bilge pump

been reading up in here, hoping to find my answer without having to post the question. anyway, my question is this.

i recently purchased a 88 v20. this is my first boat. every thing on the boat works fine. only there is not a bilge pump on the boat. the guy i purchased the boat from says this is a self bailing hull and i dont need one if i will be trailering the boat. my boyfriend (thats right, i'm a girl) says that anyone that runs a boat this size without a bilge pump is stupid. he is a fairly intelegent guy. but, has never owned a boat iether that i know of.

i will be running my boat in the lake till i get better at handling it. so, do i need a bilge pump on this boat? if so what kind? do i need it for the lake or just when i get ready for the gulf?thanks, and if someone responds to this question inaccurately (i read the admins post) i promise not to take legal action,lol. gotta love those admin ;) ;)