getLandBasesWorstCond = () => {
        var worst = 1;
        $.each(PlayerManager.bases, (i, base) => {
            if(base.action === 1) {
                worst = Math.max(worst, base.worstCond());
            }
        });
        return worst;
    }
@return {number} the worst cond value [1, 3] of all land bases which are set to sortie.
@see PlayerManager.bases
@see LandBase.worstCond