Builders Plans for Mini's ??

[Rollbar]

In you all's opinion, what are some reputable building plans on the market for a mini being constructed out of Aluminum, (12' x 7'6" or even 8').

Thanks,
Jim

[Rollbar]

I found the Lake Buggy http://www.airboatfun.com but it would have to be modified to 12'x7'6"/8'
Could make it out of aluminum.
Would the Rotax 532 be to much for it/2 people/gear?
Also with the added width 7'6"/8' can I run deep water since I'm thinking () that with the displacement I shouldn't sink or is that a misnomer and only applies to deep sided/taller gunnels/hulls.

As many know, here is the look of the Lake Buggy. But just a reminder if need be with the comment of the Rotax mounted to it.


Also found these sets of plans:
http://www.boatdesigns.com/Airboat-P...uctinfo/61-400

http://www.clarkcraft.com/cgi-local/...item=932672436

Not much out there or my search button isn't working right but this is all I found.

[fresh water hunter]

the 532 with a gearbox would work great with 2 people your boat with that motor for deep water will need at least a 5 ft bottom 6 foot would be enough for deep water width at the top will depend on your propeller length for the engine combination you us i us 20 in. deep sides for deep water here in michigan deep being 10 ft plus

[Rollbar]

Thanks. After talking to some I was thinking it I go 7'6"-8' I could run deep water and maybe some dry. ??

Motor in question.

[Papee]

Thats getting a bit wide for a mini. If you have your motor and prop figured out you really don't need anything wider than the prop length plus 6 inches, anything over that is just adding weight. A five foot bottom minimum is a must, That's five foot not including chines if you use them.

[Rollbar]

Thats getting a bit wide for a mini. If you have your motor and prop figured out you really don't need anything wider than the prop length plus 6 inches, anything over that is just adding weight. A five foot bottom minimum is a must, That's five foot not including chines if you use them.

Ok thanks. I was just going by the fact that I was told a low gunnel boat was not good in deep water so I fugured a wider one IF I was to build a kit like mentioned would be best and not as easily sinkable etc. if I was caught in some deep water if that makes since.

[Papee]

You need to decide what you want to do with the boat. Ride boats are much different than a boat that is used for fishing or bow fishing. High gunnels are good for a fishing boat. If you are hauling a passenger most of the time you need more length to spread the weight out. Minis are not like the big boat in that respect, with the bigger boats you just throw a bunch of horsepower at it and it doesn't matter how much water it takes to float it. You have enough thrust to overcome breakover.

A mini has to be built efficient so that the lower horsepower can get the hull past the breakover point and on plane. It takes more thrust to get the boat over this breakover point than it does to keep it on plane.

[Rollbar]

You need to decide what you want to do with the boat. Ride boats are much different than a boat that is used for fishing or bow fishing. High gunnels are good for a fishing boat. If you are hauling a passenger most of the time you need more length to spread the weight out. Minis are not like the big boat in that respect, with the bigger boats you just throw a bunch of horsepower at it and it doesn't matter how much water it takes to float it. You have enough thrust to overcome breakover.

A mini has to be built efficient so that the lower horsepower can get the hull past the breakover point and on plane. It takes more thrust to get the boat over this breakover point than it does to keep it on plane.

Here is my plan/what I'm thinking. 12'x7'6" (at least), hauling two people (400lbs max), then fuel 15-18gl, then a small cooler and maybe two fishing rods or a small 2 man tent in case we get stranded etc.
I would like to have the boat for riding and hanging out as well as a few other things mentioned but not a dedicated fishing boat etc. I really would like to run some dry IF I had to so I won't get stuck and there are some places I need to cross to get to more areas etc. I have seen mini's run dry to cross some places etc. I was going off the fact that wider is my friend from what I learned but I have to try to understand this whole thing. I even mentioned to my wife that by the time I purchase the Rotax and add the 4 bladed prop, I could get a 6cyl car motor and a prop for the same price if not cheaper (I'm torn right now) and maybe more HP/Torque and I'm thinking it will fit on a 11'/12' boat. I also talked to a boat mfg (Alumitech I think) about their 12' boat that is light weight he said, and I'm just checking out all my options and trying to figure out what's up.
So riding mostly and if I have to pop a hog, well, but not any major fishing because I like salt more than fresh water fishing. Hope that is clear as mud because I'm still on the fence as far as power goes.
Some have said in reading some posts that if one goes v6, they might as well add the other two cylinders and go v8 but I was checking the fuel consumption on v8's and the v6 and it is from 6-10mpg for direct drives and I can't afford a reduction set up-yet.
I just don't want to settle etc and I was thinking of the Lake Buggy and expanding it and since I would have a base set of plans, I could modify anything including sides etc. I'm still searching and trying to nail something down and as new data comes in, it gets more confusing.
But like you said, I need to make a decision and move towards that. I guess not knowing anything is keeping me from making a decision and then regretting it but YOU ALL have helped me very much and some have said that there is a April meet up/run and to go check out the different boats and ask for a ride on a few different ones.

