Not a good year, to say the least!
These incidents are not unique though, either in being accidental losses or in being returned to service. In March 1915 the American submarine F-4 and her crew were lost of Hawaii on a test dive. She was savaged later in the year, and examinations of her hull led to the correction of design defects in all existing and future US submarines, saving countless lives over the years. She was not repaired though, as she had been damaged during salvage, but the hull was not disposed of until 1940.
In 1925 the US submarine S-51 was on a training exercise when she was accidently rammed on the surface by the steam ship City of Rome. She sank with only three crew members escaping. She was salvaged the next year, and eventually sold for scrap.
In 1926 the US submarine S-4 surfaced from a training dive and was prompty rammed by a Coast Guard cutter. 6 men survived and were trapped, but efforts to save them failed. the boat was raised 18 months later, repaired, and served for several more years until being retired.
All in all the US Navy has lost 18 submarines over the years (all but 3 before or during WWII) to accidents, claiming 765 lives. But to their credit the US Navy has not lost a submarine in 40 years, after significant changes were made to the submarine construction and testing programs following the loss of nuclear submarines USS Thresher in 1963 to a bad pipe joint, and USS Scorpion in 1968, probably due to a defective torpedo battery.
The British, French, Germans, Russians, and other suffered many accidentlal losses also before and during WWII, with the USSR having probably the worst safety record. I know Russia and the UK both returned salvaged subs to service also.