Originally Posted by Davidhoy
Thinwater, can you elaborate on what you mean by "detriment"? I recently picked up an FX-85 as a backup to my primary Rocna
, and in talking with the guys are Fortress
(I can literally see their factory out the window of my office!), they recommend about 20ft of chain, then a nylon rode
. You need the stretch of the nylon to absorb shock, the weight of the chain to get a good angle of pull on the shank, and the wear-resistance of the chain especially of rocky or coral
bottoms. I'd think that dyneema
would be a less-from-ideal material for an anchor
rode, given its light weight and very low stretch...
Good questions. However, I have been working on this with Fortress
people on this, I have done a lot of anchor testing for publication, and I'm not guessing.
Chain makes the shank sink before the flukes because the anchor is very light. This prevents the flukes from biting, particularly in very soft mud. They have a picture of this on their web site.
One of the main reasons they like chain is to get the anchor down if there is current
. Not relevant for most kedge and V tandem applications.
No, 20 feet of chain does not provide catenary. It's not nearly enough to make any difference under load. That is a myth. As for setting, Fortress anchors get a faster initial set at short scope
, so once again, the chain is a detriment.
is a very poor rode material. But I did not suggest that. I suggested a 20' over-strength Dyneema leader with a chafe guard as a replacement for 20 feet of chain.
Yes, chain has greater wear resistance. However, I specifically said this was for kedge (an anchor used to pull the boat
off the mud, for example) only. I did not imply this was for the main anchor. The method is also useful for a V tandem in soft mud, since V anchors do not saw across the bottom and because there is little to cut the rode. In any event, the Dyneema/chafe guard combination is at least 20 times more cut resistant than the rope
you are using, which with only 20 feet of chain, can easily loop on a coral head
. If this is a concern to you, use at least 100' of chain.
This is a specialized tip. It makes the anchor MUCH easier to take out by dinghy
for kedge or V tandem. I am not suggesting it for anything else or for any other anchor. I believe if you think through what I have said, you will find the logic is sound for the specific set of cases I suggested.