Fuel consumption Tahoe

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Daniel79
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Joined: Sun Sep 21, 2014 9:37 am
Location: Netherlands (Europe)

Fuel consumption Tahoe

Post by Daniel79 »

Hi everyone,

I'm planning the build of a Tahoe 23 and all the costs that come with it. Right now wondering what motor to choose.
I need to consider a few things:
- purchase price (maybe a used engine
- horsepower
- fuel consumption at cruising speed and top speed

I need advice on what motor to use, if I should consider a used motor and what I can expect on the consumption of fuel. Fuel prices in the Netherlands are much higher than in the USA.
I would love for instance a mercruiser V8 because those sound awesome. But you might have other/better ideas.

Would love to hear them.

Many thanks,
Daniël.

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Bill Edmundson
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Re: Fuel consumption Tahoe

Post by Bill Edmundson »

Daniel

This may not be a help. I have a 20'-6"(6 meter) Tahoe. I run a 125 metric hp Yanmar diesel. It will run about 61 kph. We ran from Hales Bar to Chattanooga TN at the Gathering. That is about 120 kilometers. I used about 20 liters. I was in shock about how little it took.

If you do go diesel, there are other things to consider. We can talk about that when and if you want to go that way.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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Mr Hot Rod
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Re: Fuel consumption Tahoe

Post by Mr Hot Rod »

I agree with Bill -- diesel would make sense.

A UK builder, Rupert, installed a Ford PUMA 2.4 litre 4 cylinder marine turbo-intercooled diesel in his jet-powered Mist Miss.

Check out this thread :
____________________
Paul Kane
Kane Custom Boats Ltd.
Chelsea, Quebec

Building the Glen-L Hot Rod : http://www.kanecustomboats.com

Glen-L Boat Video Directory : http://www.kanecustomboats.com/pages/vi ... ctory.html

Daniel79
Posts: 38
Joined: Sun Sep 21, 2014 9:37 am
Location: Netherlands (Europe)

Re: Fuel consumption Tahoe

Post by Daniel79 »

Hi Bill and Hot Rod,

Thanks for your replies. Diesel does make sense to me too. But it will need to be turbocharged I think.
120 km on 20 litres is very acceptable. At which speed did you run, Bill? Such a trip would cost me 30 euro's. If I go on the consumption numbers of a V8 they use far more an hour. I believe even up to 40- 50 liters per hour...

I am rather familiar with car engines. These are far easier obtainable here than marine engines. If I only run my boat in fresh water, are there drawbacks on a marinised diesel turbocharged engine opposed to a true marine one? Can the horsepower on the road be directly translated to water when marinised? Or does an engine loose or gain horsepower during this process?

Grt Daniel.

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Bill Edmundson
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Re: Fuel consumption Tahoe

Post by Bill Edmundson »

Daniel

On the way up, we ran about 40 kph. against the current. Coming back, we ran about 50 kph.

My little diesel is a turbo model. Diesel doesn't have the engine compartment fume issues the gasoline has. I don't know if you would need to go to a marine, sealed, started and alternator. One key is engine rpm/gear ratio to give a shaft rpm of at least 3000 rpm.

At the time, all I could find in a down angle gear was 1.23:1 ratio. they now make a 1:1.

I was at 160 hp. It turned 3400 rpm. I couldn't make the hp/gear/prop combinations work. The dealer suggested the 125 hp that turns 3900 rpm and weighs 300 pounds less. The hp:weight ratio of the boat didn't change much. And, it cost a lot less.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

Daniel79
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Joined: Sun Sep 21, 2014 9:37 am
Location: Netherlands (Europe)

Re: Fuel consumption Tahoe

Post by Daniel79 »

Hi Bill,

those are very acceptable speeds for me. I expect a Tahoe to plain at about 20-25 KPH?
What do I have to expect to pay for a Yanmar or similar motor like you have? Did you start of brand new or with a used motor?
Apart from the motor, the gearbox is the biggest cost I believe? Am crawling around the internet but there is little info (wich I can understand) to be found.

