Tuesday, July 24, 2012

Ship Dimensions

Length Between Perpendiculars (LBP)
This is the distance between the forward perpendicular (FP) and the aft perpendicular (AP). It is usually called LPP for large ships. For small vessels, this value is usually equivalent to LWL.

Length on the Waterline (LWL)
This is the distance from the intersection of the waterplane at the bow, to the intersection of the waterplane with the stern. Often, this term is used to mean the design or target waterline length. See also DWL.

Length Overall (LOA)
This is the length of the boat from the tip of the bow to the furthest point aft on the stern.

Aft Perpendicular (AP)
This location is usually at the end of the design waterline (DWL) or located at the rudder post for large ships.

Forward perpendicular (FP)
This is the position on the boat where X=0. Usually this is set to the forward end of the design waterline

Depth (D)
This is a vague distance usually defined as the distance from the bottom of the hull (without appendages) to the highest point on the sheer line. If the program uses this number, it is only for sizing purposes and need not be perfectly accurate.

Freeboards (F)
This term refers to the distance from the waterline to the sheer line. Often, freeboards at very specific locations are needed, in which case you have to be very careful in determining exactly where and how the freeboards are measured. Sometimes the sheer point is not well defined.

Draft (T)
This is the distance from the baseline (Z=0) to the waterline at amidships. Normally, draft is used to mean the distance to the design waterline(DWL), but it often depends on its context of use. In addition, the bottom of the boat is usually located at the baseline so that draft refers to the distance from the bottom of the boat to the waterline. However, if the bottom of the boat is NOT located at the baseline, you still must calculate draft from the baseline.



Sunday, July 8, 2012

Submarine

Submarine
A submarine is a watercraft capable of independent operation under water. It differs from a submersible, which has more limited underwater capability. The term submarine most commonly refers to large crewed autonomous vessel. however, historically or colloquially, submarine can also refer to medium sized or smaller vessels. Submarines are used for tourism, undersea archaeology, military etc. Civilian uses for submarines include marine science, salvage, exploration and facility inspection/maintenance. Submarine can also be modified to perform more specialized functions such as search and research mission or undersea cable repair.
Most large submarine consist of a cylindrical body with hemispherical ends and vertical structure, usually located amidships, which houses communications and sensing devices as well as periscopes.

Submarine
Automatic Submarine
Details