Here is a listing I found on blue tick coonhounds:

The Blue Tick Coonhound were also refered to as Blue Gascons or French Staghounds. The Bluetick Coonhound origin is from Louisiana bayous and the Ozark mountains in the southern USA dating back to the early 1900's.
Their is a possible trace of their ancestry to the French hounds such as the Grand Bleu de Gasgogne bred with Bloodhounds and some foxhounds.
They are eager and alert were they are used for hunting.
They have been known to follow a cold trail of the animal they are tracking.
The Bluetick Coonhound height is 21-27" (53-69 cm) and their weight is 45-80 lbs (20-36 kg).
The coat is short but dense, and coarse to touch, with heavy black ticking on the portions of white background. There are usually markings of a tan color on the muzzle, at the eyebrows, and bottom of legs.
They enjoys walking with children. This breed loves water and has a very good temperment. The blue tick coonhound is usually tri-color and has mottled blue or black tics of color in a white coat with tan markings on its nose and ears.
They have a tendency to run off unfenced yards and go hunting.

AKC classification: Not recognized
CKC classification: Not recognized
FCI classification: Not recognized
KC classification: Not recognized

I saw a picture of a blue tick coonhound on a webpage, and I think it's entirely possible that that's what your dog is - but my knowledge is very limited!
When I looked at Scrappy's picture, I thought Beagle(or Foxhound)/German Shorthair cross. Just an opinion, of course!

Welcome to Pet Talk! I have three greyhounds, and also a little dog whose breed background I will never know! So I know how you feel - my greyhounds have folders full of papers describing their lineage, but I can't even say with certainty what breed my Pup is!
-Jessica