hot water runs out QUICKLY

Hello. My hot water starts to run out during a single, normal shower.
I have a State Industries GS650YBRT-200 50 gal. gas heater that is only 1 year old. I just moved into the house, so I do not know when this problem started.

What to do? I'm a plumbing newbie. My common sense tells me that turning up the temperature would not help the problem. The water comes out plenty hot at first.

Call in a professional or are there some things I can check on my own?

Many thanks,
Eric

heater

Without knowing what the heater's setting is now, it is impossible to tell if raising it would be the cure, but it may very well be.

The hotter the tank outlet, the less of it you use to maintain the same temp in the shower. The danger is that if you forget, you could scald yourself. The solution to that is to install a tempering valve at the outlet of the WH, this is the equivalent of you mixing in more cold, but it prevents the likelyhood of getting scalded if you forget and open up the hot too much.

How long does it take before the water runs out and what is the flowrate of the showerhead?

Assuming this is something less than 10 minutes and it is ~2.5 gpm showerhead, then perhaps the dip tube is broken?

It does sound like a broken dip tube. That is not a normal thing in a 1 year old heater, but things happen. The dip tube is located inside the water inlet and is easily removed and replaced.

heater

10 minutes with a 2.5 gpm head is 25 gallons, which is about par for a 40 gallon water heater, and even a 50 if the temperature were set at 120 or below. A broken dip tube would produce about 10 gallons before going cold, and would not have any point where it dropped to warm first.