Hello all! I am new to the audio scene. I haven't messed with car stereos since I've been a kid (11 years ago)

I just bought a boat. Its an 18 footer. It has a stereo system, which i upgraded with a JBL marine head unit, and Infinity Reference 612m speakers.

I am now looking to add a subwoofer. The boat has plenty of room and the girls love stereo systems!

I think i would like to go with a 10" subwoofer. HOWEVER, I don't want something too powerful, because I dont want to drain the boat battery too fast. I dont want something expensive either. I have already spent enough on the boat as it is.

Can anyone reccomend me an amp and sub combo? Maybe just watt reccomendations? I know RMS is what i need to be looking at correct? Forgive me its been a LONG while. THANKS EVERYONE!