TAZ5 producing rough surface

I tried printing a part for a model U-boat, but for some reason, every time I print a particular part, the surface come out rough. The unusual thing is that only the bottom surfaces are rough for about a couple of centimeters, then the part prints out smoothly. I don’t know what is going on, but it seems to be only this part. Every other part prints without issues, and I changed the print speed several times from 20mm to 50mm a second, buy the flaws continue to appear at the exact same location. I’m currently printing with PLA at 200 C. Here is a picture below. Notice that the flaws are only at the bottom. Is there something wrong with the G-code?

Is the flaw just on that one side? if so, when printing where is that flaw located in relation to the cooling fan? specifically is it opposite from the stock cooling fan location? and are you running a second cooling fan?

The flaw is greater o one side, but still noticeable on the other. I tried again by rotating the parts printing orientation in Cura to see if that would solve the issue, but the flaw stayed exactly the same. I don’t think it is the cooling fan. Ive printed other parts that are similar in size and shape, but without any flaws

Excessive exposure to humidity can cause that pattern… Were the similar parts printed with a different spool of filament?

The parts were all from the same spool. I live in a desert so humidity should not be a large issue. Adjusting the flow rate seems to reduce the amount of flaws. I’m currently building the part again at 90% flow rate and so far, there has not been any issues

I’m still fairly new to this world, so take this with a grain of salt.

Is it possible it’s areas of overhang that are printing that way. Looking at the picture it seems like those lower areas might be areas of overhang. I’ve read tips to improve overhang, to try reducing print temperature (presumably so it cools mid air quicker). Slowing + cooling might be a bad combo though so adhere to the common warnings - change one seeing are a time. Maybe try 195? (I’ve had some success with pla at 195).

Reducing layer height may also help.

Anyway, my best guess is that this is from the overhang.