Grt. Daniel

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Bill Edmundson
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Re: Fuel consumption Tahoe

Post by Bill Edmundson »

Daniel

The Yanmar is very expensive here. I bought mine in 2006. I think mine was made somewhere near you. Price could be much different.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

Daniel79
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Location: Netherlands (Europe)

Re: Fuel consumption Tahoe

Post by Daniel79 »

Have looked at various dealers in Europe but the Yanmar you have in your boat costs about 23K (euro's) That's an awfull lot of money.
I think I would rather buy a used motor which doesn't put a hole the size of the moon in my budget.
I know building a boat doesn't come cheap but this might strech the budget a bit too far.

Or am I competely delousional (might have the spelling wrong...) on what the hardware was gonna cost?

Daniel79
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Location: Netherlands (Europe)

Re: Fuel consumption Tahoe

Post by Daniel79 »

For instance I can buy a used Mercruiser 5.7 V8 (500 hrs) for 4K (euro's).
Or a new 5.0 V8 for 8.5K (euro's)

With the difference for the new Yanmar I can run the Mercruiser 5.7 for about 270 hrs at max RPM.
That's about 34 weekends continuous boating I think.

So the big question now is.... Do I choose a new engine which has a much lower fuel cost but a high price or a used engine with much bigger fuel costs but also the loads of funthat come with a big V8.

What to do, what to do.....

:P :P :P :P :P

Daniel79
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Location: Netherlands (Europe)

Re: Fuel consumption Tahoe

Post by Daniel79 »

Oops....
I miscalculated. :? Or rather I took the fuel consumption of the 3.0 Liter Mercruiser.
For the 5.7 Liter I can run the motor for about 137 hours at full RPM.

Still the question remains. What to do...
New or used, Big gasoline or smaller diesel?

Who has the solution for this big dilemma?

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Bill Edmundson
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Re: Fuel consumption Tahoe

Post by Bill Edmundson »

Daniel

I had the same question. I like the engine. But, I'm not sure that I made the right choice on the tradeoff. I just through out the diesel as an option over there.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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mrintense
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Re: Fuel consumption Tahoe

Post by mrintense »

I am having a similar dilemma on the outboard side of things. My boat is rated from 35 to 125 SHP. My cheapskate side says to buy a smaller motor for gas savings, say a 70 or 90 HP model. But I keep thinking of Bob Maskel and his 115 on his smaller Sea Knight and I keep thinking that I should go that route as well.

I am planning on an Evinrude E-Tec most likely regardless of the size.
Carl

Crafting a classically styled Vera Cruise

Clipper Boating

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kens
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Re: Fuel consumption Tahoe

Post by kens »

In reality, it is the hull that determines the fuel consumption, not really the engine.
It requires a certain amount of gasoline to push, say, a Tahoe at 25mph.
Doesnt matter if you push a Tahoe 25mph with a little 3.0L 4cylinder, or, a 350 V8. The fuel consumption would be about equal IF the same hull was moving at the same speed.

It all changes though when you go to WOT. In this case the V8 would burn about 100% more fuel than the 4cylinder, for about 50% more speed.
Oak..........the juice ain't worth the squeeze :D :shock: :o :)

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Bill Edmundson
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Re: Fuel consumption Tahoe

Post by Bill Edmundson »

My numbers say that after 40 mph it takes 2x hp to get another 10 mph. I would need 250 hp to get to 50 mph. That is also considering the additional engine weight.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

Daniel79
Posts: 38
Joined: Sun Sep 21, 2014 9:37 am
Location: Netherlands (Europe)

Re: Fuel consumption Tahoe

Post by Daniel79 »

Hi Kens and Bill,

I'm sorry but I cannot imagine that a big 5.7 liters uses about equally the same fuel to push a boat a certain speed as a small 3.0 liters engine. Or is it so that the big motor uses more fuel at the same rpm as a small motor but at that rpm the big motor makes the boat go faster

Bill, your explanation sounds familiar. I don't necessarily want the Tahoe to go 60 mph. Is that even possible without breaking stuff?

In my case it probably will come down to the amount of money I can spend and that will most certainly not be enough for a new engine of €15K +. I am however convinced that I don't want a marinised car engine. To much hassle to make such an engine suitable for boats. And there are very few (if any) places in The Netherlands where you can find these special parts.

Grt Daniel.

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