If you really want to swim in the sea, I recommend you start off by swimming in calm water in waist depth water and build on it from there. Small amounts at a time and always swim with a friend in the sea.
No I usually lap swim in my local 25 meter swimming pool and tend to see how long it takes me to empty the lane out. Once you lap others men boys a few time they usually clear out.
they means the depth of water and the person I am swimming with..i can swim fairly comfortably for 50m to 1.5km in pools but i n ocean i tend to lose all my ability to swim..the fear is killing me before drowning. I am thinking i can do it with a coach first tho