♪ ♪ (drilling) (indistinct chatter) We're the Upside Downers, and this is our raft.

HANNAH: Hi, I'm Hannah from Team Tiger, and this is our raft.

Today, we're taking our junk boats out on the water.

We designed and built our boats at the Acera School.

BOY: So it's a pretty simple design.

We took a pallet and added a few boards here so that we could add the barrels on the top instead of on the bottom, which is what most people are doing.

And then we're going to actually be sitting on the barrels, so we thought we would add a little chair just to make it more comfortable.

♪ ♪ Here's our mast.

HANNAH: To power our boat, we're going to use a sail.

Other teams are going to use paddles and paddle wheels.

We're using a tarp for our sail.

Which is a teeny bit too short because we did not have time to make custom sails, so they're all the same size.

The drawback of having the sail that's a little too small is that we can't catch as much wind because the surface area is smaller.

But it's better than nothing!

GIRL: We decided to make outriggers on our boat, which are basically pieces of wood that come out of the sides of the raft and balance on the top of the water.

The outriggers will help keep the boat from tipping.

HANNAH: Our outrigger is attached parallel to the deck with a noodle on it, it's like an arm to help steady it.

And we're attaching it to the deck by this one-by-six that is attached to the outrigger and the side of the deck.

BOY: A lot of other boats are using outriggers to keep their boat balanced, but we cannot, because most of our deck is going to be submerged under water.

So we don't really have a place to attach the outriggers to keep our boat from tipping over one way or another.

GIRL: As soon as the boats are all put together, we're going to go in the water and test their stability, which is basically us trying to flip them over.

And the reason we're flipping them over is for safety.

So if they flip over now, we'll know how to make sure that they don't flip over later.

So our barrels are sitting too high in the water for it to be stable, so we're lowering our outriggers down so that they help us stay upright better.

As you can see, these are way too high, they're not touching the water.

(drilling) MAN: Redesign on the fly, high five!

GIRL: This seems so much more stable already.

HANNAH: The water now pushes up against the outriggers, and the boat is much more stable.

BOY: We expected to be tipping back and forth a lot, but the deck is actually giving a lot more stability than we expected.

BOY: Yes!

I think that we underestimated ourselves.

We're much faster and much more balanced than we thought.

If we were to make this again, we would probably add a sail.

GIRL: So in the end, we didn't flip and we had fun, and that's what matters.

Ahoy, engineering!

Ahoy, matey!

(splash)