I'm going to step into this thread as an urgent care physician and clarify a few general things so don't take this as specific medical advice for your situation. A lot of different things can cause urinary discomfort so see a doctor on board or in port if you can.
Drinking lots of non-alcoholic, non caffeinated, low/no sugar clear fluids can help to flush bacteria from the bladder.
Cranberry juice can be helpful but not curative. And it needs to be 100% juice, tart, nasty stuff. Cran cocktails are basically sugar water. Not recommended and could make things worse.
AZO can be helpful for symptom control but it will throw off the urinalysis dipstick results and if you cannot get a urine culture on the ship (which is understandable) then you and the doctor are guessing about your diagnosis with a discolored urine strip, unless you have multiple convincing symptoms of an infection.
We have a decent amount of resistant bacteria causing UTIs in this country and it doesn't matter if you have had a lot of antibiotics in the past or not. We all get colonized (gross, I know) by environmental bacteria and some of this is resistant. If you get medication on the ship for a UTI and it's not working then consider asking for a different antibiotic or consider a non-infectious cause for your symptoms.