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Author Topic:   Fuel Efficiency Opinion

Mike Kub posted 05-12-2013 08:09 PM ET (US)
I took a ride out into the Gulf this morning.National data bouy showed 2-3 ft.seas.This seemed about right.Could go only about 20 mph. comfortably.I have an OUTRAGE 18. With these conditions, which are fairly typical, would a 115-HP or a 150-HP get the best mileage? I will be re-powering within a few months and the decision is between the (Yamaha four-stroke-cycle outboard models) F115 or F150. Peace.
EaglesPDX posted 05-12-2013 09:04 PM ET (US)
If you look at the current performance data on the Outrage 19, closest current Whaler to your 18, the most efficient low speed engine is the 150 (FOURSTROKE not VERADO), 18.7-MPH at 5.5-MPHG.
It has nearly twice the displacement of the Verado 125 and 200, 183-cubic-inches to 104-cubic-inches.
The 115 might be bit too small.
Tom W Clark posted 05-12-2013 09:56 PM ET (US)
Probably not a huge difference, but the F115 will do the better job at that speed.
We're talkin' the Yamaha F115 vs, the F150, not a supercharged Verado.
The 190 Montauk is a better comparison to the classic Outrage 18 than the 190 Outrage, though even the 190 Montauk is a much bigger boat than the classic Outrage 18.
The 190 Montauk gets better fuel mileage with the 115 HP than the 150 HP motor.
EaglesPDX posted 05-12-2013 10:38 PM ET (US)
The Montauk is lighter and less V than the Outrage 18 so I'd think the current Outage 190 gives a better comparison.
The comparison I was suggesting was Mercury 150 (FOURSTROKE not VERADO) as better choice than Yamaha 115 or 150.
Is this a classic Outrage 18 or the more modern one which was about identical to the current Outrage 19. What was the V on the classic OUTRAGE 18? Increased V eats HP.
Tom W Clark posted 05-12-2013 11:08 PM ET (US)
The classic Outrage 18 weighs 1250 pounds, is 18'-6" LOA and has a 7'-2" beam.
The 190 Montauk weighs 1900 pounds, is 19'-0' loa and has an 8' beam
The 190 Outrage weighs 2050 pounds, is 18'-10" loa and has an 8' beam
Mike is not asking about the Mercury 150 FourStroke. Start a new thread if you want to discuss that motor.
jimh posted 05-12-2013 11:35 PM ET (US)
To move any boat at a particular boat speed will require a certain horsepower. The fuel economy (in MPG) that will result will be a function of the brake specific fuel consumption (BSFC) of the engine at that boat speed.
The BSFC of an engine will vary with its load and engine speed. It is not a constant number. There seems to be a tendency for BSFC to be lowest (that is, the best fuel economy) somewhere in the middle range of engine speeds and in the middle range of engine loads.
It is hard to predict if the desired boat speed of an OUTRAGE 18 will result in either the F115 or the F150 operating at the most optimum engine speed and load to produce the best fuel economy.
What we can say for certain is the F150 powered OUTRAGE 18 will have more reserve power, will be able to accelerate faster, will reach a higher ultimate speed, and will perform better under heavy loads.
JeePete posted 05-13-2013 06:09 AM ET (US)
Mike,
It's tough to say, unless the planing speed is known and the sweet spot of the motor to get & keep you there.
The two biggest fuel consumption "spots" are just before getting any boat on plane & wide open throttle.
If the 115 gets it on plane and can hold it @ cruise without laboring out of it's sweet spot, then it might be the more efficient choice. If the 150 has an easier time getting it and keep it at cruise, then it might be the better (more efficient) choice. (as was pointed out by Jim)
The other consideration might be the weight of each, but I think the Whaler could handle either fine.
FWIW, if it were me, I'd simply be looking at having the reserve power when/if needed. Murphy was a boater, so the scenario would be late afternoon, out going tide, incoming wind, lots of people on board....you get the idea.
Just my .02
PK
EaglesPDX posted 05-13-2013 07:42 AM ET (US)

quote:
Tom W Clark- The classic Outrage 18 weighs 1250 pounds, is 18'-6" LOA and has a 7'-2" beam.
