The finale

After months of preparation and a whirlwind week of competition, it’s finally over. And we have a reason to be very proud of ourselves. Our boat completed every mission admirably. Quite respectable for a first year team with no sailing experience :).

Event #5: Presentation

After a late night practicing and critiquing our design presentation, we woke up early Wednesday morning to prepare for our early start . We were scheduled as the first presentation, somewhat to our dismay, as we were hoping to see a little more of what the other more experienced teams focused on in their presentations. However, our presentation went off quite smoothly, and we felt we did a good job of conveying our central message: although we also built a sailboat, our central focus was to build a flexible, robust, easily debuggable and extendable robot.

Our power point presentation can be found here.

Event #6: Long distance

The long distance challenge is a 10km autonomous endurance race. Each boat earns a single point for each leg of the race, for a total of 8 points. The fastest and second-fastest boats to fully complete the race earn 2 and 1 extra points, respectively. To complete a leg of the race, the boat must either pass within 10m of a marking buoy, or pass between the start/finish line. If the R/C control is taken at any time (except to avoid a moving object), the boat is docked 50% of points earned.

Blackbody Radiation perfectly completed the full mission we set out for her in just over four hours, finishing second. Due to an incredibly unfortunate mis-communication at the beginning of the race, one of the marking buoy GPS locations we told her to round was 15m south of the actual location. So although she rounded the point perfectly, the point did not align with the actual buoy. (The USNA checked waypoints in the morning, measured a 15m discrepancy in the location of the buoy compared to the stated GPS coordinates, and told our advisor, who told us. We then took their word for it and coded in the difference. In hindsight, it would have been much better to keep to the official coordinates!). However, we checked our GPS log files after we took Blackbody out of the water, and in her (intentionally) wide rounding of the incorrect location, she passed within 7 meters of the official buoy location given to us. Even accounting for GPS uncertainty!  We presented our data to the judges but their initial judgement was unchanged — for incorrectly entering the GPS location and not rounding the physical buoy we received no points for those two legs of the race.

Mismatched GPS marks was not the only excitement of the day. Just ten minutes before the race was to start, our human operator crashed the boat into the dock, knocking our sensor mount completely loose. It’s a nod to the resilience of the team that we all stayed (relatively) calm, pulled the boat out of the water into her dry-dock cradle, whipped out some 5-minute epoxy and gorilla tape, and had her back in the water within 20 minutes.

Kevin and Andrew hold the sensor mount in place as the 5-minute epoxy cures.
A close-up of the temporary solution to our broken sensor mount. Duct tape adds extra strength as the epoxy finishes curing.

Later, shortly after our boat successfully completed the first leg of her long journey, we noticed an extra line flapping around. Closer inspection revealed that one of our port-side shroud had broken loose! After brief discussion on whether we should pull her out to switch to a smaller set of sails (switching a rig in the middle of the race is allowed so long as the boat returns to the point where it was taken out). However, she seemed to be handling the loss fairly well, just spilling a bit of wind of the top of the mainsail when on a port tack due to the bend in the mast, and we decided that switching to a smaller rig would lose us more speed.

Finally, in the last leg of the journey, the jib leech line got caught on our antenna for a long stretch, significantly slowing our final downwind run. However, she finished strong and autonomously, without ever once requiring that we touch the R/C controller. 10km in 4 hours. Way to go team!

5 thoughts on “The finale

  1. We couldn’t be more proud of the Sailbot team!!!

    By the way, where can we find the official list of results, including the distance competition and overall?

    Rick

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s