Anchors, anchors again, & more anchors....

[SV Wind Dancer]

Danforth, chain and a shoe (some ppl call it 'backing the anchor') has not failed me yet, fingersXX.  Haven't dealt with a lot of rock or shingle, but does well in the gelatinous muck I've dealt with in StJohn's & throughout the southeast.  Besides, I'm cheap.

[Chattcatdaddy]

Any suggestions for a bow/anchor roller setup. My Ariel (I like the way that sounds) has no real anchor setup so I will start from scratch. Im leaning toward a 25# Manson Supreme with 50ft 5/16 G4 chain and 150ft 5/8 line The boat has a 20lbs or so danforth that I`ll use as a secondary/lunch anchor. Hard to sort thru all the bow roller options.

Just trying to sort thru all the options for an anchor setup. I would like to keep it simple and low cost(not cheap).

[Tim]

Any suggestions for a bow/anchor roller setup. My Ariel (I like the way that sounds) has no real anchor setup so I will start from scratch. Im leaning toward a 25# Manson Supreme with 50ft 5/16 G4 chain and 150ft 5/8 line The boat has a 20lbs or so danforth that I`ll use as a secondary/lunch anchor. Hard to sort thru all the bow roller options.

Just trying to sort thru all the options for an anchor setup. I would like to keep it simple and low cost(not cheap).

Sounds like a good setup to me, perhaps a little more rode depending on your anchorages.

[Chattcatdaddy]

I`m open to more line and I`d like to err on the side of too long than too short. My crusing grounds are most likely going to be the Chesapeake to start with then maybe Bahamas and the Florida Keys. All of which are shallow areas.

[CharlieJ]

On board Tehani (very close to Ariel size) I  carry 75 feet of 1/4 Hi-tensile (G-4) chain, 150  feet of 1/2 nylon and a 22 pound Claw ( Bruce copy). I also carry  a 12 pound Hi-test Danforth ( true  Danforth), with 30 feet of the same chain and another 100 feet of 5/16 nylon.

Also aboard is another 25 feet of chain and 200 feet of 1/2 nylon. Had a 16 pound folding Northill aboard, but never used it, so took it off.

In close to 10,000 miles (three trips) cruising, I rarely found the need for more than just the chain. I did use the Danforth in the few times when  we Bahama moored, which wasn't often.

This was anchoring in the Chesapeake, all along the coast, Keys and all through the Bahamas.

I think your choices are pretty good, But a 20 lb Danforth is HUGE!! I have two of them at home, and they won't really fit aboard Tehani. Way too big..

[SeaHusky]

Instead of straying off topic or starting a new thread I dug this one up for my question:

What weight/strength should I calculate for my anchor chain and line?
Is there a rule of thumb like "half the boats displacement" or something?

[CharlieJ]

ok,. some purely personal feelings here. I have never had a windlass  on a boat- always hauled rode by hand, and still will as long as I am able

On my 35 foot trimaran, light weight but tons of windage in a blow, i used 5/16 G4 chain, and 5/8ths nylon. 100 feet of chain, and 200 feet of nylon. Seldom used the nylon

On Tehani, with a loaded for cruising weight of roughly 7500, I use 1/4 G4, and 1/2 inch nylon. 75 feet of chain, and 150 feet of nylon. Used the nylon 4 or 5 times in 3 years.

I DO use a nylon snubber, with a chain hook,usually with 15 feet of line out. That provides the shock absorbsion

All that works well where I Anchor. VERY seldom in more than  20 feet

One thing you DO NOT want to do is go way heavy on the nylon. Part of the value of that nylon rode is stretch, which lessens shock loading on cleats, and the boat itself. So if you go too heavy, you negate that stretch

edited- chain hook/snubber looks like this

[SeaHusky]

Good advice, especially about the stretch, thanks! I'll try to convert that to metric... :P
But I still wonder about what forces we are talking about?
The size guide for the anchor suggests a certain dimension of chain. Should the nylon match that breaking strength or be less (the suggested chain being more about weight for shock absorption then strength)?
Does anyone know of a study on the forces acting on anchoring gear in different weather?
Surely someone has looked at this?

