Powerboat Fuel Efficiency

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fpjeepy05
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Re: Powerboat Fuel Efficiency

Post by fpjeepy05 » Fri Aug 23, 2019 10:18 am

jacquesmm wrote:
Fri Aug 23, 2019 9:55 am
Those boats are very narrow and that is what makes them so efficient.
I can guess what will happen if I design one, remarks like: "I like the boat but can we make her wider?"
If they want a wider version there are thousands to choose from... I think it would be ideal if you could design the boat so that the sole went over the engine. In which case you have a great excuse to not change the design. If it gets wider it needs more HP and then the engine will no longer fit.



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Re: Powerboat Fuel Efficiency

Post by cracked_ribs » Fri Aug 23, 2019 11:03 am

I find boats of that sort very beautiful and I commute by boat five days a week for a lot of the year; I am basically the ideal target market for such a boat.

I can sum up the reason I would not build or buy one in a single word: moorage.

In a tight bay, a thirty foot boat is going to sweep out in a big circle and that limits the spots I can put a mooring. The only practical place for me to leave it is at a dock, where I'm now paying for a thirty foot slip, in which I keep a canoe. For the same money, I could keep a small floating apartment or a serious offshore fishing monster in that space. Or, I could not rent thirty feet of dock space but just twenty, and have an extra $1500 a year to spend on fuel, in which case I can totally afford to run a more conventionally proportioned boat which will do more than just commute. Or I could trailer it easily, or leave it on a mooring in a spot that's convenient and spend nothing on slip fees and have five thousand dollars a year to play with and burn gas on a twin outboard deep V.

This is the problem that the skinny commuters always run into...they're very fuel efficient but hard to trailer and expensive to store, and they only really do one thing well.

Meanwhile, even though for my entire life I've been hearing predictions about how more efficient, practical powerboats are about to become super popular, Suzuki now makes a duoprop 350, Yamaha has half-ton 425s and Mercury is up to what, 450hp outboards? Block-long centre consoles with two or three big motors are the most desirable boats and borrowing money is cheaper than ever so the guy framing your house drives a Cummins powered 3500 and tows a Contender to the beach on the weekends.

I don't think we're really on the verge of a big shift to narrow, efficient boats. That's a real niche market for ex-sailors. And self-built efficient boats (because let's be honest, building your own boats is not cheap) is a niche of a niche.


All that said I think Jacques' Tina comes FAIRLY close to what you are asking for. It's not ultra narrow but it's narrow, and the lines are from a time when lower power was common.

fpjeepy05
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Re: Powerboat Fuel Efficiency

Post by fpjeepy05 » Fri Aug 23, 2019 1:18 pm

I totally agree, and it makes me very sad. Minimalism is nearly non-existent in America. Just because you can drive a 3500 pickup doesn't mean you should. Boat ownership in America is sad in itself. Average recreational use in America is 80hrs/yr. The amount of resources that goes into something that gets used so little and then is thrown in a landfill is disheartening. I want a fuel-efficient boat because I want to burn less fuel. Not because I want to save money. If other people had the same thinking as myself, there would be marina's that were selling narrower slips at a discounted rate. But what is happening is exactly the opposite. The marina I used to be in is being torn down and rebuilt with slips for "modern" boats i.e. wider. I saw an 18fter with 8'6" beam and a 350 on it the other day.

All that said, just because no one else is doing it isn't going to stop me.

Also can you add a link to "Jacques' Tina"? I couldn't find anyting on google.

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Re: Powerboat Fuel Efficiency

Post by cracked_ribs » Fri Aug 23, 2019 1:23 pm

viewtopic.php?f=8&t=64118

It's a new design here which is shorter and wider than either boat you've described but a relatively modern boat by current standards, while still in a hull shape that I would consider pretty multi-purpose, but which I would expect to run quite efficiently at moderate speeds.

fpjeepy05
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Re: Powerboat Fuel Efficiency

Post by fpjeepy05 » Fri Aug 23, 2019 2:23 pm

That is a cool boat. I personally am still stuck on not excessing 45hp

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Re: Powerboat Fuel Efficiency

Post by jacquesmm » Fri Aug 23, 2019 2:33 pm

The original Tina was fitted with a big V8!
It is difficult to imagine a 25 to 30' hull that would move about 8 knots with 45 HP unless we go for an unusual beam to length ratio.
Jacques Mertens - Designer
http://bateau.com

fpjeepy05
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Re: Powerboat Fuel Efficiency

Post by fpjeepy05 » Fri Aug 23, 2019 2:51 pm

Agreed. I would plan for a beam of around 60". More or less depending on the flare in the hull.

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Re: Powerboat Fuel Efficiency

Post by cracked_ribs » Fri Aug 23, 2019 3:16 pm

If you're really set on those parameters, but you can't find an older design you can adapt to modern build methods, then I think your options are either design it on your own, or hire someone to do the design work on a custom basis. They're interesting boats, the skinny commuters, but I think it will be hard to find pre-existing designs for the reasons I laid out earlier. They won't sell more than a few copies and I would think most designers doing stuff on spec would want to sell hundreds of copies of the plans to recoup the time they invest.

But if you find something I would be interested to see it, just out of curiosity.

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Re: Powerboat Fuel Efficiency

Post by fpjeepy05 » Fri Aug 23, 2019 3:45 pm

If I can't find a set of plans that I can modify, I will likely design it myself and then pay a designer to review for errors.

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Re: Powerboat Fuel Efficiency

Post by fpjeepy05 » Fri Aug 23, 2019 5:29 pm

a friend just sent me this listing... https://miami.craigslist.org/pbc/boa/d/ ... 41647.html
Different, but similar.
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