What is Too Much Rode?

[sailingunity]

Don't rule out poor holding. I once anchored in Vero Beach, and no matter what I couldn't get the anchor to hold once the wind picked up above 35 knots, I reset 4 times. Later, I learned the whole area is dredged through limestone - so I was anchored in a thin layer of mud / sand over limestone.

I also thought about the size of your anchor, and maybe its oversized? I'm no expert, but maybe your engine doesn't have enough power to properly set it?

[a64pilot]

Well we held overnight, no more dragging.
I didn’t want to pull anchor and reset largely out of laziness, and to some extent experiment.
Yesterday was an eventful, stressful day for us, and I just didn’t want more drama.
When I pulled anchor here yesterday it had clay type dark grey mud on it so I thought good holding, that and with the huge anchor I didn’t drop a whole lot of chain, I was very surprised to see us dragging.
Neighbor who was well ahead and off our Starboard bow, is now about dead even with us, Laser rangefinder has him at 139 yds, so I did not anchor close, however if I had to guess, I’d say he drug nearly 100 yds.
I didn’t see lights come on and running around over there, makes me wonder if they knew they were dragging. I was about ready to shine my spotlight on them to wake them up, but they stopped dragging.

I can only assume, poor holding and not enough initial scope.

I didn’t want to pull anchor and reset cause this eight ft I’m in is a hole, I’m surrounded by four or so Ft, that isn’t well charted, you have to feel your way around going real slow and watching depth. I draw a little over five.
For any that know the area I’m in Port Canaveral in the Ski Island pocket anchorage.

I do have a snubber, it’s two pieces of three strand 5/8” line and a Mantus hook, normally only used if it’s real bad weather, named storms bad.

[kenbo]

If you don't use a snubber except innamed storms, how do you secure your rode, chain stopper?

[mikedefieslife]

Wasn't it worked out somewhere that margins decrease dramatically once you go over 4 or 5:1? Or am I just imagining it?

EDIT: My bad. It was 7:1 published in Cruising World in 1993

[robert sailor]

Usually in shallow water I allow more scope but I've never used more than about 10 to 1 in shallow water and it needs to be really blowing. In normal depths say 15 to 25 feet a never go beyond 7 to 1 for several reasons, first I have found that I get very good holding and second I don't piss off the rest of the anchorage. Try using these large scopes some folks are suggesting in the Med and you'll have half the anchorage anchored on top of you not with standing that you don't need that much rode out in 99% of the cases. I know the story about put out all you have and if you are in some out of the way place where you have no effect on others then go for it if it makes you feel good, otherwise it's not a good idea as you are giving zero thought to others. In my mind the real key is where and how you place the anchor and set it properly, get that right and your good to go. The idea that a 20 knot breeze requires large scopes is off the wall in my mind, get up to the 40+ knot range and now you have a breeze. Some bottoms are crap holding and no amount of scope is going to help. In most popular cruising grounds there are lots of boats in the anchorage and if you start using scopes some folks are recommending you will be the scourge of the anchorage, especially in shifting winds.

[mikereed100]

Originally Posted by robert sailor

Usually in shallow water I allow more scope .....

I'm surprised nobody has mentioned this yet. In shallow water the shorter scopes and lack of caternary allow more shock loading at the anchor. In water less than 20' I use a rough formula of my boat length plus 5:1. Using this in the OP's situation we would have had 38+(8+4)(5)=98'. This is only a rough guide and I am way too lazy and slow-witted to actually do the calculation, so I usually just put out a lot more rode that I think I'll need when in shallow water.

[thinwater]

The chart Nolex posted is typical, but this relates to scope right at the bottom. In other words, even when the chain starts to lift, the angle will be less than a straight line to the boat. The ironic correlary is that the anchor is holding well with the chain down, until the boat moves back in a gust, the chain lifts a lot, and the anchor pulls.

Scope Holding
10:1 100%
7:1 85%
5:1 70%
3:1 40%
2:1 10%

5/8-inch bridle is probably too big. You also did not give the length. assuming these are 15 feet long and the combined strength is 18,000 pounds, the stretch under wind load (about 1000 pounds in a 60-knot breeze), the stretch will be about 5 inches. This is not a shock absorbing bridle. A single 11 mm climbing rope 30-40 feet long has been used on boats that size. I've used a 9 mm bridle 35 feet long. With the thinner rope that is long enough, the load will be not much more than wind load. With a short strong bridle, the load will be twice that or more. (based on a lot of load cell testing, not ancedotes or guesswork).

https://www.practical-sailor.com/iss...e_11951-1.html

And while Rocna posted some good stuff, it is based on calculation rather than testing. The in-line tandem stuff is provably nonsense laid out on a beach for pictures (try it--do what he did, then change the angle of pull 20 degrees, and watch the anchors roll out). So not gospel.

