Lofrans’ Official Australian Distributor – Southern Seas Marine The space available above and under the deck is the primary element to be considered when selecting the proper type of vertical anchor windlass. A Vertical anchor windlass features a vertical rotation in relation to the deck which allows a reduced volume above deck as the electric motor and the gear box are sitting in the chain locker. Also keep in mind that the height between the top of the stacked chain and the underdeck must be 300 mm minimum in order to ensure a fast dropping of the chain in the locker and an optimum performance of the windlass.​