Challenge: Anchoring on Slanted Bottom

[Gone2long]

Originally Posted by cruisersfarm

Displacement isn't the factor. A 40' cat has windage. 25 knots is nothing. You're going to drag when you get a storm through. Especially at this 5:1 scope.

Reread carefully. Noticed that you dripped additional info in with each post, changing the situation.

You need to grab a book or website link on on marlinespike seamanship as well, while at that chandlery.

You can't increase scope because you can't splice your rope rode into the chain?

There is nothing at all safe about this anchoring setup. A wreck waiting to happen.

Hi again,

Did not mean to be rude, but I think I need to post photos of the current "bridle" that I am using. Also, you are right, I am dripping information here, but I did not want to mention too much at once. Also, I believe that I mentioned that the boat is a very sleek Tri, weighing only 4 tons, not a top heavy 450 Lagoon, or anything similar. Will check if I posted that on a related thread, not here. If so, my apologies.

To clarify the current situation: The main line to the anchor chain has what looks like an old, manufacturer's splice that I am not sure I should trust. The spliced line is attached to a shackle, which is attached to the anchor chain. This was done by the previous owner, who was on another continent when I purchased the boat and was not available to explain his reasoning. The assumed reason for this set up is so that someone could quickly switch lines to the chain. Perhaps the original owner was worried about the splice as well.

In any case, I attached another line to the shackle that connects the main anchor line to the chain so, if the spliced line ever broke, I would have a backup. Also, this created a "bridle" that allowed me to let out some line without worrying about it chafing on rocks, and giving the anchor line a bit of "stretch" that smothered some of the racket we had experienced when the chain eased and tightened during wind changes.

That is the current situation, and I will post photos soon, in order to illustrate it a bit more clearly.

Thank you for your responses,

G2L

[Gone2long]

Originally Posted by wrwakefield

G2L,

You have received lots of very good advice already, and perhaps even already advised about what I'm going to mention...

I have had good success is similar anchoring situation using a Bahamian moor.

i.e., set a stern anchor/kedge [in leu of a shore fast] and bring its rode to the bow- attaching to the main anchor rode. Center the boat between the 2 anchors and stay in one place [relatively speaking.]

I run the stern/kedge anchor warp through a thimble attached to a line secured to the main anchor chain, then over the bow roller to a cleat. That way the stern kedge is attached to the main anchor rode, but still adjustable. Or you can always just tie the stern/kedge anchor warp directly to the main rode with an icicle hitch.

This will help protect you from dragging downhill with your main anchor when you get those 180° wind shifts, and still allows you to point into the wind.

In case this is useful.

Cheers!

Bill

Appreciate your input. Please see my responses to your posts on my other thread as well.

Thanks

G2L

[Gone2long]

Originally Posted by Nicholson58

We have done this in fresh water, no tide, no big seas but savage wind. We set one anchor in 50 feet and a stern anchor on the beach. - Then used a winch to stretch us tight between them. Other times, set the primary shallow and a second anchor deep on the slope to keep us off the beach. If you can't make it work - move.

Thanks to Captains Nicholson, Barnakiel, Wakefield, et all, for giving me nightmares, when asleep in this anchorage. : )

But, then .... fear is a great motivator : )

Truly appreciate your perspectives and advice.

G2L

[Gone2long]

Originally Posted by boatman61

Regarding anchoring I ALWAYS circle the anchorage area to verify the charted depths concur with actual depths.. storm erosion, shifting banks and bars etc.. then I will pick my spot knowing what my surrounds are and possible get outa jail free routes.
Regarding your chain.. if your concerned about your splice at the shackle (bad idea 2 fail points in one) I would definitely run another line and make a bridle.. can be managed solo by hauling in first one half then tie off and take in the slack on the other till the shackles on board.. disconnect the bridle then deal with the chain.. IF you feed into an open locker.
One thing I would definitely do ASAP however is get rid of that shackle and do a proper tapering splice direct to the chain.

Thanks again for your post. To clarify my situation, I have enclosed below my latest response to Cruisefarm, and I have attached three photos to show the situation with both lines and shackle. You may have to turn your computer upside down, however, to properly view them : ). Not sure how that happened, but the wife took the photos, and, well ... you probably know how that goes.

Hi again,

Did not mean to be rude, but I think I need to post photos of the current "bridle" that I am using. Also, you are right, I am dripping information here, but I did not want to mention too much at once. Also, I believe that I mentioned that the boat is a very sleek Tri, weighing only 4 tons, not a top heavy 450 Lagoon, or anything similar. Will check if I posted that on a related thread, not here. If so, my apologies.

