Four components, and two 10" subs would be a good place to look. Due to the lack of accoustics in a boat, subs are a must.
One four channel (75 x 4) and one sub amp (600 x 1) would be my choice.
If the $1,000 has to include installation- forget it (I hear those installers get $75/hour these days)...you're back to a head unit and four 6x9's (depending on the boat).
My 2 cents.