Then you would compare it to classic Montauk 17 which weighed 900 lbs. Or a current Montauk 17 which weighs 1400 lbs. Whaler max HP is only 90 HP on that boat.
1250 is a very light boat and I would think the modern 115 4 cycle would do well even on the deeper V Outrage, assuming it has a 21 deg V.
I wonder what the max engine weight is on the classic 18/1250 boat. The F115 weighs 400 lbs. The F150 a whopping 480 lbs. 30% of the boat weight is a lot on such a light boat.
I'd call Whaler see what the oldest performance record they have for the boat that most closely matches the classic 18 OR.
Peter posted 05-13-2013 08:41 AM ET (US)
Here are a couple of Yamaha reports to compare an F115 to an F150 on an Edgewater 188 CC.
F150
www.yamahaoutboards.com/sites/default/files/bulletins/ bulletin_4stroke_hpv6_rel_edg-188cc-f150txr_2008-07-27.pdf
and
F115
www.yamahaoutboards.com/sites/default/files/bulletins/ bulletin_4stroke_midthrustjetport_gyt3_edg-188cc-f115txr.pdf
As you will observe, the F115 does NOT provide any material advantage in terms of fuel economy but it GIVES UP load carrying capacity as is noted by the almost doubling of the time to plane statistic. Thus, one considering buying an Edgewater 188CC should go for an F150 over an F115 in my opinion.
Having owned 2 Outrage 18s over the years with 400 lb 150 HP V6 2-strokes, I would not hang an over 500 lb F150 (491 lbs dry, over 500 lbs with oil in crankcase, gear lube, propeller) on the transom. So if you are weight conscious like I am, the F115 is the only option if you limit your world to Yamaha 4-strokes.
Jefecinco posted 05-13-2013 09:49 AM ET (US)
My 190 Montauk is powered by a heavy 135 HP Verado. It has plenty of power and leaps onto plane even when fully loaded.
Given the weight and size difference between my 190 Montauk and Mike's 18 Outrage 18 I would expect a 115 HP Yamaha to deliver good performance and economy on an Outrage 18.
Butch
Peter posted 05-13-2013 10:44 AM ET (US)
I'd take a different view having had a 2.6L 150 V6 on the first Outrage 18 and then a 1.8L 140 V4 on the second Outrage 18 until it was ultimately repowered with a 150 V6. If you never had a 150 on the Outrage 18, then a 115 would seem fine because you would not know what you were missing. One important difference to me between the V4 and the V6 was not the top speed, but the cruising RPM. To cruise at 30 MPH on a calm day, the V4 had to turn 4200 RPM. The V6 only required 3500 RPM to do the same. The difference in RPM was significant in terms of noise and also the 150 had far more load carrying reserve capacity.
Marko888 posted 05-13-2013 02:50 PM ET (US)
A thought re cruise RPM of a 150 2-stk vs a F115:
The F115 firing every second revolution might sound more relaxed at 4500 rpm than the 150 2-stk at 3000rpm due to fewer power pulses. (2250 vs 3000)
Any comments on this idea?
Peter posted 05-13-2013 03:20 PM ET (US)
The noise is more than just the exhaust pulses. But just focusing on the frequency of the exhaust pulses per flywheel revolution, the number will be higher for a V6 2-stroke (6 in number) versus a 4-cylinder 4-stroke (2 in number). But each of the 6 exhaust pulses of the 2-stroke have a much smaller "amplitude" than each of the 2 exhaust pulses from the 4-stroke.
But if one sticks with just a smaller 4-stroke to a larger 4-stroke comparison, the F115 will turn 500 RPM faster than the F150 on the same boat going the same cruise speed (4000 RPM versus 3500 RPM at 26 MPH in the performance reports linked above). The power pulses of the 115 will be smaller in amplitude but greater in frequency.
Marko888 posted 05-13-2013 03:47 PM ET (US)
Thanks Peter... I laugh now seeing I had only considered a single cylinder!
I need to get out on some boats with modern 4-stk's and DFI 2-stk's to hear for myself.
cheers
L H G posted 05-13-2013 04:09 PM ET (US)
Our old friend Tony used to rave about the Yamaha 115 4-stroke on his 18 Outrage.
