⛵️Building an Exploration Aluminum Sailboat!! How to create the Hull Shape!! Ep.342

Building an Exploration Aluminum Sailboat: How to Create the Hull Shape | Ep.342

We have great news. It’s about time for us to show you some real boat building. So, let’s get started.

Hi, I’m Roberta. And I’m Duca. After bringing a sailboat that was neglected for over 22 years back to life, we moved aboard and for the next 2 years we explored the Brazilian coast and part of the Caribbean, where we got an offer that changed our lives once again.

We sold our boat and we moved to France, where we are building our new 43ft aluminum exploration sailboat. And while the boatyard is building the hull of our new sailboat we are learning the crafts by converting a campervan to get ready to build the interior and all the systems of the boat ourselves.

So, don’t forget to subscribe and to join us every Sunday for a new episode. Good news is that on the past weeks we’ve been slowly going to the yard.

When I say we I say me. Roberta is not going to the yard because as you know she’s pregnant and we don’t want the baby to hear a lot of loud noise and a lot of dust for Roberta is not good. So I’ve been going to the yard and slowly slowly I’m gaining the confidence and I’m starting to be closer to the people that work on the yard.

And that’s good because that’s the only way we can get along well and we can film the process and we can understand about our own boat. Because we really want to know how the boat comes together.

So, the boat is evolving and your French is evolving as well. I’ve been trying my best to communicate in French.

The Hull Shape Evolution

The last time we update you on the boat we had two panel of the boat welded, the bottom one and the starboard one. It’s complicated to explain but pretty much…

I tried to explain with words how the panels of the boat get to the right shape and I didn’t manage to do it because for me it’s really hard to express with words.

Visual Situations Explained

So, I’m gonna create three different situations that is gonna to explain really easy what I mean. So, situation number one.

We have two flat aluminum plates. If I get the plate number one and plate number two welded together that’s what’s gonna happen. Imagine that these are the famous tack welds.

What is a tack weld? Tack weld is a small welding just to keep the plate where you want, just to lock the plate in place.

So, let’s imagine that I weld these two plates together with an angle. When I have two straight lines the weld is gonna end up with a constant angle. If I put 90° it’s gonna be 90° here here here here. If I put 45° it’s gonna be 45° all the way.

So, that means it’s always gonna be just one constant angle. But, if one of the plates is not straight anymore…

So, this is what happened on situation number 2, when I weld the angle is not constant anymore. And that means it becomes a completely different shape.

Comparison of Situations

So, you can compare:

• Situation number one – constant angle – one straight line, one straight line, no shape on the edges. The edges are still flat, straight.

• Situation number two: the bottom panel now has a curve because of the different shape of this edge. And also the top part of this panel has a curve so it it starts to become a completely different shape than this 90° or 45 or 30° flat.

But, the boat is not exactly like that. The boat has two curved panels and when you do that you end up with something that looks a lot more like a boat already.

Unrolling Aluminum

Because the different curve in this panel compared to this one it creates a different shape for each one of the panels. And if you do the calculation right and if you draw it right it will come to the shape you want as a 3D.

And that’s one of the really important steps when you build an aluminium boat is what they call unrolling the aluminum.

That means you design the boat in a 3D shape but when you cut the aluminum it’s a 2d shaped material, it’s just a flat panel of aluminum. And in order to know exactly how the shape will end up when you weld it together you need to transform the 3D model into a 2d model.

That means you need to cut the welds, on the computer of course, and you need to make the panel flat again and know exactly the curve you cut, so when you weld it together it will go to the format you want. You have like a shape on the bottom also of the boat now…

Progress on the Boat

And that’s due to the different shape of the edges of the plates. So, this is pretty much the stage we were on last episode.

So, now if we add the other side of the boat…

If we did the drawing right when we unroll the plates we are much closer to the real shape of the boat. But there is only one problem, these panels are really long.

This is like 13 meters long that means 40 something ft long and with this much length it can deform. So, that means everything now works together but the same time it might not be exactly precisely on the shape we want,

Because we’re looking to have this edge on the right profile on the right angle.

One thing that you can do and it helps a lot of course, is to add the bottom of the frames in place.

