The "trueing" of the hull is pretty simply accomplishd using "feel" and some good plans. It helps to have a basic idea of what the finished shape should be and also some references. The class are pretty simple as most ships born before the war are, so getting that exact shape is pretty easy.
The American Fletcher Class destroyers were close in length, beam and draught to the British M Class, so using one of the Fletchers is a good common sense guide. Once you're happy with the overall shape of the hull, liberal coating with sanding sealer is mandatory. The sanding sealer gives the balsa wood strength and makes the wood smooth and glass-like for painting. Notice the dollar bill to give an overall size reference. 1/700th scale ships can be pretty small...
The mixed grey colors are combinations of primer, gap filling primer and other test sprays to guage both the smoothness of my hull and the watertightness of the wood. Ideally the wood should not pit or display a rough texture. Once that works, the scratchbuilding begins. For my ship, I've chosen to do a post-war "M" class. This involves removing the two forward 5.5" turrets and replaceing them with the newer 4.5" turret and a Hedgehog projector. The two tall boxes behind the Hedgehog are the ready use magazines.
To continue our journey from 1945 to 1948, the single 20mm guns on either side of the bridge have been replaced with twin 20's. Also, the pole mast is now a lattice mast. The original fire control director has been replaced as well. Aft of the smoke stack was a bandstand which had a quadruple pom-pom mount. Late war saw this replaced by two twin 20mm guns and a fire control director. This installation remains in 1948. Also unchanged is the quadruple torpedo tube unit.
The biggest change will be the removal of the midships searchlight platform and open mount 4" AA gun. In their place we have a tower that mounts two quadruple Tigercat SAM launchers and their dedicated fire control system. Aft of the Cats is an armored magazine providing sixteen more rounds. This AAW capability was pretty freakin' impressive for it's day. The aft twin turret was removed early 1945 and replaced with a twin 40mm "Hazemeyer" mount and another fire control director.
The last change would be the removal of the single 20mm gun and depth charges aft. In their place would be a crude central air conditioning unit and an early prototype towed array system. All parts have pretty much come from the parts bucket. The mast still needs some antenna spreaders and some radar on it.
The M Class would hold the line for the Royal Navy prior to the launch of the Leander Class Frigates and Town Class Destroyers. Once the new ships came online, the M's would be sold to Turkey. Value for money, the M's would last until 1971. At this point, the ship is built and all PE added except for the main mast. I am still searching for a photo that shows late 1940's Royal Navy radar fit. Also, she'll need to be rigged and painted. The color will be a white-ish grey that the Royal Navy adopted for Pacific use.