I have always thought an 18 Outrage weighs more the 1,250-lbs. Seeing the boats side by side, there could be no way and 18 weighs only 300-lbs more than a Montauk.
jimh posted 05-13-2013 11:05 PM ET (US)
Tony always ran his boat in the ocean, and the ocean conditions there on the Pacific coast of Northern California probably prohibited any sort of really high speed operation except on a few rare occasions.
EaglesPDX posted 05-14-2013 09:37 AM ET (US)

quote:
I have always thought an 18 Outrage weighs more the 1,250-lbs. Seeing the boats side by side, there could be no way and 18 weighs only 300-lbs more than a Montauk.
It seems very light. Current Montuak 17 weighs 1,400-lbs and Whaler only rates it for maximum 90-HP.
The newer 18 Whaler Outrages (neighbor has one) are rated for up to 225-HP. Neighbor's c.2000 18-footer with a 225 is not as fast and much less fuel efficient than my 1989 22-footer with a 150-HP.
I think it is due to the weight of the boat and motor.
jimh posted 05-14-2013 10:03 AM ET (US)
Fuel efficiency is a function of how much power is needed to move a boat. The power needed to move a boat is a function of its weight. There is nothing unusual about a boat that is lighter than another boat being able to operate with higher fuel efficiency.
EaglesPDX posted 05-14-2013 05:12 PM ET (US)

quote:
jimh - The power needed to move a boat is a function of its weight.
Well...um...no is the short answer.
A Nordhavn 62 weighs 155,000 lbs and is as fuel efficient as a Whaler 320 Outrage at 8 knots.
Speed, displacement vs. planning, beam, dead rise, hull designs, props all play a part in how much power it takes.
Two boats of identical weights but one having 16 deg V and another having 21 deg, it will take more horsepower to move the deeper v boat.
In this case, need to know the weight, dead rise and max HP rating as 18 Whaler Outrages have gone through an evolution.
jimh posted 05-14-2013 05:41 PM ET (US)
My statement is correct. The power needed to move a boat varies as a function of the weight. That boats of different weight and hull design can get the same fuel economy does not contradict the statement.
jimh posted 05-14-2013 05:50 PM ET (US)

quote:
In this case, need to know the weight, dead rise and max HP rating as 18 Whaler Outrages have gone through an evolution.
No. None of that is needed to know if a 150-HP engine or a 115-HP engine will be more fuel efficient, except for the weight difference between the engines. The boat will have the same dead rise angle in the hull with either engine. The non-engine weight of the boat will be the same with either engine. The hull rating will be the same with either engine.
To find out if the 150-HP will be more fuel efficient at a particular boat speed than a 115-HP engine, the best method would be to test them both under controlled conditions, because, as far as I know, there is no published information about the BSFC curve of these engines and we don't have real data about the exact engine speed and loading that would exist at a certain boat speed.
As I said before, there is a general trend in typical engines to see an improvement (a decrease) in BSFC at mid-speed and mid-load conditions. It might occur that one of the engines ends up operating at a more favorable load and speed combination, producing the necessary horsepower from the fuel more efficiently than the other. But I don't see any way to predict that in advance, given how little information we have on the characteristics of the two engines' BSFC curves.
We know the larger engine will weigh more, so that gives the larger engine a disadvantage it must overcome if it is going to be more fuel efficient than a lighter engine of lower rated maximum horsepower.
EaglesPDX posted 05-14-2013 07:28 PM ET (US)
[quot] jimh - To find out if the 150-HP will be more fuel efficient at a particular boat speed than a 115-HP engine, the best method would be to test them both under controlled conditions.[/quote]
Unfortunately not practical when buying engines so finding the closest Whaler to this particular 18 Outrage and looking at Whaler's test ratings with different engines would help. Or seeing if engine mfg's have old tests with the older Whaler.
Also the experiences of others with identical boat.
If the current Montauk weighing 1400#, the closest current Whaler in weight to the 1250# Outrage, is only rated for max 90 HP. The 18' Outrage may only be rated for 100HP.
Exact specs, weight, v, max hp rating, max engine wt rating are necessary.
BMack posted 05-14-2013 09:55 PM ET (US)
I repowered my 1987 18ft Outrage from a 150 Johnson to a Suzuki DF115. After 600 plus hours of use I have never felt under powered.

