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10:1 Scope?

Apr 5, 2009
899
Catalina '88 C30 tr/bs Oak Harbor, WA
All this uncertainty about scope makes me think I need to upgrade my ground tackle

View attachment 170543

At 26,000 pounds:yikes:.... should hold my H26 on a 1:1 scope.

This guy is selling three of these on the Mobile Craigslist. Anyone need a mooring anchor?
If you don't let your rode out quick enough, it will hold with a 0:1 scope after delivery barge drops it into the water for you. :biggrin:
 
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Oct 19, 2017
5,736
O'Day 19 Littleton, NH
At 26,000 pounds:yikes:.... should hold my H26 on a 1:1 scope.
All this fuss about 10:1 scope, how about 1:10 scope?
Oh wait! I was thinking rise over run (math nerd). Never mind. Length to depth is not the same thing.

-Will (Dragonfly)
 
Dec 25, 2000
4,211
Hunter Passage 42 Shelter Bay, WA
Practice here is to search for about 20 feet of water at mid tide, give or take. Drop about 110 feet of rode (50 feet of chain), then a 20 pound kellet with a 20 foot lanyard after set. Been doing this for years anchoring hundreds of times. Pleased with the Danforth holding even in strong blows. Only problem is getting it out of the deep hole that it dug itself into. Wind shifts, no problem.
 
Jun 11, 2004
868
Oday 31 Redondo Beach
[QUOTE="Will Gilmore, post: 1564987, member: 139601"I have to point out, you are NOT going anywhere on 0:1 scope.

-Will (Dragonfly)
[/QUOTE]
Thus the :biggrin:
 
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Mar 1, 2012
1,967
1961 Rhodes Meridian 25 Texas coast
and yet- I've been aboard a boat, anchored in the ICW in Florida, with a Bahama moor -two 100 pound anchors, each on 100 feet of chain.. Of course, I must point out it was aboard a 50 foot (on deck) Pinkie schooner with a dry weight of 55,000 pounds :)
 
Aug 22, 2017
1,589
Hunter 26.5 West Palm Beach
My original teachings, back in the 70's, told me that 3:1-7:1 was the range of scope to use, depending on conditions. For the most part, I still stick with that.

When I am in a tight anchorage, I sometimes use less than 3:1, but I put down some heavy gear if I am going to do that in anything stronger than a zephyr.

I have been caught needing to anchor up a 30' boat in 30 knots with only a #8 Danforth on hand. 12:1 scope, with nearly half being chain, got the job done.

When I lived in Cape Cod, I never carried more than 150' of rode. Up there, I could be 100 miles east of Chatham & still be in only 30 feet of water. Down here in south Florida, I can be 1/10 that far out & be in 1,000 feet. Anchors don't mean much around here when you are much more than a mile or two off the beach, even if you have several hundred feet of rode

A lot of factors come into play when trying to get a good enough bite from your ground tackle. Bottom type, anchor size & type, length & size of chain, current, surge, windage, maintained wind speed, gust speed & frequency, snubbers, and line size/type, all matter.

Scope is not the only thing to concern yourself with, but it is one of the important things & it is something that you can usually change quickly when conditions get more challenging on short notice.

The ability to put out 10:1 scope can be a handy asset to have in your back pocket, but it may not be practical to maintain if you are in very deep water. Also, too much chain in a bow locker can make a boat handle in a less than desirable way.

Trade-offs exist. What makes sense for you will depend on what type of boat you have, how you intend to use it & where you intend to go.
 
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Aug 22, 2017
1,589
Hunter 26.5 West Palm Beach
Beth and Evans Starzinger cruised the Beagle Channel at the tip of S America about 15 years ago. She now works at Boat US. They were anchoring in 70 or more feet. They found that 3:1 worked fine in deep anchoring situations. ...
It's been my experience, that in deep anchorages with substantial current, the anchor line bends in the current, improving the catinary angle. In deep anchorages with little current & high winds, you do not get the same benefit. Anchor line diameter makes a difference here too. Bigger lines bend more in the current & stretch less.
 

Bob S

.
Sep 27, 2007
1,479
Beneteau 393 New Bedford, MA
I love anchoring threads! There is a lot of experience here. I want to know how many have experienced dragging anchor. For the many times I have anchored and slept well I've had two experiences where we dragged. Both times were 1-2 AM still dark in a quick moving squall. I can tell you it was an eye opening experience :yikes:. I'm lucky we only have a 4ft tidal swing. On the other side, Cape Cod Bay and north you have to deal with 10+ ft which can make for an interesting decision as to how much do I pay out!
 
Dec 25, 2000
4,211
Hunter Passage 42 Shelter Bay, WA
I want to know how many have experienced dragging anchor.
Three times.

1. Cortez Bay, a notorious anchorage consisting of a thin layer of mud over hard shale. Thought I had a good set until a blow came in. Even with three hundred feet of rode in 30' of water, still drug about 100' during the night.

2. Ganges Harbor, another crappy anchorage. Again thought I had a good set until an afternoon blow. Got back to the boat just in time and when I brought the anchor up, it had an eight foot piece of 1-1/2" steel stranded cable wedged crosswise between the shank and flukes, preventing the anchor from digging in.

3. Again, Ganges Harbor, new to the boat. Brought the anchor up to move and found it tangled up with another anchor and chain.
 
Jan 19, 2010
7,351
Hunter 26 Lake Martin AL
Twice
I want to know how many have experienced dragging anchor.
Once in a bay off of the Neuse river (part of Pamlico Sound). The wind clocked almost 180 and my anchor started to drag. I pulled it up and reset it without too much trouble then set a second anchor 90 deg in case the wind continued to clock.

Second time was in a cove on a lake. I had a small branch wedged in the flukes.

Neither time resulted in a change of shorts. Just needed to reset the anchor.
 
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Oct 1, 2007
1,433
Hunter 44DS Pt. Judith
Who needs an anchor?
I so want to believe this pic is not a PShop image, but according to my rough calc each of those links weighs in at 5-600 lbs. Google tells me an aircraft carrier anchor chain has links that weigh 136 lb. Nonetheless, I always say that an anchor is only too big if it materially affects the trim of the boat (sailboat). That goes for rode too. :)
 
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