It has long been considered that the most productive and cost effective welding position within the shipbuilding industry is the flat position (PA). To satisfy this, great emphasis is put in at the design stage to maximize the use of this position.
However. Even when adopting this philosophy, welding has to be carried out in a variety of other positions. Many shipyards have found major benefits when welding a specific section of the ship hull in the overhead position (PE).
Carbon steel to carbon steel link ups. Large block sections of the ship are welded together in the block building strategy. On each section there are a large number of webs, girders and longitudinal connections to be made, in addition to the main hull connection.
The bottom shell of the hill has traditionally been welded from the inside using a single V preparation, 60° inclusive angle 6mm gap feather edge with flat ceramic tiles on the outside to produce a single sided weld.
This weld requires no back gouging treatment, and for a time was considered to be the most effective way if completing the connection. However, there were disadvantages such as:
- Welding access,
- Obstructions from webs, girders, etc
- Potentially higher defect levels on multi pass runs passing through access gaps.