【多选题】Which of the following are correct descriptions of Duct center girder箱形中桁材(also called Duct Keel箱形龙骨)?
A.
It is a watertight box structure composed of two symmetrical trusses(对称桁架) on both sides of the bottom center line, the inner bottom plate, the bottom plate and other aggregates(骨材).
B.
It is generally arranged between the E/R bulkhead and the anti - collision bulkhead (防撞舱壁).
C.
The Duct Keel can also be used to centralize the distribution of various pipelines and electrical cables in order to protect and maintain the equipment and avoid the pipeline passing through the cargo hold to impact loading and unloading.
D.
A watertight manhole and an emergency exit leading to the open deck are arranged in the duct keel, the closing device of which can be operated on both sides.
E.
It is a transverse structure.