Corky's Build

[Corky]

Thanks for all the kind words...And I want to thank everyone for all the advice and guidance on this build...I'd be lost without the help I've recieved here and I'm greatful...

This new Eastwood spool gun is working flawlessly and I'm getting better at it every time I'm using it...Now I can start to see trouble before it happens with the heat and simply stop before it's too late...I welded up the outside completely on one side and got about 3/4 done on the other side...Keep in mind I know I'll be hitting rocks so I've added a strong weld/edge where most of the rock bumping will be along the floor/sidewall seams...Here's what it looks like...

[Corky]

I tried to get a close-up of the welding seam but it did'nt come out the greatest...I kept the sidwalls back a touch more than 1/8th of an inch for the ledge making it easier to weld and what appears to be very strong...Keep in mind I used the stronger welding wire but it still seems to flow out nicely...I can only go about 2-3 inches at a time without getting nervous about the heat so that how I've been doing it...I know some good welders just take off and go but I'm just not that good yet......Anyhow I'll post the best pic I have of the welds so far...

[Corky]

I know most builds on here are using the 2x1 inch structural channel for the floor stiffening duties and I understand trying to keep the weight down...But the rock ledges on this river just keep going through my mind...I need this thing to withstand years of abuse...So when the time came to buy this stuff I compared the 2x1 structural channel to the 3x 1.5 and the added strength by just bumping it up one size was tremendous...I had a 20 foot section of each out and was flexing it and could'nt believe the difference with just 1 inch more....

To make a long story short I ended up with the three inch structural channel...OK before everyone looks at the weight difference I'll save you the time...The 2 inch structural channel is .6 per foot...The 3 inch structural channel is 1.6 per foot that's 42 lbs of added weight...BUT.......There's more......The 3 inch channel stands at 1.5 inchs tall...I don't need it to be that tall....So I cut the channel down to one inch tall...This sheds alot of weight on it's own and still retains more than enough structural integrity to do the job of keeping the floor in place much better than the 2x1 structural channels ever could...So I'm projecting with the reworked 3 inch channel I'm only adding about 20-25 lbs to the hull but have gained way more hull integrity.......I fully expect to hinge this hull over a rock at some point and want to be able to laugh about it and keep going.... When I start cutting the channel I'll weigh a 1 ft piece to see exactly where it is on the weight.....



Here's two pics first one is the profile of the original channel and the second pic is the reworked channel comparison to the original...Still a very strong channel...The close-up pics make the channel look huge but keep in mind the pics are real close and it's only 3 inches wide....

[kent]

Looking good, Corky
If you keep this pace.... you just might be ready for the river before all the "hard" water reaches Maryland !!!!
kent

[Corky]

I've been debating on just how low to make the transom dip down in the center...As usual every manufacturer seems to have theirs all over the place...Some are so low I have to wonder how the water does'nt come crashing over the back on the heavier boats...

Any thoughts on this and how it pertains to a mini build ????

[Papee]

It's not really needed on a mini. With the weight of the engines we are using there is just not that much weight up high to be concerned about. It's not like the bigger boats with 500+lbs up there. I put one on the green boat just in case we decided on a bigger motor later. It just gives you more options down the road.

Same deal with the tray, it's really not needed on most minis because they glide a while after shutting down the throttle if set up correct. The tray is another thing that is an easy addition. It also gives you more options for rudder mounting when there.

edit: Just for the info for others, the dip in the transom is to allow more prop clearance. This allows you to lower the engine. While we're here, I also advise to keep the whole prop above the transom. On the bigger boats with more horsepower they sometimes put the prop 3"-4" below the transom. On a mini you don't want any disturbance of the prop at all to get the most out of your prop as possible. Keep the prop at least even with your transom.

[Corky]

Thanks Papee... I'm going with at least a small dip just for looks...Same as the tray...I like the look of both back there...I guess it really comes down to what transom height the builder is comfortable with for the conditions they'll be running the boat in....I hate to say it but the heaviest thing up high is going to be me ! Oh well at least I'll be happy...

[Papee]

If you look at the green boat there are flat spots then the dip. No need to dip from end to end. Just stand back and imagine where the prop circumference would be.

[Papee]

Do you have pipe for your drain plug? I have some extra here if you need it.


I still haven't been able to get in touch with Tom about the rail. I drive by every time I go that way and haven't seen him around.

[Corky]

Hi Papee yes I have the pipe for the drain plug its about a foot long so I have plenty...I might put one on each side of the center U channel just to make washing it out easier....

I knew you were'nt feeling well and a few weeks ago when the weather was somewhat better I did happen to catch Tom there at his shop...He's a tough guy to get ahold of.......He was more than helpful I ended up there for about 3 hours getting the grand tour on what he was building and a crash course on boatbuilding in general...Very nice guy...I lived in Millersburg for years and knew who he was and he remembered me as well...He has two gunwale pieces for me I just need to go pick them up...I was'nt ready at the time I talked to him but I need to get up there and get them nex week when the weather is better...He actually paid MI metals to make up the dies for the extruded channel and owns the rights to the actual pieces and gets a commision if any is sold through MI...Thanks and Good call on talking to him he was the man needed for that channel and even has it in stock...

Should the gunwales go on before the U channel gets welded to the bottom ???

