Kubota Diesel Mini Airboat - Will it work? - What Prop?

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

Slidin Gator wrote:
Thu Oct 15, 2020 11:59 pm
How much is this prop?
I found a few IVO props for around $200-$300. I have since then gone another direction with the prop. I have 3 blade Powerfin hub on the way. And I found a slightly used 5 blade 65in Powerfin propeller with B blades that I also have on the way. Im going to use three of the five blades at first. If I want to try a smaller size after that I can send the other two blades to Powerfin and have them shortened and buy the third blade. Or if I want to try 4 blades, I could just get a 4 blade hub and two extra blades. So the versatility will be nice. The five blade hub that comes with the propeller is 4in Rotax 6 bolt pattern instead of 75mm. So I can't use that hub without changing prop adapters.

edit: Also this powerfin prop is rated to 3500 RPM max.
waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

I started putting together a trailer, and got the boat inside now. I got my prop and adapter. After loading it on the trailer I was able to get a look at the bottom. The right side, mainly towards the rear has a lot of cracks :shock: How bad does this look guys? Im hoping to get the trailer wrapped up this week and maybe be ready for a test run next weekend or next week sometime.
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waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

One more pic of the cracks
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waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

Couple pics of the trailer
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waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

Pics of the trailer.
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New 4in Drop axle and leaf springs
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45 degree braces at the fender mounts
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waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

Bunks Mounted
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I painted it with Rustoleum 7000 cold galvanizing zinc compound through an hvlp gun.
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waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

Bunks are carped and boat is on the trailer.
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Prop is on!
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Another of the prop
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The prop is a 63in 3 blade Powerfin with B blades. When I first put it on I started with 14 degrees and it only revved to 1250 RPM. So then turned it down to 8 degrees and it revved to 1580 RPM. Then I turned it down to 4 degrees and it revved to 1970 RPM. This is all with the stock engine besides the turbo. I'm working on adding more fuel and boost now. I haven't run the boat off the trailer, but I did pull it back about 2ft on the trailer and it could push itself forward with nobody on it. It runs super smooth with the prop on. Before the prop was on I had the idle set at about 1000RPM because the engine ran rough in the lower RPM range. Now with the prop on I can turn the idle down to 700 RPM and it runs smooth as could be.
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Rick McC.
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by Rick McC. »

Good work!
"Sights are for the unenlightened."
Rick
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waikiki sneaky
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by waikiki sneaky »

Little update incase anyone was wondering. I swapped a injection pump with the barrels turned to the max and added a heavier governor spring. I also swapped in a 2 blade powerfin hub, instead of the 3 blade and I adjusted the valves which where off a little. With this setup and disconnecting the waste gate it turned 2350RPM with 8 degrees of pitch, and 2550 with 6 degrees of pitch. I have the head off now, I ported it and am sending it off for a valve job (valves were leaky, tested with pb plaster and they leaked immediately). I also am sending the injectors in to be bench tested and adjusted if necessary. While I got it apart I also found a cam out of a D1105 T, which is suppose to have a little more lift or duration than the stock D1105 Cam. Hopefully I can get it back together soon!
SWAMPHUNTER45
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by SWAMPHUNTER45 »

Chuck would have loved to offer up advice on this build.

He did a lot of alternate power mini boats from Harley Davidson to EcoTec

Good luck with the boat and the trailer looks great.
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OneBFC
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Re: Kubota Diesel Mini Airboat - Will it work? - What Prop?

Post by OneBFC »

Your turbo won't last too long without the waste gate limiting the turbine RPM.

Recommend you start saving for a larger turbo now. You will want about 10lbs/minute air flow per 10hp of power @ the pressure ratio thats appropriate for the engine displacement.
-Russ
-----------------------------------
The only thing stopping you is FEAR
400+hp Ecotec, 12x7.6 DBDO, 80" 3B Maximus, 2.3 OX,85+mph, water = purely optional
Life begins at 2 BAR, Just a good ole boy
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