You see the profile here, you see the the angle. This is the exact angle that the plate needs to be on that position, so I know exactly where this frame is located…

And when I tack weld it in place it will naturally bring the panel even closer to what it should be. So, let’s say here.

Adding Frames for Boat Shape

Just adding the bottom of the frames in place already changed even more the shape of the plates. That’s the most important step because this step is gonna actually make the boat have the right shape, the right dimensions.

And that means the boat is gonna be straight and even, like both sides equal. So, the next step now is either to weld this last panel on the top of the side panel,

so that means to finish welding all the panels of the boat, or install the frames first and then install the side panels. The one problem about installing the panels is because there’s one thing missing.

Do you know on the side deck when you have a lot of little holes to drain the water, for drainage? Some boats have it. Yeah. Some boats have some boats don’t have it.

But we are gonna have like little holes on the edge of the panel to drain the water better and also to attach blocks and lines and stuff. And we didn’t know how it was gonna be when we ordered the panels

Framing Progress Continued

and that means they need to do it now and it’s easier to do on the ground than in place. So, before they install the panels they need to do that so that’s why I believe they’re gonna do the frames first.

That’s good. Things are moving forward, that’s something. We’re really excited. I can’t wait to have a boat. I want a boat. That’s pretty cool. It seems so much more stiff already.”

Reinforcing the Watertight Bulkheads

It’s just like three panels together and it’s already really really stiff. It’s strongall. When there was just the bottom panel I would just move with my finger really like soft and it would move everything.

Now…

it’s good. The welding of these frames are actually temporary. You might be wondering… why is it temporary if you have the frame exactly where it should be? Why don’t you already weld it fully?

The reason for that is because you need to get the shape of the boat, first of all.

But when you do that you create a lot of tension in between the frame and the hull because the hull is not fully welded yet. That means all the tension of the side plate is hold by a few tack welds, that means you have a lot of tension there,

but it’s necessary because you need the shape of the boat. So, once you get the shape of the boat you can move forward and eventually when you have more panels welded together

You can actually cut these welds. So, that means the frames we just added are gonna be cut.

And the reason for that is because once you cut these welds and you release the frame you release the tension and the hull of the boat is gonna go to its natural shape, with a lot less tension on the weld. Once you have the right shape then we’re gonna weld these frames back in place.

Installing Watertight Bulkheads

And with this we can distribute the forces and the tension throughout all the welds. So, now that we have the six bottom of the frames in place and the bow of the boat is already in a much better shape compared to what is gonna be in the future,

We need to do the same to the back of the boat, to the transom. The problem is that all these frames are like from this middle of the boat to the bow on the back of the boat all we have are 2 watertight bulkheads and the transom.

So, that means right now the boat has the transom too closed, we need to open up the transom a little bit more. And in order to do that we need to install the watertight bulkheads.”

Hull Number Two Update

But before we can do that we need to reinforce the watertight bulkheads because it’s gonna suffer a lot of tension in this first stage. So, that means if the watertight bulkhead is not reinforced it can bend a little bit on the process.

So, it’s much safer to put some brace and make it more stiff. So, let’s see how they do that…. Another cool news for this week is that hull number two is a reality now. I present to you hull number 2.

That’s the second boat of our boat that is gonna be for one of you guys that is gonna start right after the finish ours. They start this one. That’s pretty cool.”

Moments to Reflect On

That’s for a German guy. That’s gonna have a chartering company and the boat is exactly the same as our boat. So, if one day you want to sail on a Meta 43 it’s gonna be one available in 2026, I guess.

I’m not sure, I think 26. But we’ll see. That’s pretty cool. I just love that every single time I go to the boartyard the boat is a little bit different.

Every structure you put on the hull the shape of the hull is slowly goes to what is gonna be in the future. And this episode already brought the boat to a much better shape.

But if you like this episode next episode is gonna be much much better because next episode we’re gonna install the watertight bulkheads and that means we’re gonna open up the transom so much more.

We were actually to be honest a lot harder than I thought and involves a lot of brute force. We’re talking about 10 mm thick aluminum plate.

It’s one of the hardest tasks on this entire board and that’s gonna be next week. I can’t wait to share with you.”

See you guys next week. See you next week.