DO NOT CRIMP !
End of story, crimping on a boat is a no no. crimping to a bilge pump is lunacy.
Crimping is a cheap and cheerfull method of making a terminal connection.
Solder. JUST LIKE the MANUFACTURER OF YOUR BILGE PUMP did when making it.
There is NO argument between solder or crimp. There is nothing brittle about a soldered joint IF Its been made correctly and the cables dressed accordingly (hellerman sleeved etc)
When it comes to critical systems YOU solder OR you get someone in who knows what they are doing to solder it for you.