anchors

[windship]

If the sentinel doesn''t change the angle of the rode to the anchor, there''s no benefit.

Dennis

[tsenator]

Who says that adding a sentinel won''t change the angle of the rode to the anchor? It will ALWAYS change the angle of the rode to the anchor, unless its attached right at the bow of the boat.

The heavier the sentinel and further down you place the sentinel the more effect it has. Obviously in some circumstances it additive effect is minimal but it will always have some effect.

Did you look at the web site I listed or go into the Excell Spreadsheet? It has diagrams and a write up on exactly that and the Excell spreadsheet program even has a diagram/picture that shows exactly how the anchor rode will look depending on what variables you put in.

[maxcontax]

Tom,

I downloaded your XL spreadsheet, nice.

Given my usual water depths of 20 feet or less, setting out scopes of 3:1 and giving the tide 8 feet and some deck height to end up with 100 feet of line out, of which 10 feet is chain:
By sending a 10 lb. kellet down to the chain I can increase the tension from 38# to 62# and that''s a good thing.

Unhappily, the unknowns of the anchor type and the bottom do not allow any thing else to be said.

thanks

[windship]

Tom,
I''m not saying this with a snotty attitude, I''m just saying it; I don''t need to read a spreadsheet or anything else to tell me how to anchor. I''ve done alot and I''m pretty good at it.You probably wont believe it but I''ve only had one event happen to me in my years of anchoring. That was the one time my twenty-five Lb. danforth dragged in Hadleys Harbor and my small (twenty Lb. I also have a thirty-five Lb.)
CQR saved my bacon. Looking at that record, I must be doing somthing right.
Now you say if the rode is tought, and the twenty pounder isn''t working, slide a heavier sentinel down there and if that one doesn''t work,now what, send a heavier one than that? Or mabey two? How many do we stow on board?
Let me ask you this: If you were anchored and your anchor started dragging, would you send a sentinel or let out more scope?
Voyagers long ago HAD to use them because their anchors sucked and they had to use alot of scope. This is where they work best, with lots of scope, like in gale and storm conditions.
Why don''t you just put two anchors in tandem?

Dennis

[tsenator]

Dennis, You are correct, having a sentinel is no substitute for more scope or more chain. I never said it was. But there are times when scope is limited due to lots of factors (re: Anchored in a Harbor with many boats to watch fireworks, etc). I guess I could do as you say and just move on and leave, but if you wanted to stay any added weight can benefit. I am not saying I would add more and more sentinals. If you do that, then you might as well just go to all chain. So I am agreeing with you especially in gale and storm conditions. But not every night is like that. And yes putting two anchors in tandem is probably the ultimate from what I have read in cruising guides, but I have also heard that they are a bit of a pain to deploy, set and retreive. (Though if there was a huricane coming I would definitely consider doing it).

So Dennis I agree with you and I said so in the first sentence
"... nothing can fully replace adding more scope or having an all-chain rode."

But deploying a sentinel can only help, it can''t hurt.

[MaryBeth]

It has probably been said on this board before, but from just glancing through the replies here : the chain is not supposed to be used to add extra weight. The whole idea of the anchor chain, and then the use of anchor rode, is so that you 1) have a manageable way to prevent rode chafe in areas you may anchor where there are rocks or coral or unforeseen items which may chafe and cut your anchor rode, thus loosing your anchor and 2) allowing your anchor a more horizontal line so that it is more easily able to set into whatever bottom you have anchored.

Sorry, but anyway. (And yes, I''ve anchored to watch fireworks and parades and such in very, very crowded areas. I''ve also anchored to have lunch.) Maybe wouldn''t have responded if I had not currently been in retail, and trying for 3 days to tell people that the cute little mushroom anchors they want to use tied onto a 50 foot polypropolene line will not provide immediate anchorage in the current of the 50 foot deep river here. (Can''t be more than 50 feet, why do I need more than 50 feet of rope?)

MaryBeth

[windship]

Tom,
Good morning.
If the rode was tought enough the sentinel prabably wouldn''t help.
If the rode was slack, the anchor wouldn''t be in danger of breaking out. But in that space in between, if you want to bother, in a crowded area, I''ll concede, it couldn''t hurt.
By-the-way, do you ever experiance
any chafe with your sentinel?

Dennis

[windship]

Hi MaryBeth,
Yes, you want weight. Thats the trade-off. Theres always a trade-off. Larger anchor = more weight = more holding power. Larger chain = more weight = increased catenary = more holding power.
Chain also guards against chafe. And your right, boats in coral, rocks and areas with obstructions need it ,but, you have to have chain or else the amount of scope you have to let out will get ridiculous.

Dennis

[tsenator]

Dennis,

Hello, you are right, when the rode is taught the sentinel doesn''t add much (It always does add ''something'', but compared to the horizontal pull of a boat, then its just a drop in the bucket). Like I mentioned somewhere before, when I was anchored in New York Harbor July 3rd, 2000 and the front came through. My sentinel wasn''t doing much and recall seeing it just about out of the water after I was letting out more rode. The rode at that time was as tight as a cable. But I like having nylon rode for its great stretch and absorption of forces when gusts or swells hit.

With a very slack rode, the sentinel can help if you tend to be inj a location where there aree tide changes (like the Hudson River with 3-4 knots current). In between tide changes the rode could go very slack and all over the place depending on the wind and some anchors don''t set/reset as well in those conditions. Or worse yet, you might get a wrap around your keel or rudder. A sentinal in these conditions can help keep the rode down and the anchor shaft to rode geometry as close to the bottom as possible.

But like everyone says, All chain is better for this.

Tom

[tsenator]

Dennis,

(ps. forgot to address your question on chafe with sentinal).

No, I have never seen any chafe associated to the sentinal. I guess it all depends on how/what is attaching it to the rode. I have see very fancy sentinal attaching schemes, with rollers and such (I think in westmarine catalog). But I just use a big brass "snap hook" which seems to be very smooth and the sentinal is never in one spot for very long. If there is any chafe that I see on the rode then its most likely from going through my windlass.

Tom