Multihull sailboats have significantly improved stability but poor maneuverability compared to monohull sailboats under the same conditions. Therefore, this article proposes a convertible autonomous sailboat based on the transformation of an autonomous sailboat. This article analyzes and studies stability improvements that validate our design and analysis in calm and turbulent water. It turns out that in the absence of waves, compared to autonomous sailboats, our convertible autonomous sailboat has a speed loss in the range of 25% to 30%, but its stability improved by 84.13% to 88.77%. However, in the presence of waves, the velocity loss is only 15.56% to 24.44%, but the stability improved by 92.37% to 94.78%