Method 3 alternative 1.

The extracted factor can be used directly to determine a correction in tones to apply to the final displacement.

Correction (tone) = factor x TPC x hog/sag (cm)

Where: hog/sag (cm) = (DM-AMD) x 100

Method 3 alternative 2.

The graph or table itself may be adapted to give a correction table directly in tones (i.e. factor X TPC) for each centimeter of hog or sag. This would give a correction to apply to the final displacement by entering the table with the AMD and the hog/sag in CMS.

Other alternative methods.

These require additional draught/freeboard measurements at points other than perpendiculars and midships, along the vessels length. This is very difficult to establish.

CORRECTION FOR TRIM

There may be a total trim correction table included in the stability information book. This will normally combine the following 1^st.and 2^nd.corrections. Find out what it includes, and examine the ships stability data carefully before conducting a survey.

First trim correction (Correction for Layer)

The displacement scale is normally calculated on the assumption that the vessel is lying on an even keel. The first trim correction is to correct the draught midships to the true mean draught, at the center of flotation. This correction is known as the correction for layer (or layer correction).

AP Midship FP