Signed,
I'm trying, and please continue the help,
Jim

[Papee]

Those videos of the minis running dry confuses people. Sure there are those videos out the hauling multiple people across dry ground. the thing is they are not designed to haul more than one person and they are posted in best conditions for running dry. If you build a mini that will perform well in the water it is not going to run dry. My boat will move around in the yard some but I would in no way say it runs dry. If you were to try to cross a short span of land it would do it maybe with one person. If it's up hill or uneven ground you may end up pushing. We're asking a lot of these setups just running well on the water, running dry ground is pushing it.

It sounds like you need to build the hull you need and work up to the end motor setup. Airboats wether mini or full sized arent cheap. Even though you are building a mini you still need all the expensive parts to make it complete such as rigging, controls etc.

[Rollbar]

Those videos of the minis running dry confuses people. Sure there are those videos out the hauling multiple people across dry ground. the thing is they are not designed to haul more than one person and they are posted in best conditions for running dry. If you build a mini that will perform well in the water it is not going to run dry. My boat will move around in the yard some but I would in no way say it runs dry. If you were to try to cross a short span of land it would do it maybe with one person. If it's up hill or uneven ground you may end up pushing. We're asking a lot of these setups just running well on the water, running dry ground is pushing it.

It sounds like you need to build the hull you need and work up to the end motor setup. Airboats wether mini or full sized arent cheap. Even though you are building a mini you still need all the expensive parts to make it complete such as rigging, controls etc.

I guess I might be trying to fit to many things/functions into one boat. We have a few places that are made/airboat bridges, to cross to new areas and I just want to make sure I can do that, if not, to proceed, I will have to go back to the dock and put in upstream/river/swamp etc. I have been reading on how the car motors need to be forged parts etc to last and that can get expansive etc.
Thanks again, for the help,

[Rollbar]

Watching your videos now Papee.

https://www.youtube.com/watch?v=_HksaKif8yA

[Rollbar]

My wife is looking up aluminum and I told her we want the boat 7' wide.

So I told her to get two smaller pieces and we can weld the seam to get our width.

Question, do you weld the center/seam to get your width? Or do you get one 5' piece of 6061 (or ?) and then weld two sides to that and bend it up (I don't have a break).

Just wondering how you go about that.

Thanks,
Jim

[fresh water hunter]

weld the seam then you cut your sides and transom to the height you want and the front rake and weld it all together you can put a bend in the side to increase side strength if using thinner aluminum

[Rollbar]

OK thank you.

Question, has anyone tried (after welding a center seam) to just roll up the sides to the desired height as one continuous piece?
Not sure if it can be done-but I guess it can if you have the people and jigs.

The chime will be rounded and to my thinking will not bite in a turn but you will slide more.

Am I missing something?

[Papee]

I don't care for length wise seams in my builds but that is up to the builder. Length wise seams are not as strong as a width seam. As far as the chines, this really depends on your riding area and experience. If you ride in an area that has tight turns you either need the inverted chines or a hard chine. A rounded chine id the hardest of the chines to drive. they do not turn as well as a chined boat or even a hard chined boat. With a hard chined boat when you slow to corner the boat settles into the water allowing better turning. A rounded chine boat will have the rounded part no matter what part of the hull you are using in a turn.


Also if you are using the seam up the length you have the bow taper and rake to deal with.


Edit: I see you are asking this question on the other site and getting different answers. This is why I created this site, because information gets confusing. A center seam can be done as per the example there. That was a deckover boat and probably also had poly on it. Mini airboats are built different to save weight and help performance. First you need to decide which hull you want to build, a full sized big motor hull or a mini airboat hull.

[Rollbar]

I don't care for length wise seams in my builds but that is up to the builder. Length wise seams are not as strong as a width seam. As far as the chines, this really depends on your riding area and experience. If you ride in an area that has tight turns you either need the inverted chines or a hard chine. A rounded chine id the hardest of the chines to drive. they do not turn as well as a chined boat or even a hard chined boat. With a hard chined boat when you slow to corner the boat settles into the water allowing better turning. A rounded chine boat will have the rounded part no matter what part of the hull you are using in a turn.


Also if you are using the seam up the length you have the bow taper and rake to deal with.


Edit: I see you are asking this question on the other site and getting different answers. This is why I created this site, because information gets confusing. A center seam can be done as per the example there. That was a deckover boat and probably also had poly on it. Mini airboats are built different to save weight and help performance. First you need to decide which hull you want to build, a full sized big motor hull or a mini airboat hull.

