Kosta,
It would be a good idea to take someone experienced with you. Check all weather forcasts and log in with the coast guard.
On a calm day you wont have any problem getting outside as there is no bar crossing in botany bay.
As for fishing without a sounder, maybe you could throw plastics in the washes on north head. a few snapper and kingies around at the moment.
Or drifting outside for flat head in 30-50m of water is another go.
good luck mate