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Author	Topic: Fuel Efficiency Opinion
Mike Kub	posted 05-12-2013 08:09 PM ET (US) I took a ride out into the Gulf this morning.National data bouy showed 2-3 ft.seas.This seemed about right.Could go only about 20 mph. comfortably.I have an OUTRAGE 18. With these conditions, which are fairly typical, would a 115-HP or a 150-HP get the best mileage? I will be re-powering within a few months and the decision is between the (Yamaha four-stroke-cycle outboard models) F115 or F150. Peace.
EaglesPDX	posted 05-12-2013 09:04 PM ET (US) If you look at the current performance data on the Outrage 19, closest current Whaler to your 18, the most efficient low speed engine is the 150 (FOURSTROKE not VERADO), 18.7-MPH at 5.5-MPHG. It has nearly twice the displacement of the Verado 125 and 200, 183-cubic-inches to 104-cubic-inches. The 115 might be bit too small.
Tom W Clark	posted 05-12-2013 09:56 PM ET (US) Probably not a huge difference, but the F115 will do the better job at that speed. We're talkin' the Yamaha F115 vs, the F150, not a supercharged Verado. The 190 Montauk is a better comparison to the classic Outrage 18 than the 190 Outrage, though even the 190 Montauk is a much bigger boat than the classic Outrage 18. The 190 Montauk gets better fuel mileage with the 115 HP than the 150 HP motor.
EaglesPDX	posted 05-12-2013 10:38 PM ET (US) The Montauk is lighter and less V than the Outrage 18 so I'd think the current Outage 190 gives a better comparison. The comparison I was suggesting was Mercury 150 (FOURSTROKE not VERADO) as better choice than Yamaha 115 or 150. Is this a classic Outrage 18 or the more modern one which was about identical to the current Outrage 19. What was the V on the classic OUTRAGE 18? Increased V eats HP.
Tom W Clark	posted 05-12-2013 11:08 PM ET (US) The classic Outrage 18 weighs 1250 pounds, is 18'-6" LOA and has a 7'-2" beam. The 190 Montauk weighs 1900 pounds, is 19'-0' loa and has an 8' beam The 190 Outrage weighs 2050 pounds, is 18'-10" loa and has an 8' beam Mike is not asking about the Mercury 150 FourStroke. Start a new thread if you want to discuss that motor.
jimh	posted 05-12-2013 11:35 PM ET (US) To move any boat at a particular boat speed will require a certain horsepower. The fuel economy (in MPG) that will result will be a function of the brake specific fuel consumption (BSFC) of the engine at that boat speed. The BSFC of an engine will vary with its load and engine speed. It is not a constant number. There seems to be a tendency for BSFC to be lowest (that is, the best fuel economy) somewhere in the middle range of engine speeds and in the middle range of engine loads. It is hard to predict if the desired boat speed of an OUTRAGE 18 will result in either the F115 or the F150 operating at the most optimum engine speed and load to produce the best fuel economy. What we can say for certain is the F150 powered OUTRAGE 18 will have more reserve power, will be able to accelerate faster, will reach a higher ultimate speed, and will perform better under heavy loads.
JeePete	posted 05-13-2013 06:09 AM ET (US) Mike, It's tough to say, unless the planing speed is known and the sweet spot of the motor to get & keep you there. The two biggest fuel consumption "spots" are just before getting any boat on plane & wide open throttle. If the 115 gets it on plane and can hold it @ cruise without laboring out of it's sweet spot, then it might be the more efficient choice. If the 150 has an easier time getting it and keep it at cruise, then it might be the better (more efficient) choice. (as was pointed out by Jim) The other consideration might be the weight of each, but I think the Whaler could handle either fine. FWIW, if it were me, I'd simply be looking at having the reserve power when/if needed. Murphy was a boater, so the scenario would be late afternoon, out going tide, incoming wind, lots of people on board....you get the idea. Just my .02 PK
EaglesPDX	posted 05-13-2013 07:42 AM ET (US) quote: Tom W Clark- The classic Outrage 18 weighs 1250 pounds, is 18'-6" LOA and has a 7'-2" beam. Then you would compare it to classic Montauk 17 which weighed 900 lbs. Or a current Montauk 17 which weighs 1400 lbs. Whaler max HP is only 90 HP on that boat. 1250 is a very light boat and I would think the modern 115 4 cycle would do well even on the deeper V Outrage, assuming it has a 21 deg V. I wonder what the max engine weight is on the classic 18/1250 boat. The F115 weighs 400 lbs. The F150 a whopping 480 lbs. 30% of the boat weight is a lot on such a light boat. I'd call Whaler see what the oldest performance record they have for the boat that most closely matches the classic 18 OR.
