Time to replace my anchor rope. A question for all the brains trust I have a Santana 28 about 3.5 ton What would be the recommended anchor rope breaking strain required
Time to replace my anchor rope. A question for all the brains trust I have a Santana 28 about 3.5 ton What would be the recommended anchor rope breaking strain required
Any help much appreciated
Breaking strain has not much to do with it. 12mm nylon will be more than adequate breaking strain wise, 14 mm is better on the hands when pulling the anchor. If you are using nylon for a warp because you wish to benefit from its stretching characteristics then thinner is better. I personally would use 14mm "Seagreen" or silver for a yacht up to about 40 foot. One foot of 8mm chain per foot of boat and a modern anchor of your choice, Spade, Ultra, Rocna. Manson etc.
Useful background info from the American Boat & Yacht Council's typical horisontal design loads (in pounds) for anchored boats:
30ft yacht in 15kt wind: 175lb 30ft yacht in 30kt wind: 700lb 30ft yacht in 42kt wind: 1400lb
To get force in Kg, multiple pound (lb) by 0.45 or take half the lb value.
So the Working Load (not Breaking load) of rode and shackles should be in excess of the above "typical" loads. Note how the force jumps with increase in wind strength from 15kt to 30kt.
Note also that the figures reflect horisontal forces due to wind, and do not factor in the potential additional vertical forces exerted when the bow pulls on the rode due to wave action. Even so, it's nice to have a ball park idea of the forces on your boat, in relatively flat water, due to wind.
Now, a good question would be: What is the maximum wind speed you should plan for?
Obviously, we all "intend" to be anchored in nothing over 20kt, but then you could always be ambushed.
On the Australian East coast, if you avoid cyclone season, how does a sustained 50kt max inside an anchorage sound (ignoring gusts)? Way too much, ... or not enough?
Now, a good question would be: What is the maximum wind speed you should plan for?
Obviously, we all "intend" to be anchored in nothing over 20kt, but then you could always be ambushed.
On the Australian East coast, if you avoid cyclone season, how does a sustained 50kt max inside an anchorage sound (ignoring gusts)? Way too much, ... or not enough?
Last year on the Shoalhaven river my yacht and other boats came off moorings when the wind was a steady 60 knot Westerly. The mooring rodes wore through over the rollers, I had leather anti chafe material and that wore through. Summer NE will often blow at more than 50 knots during the night. The wind strength will be a lot less at deck level though because of friction over the land if your anchored inside versus outside. The yacht will yaw about and chafe will be more of a concern with rope rodes and annoying jerks with chain.
