79,Frame spacing

The fore-and-aft distance between the heels of two consecutive frames of a ship

In ships, frames are ribs that are transverse bolted or welded to the keel. Frames support the hull and give the ship its shape and strength.

Transverse framing

Transverse framing is used primarily for ships less than 120 m in length. The floors, frames and beams form rings spaced closely together. Longitudinal strength is provided by the keel, centre girder, side girders, deck girders, the entire bottom, deck and side shell plating, and the tank top. Transverse framing ensures good cross sectional strength to handle overall stresses, vertical loads, rolling and dry docking. However, on very long ships, sheer stresses can cause deformations between the rings.

The hull requires a plate floor every 3.05 m and a frame every 1 m. Hence there are 3 frames for every plate floor. The two frames are attached to the floor angle iron transverse.

For the aft framing of the aft peak tank or the for'd framing of the for'd collision bulkhead the maximum framing pitch is 0.61 m. Also for the for'd 0.2 l of the ship the maximum spacing of the frame is 700 mm (this helps to prevent damage due to slamming).

Underneath the engine seating a plate floor is required every frame.
The keel plate is made from heavier section of plate and has its ends tapered to allow it to be welded onto the normal hull plating 

Longitudinal framing

Longitudinal framing is mandatory for very large ships, oil tankers and bulk-ore carriers. The rings are formed of floors, deck beams and web frames that replace the frames. These rings are farther apart than in transverse framing. The longitudinal reinforcement members are deck girders, girders, the keel and a large number of deck, bottom and side longitudinal. The longitudinal are slender but there are very many of them.