Seamanship 6: Sample problem solving. How to get GM (Metacentric Height) using method A and method B

A ship of 5000 tonnes displacement enters a drydock trimmed 0.46 meter by the stern. KM=7.6 meter, KG=0.6m and MCTC=125 tonnes meter. The Centre of Fluotation is 65m from aft.

Find the effective metacentric height at the critical instant before the ship takes the blocks overall, assuming that the transverse metacentre rises 0.076m.