Builders Plans for Mini's ??

[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 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.

[Rollbar]

Question, for those of you who have built a mini and riveted the boat, what size rivets did you use and did you use a air rivet tool or ?
And, if riveted, did you use aluminum rivets or ?

Thanks,
Jim

I did fined this on HF:
http://www.harborfreight.com/1-4-quarte ... 98898.html

[Rollbar]

Also, I just bought the Lake Buggy 2 person plans and I am going to modify them and go from there/use them as a base or foundation as it were.

[Coyotes-R-Us]

I'm going to use rivets and glue on my cat.
But I'll going with round over rivets ,not blind rivets like your going with.

[Rollbar]

I'm going to use rivets and glue on my cat.
But I'll going with round over rivets ,not blind rivets like your going with.

Please link your build. Thanks for the tip. What glue are you going with?

[Coyotes-R-Us]

Still in a "planning" mode till I get my drive finished and prop.

Glue

Permabond ET538

Permabond TA4610

I will do pictures

[aerokirk]

For boat building I would definitely go with bucked aluminum rivets and not "pop rivets". The air riveter bucked rivets will not leak if done properly. JMO

[Rollbar]

For boat building I would definitely go with bucked aluminum rivets and not "pop rivets". The air riveter bucked rivets will not leak if done properly. JMO

Thank you-good point.

[Rollbar]

Question, would it be possible to skin the bottom of the stringers/runners with aluminum instead of wood while still using wooden runners?

If so, and screwing it down, what adhesive / glue would work with both wood/aluminum to make it H20 proof?

Note: Lake Buggy 2 build ideas to make it lighter.

[Rollbar]

Step Hull Questions.

Hull size: 12' x 7'6" (to maybe 13'6" x 7'6").

1. How far from the transom to edge of step
2. How deep should the step be
3. Should the step be square/perpendicular to the hull or angled toward the front some like a wedge cut
4. What should the pitch, or angle be, from the step back to the transoms edge
5. Does the transom height equal the same height as the boats sides just before the step/front of boat
6. Build Pics?

I plan to run shallow but not always/(never can tell what you get into etc).

Thanks for the help,

[Rollbar]

Since we were talking about build plans a question popped into my mind.

Question about the rudders.

Why do most rudder/length only appear to be 1/4 way above the center-line of the prop hub, seeing no real air flow is from the center of the prop?

Shouldn't the rudder be taller? The lower part of the rudder is fine, but the upper part being short, I don't get.

Are you only concerned with that much air flow across the rudder, or is more to responsive when the stick is moved etc.?

Thanks,
Jim

[Rollbar]

Ok as in the other post I made and posts that I have read to build the boat around the motor etc. Well I just bought a NOS 4a084-4 off eBay and my personal thanks for the continued help,

Jim

P.S. I decided to post again that I purchased this motor to make it clear what route I am going so there is no confusion if someone new reads this post/info in it.

[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

[Papee]

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



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

Thanks,
Jim

The step depends on how long your hull is,motor, seating arrangement, and weight
distribution. For the most part it is between 4-5 foot from the transom.

The transom arch will take care of itself as you lay the hull, it will become less naturally as you go forward.