Daniel,
Here goes:
GENTLEMEN'S DRESS
Gymnasium - Most men would have been in trousers and a sport coat (or cardigan) over a button-front shirt (with collar and tie) or else a Norfolk suit worn with a tie. Caps of the snap-brim variety or other casual styles would have been worn. For strenuous exercise, a man would have removed his coat/cardigan, and collar and tie, naturally. Mind you this was shipboard so consideration would have been paid at all times to the necessity of walking through corridors where one might encounter blushing ladies. So no man, excepting a die-hard athlete, would have actually walked through the ship in a sleeveless shirt and shorts. The chilly weather also would have (hopefully) prevented this lapse in decorum
.
Another choice of attire for a fashionable male in the gym would have been a pullover sweater and trousers. The possibilities really would not be very unlike clothes which a particularly natty golfer might wear today. The difference would be only in the details. For instance, trouser legs were narrower and shorter (so that socks showed). Suspenders were worn quite often. Collars were stiff and removable. Materials were finer - tweed, cheviot, mohair, heavy grade cottons, and pure linen.
Turkish Bath - A man would have entered the Turkish Bath in normal dress, whether sportswear or street clothes. He would then have undressed completely (or at least down to undergarments) and gone into the steam-room robed.
Swimming pool - Again a man would have arrived at the pool in sports clothes, undressed, and emerged in a bathing suit, then a snug, dark-color, one piece affair generally, short sleeved or sleeveless, with trunks about thigh-high, sometimes longer.
LADIES DRESS
Gymnasium - Women would have worn either a casual shirtwaist (blouse) and skirt, covered by a loose sport-jacket or coat, or else a sports dress of a light wool or linen which would have been open-necked, three-quarter sleeved, simply belted or sashed, the skirt being of moderate width, perhaps pleated, and reaching to the ankles (or just above after the fashion of lady tennis players). A tie or flat bow or some sort of a jabot or fichu would likely have trimmed the neck of the blouse or dress bodice. Bloomers of jersey or satin and a light linen shirtwaist would have been the choice of very health-minded ladies. Hats and caps of simple shapes and materials would have been worn.
Turkish Bath - Women would have arrived in street or sports dress, removed their clothing (or as much as modesty would permit), and reappear robed.
Swimming Pool - Again women would have entered the pool area fully dressed and changed into a bathing dress which then generally consisted of a three-quarter sleeved, low necked bodice, the waist marked by a sash or belt. Knee length shorts would have been surmounted by a gathered skirt ending just over the knees. Most women did not as yet go bear-legged into a pool where there was "mixed bathing" (as I assume was the case on Titanic), so they would have worn silk or lisle stockings. They also wore flat heeled satin bathing shoes that laced up the leg. On their heads they wore caps or bandeaux.
If I were able to load a picture or two, I could show you examples of the types of dress I've described.
To see some great images of Edwardian clothing log onto
http://www.costumes. org
Randy