Gershom Bradford, 98, a retired senior nautical scientist with the Navy Hydrographic Office, died Wednesday at Sibley Memorial Hospital. He had been a resident of the Wisconsin Avenue Nursing home for three years.

He joined the Hydrographic Office in 1908 and retired in 1942. He then conducted classes in navigation for naval reserve officers for three years.

Born in Kingston, Mass., Mr. Bradford grew up in Duxbury, Mass, and was a graduate of the Partridge Academy. Trained to be an officer in the merchant marine, he was a bridge officer on East Coast steamers for the U.S. Coast and Geodetic Survey before joining the Hydrographic Office.

Taking time from the Hydrographic Office, Mr. Bradford became navigator of a training ship, the U.S.S. Newport, in 1917 and was appointed its executive officer with the rank of lieutenant in the Navy Reserve when it was taken over by the Navy a year later.

He later spent two years as a navigation instructor with the U.S. Shipping Board School in Boston. He was licensed to command vessels of the U.S. Merchant Marine.

Mr. Bradford was the author of a number of books on the sea and contributed of books on the sea and contributed articles to newspapers and maritime magazines.

He was a member of the Society of the Cincinnati, the Naval Historical Foundation, the Society of Mayflower Descendants, the Pilgrim Society, the Bradford Compact and the Duxbury Rural and Historical Society.

There are no immediate survivors.