[a64pilot]

Originally Posted by kenbo

If you don't use a snubber except innamed storms, how do you secure your rode, chain stopper?

In light winds, yes.
The dual 5/8” is for heavy winds, I guess I ought to come up with an in between solution. The dual line is just regular docklines, so maybe 40 feet? Unsure actually, but way longer than 15 feet, by at least double.

If I single line, that of course has me tying off to the bow cleat, and the line will come off at an angle to the bow.

[IslandHop]

Another suggestion I didn't see which is a good one I think as it works for us. Using a larger length of chain right off the anchor gives you better catenary, and angle of approach to the anchor. A good trick for people with nylon Rhodes and smaller anchors as well. Combined with a long thin snubber works great

[boatman61]

If an anchorage is to crowded to accommodate my style of anchoring I move on.. if everyones sitting on top of others anchors screw that for a game of soldiers.. no beach or bar is that good..

[boatman61]

Originally Posted by thinwater

And while Rocna posted some good stuff, it is based on calculation rather than testing. The in-line tandem stuff is provably nonsense laid out on a beach for pictures (try it--do what he did, then change the angle of pull 20 degrees, and watch the anchors roll out). So not gospel.

But it sells anchors to the believers of product trumps method..

[robert sailor]

Originally Posted by a64pilot

In light winds, yes.
The dual 5/8” is for heavy winds, I guess I ought to come up with an in between solution. The dual line is just regular docklines, so maybe 40 feet? Unsure actually, but way longer than 15 feet, by at least double.

If I single line, that of course has me tying off to the bow cleat, and the line will come off at an angle to the bow.

Single line is no problem, been using that method for close to 40 years without any issues.

[Dave22q]

Originally Posted by boatman61

I am a luddite.. 54 years ago I learnt that when anchoring lay 3.5 times the boat length plus depth for secure anchoring in good to fair weather (calm to 20kts).. increase with wind as needed and its kept me safe..
What I dread are the people who charge in.. stop n drop.. piling chain on top of their anchor as I know damn well if they're in front off me its time to string the fenders.
I pick my position, go slightly past then drop my hook as I start falling back letting the boat lay out the chain.. when 50% is out I hold till boat swings to the wind.. then once more fall off as another quarter goes out.. hold then repeat till required length is laid..
Result.. straight chain and sufficiently dug in anchor.. any further loads will dig her deeper.
Detest boats with rope rodes.. dangerous daysailing cheapskates spouting crap about loads in the bow.. its allowed for by any halfway decent designer.
Thats why some boats have anchor lockers and the crap have wells in the foredeck.
Okay.. Where my flak jacket..

Luddite? no. Opinionated? Absolutely. Lacking imagination? Of course. Chain is superior in that you need less scope. Good in crowded anchorages. For many it creates dependency on electric winches which is generally a bad thing. Avoiding crowded anchorages and using right sized anchors works better for me.

[waterman46]

Do the catenary math or find it online, but I'd guess that with 8' of water and about 4' of deck height forward, 100' of chain will require way more tension on it, to lift the anchor shank at all, than your boat's windage and the current could possibly produce. In such soft mud it seems you may need an anchor with more fluke area. In fact you proved that when after starting with a proper scope, you let out more scope and it still dragged.

One thing you could do is to back down just to where it starts to drag, then reduce RPM to the point where it stops dragging, still in reverse, and give it 10 minutes in that condition to settle into the mud before testing at gradually increasing RPM.

I think its good to know the point when more scope is no better. One of my biggest gripes is when I am looking for a spot in a crowded anchorage of less than 12' depth and the guy 150' away waves me off shouting "I have 180 feet of chain out". Most times I think its a lie but you never know. I am often tempted, sometimes successfully, to answer such ridiculous claims with a sarcastic "Oh Really?".

[waterman46]

Originally Posted by sailful

More rode will never mean less holding. If you have the room I would put out all the chain you have. Each link in the mud adds friction, helps keep you in place.

More rode makes no difference after the chain is long enough that the weight of chain is enough to ensure the anchor shank is not lifted at the maximum chain tension. And chain dues not have any meaningful friction except if it gets wrapped around another object on the bottom.

This assumes that your chain is correctly sized for your boat. Using the heaviest chain recommended by experts for your boat, is very important.