Tinsdale was a Grayson citizen and an officer of the Grayson Space Navy. Holding the rank of Commander, he served as the commanding officer of the light cruiser GNS Nathan. In late 1908 PD, he was charged with transporting Lady Honor Harrington, Steadholder Harrington, back to Manticore for her return to active duty with the Manticoran Navy. (HH6)