Help with problem on revo 13 chair.

i've been out a couple times on my revo 13 and by the end of my trip i'm sitting in a puddle of water. Should I replace my scupper plugs under my chair? Also is there anyway to upgrade my chair to the new vantage chairs? Trying to make the yak more comfortable, this last trip ruined my back.. need help with a lot of things. Any of advice will help !!

Generally you want the scuppers unplugged so the water drains out.

I don't know anything about your age, size, or physical condition, or anything about back problems you may have.  And you didn't identify the model year of your Revolution, so I don't know what kind of seat you have.  But I have a 2014 pre-Vantage seat Revolution, and have a couple of general thoughts which may help you. 

First, a Revolution is not a Barca-Lounger reclining chair.  It's a pedal-driven kayak.  Tighten the straps which hold the seat back until you are sitting quite upright.  Then adjust the pedals until the fins don't quite hit the bottom of your kayak when your forward leg is almost straight.  On the back stroke, your knees should come pretty close to your chest.  Look at still pictures of bicycle racers, and note the relationship between their chest and their thigh when the pedal is at its highest position. One reason bike racers lean over is to reduce wind resistance.  But this position also produces a powerful pedal stroke. If your seat is leaning way back, your pedal stroke won't be as efficient or powerful.

Second, don't slouch in your seat with just your shoulder blades touching the back of the seat, and with your lumbar region unsupported.  Slide your butt back until the back of your hips is supported firmly by the back of your seat, and your back is straight and upright.

Third, experiment with the lumbar support provided by your seat.  If your seat has a thermarest-style lumbar pad, try blowing it up more firmly.  If that doesn't help, try adding a piece of closed-cell foam or other pad which firmly supports the back of your hips.

Fourth, remember that pedaling a Hobie kayak is a physical activity, and that you may need to get in shape for this specific activity.  Experienced and fit bicyclists who switch from an upright bike to a recumbent bike typically notice that it takes them several months to develop the somewhat different muscles which are used to pedal a recumbent bike.  Keep pedaling around and fishing, and if you follow the previous suggestions, you may find that your back problems disappear as you get in shape for pedaling a Hobie.

I find that if the back of my hips isn't supported firmly, and I'm not sitting upright, my back can start bothering me after a couple of hours of pedaling.  But if I sit upright with the back of my hips firmly supported, I can pedal for 8-10 hours for day after day without any discomfort.  I hope that these suggestions help you.  But unfortunately if you have significant back problems, none of these suggestions may help you, and buying a new kayak with a Vantage seat may not help you.