Aluminum Hydro progress 12 Nov

[Winger Ed.]

Here's where I'm at:

Sorry I haven't checked in sooner.
..

I pretty much finished the framing tonite with the addition of the 1/8 " sheet nose piece.

I had it flipped over a couple weeks ago, and put the skin on the bottom for the rear 10ft. and the sides of the bottom behind the sponsons.

It only took about 800 rivets for that with a one inch spacing between them.

(Whew! I wish I'd bought a phneumatic pop rivet gun a LONG! time ago)


The framing is done all the way to the front.

I'll need to tweek 2 of them to make the top of the airfoil come out just right.

About all that's left before flipping it back over is nail down the .080 3 x 4 Al angle stock along the bottom of the cockpit.

I'm doing the cockpit walls in 2 pieces rather than one.

The bottom part of the wall and reinforcement for the floor is the 3 x4 angle.

Each half is nuked down to the vertical parts of each frame which are 14" apart, center to center- I think that combination should be enough to resist a fore & aft upward flex when combined with the skin on the bottom and the decking inside the cockpit..

The top half of the wall- which will have a gap between it and the bottome part, will be added after the top of the airfoil is covered.


When turned on it's side, this will allow the foam to pour in, and properly fill each space between the frames, and give it room to blow up & out, rather than bulge the skin as it expands.


Thanks for all yawl's interest and letting me share this project with ya.


Ed.

[Winger Ed.]

Here's a front view,,,,,,,,,,,


Its a bit fuzzy. That's how the pic came out after I trimmed & shrank it to fit.


Its coming in at 16' & change. And I figure its at about 165 pounds so far.

We're a long way from floating it, and adding more and more weights at the rear in addition to the 250lb in the driver's seat, plus gas & battery that will be in front of the rear of the sponson, in order to see how heavy an engine it will tolerate. But I sure have my eye on a 200 Evinrude........
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Anyway- back to the present-

There are a few angles that look a bit 'abrupt' right now. But not to worry, I have 8lb. hammer that will smooth them out a bit before the paint job goes on.

The skin & decking is heavier than you'd think, at least 125 pounds for all of it that remains to be nailed on, and I'll end up pouring 90 pounds of foam* into it to make the entire machine totally solid.

*Adding that much weight for such gains in strength and safety,,, I figure its a fair trade off.

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The name & paint scheme is still open for suggestions.

At present:

I'm torn between 2 ideas-

Painting it in 2 tone Orange/Golds that look like light & dark colors of fire, but in a scaled pattern that will look like a giant Carp.

Or-

solid black with a flame pattern done over it in different colors of pearl.

In certain lighting conditions, it will just look black. In others, from different angles, it will really look like real flames.


And I haven't arrived at a name yet, except perhaps, "Mama's Worries".


Any ideas on a better name, or more distinct paint scheme would be appreciated.




Thanks,

Ed.

[David_L6]

What was you final choice for motor (if you have made one)?

[Winger Ed.]

Originally posted by David_L6
What was you final choice for motor (if you have made one)?

Not yet. I figure I still have a few months to go before it gets critical.

I'd really like a V-6 OMC either a 200 or 235.

If I can't find one cheap that I can re-build, I may just have to sabotage Hooty's transom re-do project on his Speedliner, and borrow his.

[wing nut]

that thing is freakin cool! cant wait to see the finished product. just wondering but wouldnt it be easier to put the bottom on, pour all othe foam in and then sand the foam to the spae yo want insted of risking a blow out? jmo..

scott

[Winger Ed.]

[QUOTE]Originally posted by wing nut
[B]that thing is freakin cool! cant wait to see the finished product.

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Yeah. You and me both,
har, har, har,,,

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just wondering but wouldnt it be easier to put the bottom on, pour all othe foam in and then sand the foam to the spae yo want insted of risking a blow out? jmo..

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I did the foam that way on the last hydro.

It'll work. But hanging that big a motor on it-- I want to be at the top of my game with this one.


The difference between that, and how I want to do this one is in the sandwitching*.


If the foam is chemically bonded to a epoxy primed top as well as the bottom, and 'nooks & crannies",

it will be much, much stronger than if the skin for the top just spanned over and coved the foam without bonding.


.....

What I'm trying to do with Aluminum skin & foam is sort of like a ultralite airplane wing, or a modern surf board is made.


