Originally Posted by BogMonster
I haven't used it yet but I looked at the anchor on mine and thought it was a bit small, its a Danforth type not sure of the weight but prob about 8-10kg.
Can I hijack the thread slightly; how often do folks think you should change the rope on the anchor? Deterioration of the chain is fairly obvious but rope....? It's probably the original one so about 6-7 years old.
A 20 lb Danforth anchor is huge. I have an 18' or so aluminum RIB, and I use an 8 lb Danforth clone. Fluke anchors have a very large surface area for their weight, so they don't have to be heavy unless you primarily anchor in compacted mud.
Anchor line should be replaced when the rope starts going off (chalky, brittle, stiff, picking threads, abraded, etc.) A decent line that is not abused should last at least several years. It is, however, a last ditch piece of emergency equipment, so a little conservatism on use may be called for.
The grapnel anchors (going back to a different reply; sorry, Stephen) are, IMO, pretty much useless. They won't hold in sand, usually won't hold in mud, and hang up in rock (not to mention hanging up on everything inside the boat while you're trying to deploy it.) They do, however, make great gifts for boaters that you don't like.