Strength; Space inside; Sailing ability. All boats are compromises with different formulas. Skip space; you need less than you think. Go for full keel, with hung rudder, so you can hit that container offshore or reef, and keep going. Forget balsa core, get a solid solid glass hull. Look for a boat that will sail off a lee shore without a motor, that can compete in cruising class racing, and that is easy to single hand and sail with just a bungee cord on the tiller. Think something like an Alberg 35, and you're affordable.