Need help...could make you some lunch money

I have tried unsuccessfully to make an amplifier for my boat. I have used a couple of single board amps (XH-643 and LM386 off amazon) but the noise is just to great. Maybe the amp needs shielding..I don't know, but I do know I need help. As a 61 yo male I am no damsel, but I am in distress :cool:.

My email is [email protected] if you want to talk about my requirements.