Robotic Sailboats and Airborne Viruses

by Dermot Tynan in Microtransat

Posted on Tuesday, March 16, 2021 at 11:19

A tropical paradise.

One would think that a global pandemic would be a great opportunity to hunker down and get some work done on one or other robotic sailboats. Unfortunately, this hasn't turned out to be the case. I am still knee-deep in hull work on boat #2, the main entrant. However, due to lockdown restrictions, I can't physically access the hull and so it has spent most of the last twelve months, waiting for more sanding and filling (side note: never let anyone tell you that you can "fix it at the sanding/filling stage"). But it's not all bad news. The lockdown has been good for boat #1, the test vessel.

As you may remember, I decided to ditch work on the first hull (The Reboot) and instead switch to a 2.4m MegaMOOP design by Professor Paul Miller. While work on that hull is progressing at an extremely low rate, Hull #1 has been sitting idle. I left it exposed to the elements to see what the worst of a winter of Atlantic storms would do to the hull and supposedly watertight electronics. After it failed that test and seized a stepper motor, I brought it indoors and that's where it has been resting, ever since. Meanwhile, Hull #2 is still on the strongback, which means it is a long way away from being ready for the water. As mentioned, also, the lockdown has constrained my ability to work on the hull. Rather than let this time go to waste, I have decided to do more experimentation work with Hull #1.

This has actually been a refreshing change of pace. One of the big obstacles with a transatlantic crossing such as the Microtransat, is the fact that there needs to be an enormous concentration on robustness and simplicity, especially of mechanical systems. As a result, even something relatively simple like the rudder, requires considerable research and testing. On a model boat, you might use a store-bought servo with plastic gears and a simple linkage to the tiller. While this will last many years when the boat is pulled out once a month and sailed for an hour or two, it won't work if the rudder is working constantly, twenty four hours a day, for weeks at a time. The gears will burn out within days and the boat will be rudderless. The down-side to this obsessive desire to create "battle-hardened" systems is that every component design must be researched, tested, tested again, modified, considered, and so on. It takes the fun out of just building a boat, sticking a computer on board, and letting it head off in search of the Americas! It also makes the design and build a very slow and laborious process.

By switching back temporarily to a hull which will never cross the ocean, it is possible to make design trade-offs. One such trade-off is the fact that Hull #1 uses a regular "cloth" sail rather than a wingsail (The New Winged Sail). Also, the mechanism for adjusting the sail angle is a simple servo-winch system comprising a stepper motor and a 3d-printed winch. As these would not stand the rigours of an ocean crossing, and in fact are likely to get encrusted with salt within a few hours, they are not suitable for the main design. But being able to quickly create a winch means that it is possible to get the boat functioning a lot sooner.

Over the coming weeks, I will add a few more blog posts for systems and components which are being added to Hull #1, free from the torment of ocean-going reliability constraints. Hopefully, if we get out the other side of this whole Covid-19 pandemic, I might be able to get some footage of Hull #1 doing its thing.

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