To clarify the current situation: The main line to the anchor chain has what looks like an old, manufacturer's splice that I am not sure I should trust. The spliced line is attached to a shackle, which is attached to the anchor chain. This was done by the previous owner, who was on another continent when I purchased the boat and was not available to explain his reasoning. The assumed reason for this set up is so that someone could quickly switch lines to the chain. Perhaps the original owner was worried about the splice as well.

In any case, I attached another line to the shackle that connects the main anchor line to the chain so, if the spliced line ever broke, I would have a backup. Also, this created a "bridle" that allowed me to let out some line without worrying about it chafing on rocks, and giving the anchor line a bit of "stretch" that smothered some of the racket we had experienced when the chain eased and tightened during wind changes.

That is the current situation, and I will post photos soon, in order to illustrate it a bit more clearly.

Thank you for your responses,

G2L

[Gone2long]

Originally Posted by boatman61

Regarding anchoring I ALWAYS circle the anchorage area to verify the charted depths concur with actual depths.. storm erosion, shifting banks and bars etc.. then I will pick my spot knowing what my surrounds are and possible get outa jail free routes.
Regarding your chain.. if your concerned about your splice at the shackle (bad idea 2 fail points in one) I would definitely run another line and make a bridle.. can be managed solo by hauling in first one half then tie off and take in the slack on the other till the shackles on board.. disconnect the bridle then deal with the chain.. IF you feed into an open locker.
One thing I would definitely do ASAP however is get rid of that shackle and do a proper tapering splice direct to the chain.

As per my earlier note, I have attached a better photo. Not sure why the shackle might be a problem as it is strong and I have a preventer wire on it. The shackle allows me to change the iffy, spliced anchor line, if need be.

The new photo shows more clearly how the primary, spliced, anchor line is connected to the shackle and how I have tied the secondary line to the anchor chain, just beside the primary line. Again, the photo is sideways, but that perspective allows the most detail.

Note that the line diameters are half inch and the chain is about 3/8s inch.

Do any of these "links" seem insecure to you?

Thanks for your help,

G2L

[Gone2long]

Please see my latest response to Boatman 61 for further clarification.


Thanks for your input,


G2L

[wrwakefield]

Originally Posted by Gone2long

As per my earlier note, I have attached a better photo. Not sure why the shackle might be a problem as it is strong and I have a preventer wire on it. The shackle allows me to change the iffy, spliced anchor line, if need be.

The new photo shows more clearly how the primary, spliced, anchor line is connected to the shackle and how I have tied the secondary line to the anchor chain, just beside the primary line. Again, the photo is sideways, but that perspective allows the most detail.

Note that the line diameters are half inch and the chain is about 3/8s inch.

Do any of these "links" seem insecure to you?

Thanks for your help,

G2L

Hi G2L,

I'll offer some quick feedback. [And please keep that perspective; it is just feedback. There are many ways to accomplish your end goals, and all that work are viable... I also apologize in advance if I am missed any details that have already been mentioned...]

First, your set-up appears to be secure, but could be greatly simplified and streamlined if you wanted to.

It looks like you have a combination chain and double-braid rope rode. [I'm stating what I see so you can correct me if I'm misunderstanding...]

Your line appears to be double-braid so unless you are using a snubber [or preferable a bridle since you have a multi-hull?] it won't do much to absorb shock loads in inclement conditions [i.e., double-braid won't stretch unless it is dynamic climbing rope, which you wouldn't use for anchor rode, but is OK for a snubber/bridle...]

Therefore you have some choices as I see it [speaking from a monohull sailor's perspective... I would defer to the multi-hull aficionados for even more specific feedback...]

1) Keep the rode set-up you have and add a bridle of suitable length and material to relieve any shock loads you might encounter. [e.g., a 50 ft length of 3/8" to 1/2" (guessing again...) 3-strand nylon or appropriately sized dynamic climbing rope Prusik hitched to your anchor rode in the middle of the snubber length. [I'm assuming you would be connecting the snubber to the rope portion of your rode, but this will work whether you are attaching to the chain or rope portion...]

This same approach would work for a snubber as well...

