Otto Joseph Gerdeman, Jr., 87, of Defiance, Ohio went to be with his Lord and Savior on Wednesday, December 15, 2021 at his home. Born July 24, 1934 in Landeck, Ohio (near Delphos), he was the first son of the late Otto Joseph Gerdeman, Sr. and Marcella (Kroeger) Gerdeman. He is survived by his loving wife of 66 years, Constance (Macke), whom he married July 16, 1955 in Columbus Grove, Ohio. Survivors also include children Diana (Paul) Bauer, David (Denise), John, Michael (Kelly), Dennis (Dianne), Christopher, and Angela (Peter) Gerdeman; 14 grandchildren: Matthew, Kristin, Megan, Lindsay, Otto III, Benjamin, Sara, Michael, Jesslynn, Steven, Krysta, Kayla, Simon, and Ava; 16 great grandchildren; brother Merlin (Arlene) and sisters Yvonne Krysztofiak, Cheryl Kohler, and Marsha Gerdeman; brother-in-law Jerome Macke and sister-in-law Louise Teegardin. He was preceded in death by his siblings John Gerdeman, Joan Schumacher, Ethel Niese, and Romaine Schroeder; brothers-in-law Raymond Schumacher, Donald Niese, Rudy Schroeder, and Calvin Teegardin; sister-in-law Marilyn Macke; grandson Christopher Kit Gerdeman, and grandson-in-law Duncan Lowne. Otto was a 1956 graduate of Ohio Northern University with a B.S. in Civil Engineering and was a registered professional engineer and licensed professional surveyor.   He began his engineering career with the Ohio Department of Transportation and later took a position as the Defiance City Engineer, which is where he and Connie established roots and built their life.  He worked at E.C. Gerken & Associates, then Poggemeyer Design Group, where he became a partner. Retiring from Poggemeyer in 2008, Otto continued as a consulting engineer for several nearby towns, as well as property developers in Defiance and Paulding, up until the time of his death.  Otto loved being an engineer - it was a calling and not just a profession to him; this was evident by the respect he received and the inspiration he was to many, including his children and grandchildren. He was a member of the Defiance Lions Club, Defiance Rotary Club, Defiance Regional Medical Center Board, Defiance County Senior Center Board, Maumee Valley Chapter of the Ohio Society of Professional Engineers, and the National Society of Professional Engineers. He was a Bunny League coach for many years and was a Boy Scout leader with Troop 76. Otto encouraged and supported all his children and grandchildren in their educational pursuits and professional careers. His family was his pride and joy. An active member of St. Mary Catholic Church, Otto was always involved in lay ministry. At different times, he was a lector, lay distributor of the Eucharist, volunteer with the Furniture Bank, and was very committed to the RCIA (Rite of Christian Initiation for Adults) program, passionate in helping others come to the Catholic faith. His faith in Jesus was paramount in his life. Otto had a life-long love of everything outdoors, as demonstrated by the numerous fishing trips and hunting expeditions he organized for his many children, grandchildren, and friends.  He always seemed happiest while spending these special moments with those he loved.  The only thing that seemed to make him nearly as happy was the countless hours he spent in his woodworking shop creating grandfather clocks for all his children, and rocking horses, hope chests, and toolboxes for all the grandchildren and great grandchildren. Visitation will be Sunday, December 19, 2021, from 2:00 p.m. to 6:00 p.m. at Schaffer Funeral Home, 529 Jefferson Avenue, Defiance, Ohio 43512. A Catholic vigil service will be held at 6:00 p.m. The Mass in celebration of Otto's life will be held at St. Mary Catholic Church, 707 Jefferson Avenue, at 11:00 a.m. on Monday, December 20, 2021. Burial will follow at Riverside Cemetery, South Clinton Street, Defiance. The family suggests memorials in memory of Otto be made to the St. Vincent DePaul Society c/o St. Mary Church, or to Relay for Life of Defiance County. Due to the ongoing COVID pandemic, the family is requiring all who visit the funeral home and come to the services to wear masks.