This is the distance from the forward perpendicular (FP) to the aft perpendicular (AP). This is the same as LBP, but this term is more common in the big ship world.
Lo ngumgama osuka kunkqo ongaphambili. Ukuya kunkqo ongasemva. Oku kuyinto neLBP kodwa ke olu uhlobo luqhelekile kwilizwe lenqanawe.