Peter	posted 05-13-2013 08:41 AM ET (US) Here are a couple of Yamaha reports to compare an F115 to an F150 on an Edgewater 188 CC. F150 www.yamahaoutboards.com/sites/default/files/bulletins/ bulletin_4stroke_hpv6_rel_edg-188cc-f150txr_2008-07-27.pdf and F115 www.yamahaoutboards.com/sites/default/files/bulletins/ bulletin_4stroke_midthrustjetport_gyt3_edg-188cc-f115txr.pdf As you will observe, the F115 does NOT provide any material advantage in terms of fuel economy but it GIVES UP load carrying capacity as is noted by the almost doubling of the time to plane statistic. Thus, one considering buying an Edgewater 188CC should go for an F150 over an F115 in my opinion. Having owned 2 Outrage 18s over the years with 400 lb 150 HP V6 2-strokes, I would not hang an over 500 lb F150 (491 lbs dry, over 500 lbs with oil in crankcase, gear lube, propeller) on the transom. So if you are weight conscious like I am, the F115 is the only option if you limit your world to Yamaha 4-strokes.
Jefecinco	posted 05-13-2013 09:49 AM ET (US) My 190 Montauk is powered by a heavy 135 HP Verado. It has plenty of power and leaps onto plane even when fully loaded. Given the weight and size difference between my 190 Montauk and Mike's 18 Outrage 18 I would expect a 115 HP Yamaha to deliver good performance and economy on an Outrage 18. Butch
Peter	posted 05-13-2013 10:44 AM ET (US) I'd take a different view having had a 2.6L 150 V6 on the first Outrage 18 and then a 1.8L 140 V4 on the second Outrage 18 until it was ultimately repowered with a 150 V6. If you never had a 150 on the Outrage 18, then a 115 would seem fine because you would not know what you were missing. One important difference to me between the V4 and the V6 was not the top speed, but the cruising RPM. To cruise at 30 MPH on a calm day, the V4 had to turn 4200 RPM. The V6 only required 3500 RPM to do the same. The difference in RPM was significant in terms of noise and also the 150 had far more load carrying reserve capacity.
Marko888	posted 05-13-2013 02:50 PM ET (US) A thought re cruise RPM of a 150 2-stk vs a F115: The F115 firing every second revolution might sound more relaxed at 4500 rpm than the 150 2-stk at 3000rpm due to fewer power pulses. (2250 vs 3000) Any comments on this idea?
Peter	posted 05-13-2013 03:20 PM ET (US) The noise is more than just the exhaust pulses. But just focusing on the frequency of the exhaust pulses per flywheel revolution, the number will be higher for a V6 2-stroke (6 in number) versus a 4-cylinder 4-stroke (2 in number). But each of the 6 exhaust pulses of the 2-stroke have a much smaller "amplitude" than each of the 2 exhaust pulses from the 4-stroke. But if one sticks with just a smaller 4-stroke to a larger 4-stroke comparison, the F115 will turn 500 RPM faster than the F150 on the same boat going the same cruise speed (4000 RPM versus 3500 RPM at 26 MPH in the performance reports linked above). The power pulses of the 115 will be smaller in amplitude but greater in frequency.
Marko888	posted 05-13-2013 03:47 PM ET (US) Thanks Peter... I laugh now seeing I had only considered a single cylinder! I need to get out on some boats with modern 4-stk's and DFI 2-stk's to hear for myself. cheers
L H G	posted 05-13-2013 04:09 PM ET (US) Our old friend Tony used to rave about the Yamaha 115 4-stroke on his 18 Outrage. I have always thought an 18 Outrage weighs more the 1,250-lbs. Seeing the boats side by side, there could be no way and 18 weighs only 300-lbs more than a Montauk.
jimh	posted 05-13-2013 11:05 PM ET (US) Tony always ran his boat in the ocean, and the ocean conditions there on the Pacific coast of Northern California probably prohibited any sort of really high speed operation except on a few rare occasions.
