With the home side holding a narrow 7-3 lead, their try scoer James Coughlan wing Shane O'Halloran and prop Mick Powell were all forced to retire injured, Coughlan looking the most serious with a knee injury.
Ul Bohs took full advantage to score a try through wing Ian Hanley.
However, Dolphin out-half, John O'Mahoney repeatedly kept the visitors pinned back with his astute kicking and penalties from him in the closing ten minutes earned his side the valuable points.
In the only other game played Sunday, Bective Rangers were 18-17 winners over Highfield in Donnybrook.
AIB League Division 1 Belfast Harlequins 56-14 Buccaneers Blackrock College 8-8 Cork Constitution Clontarf 19-13 UCD Dublin University 5-6 Garryowen Galwegians 52-10 Co. Carlow Lansdowne 5-45 Ballymena Shannon 52-8 Dungannon AIB League Division 2. Barnhall 11-28 DLSP Malone 18-5 UCC Old Crescent 20-3 Ballynahinch St. Mary's College 27-17 Midleton Terenure College 27-13 Thomond Young Munster 29-13 Old Belvedere Bective Rangers 18-17 Highfield (Sun 20th Feb. 2.30pm) Dolphin 13-8 UL Bohemians (Sun 20th Feb. 2.30pm) AIB League Division 3. Ards 14-14 Banbridge Greystones 23-14 Connemara Old Wesley 11-12 City of Derry Queens University Belfast 8-31 Instonians Skerries 33-29 Corinthians Sunday's Well 62-3 Ballina Suttonians 12-15 Bruff Wanderers 13-11 Portadown