Guys look at this picture setup help!

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
cudacat
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Guys look at this picture setup help!

Post by cudacat » Fri Dec 18, 2009 10:49 am

Can you see the area between the prop and transom? It’s at least 20” if not more. What would the pros and cons be if I pushed my rigging back 20”?

I would have very little modification to do if I push everything back and I would like the extra room up front if it didn’t hurt the performance.
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16’ 8”x8’ Diamondback…..ZZ4 350…..2.3.1Beltdrive……..3 blade Falcon…….Texas coast

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CactusJack
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Re: Guys look at this picture setup help!

Post by CactusJack » Fri Dec 18, 2009 11:03 am

Nice pic, that can be my desktop pic for a while :wink:

Just my noob opinion, how does the boat sit, ride & run now? awsome? there is that old saying, if it aint broke, dont fix it, but I can imagine having that foot & a half of missing space to store stuff would be great to have back..... also the rudders might be better if the prop was closer.... actually, I guess it really would be good to move the motor back.

I see what you mean, it dont look too difficult to move the motor mount back & shorten the front half of the cage, I cant see from that pic if the last hoop of the cage will have prop tip clearance if the prop comes back to within a few inches of it.... the job might be a bit more fiddly than you think, but the outcome should be fine :bounce: :mrgreen:

Hopefully some of the experienced dudes will chime in & help you out.... I personally think it would be a good winter/off huntin season job for you to do, so it dont interfere with your huntin :shock:

I wonder who put the motor there and for what particular reason? where did you get the boat?

Good luck, take care

Edit: Oh, & by the way, I have been told on here that the proper... official way of setting prop-transom distance/clearance is as follows:
prop 1 beer can back from the transom..... tip 1 beer can below the top of the transom :lol: It dont matter what brand of beer, but you better go buy some and check for yourself :drunken: :mrgreen:
Last edited by CactusJack on Fri Dec 18, 2009 11:07 am, edited 1 time in total.
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Re: Guys look at this picture setup help!

Post by Whitebear » Fri Dec 18, 2009 11:05 am

In my mind its a win all the way around. It will change the boats handling some but its just working out the overall trim of the boat. Added room, plus your rudders will have more authority. If you have a trim tab now you may just find to trim the boat at whatever speeds the actual tab position may change a little one way or the other. I have always felt that triple roll cages were needlessly heavy and let the engine sit too far forward.

You have room to experiment if you want the tank to move with the rest or not it seems. I would do it were it mine. You can always move it back if you don't like it, but for me it would be worth the try. You have a bit to gain by doing it.

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T. Gaffney
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Re: Guys look at this picture setup help!

Post by T. Gaffney » Fri Dec 18, 2009 11:09 am

I saw this pic yesterday or the day before and was wondering to myself why the engine was so far forward? Traditionally, the prop is as close to the transom as possible. You want the weight to the rear as much as you can to keep the boat from running on its nose. You will have all around better performance. Cruise, top end speed and manuvering will all improve.

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Re: Guys look at this picture setup help!

Post by cudacat » Fri Dec 18, 2009 11:43 am

The boat runs good now. My cruise rpms are a little high but I am working on that with the prop pitch. The boat does start to porpoise a little bit approaching 38-40mph. but I can stop it with a little rudder movement. I bought the boat used last July and have been changing and adjusting things ever since. I think the reason it’s so far forward now… it may have had a different reduction on it that took up more space. (just guessing) if I do push it back the prop will have more room for the prop. The prop would be pretty close to the center hoop in the cage. I do like now when working in the cage I can walk from side to side behind the prop, but would be willing to give it up for performance.

Also I the picture I don’t know if you can tell or not there is a 30 degree plate on the transom. Does this hurt the performance ? I believe it’s to keep water out of the boat if you come to a quick stop in deep water. basically a back splash that stops the water….
16’ 8”x8’ Diamondback…..ZZ4 350…..2.3.1Beltdrive……..3 blade Falcon…….Texas coast

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Re: Guys look at this picture setup help!

