CONSTRUCTION PROGRESS

Since the beginning of August we have been busy building the main hull shape. (For more details on the design, see this post from yesterday). The photos below show the story of our 10 days of building. From now until September we will finalize the electronics design and acquire the funds we need to buy the rest of our components.

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The stringers on the hull sides are held in place by nails in the MDF stations, which determine the shape of the boat.
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With a cedar core and a fiberglass shell, the hull sides are attached to the stringers with resin epoxy. The planks are held in place with clamps until the epoxy curing process finishes.
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Luca Froelich tapes the last plank to the hull sides.
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After finishing all the planks, we used SNA foam to make fair, rounded corners. These corners are sacrificial, meaning that if they break upon impact with another object in the water, the boat will still float. Here, YYen Gallup is sanding the corners to make them fair.
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The solar cell array on top of the boat needs a cylindrical surface to rotate on. To achieve this, we made a fiberglass lay-up inside a PVC pipe. The lay-up consists of 5 layers of fiberglass with epoxy resin as an adhesive core, and will provide us with the puncture resistance that we need. Here YYen Gallup, Torbjørn R. Fyrvik and Don Martin are soaking the fiberglass in resin.
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After 10 days of hard work, we finished the main hull structure and started building some of the other components. This photo shows the finished hull with our PVC mould by its side.

 

THE DESIGN

There haven’t been many updates on this website over the last few months. One of the reasons for that is that we have been busy finalizing the design of our Transatlantic vessel. In April we tested our prototype extensively on water. Building on these results, we decided to go with a rather unconventional design.

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Our Transatlantic vessel does not look like most ships. Read on for the justification of our unconventional design.

The extremely narrow hull (5 m by 25 cm) minimizes drag while supporting a large solar array (4 m by 1.5 m). This array tilts transversely to maximize power production. A submerged pod with the battery pack, motor and propeller carries half the boat’s weight and provides the stability needed for the large solar array.  Additionally, the pod keeps the propeller under water at all times and provides the righting moment needed when the solar panel is tilted in strong winds.

To accomplish what no one has accomplished before we have to think differently. We believe that this craft can travel autonomously not only across the Atlantic, but also on longer voyages.

Check back tomorrow to see photos from our building weeks at the beginning of the month.

 

CONSTRUCTION

We’re back!

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YYen Gallup, Luca Froelich and Don Martin discussing the boat drawings.

After a summer of remote planning and finalizing the design of our boat, we are finally back in Vancouver. Those of you who follow our Instagram account and newsletter may already know that we started construction last week and that we are making great progress.

Stay tuned for a description of our transatlantic vessel design.

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The stations (our upside-down building jig) are already up. Next, we will use this jig to mount the cedar-fibreglass composite that forms the hull of the boat.

 

 

PROTOTYPE TESTING

Since our initial launch about a month ago, we have been busy testing the prototype. Through a sophisticated testing program, we have characterized relationships between velocity, drag and power consumption. We expect these results to scale well to our final craft.

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Team captains YYen and Torbjørn hooking up the current sensor.

To find the relationship between power consumption and speed, we measured the current drawn by the motor with a current sensor. Timing the boat over an interval of known length, we were able to relate the current to the speed of the boat.

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Team captain YYen and team mentor Don Martin setting up the block and tackle system.

Additionally, we need to know how drag force relates to velocity when designing our Trans-Atlantic vessel. To find this relationship, we used a block and tackle setup with calibrated weights to exert various constant known forces on the boat. By measuring the terminal velocity, we determined the generalized drag curve for the hull.

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A plot of some of the experimental data, showing how both drag force and current are proportional to velocity squared.

From theory, we expect both current draw and drag force to be proportional to velocity squared. As seen in the graph above, this behaviour was seen from the experimental data.

Looking forward, we will use these findings to decide on the parameters for our final craft concept. Stay tuned for updates on this design concept later this week!

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The prototype cruising in front of downtown Vancouver.

PROTOTYPE LAUNCH

“It floated!”

There was no doubt that the crew was excited after today’s successful prototype launch. This morning, a group of 6 team members went to the Royal Vancouver Yacht Club to check how the boat sat in the water. Although she is not autonomous yet, we drove her around with a remote control to do some initial speed testing. At 4 knots, we were surprised at how fast she cruised through the water.

This week we will be accelerating our development of a basic autonomous navigation system, and hopefully have something autonomous ready by next weekend. Needless to say, we are very excited about our progress and what is to come next.

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At only 25 kg, the prototype can be easily lifted into and out of the water.

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The small ship reached an average speed of 4 knots over 200 meters.

FINALISING THE PROTOTYPE

Since the beginning of March, the team has worked intensively on getting the prototype ready for on-water testing. Last night, the final touches were made, and tomorrow we will put her on water for the first time. We are very excited to see how she sits in the sea, and to do some initial testing!

Stay tuned for updates over the weekend.

Here are some pictures from the yesterday’s session:

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