Upgrading Our Nursery Anchors

Prototype of the new sinker design drying in its mould

As part of our ongoing commitment to improving coral restoration techniques, our team is currently constructing 60 new sinkers to secure our 14 floating coral tree nurseries and 8 depth gradients to the reef at a depth of 10 meters. Over the past five years, we learned a lot from our earlier design, which used bucket-shaped concrete blocks with metal rebar handles. Unfortunately, these handles gradually corroded, and under rough ocean conditions, the friction between the metal and the connecting ropes sometimes caused the ropes to snap. In addition, since the sinkers are aligned along a rope anchored to the reef on both sides, the rebar handles often caused tangles with the nursery ropes.

Our new and improved design addresses these issues. Each sinker now has a straight hole through the middle, allowing the sinkers and nurseries to be connected more securely in line with the reef. The metal rebar handle is now protected by a PPR pipe sleeve, which not only reduces friction on the connecting ropes but also slows the corrosion of the rebar. We plan to deploy these new sinkers in October, replacing the old anchoring system entirely. This upgrade will ensure that our nurseries stay in place longer, even under challenging ocean conditions — helping us safeguard the precious corals we are growing there.