242LS might be able to verify my estimate from his 271????

With the added fuel burn you get ALOT more room and ALOT better riding boat.....but I agree, if you can't afford to run it what good is it!

Generally speaking, fuel burn is primarily dependent on weight. A 4,000 pound boat will deliver about 3 mpg, a 8,000 pound boat about 2 mpg, etc.

That's what I was afraid of, looks like I better stick with a single. I only boat of freshwater lakes and never overnight so the 271 should suit me fine, or even a 252 BR. I just like the quality and style of the Formulas, also looking at Checkmates and Donzis.

i wish my 6000 lb boat got 2+ mpg, 2 big blocks are burning twice what my last single engine boat was burning, i know many variables but i'm def getting less than 2 mpg more like 1-1.3

Yeah, I like to cruise all over the lake, not just sit in a cove all day, and would like to maybe do a small poker run or two each year. I have a good friend that has a 42 Fountain with trip 600s, but he literally can't afford to run it. He only brings it out on Saturdays, never Sunday, and goes straight to Party Cove, then straight back, thats not me. To sell the boat he would have to give it away with that engine package, not to mention the 600s (carbed) are mated to stock Bravos :eek:

I know you're concerned about the fuel, but what about other factors, better ride, more space, easier to manuver, with twins there's also a additional engine safety factor, I wouldn't look at just the fuel costs, look at everything then make a decision before you go shopping.

I use my boat 3-5 times a week minumum

I understand all of these other factors, but most of these don't apply to my usage. Like I said, I never overnight so a large cabin is just a waste, also I am single with no kids so as long as the cockpit will hold 4 or 5 comfortably I'm fine. The extra engine safety factor doesn't apply either as I boat on inland lakes with friends and family if problems should arise.

Don't get me wrong, I would love to have the larger boat, but not if its gonna cost me 2X as much every weekend with no appearant gains other than a lighter wallet to carry around :drink:

If your looking for fuel efficency, might I suggest a sailboat. No matter how you spin it, getting 2 miles to the gallon just isn't fuel efficient. I'd be thrilled if I could get 4 but it's still not fuel efficient.

If your buying a power boat, your not all that worried about efficency or gas prices. Gas prices haven't stopped me from boating, I just cut out the long trips. Why go 10 miles away the dock to drop anchor and sit all day, when you can go 2 miles to a similar spot and do the same thing. That type of thing.

and what is your mpg?

Some food for thought. Just from my observations over the years. I was in the same spot 4 years ago trying to decide with Formula model to go with. Theres a two step process when trying to determine which length of boat to go with.

Step 1 - Pick the one model that fits you the best. Fills all your needs.

So in your case your a single guy, no kids. You don't over night so cabin space isn't important. Needs to fit 4-5 people. Your right on that the 271 probably fits you the best. So now proceed to Step 2.

Step 2 - Now go one model size bigger then the boat selected in step 1. This is the boat you should end up with.

If not within a year your going to say I need or should have gotten a bigger boat.

Hence my tag name Splitdecision271. I ended up with a 292 fastech. I went back and forth. 271 fit me perfectly, but the 292 ended up being the right decision. Now almost 5 years later, I'm starting to think about going bigger.

I understand the costs associated with powerboats, I have been around them my whole life. I just don't want to buy a bigger boat than I really need just to tell all my friends that I have one, but not be able to afford to run it how I'd like. The joy of owning a powerboat is DRIVING a powerboat.

My friend I mentioned in a previous post with the 42 Fountain did just that, bought a boat he can neither afford to run as he would like, or sell due to the fact he is upside down. Sure, it looks cool and sounds cool, but I would rather have a Bayliner and be able to go anywhere anytime. Whatever I buy, I will be buying with cash as I don't want to be like my friend.

+1

Thats some good advice Splitdecision271, thanks. That's actually kind of what I was doing. I looked at a 271 here locally and absolutely loved the boat, then began shopping online and noticed that if went just a few years older I could get a 311 for the same price, but if it is going to cost that much more to operate, I should stick with a 271. I plan to put many hours on the boat and just don't want to have to worry about what it will cost every time I want to go for a long cruise.

You're in Louisville, on a lake or a river. You don't need a 311. Get the 271 if you want a stabbin' cabin, get the BR (252 or 232) if you want plenty of room and just need a boat to get the party around.

I had a 311 but it just didn't suit my needs. Two kids, dog(never allowed NEAR the Formula), always in & out of the water, a 30ft+/- center console with v-berth is what we need.

Stick with the Formula brand and you'll always be impressed with the things you're boat will have that others won't.

From reading all your posts, it's like you're talking yourself out of the bigger boat, so you've made the decision already, you're just looking for confirmation that it's the right choice.

If you're worrying about a few hundred dollars extra in fuel each year you might not want to buy a boat yet, there's just nothing cheap about them, think about it.

Go get a 271 and enjoy yourself for a year or two, but please come back here and tell us that you wish you would have bought the bigger boat, sorry, just trying to be honest.

I have been a boat owner for 11 years and currently own 2, so this is not my first purchase, trust me I know all about the cost of boat ownership. And it wouldn't be a few hundred dollars extra each year, it would be a few hundred dollars extra every weekend or two.

I was hoping to hear that the 311 would burn maybe 50% more fuel than the 271, but it sounds like its more like 100% more so that i cancells that thought. At current fuel prices it would be possible, but not if next summer was $5 a gallon. I don't want to be like others that bought their boats when fuel was <$2 gallon and now can't use them like they would like.

