Join Date: May 2012
Location: On my boat
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Re: Anchor question
This is a discussion that apparently will never end. Physics is governed by certain "laws". If I have 150' of 3/8' chain out at approximately 225 lb.(less 13% for steel in salt water or 196 lb.), even if the wind is howling and the chain pulled straight, the mass or weight of the chain remains unchanged and presses down both on the bow of the boat as well as the anchor. Because it is not a straight rod, it also, stated simply, exerts force inwards >< .
A small, lightweight, aluminum Fortress or Danforth on a nylon rode is absolutely fine for many applications. Day sailors have relied on this equipment for a long time without too many problems. But, an aluminum anchor that weighs 10 lb. in your hand only weighs about 6 on the bottom (a 10 lb. steel anchor weighs about 8.5 lbs. in salt water) So, if you have a hard or grassy bottom you will have issues. If the wind comes up or the current switches around, you will have issues. The same anchor, made from heavier material will work better. It may only be slightly better but more weight is what you want for holding, period. The size of the flukes will only matter if they get buried.
There is a very good reason why so many people are switching to more modern designs, they work better.
My primary consideration was not storage but keeping my home where I put it. I employ the heaviest anchor I feel I can work with in difficult conditions, 77 lb. I chose a design that works better on most bottoms than others, a Rocna. I attached it to the boat with the heaviest rode I could deploy and recover manually even in deep anchorages, 3/8" D70 at 1.5 lb./ft.. I also use a 3/4" bridle with up to 25' leads. Of course my boat is a 41' Bristol cutter and weighs, supplied, 16.5 tons. I have remained firmly at anchor in 4.5 knot current that shifted 4 times a day, did not drag in winds topping 50 knots (that is 4 times the force of a 25 knot wind) and set it in rock, mud, sand, gravel, grass and weed. Chances are good that you might not need to cover that. A 25' boat on the Chesapeake would use considerably less. I would not choose a primary anchor under 20 lbs. though and would use (or at least carry) 25' of chain to add to the end of the rode. Rocna, Manson and others make smaller versions for small boat and day use. They work vastly better than older types but, in mud, with little current or wind, a 20 lb. rock will work.