The hull of this kit poses a couple of serious problems. First, the hull is approx. 1/4 inch too high at the bow, and about the same amount too shallow at the stern. When I did the Cushing (DD-797), I struck a line from 1/4 inch down the bow back to the stern, then proceeded to cut away the 'wedge' from the top of the hull. This worked quite well, and actually resolved some issues upcoming with the main deck.
Technically, the hull of the Fletcher at the main deck is actually concave towards the stern. The kit's original hull line is straight, and unless you're very careful, your best bet is to keep your cut straight as well. Although it is quite noticable as you're building, it is reduced by the addition of the superstructure later on.
The stern is far too shallow, and fixing it is a royal 'rochambeau'. I was originally inclined to correcting this problem, but decided to do a quick fix instead. The angle of the stern to the keel is far too great. On the kit, the stern meets the keel between the No. 4 and 5 turret. Plans indicate the stern meets the keel around the center of the after deckhouse, between No 3 and 4 turrets. I struggled with a way to fix this, thinking a belt sander was a good idea,until I realized I was cutting into the sidewalls of the hull, and would be reducing the depth of the stern even further. I ended up layering several sheets of styrene onto the underside of the hull, then feathering the laminate into the contour of the stern.
It succeeded in adding some depth to the stern when viewed from behind, but obviously didn't correct the angle in profile. This also allows you to cover up the holes for the twin rudders and the prop skegs. If you decide to model any of the last four ships in the class, DD-801 thru 804, KEEP THE TWIN RUDDERS! That's right, Lindbergh wasn't technically wrong with the twin rudders. The last four ships in the class were fitted with twins as a design test-bed for the Sumner Class. Lindbergh decided to call this ship the 'Blue Devil', the USS Melvin, which had the single rudder, so..it's wrong. Had they called it the USS Calhoun, Gregory, Little, or Rooks, we'd be OK. By the way, all four ships were square bridge, all wore dazzle patterns at one point, and all wore Ms. 21 or 22, so the only difference is the hull number, basically.
The props are, as you may have guessed, wrong. Fletchers carried 3 bladed props, not 2 bladed. I got lazy at this point, and simply put the two blade props on. I have since gone to my local shop, and purchased a pair of scale RC props from Dumas boats. They look perfect. The prop skegs are far too short, you can use the line drawings above to scratchbuild new ones, but the support struts are within acceptable tolerances.
That completes the modifications that need to be made to the hull. There are a couple of plan view issues with the shape of the hull when viewed from above, but if you consider fixing these errors, save yourself hours and hours and scratchbuild a new hull.
Estimated time to accomplish hull repairs: about the same amount of time to build a real one.