If you are considering laying a mooring with a single weight, forget concrete, its not as heavy in the water as it is on land. What you need is solid steel dead weight. We have just the thing. Approx 300kg steel train wheels with a concave underneath which sucks onto the mud. Several links of heavy chain are welded to a crossbar, onto which the riser chain is attached.

We also have -
15 Kg & 50Kg Anchors- Admiralty type pattern.
Chain- self colour- long link- grade 30- 18mm X 90 mm - tested.
Shackles Dee BS 19mm X 22mm tested.
Swivels 22mm Blue line tested.
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Dwyer & O'Shea Marine Agencies,
Unit 7 Ramhill Ind Est,
Ballinacurra,
Midleton,
Co. Cork.
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Official Distributors in Ireland of
VERSADOCK Modular Pontoons & Drive-on Docks