Luckily the create mod has something which helps with this too! I've gotten myself a full diving suit :D
You fill the backtank with compressed air by giving it sufficient rotational power for a while. Then you can use the diving helmet to breathe underwater for about 15 minutes on a full tank. The diving boots make you sink very quickly so you can almost walk underwater, which is very handy.
Even though this made collecting a lot more fun it still took a while