Siyul is the name for two islands that lie about a 20 minute boat ride south-west of Abu Nuhas. The smaller of the two islands "Siyul Saghira" (Arabic for small Siyul). The smaller island's reef is approximately 4 times the size of the large islands reef. However, the smaller island offers significantly more shelter on the south side within the reef's crescent shape.
The dive boats tend to stop in the slightly deeper end on the south side and drop the divers off with the RIBs on just on the edge of the reef, which is only about a meter deep. If you stay in the crescent, the depth doesn't exceed much over 16 metres and there are lovely underwater pinnacles doted on the West side. The bottom slopes away slowly to about 25 metres.
If you venture a bit further out, it slopes away on a sandy bottom to about 50m. As this often used as a sheltered alternative site, you have to be careful that the current doesn't carry you away when you venture out to the deeper end.
On the North-Eastern side, the drop off is much stronger and it is often accompanied by quite a current rushing along the reef. You can do a fantastic deep drift dive there, if you plan the RIBs to follow you. The current was a full 2.5 knots when we did it last - quite a ride. At the end we were on the other side of Siyul Saghira.