Frederick G. Knatz was born on October 23, 1896 in New York City. He is the son of Jacob Knatz (my grandfather’s brother) and Kate Hill. Fred entered the service as a private on May 14, 1915. He was promoted to a Sergeant on August 1, 1917. He departed for Europe on April 23, 1918 from Hoboken New Jersey on the troop ship Tenadores as part of Battery C, of 101st Field Artillery Regiment, 3rd Infantry Division.
During World War I, he was captured by the Germans when his unit was out on patrol. He was first reported as “missing in action” in the newspapers of September 5 1918. Only later when soldiers returned did the New York Times report on March 19, 1919 that Frederick had been captured by the enemy and taken prisoner while he was with a scouting party on July 15, 1918. In the course of helping the escape of a lieutenant captured with him, Frederick was shot and killed. His body was never recovered. 
Frederick is memorialized in the Tablets of the Missing in the chapel at Aisne-Marne American Cemetery at the Aisne-Marne American Cemetery in Belleau France. I visited the memorial in France in September 2014 to see his memorial and climbed up the hill overlooking the cemetery where you can see remains of the WWI trenches.
GEORGE H. KNATZ- his story coming soon
Pvt First Class George H. Knatz, born 3/11/1897 served from July 16.1917 through Jan 2, 1919. He is buried in Long Island National Cemetery. His wife Lillian is buried with him. George H. Knatz’s application for a social security card is given below. In addition his military records indicate he was severely wounded on or about September 2, 1918.
Sgt. U. S. Army Charles Conrad Knatz, born 2/24/1893, served from June 19, 1916 through April 3, 1919. He is buried in Long Island National Cemetery. His picture below is believed to have been taken in Camp Smith, New York, before he went overseas.
3. Sgt. Philip C. Knatz, born 12/23/1897, served from May 26, 1917 through Jan 26, 1919. He is buried in Long Island National Cemetery. His wife Margaret Anna is buried with him.
On the US Side, the following additional Knatz men registered for the draft in WWI based on a list of WWI Draft Registration cards, 1917-1918. Even though they registered, that does not mean that they served.
1. Harry Melvin Knatz, born April 26, 1894 in Maryland, registered in Allegany, MD
2. John Michael Knatz, born Dec 31, 1898, registered in Baltimore, MD
3. P.H. Knatz, born July 2, 1892 in Maryland, registered in Baltimore, MD
4. Edward Gerhardt Knatz, Jr., born Jan 2. 1892, in Maryland, registered in Baltimore, MD
5. Albert Frederick Knatz, born Nov 20, 1881, registered in Baltimore, MD
6. Arthur Charles Knatz, born Apr 21, 1900, registered in Monroe, MI
7. John Knatz, born Dec 1890, in New York, registered in Bronx, NY
8. Louis Knatz, born Jul 7 1877, registered in Brooklyn, NY
9. Adam Edward Knatz, born Aug 3 1881, registered in Brooklyn, NY
10. Robert Knatz, born Dec 10,1873, registered in Rochester, Monroe, New York
11. Henry Knatz, born Nov 16, 1872
12. Joseph Knatz, born Mar 11, 1898, registered in Athens. OH
13. Albert H. Knatz, born May 13, 1896 in Ohio, registered in Auglaize, OH
14. Carl H. Knatz, born Aug 29, 1888 in Ohio, registered in Auglaize, OH
15. Carl John Knatz, born Dec 10, 1897, registered in Auglaize, OH
16. Charles H. Knatz, born Jan 24, 1876, registered in Auglaize, OH
17. Gottleib Knatz, born 24 Jun, 1885, registered in Sheboygan, WI
18. Frederick William Knatz, born Dec 20, 1879, registered in Sheboygan, WI