Post by cudacat » Fri Dec 18, 2009 11:46 am

here is a picture of the 30 degree thing I call a splash guard
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Re: Guys look at this picture setup help!

Post by SWAMPCRACKER85 » Fri Dec 18, 2009 12:01 pm

Yea I would definately try moving the motor stand back a little...You said there's roughly 20"s of room? You can also try moving it all back half of that distance then bolt it in and run it to see how it performs say moved back the first 10"s then if it gets better then I would unbolt again and slide it back a few more inches to where you feel comfortable with how it rides and the performance...The closer you have your prop to the transom the more push you'll get from the prop and more turning response from your rudders...Hope this helps...Also that backsplash will not be a problem in this...Just check your tip clearance to the cage hoops and if it clears then you should be in the clear with it all...Hope this helps...
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Re: Guys look at this picture setup help!

Post by K-mac » Fri Dec 18, 2009 12:07 pm

Try it and see what happens. You can always put it back
if you don't like the results.
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Re: Guys look at this picture setup help!

Post by Waterthunder » Fri Dec 18, 2009 12:17 pm

When you ride on a plane where down the side of the hull does it start spraying off water! the front, the middle the rear! The further back you move the rigging the free'er she will run untill you go to far and then start to porpoise!
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Re: Guys look at this picture setup help!

Post by ffcracker » Fri Dec 18, 2009 12:33 pm

Looks like it may of had a counter-rotator on it at one time. move it back and see what it does. If it hops then move the stand forward around 3 inches at a time. Dont cut the exaust flex until it rides good and you are happy with the ride. this is a trial and error thing but in the end you will love the outcome.
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Re: Guys look at this picture setup help!

Post by cudacat » Fri Dec 18, 2009 12:35 pm

Waterthunder wrote:When you ride on a plane where down the side of the hull does it start spraying off water! the front, the middle the rear! The further back you move the rigging the free'er she will run untill you go to far and then start to porpoise!
I would say 2.5 feet or so in front of the drivers seat.
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Re: Guys look at this picture setup help!

Post by BigJakesrq » Fri Dec 18, 2009 12:41 pm

JMO, but if you move it back and you already having some porpoising issues they'll probably get worse. Though you would gain a lot by moving it back. I'm with everyone else move it back and if you find it porpoising too bad try shifting the gas tank forward or a mechanical trim tab.

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Re: Guys look at this picture setup help!

Post by T. Gaffney » Fri Dec 18, 2009 1:02 pm

cudacat wrote:
Waterthunder wrote:When you ride on a plane where down the side of the hull does it start spraying off water! the front, the middle the rear! The further back you move the rigging the free'er she will run untill you go to far and then start to porpoise!
I would say 2.5 feet or so in front of the drivers seat.
It's riding on its nose a little. I would definitely move it back and it should feel like a completely different boat.
I bet it sprays water out of the front a little when you put it in a turn...huh?
If it starts porpoising, don't automatically start moving it back forward. Check the bottom for an outside hook. Does the boat have jacks in it?

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Re: Guys look at this picture setup help!

Post by cottonmouth airboats » Fri Dec 18, 2009 1:38 pm

Everybody is right about moving it back but remember your going to have to do something about your cage bolting back up when you go sliding your engine stand and foot stand back 20". Doesn't look like you have enough room from the front of the cage to the rear of the drivers seat to go back to much further without doing some cutting or buying a new cage.

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Re: Guys look at this picture setup help!

Post by Aces over 8s » Fri Dec 18, 2009 2:52 pm

The cage might be separate from the engine stand? JMO
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Re: Guys look at this picture setup help!

Post by cottonmouth airboats » Fri Dec 18, 2009 3:12 pm

Aces over 8s wrote:The cage might be separate from the engine stand? JMO
Ok so when he unbolts the cage from the engine stand then pushes the engine stand and foot stand back whats going to happen?

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Re: Guys look at this picture setup help!

Post by yobee » Fri Dec 18, 2009 4:31 pm

He's got a little room before the seat stand hits the cage. If you say its spraying a foot in front of the driver seat then move that sucker back!
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Re: Guys look at this picture setup help!