EaglesPDX	posted 05-14-2013 09:37 AM ET (US) quote: I have always thought an 18 Outrage weighs more the 1,250-lbs. Seeing the boats side by side, there could be no way and 18 weighs only 300-lbs more than a Montauk. It seems very light. Current Montuak 17 weighs 1,400-lbs and Whaler only rates it for maximum 90-HP. The newer 18 Whaler Outrages (neighbor has one) are rated for up to 225-HP. Neighbor's c.2000 18-footer with a 225 is not as fast and much less fuel efficient than my 1989 22-footer with a 150-HP. I think it is due to the weight of the boat and motor.
jimh	posted 05-14-2013 10:03 AM ET (US) Fuel efficiency is a function of how much power is needed to move a boat. The power needed to move a boat is a function of its weight. There is nothing unusual about a boat that is lighter than another boat being able to operate with higher fuel efficiency.
EaglesPDX	posted 05-14-2013 05:12 PM ET (US) quote: jimh - The power needed to move a boat is a function of its weight. Well...um...no is the short answer. A Nordhavn 62 weighs 155,000 lbs and is as fuel efficient as a Whaler 320 Outrage at 8 knots. Speed, displacement vs. planning, beam, dead rise, hull designs, props all play a part in how much power it takes. Two boats of identical weights but one having 16 deg V and another having 21 deg, it will take more horsepower to move the deeper v boat. In this case, need to know the weight, dead rise and max HP rating as 18 Whaler Outrages have gone through an evolution.
jimh	posted 05-14-2013 05:41 PM ET (US) My statement is correct. The power needed to move a boat varies as a function of the weight. That boats of different weight and hull design can get the same fuel economy does not contradict the statement.
jimh	posted 05-14-2013 05:50 PM ET (US) quote: In this case, need to know the weight, dead rise and max HP rating as 18 Whaler Outrages have gone through an evolution. No. None of that is needed to know if a 150-HP engine or a 115-HP engine will be more fuel efficient, except for the weight difference between the engines. The boat will have the same dead rise angle in the hull with either engine. The non-engine weight of the boat will be the same with either engine. The hull rating will be the same with either engine. To find out if the 150-HP will be more fuel efficient at a particular boat speed than a 115-HP engine, the best method would be to test them both under controlled conditions, because, as far as I know, there is no published information about the BSFC curve of these engines and we don't have real data about the exact engine speed and loading that would exist at a certain boat speed. As I said before, there is a general trend in typical engines to see an improvement (a decrease) in BSFC at mid-speed and mid-load conditions. It might occur that one of the engines ends up operating at a more favorable load and speed combination, producing the necessary horsepower from the fuel more efficiently than the other. But I don't see any way to predict that in advance, given how little information we have on the characteristics of the two engines' BSFC curves. We know the larger engine will weigh more, so that gives the larger engine a disadvantage it must overcome if it is going to be more fuel efficient than a lighter engine of lower rated maximum horsepower.
EaglesPDX	posted 05-14-2013 07:28 PM ET (US) [quot] jimh - To find out if the 150-HP will be more fuel efficient at a particular boat speed than a 115-HP engine, the best method would be to test them both under controlled conditions.[/quote] Unfortunately not practical when buying engines so finding the closest Whaler to this particular 18 Outrage and looking at Whaler's test ratings with different engines would help. Or seeing if engine mfg's have old tests with the older Whaler. Also the experiences of others with identical boat. If the current Montauk weighing 1400#, the closest current Whaler in weight to the 1250# Outrage, is only rated for max 90 HP. The 18' Outrage may only be rated for 100HP. Exact specs, weight, v, max hp rating, max engine wt rating are necessary.
BMack	posted 05-14-2013 09:55 PM ET (US) I repowered my 1987 18ft Outrage from a 150 Johnson to a Suzuki DF115. After 600 plus hours of use I have never felt under powered.