Mannschaftsmütze or the Bordmütze?

[geahanse]

During the war and even in the later war years, which kriegsmarine cap was most often used on a surface ship? The Mannschaftsmütze (the donald duck cap with the tally) or the Bordmütze (the side cap that was worn on uboats). Was there a certain reason to wear one or the other? In the film U 571, the scene with the German destroyer shows sailors wearing both..not saying that its accurate because its a movie but could this have been the case? Also, did they only wear white or blue depending on the season and weather or could they wear whichever they chose? If I'm not mistaken there was a version of the Einheitsfeldmütze cap in not only tropical tan but in field gray also..was this only for ground units or could sailors wear that one on ships too? I know this is a multiple part question but I can't seem to find the answer anywhere. Thank you