They rasp out a chunk of foam, then cover it with a layer of fiberglass cloth & epoxy resin.

The foam gives the shape and resists the forces of compression. The fiberglass resists the forces trying to strecth or pull it apart along a axis/line.


By rasping down the foam in the boat hull, covering it and the frames with a aluminum skin rather than it being bonded to it would weaken it as much as if you split a airplane wing, or surf board to half it height from top to bottom.


Without totally filling out the spaces or being bonded to the top half, none of these applications would be half as strong as they were--- but only be a fraction as strong.


I got by with that before on the 'D'. But I only hung a 50 hp engine on the back of it.


I don't want to take the chance with a 200 horse (+) on this one.

Plus, if its all bonded, and one solid 'thing' I know water can't ever seep in anywhere, get stuck, and finally water log the foam; since I didn't 'disturb' the crust it forms as it expands & 'sets'.



*
I don't know if I spelled the word 'witch/which' correctly, for the way it was used.

But I do know why real witches don't wear skivies:

---That way, they can grip their brooms better.


Ed.

[Raceman]

I think you've got a really neat project goin' here, but I'm curious about your use of pop rivets. Are you using alum or steel rivets? Are you concerned about leaks and/or the rivets working loose, especially if they're alum? Is the structure itself welded?

I hope you'll keep posting pictures as it progresses.

[Mark75H]

Ed, how much foam did you use and how much did it cost?

I'm thinking of foam to increase the strength of the deck of a boat I have. Right now there is no way in or out of the cockpit except over the nose ... the deck is too weak.

[Winger Ed.]

Originally posted by Raceman
Are you concerned about leaks and/or the rivets working loose, especially if they're alum? Is the structure itself welded?



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Raceman, Sam, I'll put these together.

I'm using 3/16th Alum. rivets with a Alum. mandrel.

If you use a Alum. rivet with a steel mandrel, it will suck down a bit tighter, but the steel nub that's left down in it will rust. And being a boat- I don't trust the steel mandrel nub that's left behind not ot set up a dissimalar metal corrosion situation in a few years.
(I'm 48. This will probably be the last boat I build from scratch, and I want it to last as long as possible)

They wouldn't work if the hull wasn't being totally foamed. They'd wiggle loose. Also, Alum. boats that are open on the inside are assembled with a strip of 'gooey' between the sheets and wherever a rivet goes through the hull to hold something.


The rear parts on this one will hold water on the inside now(without the 'gooey' between or around everything, but without the foaming, I doubt if it would after being trailered about 10 miles.


The frame is all welded. I'm almost done with Argon tank #9 today. Some sheet is welded; the rear of the sponsons, the back ends of all three transom plates.

The thin stuff is incredibly hard to weld. The heat just makes it go nuts. It expands at odd rates, and leaves 'oil can' dents that I can't shrink out, so most of the skin is riveted down with rivets about an inch apart.

The rear bottom sheet-10ft so far, the ,080 3x4 angle along the inside edges of the cockpit, and the sides of the bottom behind the sponsons are done. So far, I've used about 1,250 rivets.

I"m figuring about 2,000 for the top deck panels.

With them, and the skin being epoxy primered so the foam will stick to it like poop on a baby blanket- I think I'm safe as far as the structure is concerned.

I did the 'D' like that, and its tougher than lion's breath as far as rigidness goes. Without the foam, It'd probably leak like crazy, and I would sort of have my doubts as to the frame & skin lasting more than a few years without some stress cracking.

.....

I got the foam from Clark Craft. Any net search will take ya straight to them.

They are great to deal with and ship fast. Usually the day you call if you get your order in before lunch time.

I've since seen the stuff listed somewhere else a few bucks cheaper, but I forgot where.

I don't know if I'll use it all, but I got 6 gallons of the stuff for this thing 3 gallons of each side-- its a 50/50 mix.

The warmer your shop is, the more it will expand before it sets. At about 80 degrees, a gallon blows to about 10 cubic feet, and weighs about 2 pounds a cubic foot.


The Clark Craft site has some pretty good info on it. And it comes in quart bottles too. For what you're doing, a quart of each part should be plenty as it blows to aobut 2.5 cu.ft. And the compression of it is about 40psi.

I've used it before, and just think the world of it. It's closed cell, doesn't crumble after a few years in this Texas Sun, I've had water stand in the 'D' for over a year- and it hasn't begun to waterlog , and gas won't melt it.


Ed.