Thank you very much. Yes I did ask on the other site and just looking for more info/opinions. I do hold the knowledge of the min's here though. The reason I asked about the center seam is that I was thinking in my mind of it being a weak park of the boat but then some disagreed and then I got to thinking etc.

I did watch your hull videos and learned and while I was at the center seam question I thought about rolling up the sides etc. There are parts here whereas it is tight then opens up and I have watched videos on that. Being the possibility of me building a first boat, I was looking for ease of the build and less welding but I see that might not work unless I actually put a seam/small Tbar on the rear section of the hull to grab corners to turn tighter. Maybe a 3' piece (wonder if that has been done) riveted maybe just above the water-line or at to help in a turn. I appreciate all the help and answers and I'm just going at this now so when I do start, I won't need to stop/turn back etc.

Thanks again for the help,
Jim

[Papee]

There are lots of builds here to follow progression. If you're on the first build a long seam probably isn't the best choice. It's difficult to weld a long seam and have no deflection in the material. Most of the builds are made from 5' wide material to save money. If you are building a wider hull with a wider bottom the sheets can be bought is a wider sheet. Since you have access to a bender I would also recommend putting a "Z" bend in the gunnels to strengthen them. There really isn't a set of plans that covers everything. As said, you have to determine what you want to do with the boat. Corky and I are using these boats for mainly fishing. This means we want a nice sized bow platform and a front rake that allows the boat to be stable while fishing from the front deck.

I like to make my bottoms in two pieces creating the "step" where your boat will ride on when on plan. This creates a little vortex at the leading edge of the step to make the bottom more efficient. The Transom bottom is not flat but slightly arched to add strength and also allow the boat to slide. Most hulls are not rectangle shape, same width from front to back. The hull usually tapers from back to front. The taper is decided by your bow arch. The taper starts where your bow starts to arch up. It's pretty simple, you decide on the rake/bow arch you want and draw it out, this will tell you where your boat will start to narrow.

[Corky]

I agree with Papee on a few key points that really are the determining factors on what route you're going to take...Are you an experienced aluminum welder ??? If not don't plan on welding that center floor seam and not have trouble...If by some stroke of luck you get the perfect penetration and would'nt have any leaks the chances of bottom warpage are very great.. The sidewalls will already be standing...You'd need some serious bracing for the sides and the bottom panels to try and keep the warpage in check..If you warp the bottom the T bars or C channel welding will be a nightmare...

Another point to make that the florida airboaters don't need to worry about...If you're planning on running any terrain other than vegetation or sand that bottom/sidwall bend is going to take the majority of hits as you run across debris diagonally and will eventually need some touch-up welding...I'm speaking from experience with that...

And lastely anyone just learning to weld will appreciate the "lip" where you stand the sidewall on the floor sheeting creating a ledge to weld to...Makes it easier to fix mistakes and you now have a thick seam where you need it ...

There's two mini's here that have the welded center seam and both are running rotax engines ...But these guys are experienced welders and have made the wrong choices to get where they are now...

I'm not saying which build is good for you I just need to stress these points so you can make an educated decision on which route is yours....

[Rollbar]

I like to make my bottoms in two pieces creating the "step" where your boat will ride on when on plan. This creates a little vortex at the leading edge of the step to make the bottom more efficient.

Can you show me in a diagram where the step would be?

The Transom bottom is not flat but slightly arched to add strength and also allow the boat to slide.

How many degrees and how far up from the back edge of the boat?

Thanks,
Jim

[Rollbar]

I agree with Papee on a few key points that really are the determining factors on what route you're going to take...Are you an experienced aluminum welder ??? If not don't plan on welding that center floor seam and not have trouble...If by some stroke of luck you get the perfect penetration and would'nt have any leaks the chances of bottom warpage are very great.. The sidewalls will already be standing...You'd need some serious bracing for the sides and the bottom panels to try and keep the warpage in check..If you warp the bottom the T bars or C channel welding will be a nightmare...

Another point to make that the florida airboaters don't need to worry about...If you're planning on running any terrain other than vegetation or sand that bottom/sidwall bend is going to take the majority of hits as you run across debris diagonally and will eventually need some touch-up welding...I'm speaking from experience with that...

And lastely anyone just learning to weld will appreciate the "lip" where you stand the sidewall on the floor sheeting creating a ledge to weld to...Makes it easier to fix mistakes and you now have a thick seam where you need it ...

There's two mini's here that have the welded center seam and both are running rotax engines ...But these guys are experienced welders and have made the wrong choices to get where they are now...

I'm not saying which build is good for you I just need to stress these points so you can make an educated decision on which route is yours....

Thank you. I like the multi seam and not center seam after this discussion. Seems to not contribute to multiple potential problems.