Ship Framing System has an essential role in ship building. A ship is subjected to various stresses and the shell plating is not strong enough to withstand these stresses and it requires to be framed throughout the length.
Components of Framing
Following are some of the main components used to frame the vessel:
| Frame |
: |
On side plating, running vertically (up and down) |
| Beam |
: |
Under decks, runs transversely |
| Transverse |
: |
Under decks (deck transverse) and on bottom plating (bottom transverse) but not in Double Bottoms. Runs transversely but much heavier in construction than a beam. |
| Floors |
: |
Found only in double bottoms, running transversely. |
| Stringer |
: |
On side plating and longitudinal bulkheads, runs horizontally, forward and aft. |
| Longitudinal |
: |
Found in longitudinally framed ships, under decks, on side plating, on longitudinal bulkheads, on bottom plating and under the tank too. These members run fore and aft. |
| Girder |
: |
Found under decks and on the bottom plating. Girders run forward and aft and are deep and heavy in construction. These are important longitudinal strength members. Also increase the breadth of the forecastle and provides space for the mooring. |
| Scantlings |
: |
A ship construction term used generally to define dimensions of various parts of the structure. Used to mean breadth, length, diameter, thickness, height etc. |
Different Types of Framing
Transverse Framing
This is system of framing is used in vessels of relatively less length, where longitudinal bending moments are not excessive. The framing system consists essentially of rings of strengthening around the shell plating.
Under the deck, deck beams are fitted at every frame space. A frame space is the distance between one frame on the side plating to the next frame.
On the side plating, frames are fitted to stiffen the plating. The deck beams are connected to the frames on the side by means of beam knees. Beam knees are very efficient connections as compared to joining the bean directly to the frame.
Longitudinal Framing
This is a common method of framing found in long ships usually those exceeding 100 m in length. The system is designed to withstand longitudinal bending moments, which are pronounced in long vessels.
The main feature of strengthening in this system is the longitudinal – an L shaped stiffener, which is fitted under the decks, on the side plating, on the bottom plating under the tank top and on the longitudinal bulkheads as well. The longitudinals run the full length of the vessel, from forward to aft, providing longitudinal strength.
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