Lots of ways to make those 55's much heavier to the muscles. Might try the one and one half system, which should make those 55's feel that much tougher. Probably want to start with a pair of 30's or so. Incline or flat, start the press with the the DB's from the bottom position all the way up and lower only halfway down and than all the way up again. Now lower all the way down to the starting bottom position. That would be one and one half rep. Brings more time under tension (TUT) to the chest area rather than just throwing up the DB's like a lot of people do. The reps are slow and controlled throughout the movement. Aim for 8 to 12 reps. You should get a very good pump in the whole chest area. 3 or 4 sets.
As suggested, dips are an excellent muscle mass exercise. Might try a set of dips follower right away by a set of incline/flat DB bench presses. Probably you will start with a lower pair of DB's. Effective SS for the chest area. If a Tri set peaks your interest, than start with a set of push-ups of 12 to 15 reps. Without rest do as many dips (bwt) as you can. For the last phase of the chest workout grab a pair of DB's to do inclines and try for 8 to 12 reps. Try for 2 or 3 cycles of SS's or tri sets. Again, you should get a traffic pump in the whole chest area. Though a super pump it's self is never a suggestion that muscle mass will follow.
Another version of DB presses is to start with a hammer grip (fingers of the hands facing each other) and the DB's touching the side of the chest area. Now press the DB overhead but keep the elbows nearest the body at all time, never have the elbows flair out. As the DB's come up, twist the grip/wrist so at the top/finished position the fingers are facing forward. That should make the 55's (or whatever you are using at the time) feel that much heavier.
Might even consider doing GVT (10X10's) with those DB's and see what happens. GVT should improve your regular bp also.
When you service requirements are done at the academy (Coast Guard?..Merchant Marine?) and you get a duty station you should be able to hook up with a regular gym somewhere. The above example are just to hold you over until you can begin starting a more serious and heavy lifting program. Though, for a lot of guy's, this type of training (1 & 1/2, ss & tri sets) have built impressive muscle in the past. Thinking of the classic BB'er of the late 60's and 70's. Good Luck.