General Launching Particulars

The draft and trim are calculated for each interval of travel, allowing for camber and the position of the ship relative to the ground ways. The draft and trim are then used to interrogate the geometry model in order to determine the transient hydrostatic particulars. The buoyancy, moments of buoyancy, moments of weight and pressures on the fore poppet and way ends are computed allowing for stern lift. The process is repeated for each interval of travel until either the buoyancy is greater than the specified launch weight or the limit of the number of increments is reached.

When the moment of buoyancy about the fore-poppet exceeds the moment of weight about the fore-poppet, the ship is then balanced about the fore-poppet to give the draft at the AP.

Once the stern has lifted the pressures on the way ends and fore poppet are no longer given and the program continues until the ship finally floats off or passes the way ends and drops off, that means, suddenly becomes unsupported. No attempt is made to estimate the severity or consequences of the drop off. The free float drafts at the AP and FP are then calculated.

After the three tables of launching particulars have been produced, a series of parabolic interpolations are performed on the various curves in order to determine the stern lift characteristics, anti-tipping moments and any drop-off as follows:

• Stern lift travel.

• Loads on the fore-poppet at stern lift.

• Fore and aft drafts at stern lift.

• Maximum tipping or minimum anti-tipping moment and corresponding travel. Maximum pressure on way ends at corresponding travel.

• Free float drafts.

• Drop-off at fore poppet.

The output is also presented in graphical format.