The 1.2 meter (4-foot) long MaxiMOOP is a small boat designed during a joint project of the U.S. Naval Academy and Aberystwyth University specifically for autonomous sailing. It differs from the typical remote-controlled model boats that were designed for racing (or scaled down from full-size sailboats) in that it carries a much larger payload (to handle the computers, larger batteries and solar panels) and was designed for directional stability, durability, ease of construction, one-person logistics (a MaxiMOOP weighs about 20 kg/45 lbs) and flexibility in rig and rudder choices. As of October 2019 about 30 MaxiMOOPs have been built or are in construction world-wide. While not as fast as a 2 meter SailBot, they do reasonably well competing or voyaging. ABoat Time averaged 2 knots on her four ocean voyages and in racing mode an average speed of 2.5 knots is common. Dewi (below) from Aberystwyth University has done quite well in multiple events. The 2nd and 3rd Place finishers at the 2018 SailBot regatta were both MaxiMOOPs!
For more information see this paper presented at the 2014 IRSC. Since that paper was written, MaxiMOOPs have accumulated over 1500 offshore miles of sailing. The proposed design modification at the paper’s end became the MaxiMOOP V3, which differs from the V2 design by carrying almost twice the payload with a slightly deeper keel. The speeds of the V2 and V3 are similar. Shown below is a USNA test boat with a light air racing rig.
This file contains the 3D iges file of the V3 MaxiMOOP. Hull molds (V2 or V3) are also located in Aberystwyth and Mystic, CT for those interested in building one. There are no royalties for using the design.
To be called a “MaxiMOOP” the basic hull shape (V2 or V3) cannot be significantly modified to increase length, beam or draft in a manner that will improve performance. There are no restrictions on the steering method, or rigs, but the boat must be propelled solely by the wind.
ABoat Time at the start of her first ocean voyage. She sailed about 250 NM before a scallop dragger made her the “catch of the day”.
As an initial autonomous sailboat platform the MaxiMOOP is a good compromise between portability, performance, flexibility, ease of construction, seaworthiness and payload.
Teams new to autonomous sailing develop their own strategies to achieve their goals. It is extremely challenging for a small team to build, program and sail one of these in a single academic year! In fact, it might never have been done! The successful small teams use a long-term approach with intermediate goals, perhaps the first year’s goal having a boat sailing under remote control with autonomous sail control, and then adding navigation the next year and experimenting with different rigs, sensors or controls.
Trying out a wing sail concept on “Mid Life Crisis”, the Naval Academy’s MaxiMOOP test platform.
Larger teams can accomplish more but require even better management skills. In this case there is often a “Boat Team” that builds the boat and gets it sailing under remote control (noting that a boat that does not sail well under remote control will not sail well under autonomous control) and a “Systems Team” that develops the systems. Almost all systems development can be done in the lab or on a mobile cart in a parking lot on a mockup representing the boat’s dimensional boundaries. The two teams come together about a month before the competition to integrate, develop and refine the on-the-water performance.