New Zealander develops new class of anchor

Inventor Peter Smith with the 115kg Rocna anchor, custom-built for an American owner's 25m powerboat.

It's all about parking. When boaters in craft of all shapes and sizes want to stop, they need an anchor that's going to make sure they stay stopped.

That's when the anchor does its thing. Over the centuries anchors have evolved from simple weights on the end of a line to a variety of devices created to hold the craft safe. They include ploughs, kedges, Deltas, Danforths and CQR, Stockless, wishbone and grapnel types.

Now comes another that its inventor says is a big step forward in the evolution of the contraption that keeps your boat where you parked it.

The man is New Zealander Peter Smith, professional boatbuilder and yachtsman. Many will remember him as founding partner of Cavalier Yachts back in the 70s when production yachts were still being built here.

In the 20-plus years since then he has been sailing yachts, delivering yachts and building boats all over the world. For 10 years he ran his own yard at Colchester, England, where he built Kiwi Roa, the 15m sloop he regards as the ultimate cruising yacht.

Kiwi Roa is built from aluminium, 10mm alloy plate (up to 25mm in some sections), displaces 27 tonnes and is designed to withstand the worst conditions the sea can throw at her.

Peter, wife Jo and son Craig sailed Kiwi Roa from England to New Zealand between 1994 and 1998. During that journey they experienced frequent problems when they dragged the anchor in soft mud anchorages on the English East Coast and the Chesapeake and Delaware bays.

"We carried a 110lb CQR, an 88lb Delta and a ll0lb Bruce and there was always a feeling of insecurity," says Smith. "So having over the years used every type of anchor known to man I decided to develop the ideas I had for a new design."

The result was the creation of a 50kg prototype Rocna anchor. It was built, tested and refined in all sorts of situations. Then came the ultimate test, a 10-month circumnavigation of New Zealand, including 70 knots on and off for 10 days at Stewart Island.

When other boats were having trouble, says the inventor-skipper, Kiwi Roa did not move.

Smith says the Rocna does not waste energy with extra lead and cast iron weights, always attaining its setting attitude with its unique design regardless of how it hits the bottom.

This means weight is more efficiently used in extra blade area and structural strength. It digs straight in, offers incredible holding power, and will not easily trip out on load reversal, which adds up to safety, security and dependability.

The main features of the Rocna include:

* Instant setting: buries in less than 1m on most bottoms.

* Ultra-high holding power: testing indicates up to twice the stopping power of equivalent weight plough and claw types in soft sand or mud.

* Roll stable: remains embedded and retains attitude if dragged beyond its yield and will not roll-out during load reversal.

Rugged strength is attained through design - the use of high-strength alloy steels, hot-dip galvanising and a lack of moving parts.

The shank has a slotted attachment hole that the head of a shackle can fit through so only one shackle is needed. There is a hole on the shank for attaching a tandem anchor and one in the blade for attaching a buoyed retrieval line.

The anchor is available in sizes from 4kg to 100kg and suitable for boats from small runabouts to up to 50 tonnes.

Smith says that in all his years of sailing and talking equipment and safety with other mariners, he has always been amazed at the number of boaters who think nothing of spending $10,000 on electronics but tend to skimp on one of the most vital pieces of hardware on any vessel.