Who is the patron saint of navy?

There are no patron saints of the navy per se except for a few countries who have chosen a patron for their navies. However, there are a number of patron saints of mariners:Adjutor of Vernon

Andrew the Apostle

Anthony of Padua

Barbara

Botulph of Ikanhoe

Brendan the Navigator

Brigid of Ireland

Budoc of Brittany

Christina of Bolsena

Christopher

Clement I

Constabilis of Cava

Cuthbert

Erasmus

Eulalia of Barcelona

Francis of Paola

Gulstan

Hardoin of Brittany

Honorina

Idesbald of Dunes

Isidore of ChiOS

Jodocus

John Roche

Julian the Hospitaller

Lucy of Syracuse

Michael the Archangel

Nicholas of Myra

Nicholas of Tolentino

Nuestra Senora de Guia

Our Lady, Star of the Sea

Our Lady of Guidance

Our Lady of Mount Carmel

Our Lady of Solitude

Peter Gonzales

Phocas the Gardener

Spyridon of Cyrpus

Torpes of Pisa

Walburga