bilge pump

[willy]

Parrot, welcome and what water you have the boat in makes no difference. The self bailing hull refers to the boats ability to drain water that comes on deck from waves rain swimmers dripping etc. But there are numerous ways water gets below the cockpit floor under normal conditions and in a collision with an object, floating log rock dead terrorist some V20 snagger left behind or other problems such as a thru hull breaking etc. will cause your boat to flood out and sink or at the very least cause it to roll or make handling the boat to safe waters hard or impossible.
Whether or not you are trailering or keeping the boat in a wet slip you should have a bildge pump installed. In fact it is the considered opinion of many boaters that there should be two installed on every boat. Each tied to a different battery, oh yea you should have two battery system also for redundant safety just like the two pumps.
Some guys here who I respect very much don't even have a pump on their boats and run off shore all the time. But as much as I love em they are tempting fate and living dangerously in my opinion. And I wish they would change it. I don't want to mention any names but one in particular talks with the wind and has a velour decorated cuddy with handcuffs attached to the starboard bulkhead.
Go with the pumps it is for your safety and they work, in fact often times you may find out you have a problem going on you did not realize because you noticed your bildge is pumping out the side for some reason.
JMHO