Well, realistically speaking, you'll probably be doing around 10 knots on the crossing, especially so if doing the trip with another boat that can't do more than 10 knots.
On top of which, you have to allow for the northerly set of the
Gulf Stream.
As the crow flies, the distance from WPB to WE is around 65 miles, but seeing as you'll be crabbing across, you can expect to add to that, so say, 70 miles.
Converting that to nautical miles is about 61 nautical miles.
Plus add some miles from wherever you are docked to the inlet, etc, and allowing for some
safety factor, etc, you might want to figure on around a 70 nautical mile trip.
At 10 knots ave. that is 7 hours.
Finally, no telling what the
weather will be doing, but a northerly
wind tends to set up some seas, likely causing you to slow down even more. Even a 15
knot SE breeze will set up some waves for you to contend with.
I can guarantee you that bashing into waves is gonna knock the fillings out of your teeth. Powerboats tend to be quite rolly in those conditions, and you can expect to rocking from side to side, so hopefully you (and crewmates)are not prone to seasickness.
There is no telling what the
weather will be. You might get lucky and have all smooth sailing, but more than likely, you can expect some
wind and waves on the nose. If the weather gets to be really gnarly, crossing is not likely to happen.
Just some
food for thought for you.