Otoko no Tabidachi: WILD ADVENTURE

Yoichi, the older brother, is quick to fight but has excellent athletic ability, while Shinji, the younger brother, is a genius boy who can speak seven languages. The two polar opposite brothers go on a trip with their family on a yacht, but an unfortunate accident occurs and the yacht capsizes... Separated from their family, the brothers end up washed up on a certain sandy beach, but...!?