The heavy spear-tipped anchors are used to hold 1m triangular race buoys in position in the sand and can be very sharp.
"The come down like a point. If you touch the end it'd just about prick your finger,'' Mr Black said.
Four lifeguards responded to the incident, staying with the injured man until an ambulance arrived. A Tauranga St John spokesman said the man was taken to Tauranga Hospital.
"(He) was swimming out to put the anchor out. A wave came over him and impaled him and exposed some of his contents. He was treated very well by some of the Mount lifeguards.''
Head lifeguard James Roy said his team met the group of racers who were carrying Mr Appleby about half-way up the beach and took over.
"We stretchered him to the lifeguard station. We just did the usual first aid ... we managed the shock and we managed the injury. Obviously, with the injury, he was in shock.
At Tauranga Hospital, Mr Appleby was rushed straight into theatre for surgery, where it was discovered he had also developed a blood clot from the injury. He remained in a stable condition last night.