the pump is not jammed,even with the pump and float switch unpluged it still blows fuses.Ayuh,.... Welcome Aboard,.... Like Bob said, it's either jammed, or burnt out....
The Big question is,.... How hard is it gonna be to Get To,..??
or the pump is shorted either way your looking at some troubleshooting, Got a Digital Volt Ohm Meter(DVM)?
Also your location would help as will your being around more, at this rate it will take all summer to get your bilge working correctly.