A whole range of different hand pumps have been used as bilge pumps - piston, plunger, semi-rotary and diaphram - I guess any pump that will do the job, this one included, would make a good bilge pump - if not for a designed for use on a canal boat, maybe a sump pump for a basement area?? The lack of integral fixing brackets suggest these may have been fixed to the frame or wall, and the pump removable for servicing etc.. Are there any marks on the barrell indicating where it may have been clamped???