Now that the boat is almost finished, I can start planning the launch. It’s reasonable to wait until summer when there’s more sunlight and better weather conditions. The shortest path across the Atlantic is from Newfoundland to Ireland, but it also has some unique challenges. It looks like I’m forced to choose between hurricanes and…

In the past few months, I have been writing thousands of lines of code to bring the boat to life. The boat can be controlled from a web browser over wifi and the program can be uploaded remotely. It’s useful for testing when the boat is close to the shore. I attach pictures of a…

When I was simulating the boat movement in rough ocean waves, the compass output was too noisy and I wasn’t satisfied with the result. As the boat will be constantly climbing up a wave or surfing down a wave, the magnetometer is not reliable enough to estimate the correct heading. Fortunately, this kind of problem…

Over the past few years, there were several autonomous boats in which the autopilot stopped working just because some water entered the hull. It won’t happen with this boat. Because all the electronics is enclosed in a waterproof housing, it will remain fully functional even if the hull is flooded. The electronics is enclosed in…

As the sailwing is free-rotating, I had to build a crazy concept where there is no electrical connection between the sailwing and the hull. A cable could easily overtwist and break. Waterproof rotary connectors have a high friction and unknown life span. All the power needed for the actuator comes from the small solar panels…

Removable keel makes the boat easy to transport. The keel is large enough to compensate high ocean winds. There are aluminum profiles reinforced by fiberglass roving inside the carbon fiber shell. The outer shell and other parts were glued together with epoxy putty. The empty space inside the keel will be filled with water that…

The lead bulb for the keel was made by sand casting – a technique developed in the Bronze Age. (Everything I do here is dangerous!) The bulb model was 3D-printed in two symmetrical parts. The first part is placed on a flat surface and prepared to be buried in “green sand”. The other half of…

The hull has been filled with a closed-cell PUR foam that will stay afloat forever. As the foam is a good thermal insulator and the batteries generate heat when charging, there are several vents leading to the battery tubes to prevent overheating. The two compartments that are not filled with foam will be completely separated…

The rudder on such a small boat can get easily entangled in seaweed or fishing nets. Numerous autonomous boats were recovered with a missing rudder which suggests that the rudder is often underestimated. This very unique rudder combines two interesting features: It avoids entanglement around the rudder shaft It’s symmetrical, i.e. the force needed to…

All communication modules have been waterproofed and placed under the deck while meeting these requirements: The GPS and antennas must be far away from the sailwing as carbon fiber partially blocks the signal. The communication modules must be at least 30 cm from each other in order to prevent interference. The compass must be far…

It can act as a backup wind sensor which is less accurate, but more robust. For example, I was told that the ultrasonic wind sensor may not work correctly in a heavy rain or when the boat is heeling too much. The algorithm will constantly compare the sailwing position with the wind direction. If there’s…

The sailwing is now equipped with a flap that is turned by the waterproof actuator. The beauty of this concept is that it requires a small force to adjust the sailwing even in high winds. Here’s a video of the actuator in action: https://www.youtube.com/watch?v=d15B6v7aHtc I decided to move the actuator higher than in the original…

The sailwing is almost finished! The next step is building the flap that will control the sailwing orientation. Both parts of the sailwing were joined with epoxy putty and a fiberglass tape. The solar panels will charge batteries located in the electronics compartment.

The sailwing has to be lightweight and strong enough to withstand high winds and storms, but robustness comes at the expense of weight. The inner skeleton makes the sailwing very hard to bend or break. For maximum reliability, there won’t be any electrical connection between the hull and the sailwing. The actuator will be controlled…

A lightweight and waterproof actuator is needed for adjusting the flap on the sailwing. The problem is, there is no such thing on the market – there are either small actuators, which are not waterproof, or heavy industrial products. So I tried improving a typical hobby actuator. The modified actuator has survived a few thousand…

This is the worm drive with position feedback that was tested a while ago. It has survived over 3 million cycles under load, therefore it’s my winner for driving the rudder. I have published the hardware schematics & software on GitHub: https://github.com/OpenTransat/ServoEncoder https://www.youtube.com/watch?v=95Na8EOg1Mo Three shafts are mechanically coupled together: the rudder, motor and magnetic encoder…

The boat will be powered by 8 LiFePo4 cells, providing a total output of 12.8V and capacity of 30Ah. That’s enough to actively sail for a week without any sunlight. The batteries are protected by impact resistant polycarbonate tubes which are made to be waterproof for full submersion. They will work even if the hull…

This is the last carbon fiber part made by resin infusion. The keel has to be exceptionally strong as it will carry the heaviest part of the boat – the lead bulb. Just a reminder how the keel will look like. It’s swept back to prevent catching debris. The foam plugs The molds The first…

The same process from building the molds to resin infusion was repeated to make a strong and lightweight sailwing. Building foam plugs using a CNC foam cutter The finished plugs The molds released from the plugs Those black plastic sheets you see on the molds will form cavities on the final parts. The cavities will…

