オーストリア＝ハンガリー帝国海軍
After "SS-3"s March 1911 launch, Whitehead tried to sell "SS-3" to the Austro-Hungarian Navy, but because the evaluation of the first two "U-5"-class boats was still underway, they declined to purchase. Over the next three years Whitehead attempted to sell the boat to the navies of Peru, Portugal, the Netherlands, Brazil, and Bulgaria, before the Austro-Hungarian Navy rejected an offer for the second time. With the outbreak of war, however, the Austro-Hungarian Navy purchased the unsold submarine to quickly bolster its fleet.