front rear and sub amp wiring

Hi, i was just wondering if i can do what I'm going to explain. I want to run my rear speaker and a sub off my 4 chan amp, but I would like to install a front set of speakers as well. Is it possible to just run the front speaker off my deck power while using the rca output for the sub output to the amp. I don't have a sub output on the deck. i should mention this is for a boat. I just would like to add some fronts just to make it easuer for the front person to hear the radio while fishing so I don't have to turn up the back speakers to loud. Just looking for some advise on this or recomendations on what I should do without spending a lot of cash. Thanks fo rany help

You can do it if thats what your budget allows. If it were me I would look for a 5channel amp. It would make everything easier.

Thanks. I wasn't sure I could use both outputs at the same time. I might look at a 5 channel as well. I just purchased this 4 channel so I would take a bit of a bath on it if I tried to sell it to move to a 5 channel. I guess the other problem I would have is using the fader would also affect the channel I run my fronts with. Thanks again

I'm thinking stay with the 4ch & ditch the sub. It'll scare the fish. Seriously I'd have even power all the way around or you'll risk loud spots & quiet spots, it'll be weird & you won't like it. As for the sub I'm thinking the open air environment is going to screw with your acoustics. A couple midbass drivers might sound better.