I’m not sure but I have a guess.
It’s my understanding that with the USCG (and likely also the Navy) the actual engineering expertise is held by Chiefs and the officers are mostly there as management. Since NOAA doesn’t have enlisted personnel they need to hire that specialized knowledge from outside.
They could if they wanted to as according to their requirements officers must have college level math and/or science education. But it is hot and dirty down there, not nearly as glamorous as standing in uniform on the bridge wing entering or leaving port.
It’s not about competent. The issue is competency AND cost. Civilians do the job better and cheaper.
oh yea, i forget that little detail !!