So it sounds like a 271 is for me and I am okay with that. Trust me, I will be happy with it for years to come, I think the "bigger is always better" attitude has helped in the demise of this sport. Many of the big beautiful boats that used to rip up the lake every weekend now sit silently on their lifts or in their boat storage, thats not my kind of boating.

You got it under control and I'm sure the 271 will be great boat for you, when you buy one give us a yell and see some pics of it. Good luck finding which one you want.

I found a nice looking 271 on Birmingham Craigslist, but am still waiting on photos promised over a week ago, must not want to sell.

[QUOTE=Bathtub;3474297] The joy of owning a powerboat is DRIVING a powerboat.QUOTE]

For me the joy of boating is just being on my boat. Doesn't matter if I'm driving it or just lying on the sunpad. I love anchoring in a cove and just waxing the top deck or scrubing the vinyl. It's personal preference. I don't need to run my boat and put $100 in the tank every weekend.

I'll get 3-4 weekends from 40 gallons. Doesn't mean I'm enjoying my boat any less. If anything I'd say that I'm enjoying it more because I'm not worrying that I just put $100 in 5-7 days ago and I need to fill up again.

well I don't measure mile to the gallon, then I shouldn't be boating, or I should be running a small v8, :lolhit: the 271 is agreat boat, me and the wife love it, but i have a 11 yr old and we are outgrown it so either I'm gonna get a camper top made or rule out extend a weekends in the future which I love, so probally a camper top, but now and then I still think about that next step so you never know, I would like to find a 303 with the same graphics/colors or move into a newer 292 or 312, go shopping, and enjoy! Keep us posted I will be glad to help and I know these boats well, my 271 also came from Alabama


http://i495.photobucket.com/albums/r...0805011814.jpg

Some track it, some don't. I always reset the GPS odometer everytime I filled the boat up to get a feel for what my 382 was burning. Not that it changed the way I used it (ran nearly 2,500 miles the last summer I had it). I needed to know cause I traveled pretty good distances, over 300 miles each way 4 day weekends and sometimes 80-90 miles each way day trips.....I simply wanted to know exactly how far I could travel without running out of fuel!!!!

gotcha, i guess in that aspect i know where a 1/4 tank will get me lol

My 271 with 502 EFI and Bravo 3 is very efficent.

I don't measure mpg, just dollars per day.
At close to $5 gallon in Canada and typical use for me,
some cruising, some wot some rafting, I am at
$60-70 per day.
I spent more than that for a waterfront snack for 2 on Sunday.
If I moved up in size I would go to a 353, and get a proper
head, and not much more fuel than smaller twins.

90% of our boating is on LOTO so we don't have the problem of worrying about running out of fuel, it's everywhere.
87 is around 4 bucks now and I burn through about 40-50 gals a normal weekend, but if we go on a fun or poker run all bets are off and I've got to break out the wallet, could be a 100 gal day.

Thanks nsformula. I figure with my use I would be around $100 day in fuel which is fine with me, just don't want it to be double that, which it sounds like with a 311 would be.

I notice yours has a Bravo 3 drive, how much more efficient is it than a Bravo 1 at cruising speeds?

Consider 1 important factor: Pounds/horsepower.
A 311 weighs 7400 lbs. with stock 365s (730hp) is 10.13 lbs/hp.
A 271 weighs 5250 lbs. with stock 7.4 L (310hp) is 16.9 lbs/hp.

I don't believe a boat with twins burns twice the gas a single engine boat does...With the same hull. The lower the ratio, the more efficient the boat will be not bringing hull design into the equation. Air entrapment will make a hull more efficient but more horsepower will too. If you compare a 271 Fastec with a heavier 311 SR1 then the power to weight ratio changes, but not by that much. I wouldn't be making my decision on gas mileage, but rather cockpit layout, condition and reliability. I've owned lots of great boats and they've all been different. Buy a boat that suits your needs, not how much gas it burns.

Lbs/HP is for speed comparison, not fuel efficiency. There's some correlation when you're comparing apples to apples: say a 311 with 330s vs 365s or a 271 with the 310 vs 365. But fuel burn is not rocket science: double the volume, double the burn.

Real world mpg numbers.
 

I've owned a 272 and a 311.Both big block Bravo drive boats.I don't boat often but when I go I will typically do a day trip of 90 to 180 miles.Usually cruise at 3000 rpm, carb is just at the point before the secondary barrels open, and running Bravo 4 blade props, 26 pitch. Boat is going about 42 mph, a little trim and no tab.Both boats would consistently get 1.5 to 1.6 mpg cruising like this.

I agree. And there is also a relation between horsepower and fuel burn. Typically an engine burns 10 gallon per 100hp per hour.
The difficult point is how much hp is required to push the boats in this example to a certain speed. WOT is an easy calculation, but below that it is difficult. Also the rpm's don't relate lineair to fuel burn, the produced torque at that specific rpm's gives horsepower and fuel consumption.

In the above given example, in my opinion the single engine of an 271 needs to produce more hp than each engine of the 311 does presumed both boats are at the same speed. For that reason the 311 would not burn double what the 271 burns.
Double fuel burn would more or less apply at twice the weight with comparable hulls, or a higher speed of the 311.

Just my thoughts

twins vs single
 

If comparing twins vs single in the same hull, twins will always be more thirsty and less efficient.In addition to the engine friction of the second motor, the twin engine boat is dragging that second drive through the water.The hull is also dragging more due to greater weight.I think that buying the boat you need for the conditions you boat in should be a bigger concern than fuel economy.