Another way of getting better holding is a "kellet," also called a "sentinel" or an "angel" - a substantial weight, shackled to run along the anchor rode and lowered on its own line to just graze the bottom. I figure 20 lbs of excess scuba weights, on a spare Wichard halyard shackle I have on hand, ought to do the job for a trial.
There is a commercial product, the
"Kiwi Anchor Rider", that is supposedly optimized to do this job. Their website FAQ asserts that its "shock absorber" qualities will help to minimize the "anchor dance" observed in high-windage boats. (Like our Macs.) They also assert that it "almost doubles the holding power and reduces the working load of the anchor by up to 50%" (direct quote). The site also explains, most carefully, why their product is more convenient and chafe-proof than a homemade version like mine. (Hardly surprising, their self-interest is at stake!)
They don't list the price on their website, and I suppose that the cost of shipping a 30-pound item is part of the reason why, but they showed a review from a British magazine (
Yachting Life, Nov 2002) that listed the price of a 20-lb Kiwi Anchor Rider as "£90 including VAT". That's supposed to be good for up to a 30-foot boat. The U.S. agents only sell a 30-lb model, which was listed in the Yachting Life article at £95.
I am not afraid to pay too much for superb ground tackle - see my post in July 2009 about "the ultimate Mac anchor" - but I figure that my home-made kellet will do the job quite well, for no cost (seeing as I had the makings of it in my basement!) And I'll post any reply I get from the company.