23 ft Hartley Cabin boat repair/rebuild and hull extension

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magoo_za
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by magoo_za »

Hi Fallguy

I will send you a PM.

Tx a lot

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magoo_za
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by magoo_za »

Hi guys

Just an update.......got a new injector installed and she is running well. Will do a water test on Saturday, weather permitting and perhaps some fishing as well.

Cheers!

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magoo_za
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by magoo_za »

Hi guys.

Some figures with the new injector replaced. I will lift the motors up one hole as the anti-cavitation plate is not clearing the water surface on plane. Trimming up reduces the effect but I think one hole should do the trick. She has already received some nicks but all is holding up grand. I have an idea to add a rocket launcher type of pedestal with drawers in the near future and will update you as I build.

Cheers
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fallguy1000
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by fallguy1000 »

I decided awhile ago that speeds above 30 are hard to slow enough for hazards, so after that I become more interested in fuel economy. I'd be curious what your fuel burn would be just over the hump.
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magoo_za
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by magoo_za »

fallguy1000 wrote: Sun Jan 31, 2021 9:16 am I decided awhile ago that speeds above 30 are hard to slow enough for hazards, so after that I become more interested in fuel economy. I'd be curious what your fuel burn would be just over the hump.
Over the hump?🤔?

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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by fallguy1000 »

magoo_za wrote: Sun Jan 31, 2021 9:24 am
fallguy1000 wrote: Sun Jan 31, 2021 9:16 am I decided awhile ago that speeds above 30 are hard to slow enough for hazards, so after that I become more interested in fuel economy. I'd be curious what your fuel burn would be just over the hump.
Over the hump?🤔?
Get her up on plane and back it off, but stay up.

The hump is a top of a graphical place where the boat is performing poorly before she planes and is free. Fuel burn is lowest per mile just over the hump.

The picture here just past 10mph is the sweet spot.
42E191C8-2446-42F1-B78C-1168DB6C3F1C.png
Just for fun, rockets have a hump as well!
8CB680C9-AB62-4EBB-96F5-E6C4DCE83D0D.png
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magoo_za
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by magoo_za »

Eureka! Ok Now I understand. I will test this as she planes at around 38ish km/h running at 4000 to 4150rpms, if I recall it was at about 22l/ph. Once I have moved the motors up, reducing drag I will test the setup again and post some figures.

Cheers!

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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by fallguy1000 »

The goal of knowing is to learn where the boat gets the best fuel economy which is the highest mpg or for you km/l.

Many get hung up on gallons per hour or liters per hour, but that is meaningless because you don't know rate of travel.

Typically, one can understand the cheapest way to run the boat.

For semi-displacement hulls; generally lower speeds are better, but even they may have sweet spot which is understood by metering.

I don't see much value in metering for the Skoota, but it is so tempting.
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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by Fuzz »

With a GPS and a flow meter I found something strange on one of my boats. I only use 1/2 GPH more at 28mph than I do at 22mph. Did not seem right to get better mileage when going faster but there it was.

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Re: 23 ft Hartley Cabin boat repair/rebuild and hull extension

Post by fallguy1000 »

Fuzz wrote: Thu Feb 04, 2021 2:55 pm With a GPS and a flow meter I found something strange on one of my boats. I only use 1/2 GPH more at 28mph than I do at 22mph. Did not seem right to get better mileage when going faster but there it was.
Probably some major drag reduction between those two. Just a hunch, but interesting. I'm guessing plaing hull.
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