Post by Daddy Dave » Fri Dec 18, 2009 6:11 pm

If you look closely at the cage - it looks to be twice too deep - it wold cover a 24" wide blade. There looks to be a foot between the seats and cage cone and another un-needed foot in the cage - but - if it ain't broke ... Good Luck ...
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Re: Guys look at this picture setup help!

Post by C1gator » Fri Dec 18, 2009 7:23 pm

I have to agree with Mr Gafney and WT, if it is spraying that far up on the boat, it needs to be moved back.....Just for the Heck of it, I would do a little research on the boat....If it was put together by a back yarder or novice, I would definately get to moving the rigging....If it came from a manufacturer like that, call them and find out why it is set up like that....Might save you a lot of work in the long run....JMO good luck......

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Re: Guys look at this picture setup help!

Post by hogdoggin » Fri Dec 18, 2009 11:38 pm

The way its set up looks like it might of had a couter rotating prop on it at one time.

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Re: Guys look at this picture setup help!

Post by air-roberts » Sat Dec 19, 2009 7:29 am

definitely move it back yea it had a different reduction at one time when it was built thats the new blue lightning beltdrive they really look good it's like one i was going to build years ago they just beat me to it how do you like it? but yes move it back until the center of prop is inline with where the transom and bottom comes together theres other ways to get porpus out
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Re: Guys look at this picture setup help!

Post by air-roberts » Sat Dec 19, 2009 7:30 am

definitely move it back yea it had a different reduction at one time when it was built thats the new blue lightning beltdrive they really look good it's like one i was going to build years ago they just beat me to it how do you like it? but yes move it back until the center of prop is inline with where the transom and bottom comes together theres other ways to get porpus out
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Re: Guys look at this picture setup help!

Post by cudacat » Mon Dec 21, 2009 8:50 am

cottonmouth airboats wrote:
Aces over 8s wrote:The cage might be separate from the engine stand? JMO
Ok so when he unbolts the cage from the engine stand then pushes the engine stand and foot stand back whats going to happen?

Guys, thanks for all the feedback. I am going tackle it right after duck season. It would be easy to push it back. There is a little piece of the cage right behind the divers seat that unbolts. I just won’t re-use it. All that little cage pcs does is wrap around the front of the engine and does not serve any purpose that I know but add weight and look good. Once I remove it I will gain a 18 to 20” and push the seats right up to the cage. The cage is separate for the engine stand. The only thing that worries me is I am pushing a bunch of weight back…….. the motor and a 80 gallon tank. from all yalls responses I need more weight in the back………..

I never figured it was running on it nose….. would a boat running on it nose porpoise at the faster speeds. Yes it will push a little water out front in a semi hard turn but still just thought it was normal. I hope by doing this it will affect my cruise as well….. by getting more boat out of the water it may have less resistance.

Yes the boat has 2 jacks. 1 about 25” from trans and the other 3 or so feet in front. I think it would be hard to get a hook in the bottom of this boat. it was way over built. It has at least 11 runners and had 3 I beam cross braces. I took 2 of them out to save a few ponds.

The belt drive has worked flawless so far.
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Re: Guys look at this picture setup help!

Post by yobee » Mon Dec 21, 2009 7:40 pm

After you slide it back, you can play with your engine angle a little bit, also check for a hook, as overbuilt as it may be it can still happen, possibly a dent or something between stringers, ya never know.
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Re: Guys look at this picture setup help!

Post by belly_up » Sat Jan 02, 2010 12:05 pm

Spent a lot of time in that boat. It did porpoise some at higher speeds but we would never run that fast very much anyways. I think you could just slide it back then maybe play with the engine angle some once you see what it does after moving the rigging.

It should be really easy to slide that all back, when we painted that boat we removed the cage and rigging pretty quickly.

That plate on the transom was put on there when it was still with the border patrol, I really dont think it is needed, my buddy runs a similar hull and we never have water come over the transom...i think its more for peace of mind..
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