[CharlieJ]

Here's links to  two West Marine Advisor articles-

Selecting a rode

http://www.westmarine.com/WestAdvisor/Selecting-An-Anchor-Rode

and an anchor

http://www.westmarine.com/WestAdvisor/Selecting-The-Right-Anchor

[Godot]

Anchoring is black magic. Or perhaps art. There are so many different things that can happen, based on wind, bottom conditions, current, anchoring technique, sailing philosophy, boat windage, surge, etc... If day sailing in gentleman's weather is your cup of tea, a light anchor and some line will more than likely serve you well for an entire sailing career. If cruising the remote places of the world, sooner or later you are likely to find yourself in an anchorage with a serious blow and surge coming through. Given that the holding power of anchors is so dependent on set, bottom type, etc, I think the manufacturers are mostly guessing. And when they guess they generally lean towards the majority needs of daysailers/weekenders as it makes their anchors look like better values. This is why there is the old suggestion of upsizing a size or two.

I think the new modern anchors are  using a different philosophy for sizing recommendations. They are really not necessary for the needs of the typical daysailer, where a lightweight Danforth seems to generally be adequate. I think they are instead targeting cruisers. Rocna made a big point on their website that the anchors are sized conservatively to the needs of cruisers. Manson Supreme recommendations appear similar. If your boat is near the top of the anchor recommendation range on a new gen anchor, perhaps it is smart to upsize one size. Otherwise, based on the anecdotal evidence I hear on web forums, the recommended size is probably adequate. Your mileage may vary, of course.

As to the anchor rode, the rule of thumb that I've typically worked under is twice the size of the chain. On Godot I had 3/16" chain and 3/8" line. It seemed to work fine; although despite plans, I never did get her out of the Chesapeake. I was definitely under-anchored with a lightweight Bruce knockoff that required careful setting to be effective. Many people have suggested that the minimum size for any kind of cruising would be 1/4" chain and 1/2" line; but with such a small boat as a Seafarer 24 I think I was OK. If I had taken her further afield I probably would have upgraded both the anchor and rode, though.

As to the study you are looking for, I've seen attempts at measuring freeboard and wind forces and the like, although I don't immediately remember where. I think the Jordon series drogue website has some info. Personally, I think you will be well served by following the suggestions on the West Marine Advisor site.

[Godot]

Check out http://alain.fraysse.free.fr/sail/rode/rode.htm. Maybe that is what you are looking for.

[Grime]

Little more information about anchors and holding.
http://www.petersmith.net.nz/boat-anchors/independent-performance-testing.php

[SeaHusky]

Thanks! I will get back when I have had time to read it all.

[SeaHusky]

Thanks!
The Alain Fraysse link is great (if you enjoy physics, which I do)!
Tomorrow there is a spring sale at my marina with 20% off on lines so I hope to buy some.
One quick question if anybody has the answer:
Is a 3-strand nylon rode more or less elastic than an 8-strand, multi plait rode?
Which should I choose?   

[Grime]

Me I'd go with the 3 strand nylon. 

[SeaHusky]

Me I'd go with the 3 strand nylon.

For what reason?
I see that the 8-strand has a higher breaking strength for the same diameter so I suspect that it is less elastic?

[CharlieJ]

I've always used 3 strand. VERY simple to splice.

[Grime]

A lot of question are easy to answer. Me I walk the docks and look at what others are using. I specially look over what the long time sailors use. Then I make my assessment from there.

To answer you question. Yes nylon is more elastic than braided line.  You want a give in your anchor rode and your dock lines.

Today at the marina I noticed a new member to the marina that has all nylon rode connected to a Bruce.. This is a 40+' ketch. There is no way this setup would hold. 

[Godot]

I've got 200' of 8-plait 1/2" line on Seeker, which is spliced on to 90' of 1/4" hi-test chain.

The splicing is a little more involved, probably, than three strand; but the instructions are readily available online and it is certainly within the skill set of any reasonably handy person.

The plait is quite a lot more compact. I think it is somewhat more expensive as well. So far it seems to be great; but truthfully, so far I've rarely needed more than my 90' of chain.

[CharlieJ]

Talked to them today. Measuring for sails. Just bought the boat- survivor of Katrina in NO. I seriously doubt that nylon to anchor will be left that way. He has a lot of work to do- take a look at the wrecked bow pulpit