boat wont get up on plane... super slow

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
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nick78
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boat wont get up on plane... super slow

Post by nick78 »

I had never driven an airboat 3 weeks ago, but I now drive one for work a few times a week. I'm am getting used to the setup but I think something needs tweaking... or maybe I should (or have to) just live with it? Its around 16' and has a small block chevy. seems like it should have tons of power, yet it tops out around 8mph when I'm fully loaded. I'm thinking my problem is the weight I have to carry around. I have 1 or 2 other people on the boat with me and I'm guessing about 800lbs of cargo...
I cant carry less "stuff" so do I just need to live with it? I am mostly just driving at idle speed anyway, but It would be nice to jump from one spot to another quickly... Or should I be able to get up on plane with that much weight in the boat? I'm sure you guys need a dozen other specs that I don't have right now, but if you let me know what other variables are needed to answer my question, I will get them for you. Thanks guys, I love the forum!

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lilly-Pad
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Re: boat wont get up on plane... super slow

Post by lilly-Pad »

Welcome to SA, easiest way would be to post pics of your setup (picture is worth a thousand words).
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slidingforhogs
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Re: boat wont get up on plane... super slow

Post by slidingforhogs »

Well question is does it have a gearbox on it , what is the max rpm your turning , what size prop is it and pitch? We need to know alto more details about what u have,. I know if its a direct drive its not going to get on a plane up with what you have already posted about,, help us so we can help u bro,,,
11'7 gore ,
220 gpu swinging a woody...

Stomp on it!!!!

nick78
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Re: boat wont get up on plane... super slow

Post by nick78 »

Thanks for the reply guys! Unfortunately, I won't be back in the office to check out those specs and grab a picture untill Tuesday. But that was the exact reply I was looking for, ie; what info do you need to help me. lol
So I will check into gearbox, which I think would look like a small tranny shape thing between the prop and crank? And prop info, I assume is labeled on the prop somewhere? I know it looks like laminated wood, 2 blades and has a metal edge. Probably stands about as tall as me... But like I said, Ill figure those things out for you guys and post some pictures after tuesday.
Thanks again!

mirage
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Re: boat wont get up on plane... super slow

Post by mirage »

I had that problem one time it was a check valve on the gas tank but I had two tanks.

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Deano
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Re: boat wont get up on plane... super slow

Post by Deano »

nick78 wrote: . . . So I will check into gearbox, which I think would look like a small tranny shape thing between the prop and crank? . . .
If there is or is not one there, it will be readily apparent either way. If there is not, and it is a direct drive, the only thing between the prop and the flexplate will be a prop adapter. Usually aluminum and two or three inches thick.
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CactusJack
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Re: boat wont get up on plane... super slow

Post by CactusJack »

It sounds like direct drive with a 2 blade laminated prop (depending on how tall you are) :wink:

I would think a 16' boat with a DD small block carrying 800# and 3 people would be the answer to your problem... not enough push for the load. Sounds like a big boat for not enough motor to me.

If it has a gearbox, perhaps the prop is not a good match :dontknow:

What hull is it? Poly? What small block? Is it wore out or new? How big/heavy are your passengers? (are they wore out or... never mind) :lol:

Like the others said... pics please :blackeye:
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nick78
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Re: boat wont get up on plane... super slow

Post by nick78 »

Image
Image
Image
Sorry I did not post these during the week, but work is busy atm... Here you can see the prop and, what looks like to me, a direct drive. Even when its not fully loaded, (just 2 people and maybe 200lbs of gear) it still does not want to get up on plane. I'm not sure if there is any room in the budget to purchase anything expensive, but any suggestions?

slidingforhogs
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Re: boat wont get up on plane... super slow

Post by slidingforhogs »

Yep d..d .. Sbc. With woody, , for that rig I see in the pic it def needs a gearbox And a much better prop. That setup is for mulling around as u were doing.. Not really much of anything you can do with the existing setup like it is....
11'7 gore ,
220 gpu swinging a woody...

Stomp on it!!!!

stonny9
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Re: boat wont get up on plane... super slow

Post by stonny9 »

I have to wonder how long they have been using the current setup. Did they just throw what was laying around together? Maybe the thought was slower is safer because of the "untrained" workers that would be driving it.

nick78
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Re: boat wont get up on plane... super slow

Post by nick78 »

The boat was purchased from another company who used it for the same purpose, which again included only slow speed trolling and carrying a load. I am assuming it was purpose built by them (or the manufacturer that built it) while not adding anything unnecessarily expensive, such as a higher quality prop and/or gearbox, since it is not "needed" for our job. The main boat operator has been driving commercially for many years.
I'm thinking I will have to wait until the prop needs replacement and then recommend a higher performance one and maybe then a gearbox would be in the budget! I could see something small like an X pipe in our near future to both quiet it down and add some HP, but I don't think that will make any difference in the ability of this boat to get on plane...
Edit- answered one of my own questions....

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