I have a unique opportunity here with this hull being built on a flat table...The transom has an 1 1/8{+or-} arch in the bottom...Moving up to the 4 ft bottom seam that's overlapped I have about 1/2 arch in the floor bottom...As I pick up on the hull bow I can actually transfer some of that arch up the boat to around the 10ft mark...It's not much only a fraction of an inch but would there be any advantage/disadvantage as to where that arch starts ??? In other words how far up the bottom of the boat is too far to start the gradual arch that ends up back at the transom??? With the boat sitting securely on the table the floor is dead flat until the bottom seam...

[Papee]

No advantage of continuing the arch past where the boat will ride on plane. Your boat should ride on about five foot of the hull if it's set up right. It should be about a foot in front of that seam so it uses it as a step. It's not much of a step but it does help. Keeping the front part of the boat flat will make the hull more stable for fishing.


how long are the gunwale pieces he has an what does he want for it. You can pm me the price if you don't want to post it. I want to get enough to do my boat to make it look a little better. I'm going to drain my oil soon as it gets nice and lay my boat on its side so I can get the bottom painted. That way I won't have to remove anything. Then after the new top pieces are on, a fresh coat of paint.

[Corky]

OK so flat it is...I was fitting the U channels and gave the center a small notch{where the step is} to lay more flat along the length of the floor..Did'nt take much but it sure helped...

[froghunter]

personally i would install the gunnels first. this will stiffen up the sides and then i would ratchet strap it down again. i FOUGHT the first aluminum boat i built to get the warp and twist out of it and learned alot. tack the gunnels in, tack the c channel in, then tack the side ribs in. pull the straps and run a string line down the middle checking for an even lines on both sides. if your happy re apply the straps and stitch weld. check yourself every once in a while with the string again and also use the ol' eye ball method. standing a ways in front of the boat get eye level with the bow (your 2" pipe) and line it up with the top of the transome. this is an easy way to detect twist in the hull.

[Corky]

You know I was just out in the shop and came to the same conclusion that you're suggesting froghunter your post just confirms what I was thinking thanks for the reply on what to look for...Believe it or not the sides are real close to each other using the centerline stringline I saw in your post...It's only about an inch off just sitting on the table with no support I think that's pretty good for my first build...I can easily pull out on the side that needs a little help and came to the conclusion that I need to get the sides correct then deal with the bottom supports...I'm assuming if I put my wood spacers back inside the walls,get everything concentric from side to side and tack the gunwale on it should stay ???

The shop I'm buying the gunwale from said to mark a line down on the sidewall where the trim sits correctly installed that way if it's not completely down on the sidewall you can see it and tap it down before tacking...It was also suggested to start at the bow and pull/radius the trim into position...I guess we'll see how that goes....

Right now I'm working on alot of other hull pieces that need to be made up so more pics are coming after this weekend....

[Papee]

It's really nothing to be concerned about at all. The bow deck will fix all that.

[Corky]

Well today was alot of figuring and preping...I've got the cuts made in the U channel...Made up the drain plugs and did a fitting for them...Even the smallest details need decisions...The drain tubes would weld up easier if the tubes were flush with the transom on the outside but I like the idea of having them protrude back onto the lip a little bit...They might just add a little strength to the lip for the rock duty....I'm planning on installing the rubber plugs from the inside...

[Corky]

I'll share one from the "swing and miss" department...I'm in the process of laying out the transom center dip and thought it would be a good idea to mock-up the prop diameter to see just where it would actually fall into place if I droped the transom 4 inches in the center...Well, after the radius was drawn I felt it was just too low...The one I have layed out now is only a 3 inch drop in the center and a wider.sweeping curve than what the prop actually needs and it looks much better...I figure the more air moving back there the better...I'll post the final layout for the transom tomorrow...

[Corky]

And here's what the transom ended up looking like...I cut the tray today and need another bottle of argon to keep the ball rolling on the hull......I'm keeping a tally of materials both aluminum goods and consumables to let other readers know just where I was at in the end....

[Corky]

Here's a pic of the U channel in it's place at the rear transom area...As I stated earlier I did fit the channels to the bottom seam to sit flush so there would be no high/low areas,channel arching, or just plain too much air gap going over that area keeping the contact areas tight...I'll post what was done at the bow with these channels when I get to the welding ceremony...

[Corky]

I wanted to touch on this while I was working on the U channel..I used a carbide bur in a air powered die grinder to easily shape the channel to the contour of the floor step...There's a difference in the burs and I wanted to point out what's needed here...Take a good look at the burs I've posted...See the one second from the left...Yes, the one that's completely clogged up with aluminum...That's a single cut ferrous metal bur...That's an entry level bur for general steel/iron cutting....It does great on steel but look at it from only a few minutes on the aluminum...Even with the cutting wax it died a horrible death in a few minutes..
The two on either side of the single cut are the ferrous metal double cut burs...And as you can see it has more fluting to help clean the tool better and they do an even better job on ferrous metals but they're still not designed for aluminum...
Which leads us to the real deal, the two on the right...The aluminum cutting burs...WAY different than the steel burs....Look at the spacing on those cutting edges !!! I"ve got the one chucked up in the tool and it's got the cutting wax on it but make no mistake about it those babies cut!!! It's almost effortless with the cutting action and to be honest you have to watch you don't let it get away from you and cut too much...

I'm not sure anyone has pointed this out in their build thread and I felt it was something that should be addressed...