The aluminum skeleton inside the hull will hold all the critical parts together – the sail, keel, rudder and wind sensor. Precise cutting, milling and welding were beyond my skills, so different craftsmen and fablab did an amazing job helping me build a really robust skeleton. The skeleton is secured with carbon/Kevlar and waterproofed with…

The parts were released from the molds and trimmed. As you can see, the hull is coated with a transparent gelcoat in order to identify any dry spots just in case the infusion process fails. Everything seems perfect. The hull will be painted with an antifouling paint to prevent marine growth. The deck has a…

In this video, the molds were used to make strong parts from hi-tech materials: carbon fiber, Kevlar and a special foam core. The infused parts must be cured for 24-48 hours. Let’s hope they will turn out OK! https://www.youtube.com/watch?v=kaJU3h57iYY

The molds are ready! Here’s a video showing how they were built. The most exciting moment was releasing the molds from the plugs. https://www.youtube.com/watch?v=AgcCIt4xGmg

https://www.youtube.com/watch?v=U8pHx2xxn4A

This is exactly how the hull shape will look like. I will post a video showing all the steps how these plugs were made! The top part will actually be more complex – there will be grooves for solar panels, but I will accomplish it by modifying the mold.

Just a quick update – manual hot wire cutting didn’t provide acceptable results, so I have put together this foam cutting CNC machine, making the cuts easily and precisely. The foam hull will be used for building the mold.

After countless hours of experimenting, calculating, fine-tuning, talking with experts from different fields and reworking, here is the final design. It looks realistic, but it’s just a computer model! Key improvements: More streamlined and balanced hull Boat length is reduced to two meters Unique rudder design never seen before Improved keel Flap controlled by a…

Here’s a video of the small-scale model that has been built to test the concept. I’m really excited that this wingsail works surprisingly well. Now I’m confident in the design, so this experiment was the last one. It’s time to start building the ocean-going boat! I have a long todo list of design improvements based…

This is a small-scale model of the boat. It has been built to test and tweak the concept before spending a lot more time building the bigger boat for extreme ocean conditions. It also makes software development pretty easy. I’ve got plenty of new design ideas while testing. The first tests went really good, but…

The navigation controller has been tested on a hobby RC boat which was navigating through multiple waypoints on a lake. Different approaches were evaluated to find the best algorithm working at high speeds. Stability at high speeds would be difficult to test with a sailboat as the winds in the middle of the ocean can…

This is a 65-cm prototype of the wingsail. It’s made from a foam wrapped with carbon fiber. This kind of sail seems to be pretty heavy and mechanically complex when compared to a typical sail. However, the advantage is BIG – it automatically maintains an effective angle of attack using the small “tail” behind the…

The boat design consists of 12 carbon fiber parts that will be made by resin infusion – a modern technique providing the best strength properties. Building a mold for each part is a labor-intensive process that may take several days or weeks. Once the molds are ready, the carbon fiber parts can be made with…

A month ago, I published a test of a worm drive that is going to do the most critical job – steering the rudder. The motor made over 3 million cycles under decent load until it failed last week. You can see in the picture that the worm gear is completely worn off. The motor…

There are three widely used materials for boat building, each one with its own advantages: fiberglass, carbon fiber and Kevlar. How to combine them properly to withstand the extreme ocean conditions? The way to find out is to test all possible combinations and examine their properties. Numerous tests have confirmed that the best composite is…

A quality webcam has been teared down and the bare PCB has been sealed in a laser-cut acrylic case. The result is a robust lightweight camera that will be plugged into a Linux computer. The computer will be turned on on-demand, having a full control over the camera like taking pictures in different sizes or…

One of the critical parts of the boat is the hatch. It can be opened in order to access the electronics and it has to be perfectly watertight. The hatch in the pictures, which is normally used on yachts, has been mounted on acrylic “aquarium” for testing. It was left underwater for 7 days and…

Rudder failure is a common issue in autonomous transatlantic attempts, therefore the rudder control requires a special attention. If we expect a rudder movement every 3 seconds for a duration of 6 months, that makes over 2.5 million cycles! That’s more than any servo manufacturer can guarantee (besides some very special and expensive products for…

As unbelievable as it may seem, all PCBs you have seen in the previous posts were manually assembled. The following pictures show step by step how prototyping is being done without expensive equipment.   Step 1: Preparation. Collecting all the parts and laying them out on the table for convenient access. This is the bare…

The boat controller is finished and it’s going to be tested on a hobby model boat. The Navigation Board revealed in the previous post is designed to be universal for any autonomous boat. In the picture below, it’s mounted on top of Expansion Board that will provide additional functions more specific to the boat. This…

This custom-designed PCB is the brain of the boat. It will be responsible for the most important tasks like navigation, collision avoidance and sending messages. Here are some interesting features: The microcontroller is Atmega2560 running at 16 MHz. It has been chosen because it’s widely used in development boards like Arduino Mega and there’s a…