2) If a snubber/bridle is not desirable- or if you want to streamline that rope-chain connection- you could remove the shackle connecting the chain to the swivel and set all that aside for recycling. Then splice an appropriately sized 3-strand nylon rode [5/8"? -just a semi-educated guess...] directly to the chain with a rope-chain splice. [Which is actually quite easy and satisfying to accomplish...]

Above are a couple of approaches to help improve and streamline your ground tackle set-up.

There are many more approaches, and sometimes certain situations require creative thinking...

In case this is helpful.

Cheers!

Bill

[rognvald]

"Is your 45 foot of chain enough to hold you when you swing into the deeper water and get hit with 25 knot gusts? If not, what is the solution?"
GTL


GTL,
The simplest answer is to find a better spot to anchor. If one is not available, setting two hooks is the only practical solution. However, in over 25 years of cruising from fresh to salt water, I have only encountered a challenging anchoring dilemma once when dropping the hook in an unplanned anchorage in storm conditions. Part of successful cruising is finding safe and secure anchorages beforehand as part of your cruising plan. Good luck and safe sailing.

[barnakiel]

We have used a similar chain and rope set except our line is a fat (1/2) multiplait (which I prefer over 3-strand) and I do not use swivels (a swivel is nor required on rope and chain rode). Never any problem as long as all components are up to the loads.

I also do NOT splice rope onto short chains as this makes extending chain on chain (with two shackles) difficult. So our set up is like in the pictures: chain, shackle+rope (on a thimble).

We use plenty of chain so it is most of the time that we will simply tie a non-slip stopper onto the chain and use it as a snubber.

I have noticed that when I hand the excess chain from the bow the boat will sail way less.

b.

[boatman61]

First.. I hate swivels.. the rest.. I'd rather not comment on from a picture.. to much at stake.
Get rid of the swivel and use the largest bow shackle that will fit the chain..

[s/v Jedi]

Here's the Jedi POV

The Jedi rule is that in 99% of all cases you anchor with only one anchor, which means you must do what Boatman and Mark write. All experienced cruisers will give that same advice.

But there is that 1%... if you swing 180 degree like with tides or afternoon wind reversals etc. and there really is not enough room to make a safe swing with enough scope, then you may have a case for the 1% where you need two anchors. You start with the primary anchor and just anchor normally, giving the right amount of scope like others explained. Mark your chain at the windlass and now run out twice as much or whatever you have. Here, drop our secondary anchor, which may be a Danforth or Fortress style anchor FROM THE BOW. While putting out rode for this anchor, use the windlass to retrieve that of the primary anchor and keep at it until you're back at the mark you made.

Now, when the tide turns, you will switch to the other anchor. You may have to let out a bit more rode to fine tune.

If done right, you can limit your swing to almost nothing.

[JPA Cate]

G2L,

Just a few more thoughts....

Part of what you're discovering is that 40 ft. of chain is so short that it's hard to work with safely, for the boat, and I'm assuming you do not have another anchor with some chain on it, due to storage and weight considerations. If you have only what you have what you have writte about here, the idea of anchoring back out in the 22 ft. would be a good idea, or even further out, so you could swing. The problem with the line ashore or to a stern anchor in the shallows using rope rode, is how to place them so that no coral chafe occurs and leaving is easy if it must be done. If possible, dive the setup once it's all secure, and make sure the rope section of the rode cannot chafe on the coral around there. [Yeah, chain chafing on coral is noisy! But rope is silent. ]

wrwakefield suggested 5/8" triple strand nylon for the rode. I would have thought that 1/2" would probably do for a 4 ton boat. However, I have a prejudice against the plastic thimbles. S/s thimble.

I'm wondering if you need the swivel. Some people like them; others, not so much. Jim took ours out of the system. Yours is ready for re-galvanizing, but the chain looks really good. Have you put seizing wire on the shackles?

Hope you can get your o/b sorted fast. It must feel rather fraught, sort of trapped in a not-the-best-situation, and the boat often at risk.

If you have a second anchor aboard, you might try placing it further out towards the deeper water, and lie between the two with the second anchor limiting your swing towards the rocks. The danger with this is that the two rodes might foul each other; however, for short periods (like one wind or tide cycle) we have done it with success and no fouling.

Good luck with finding a creative solution.

Ann

[barnakiel]

How does that count that 99% of the time someone anchors with one anchor while someone else may be anchoring 100% of their time over a slanted bottom, where two anchors may be the sensible choice.

If we use any kind of statistics, let's try to make sure the base rate is derived from a representative sample - that is to say, ask 100 sailors who anchor over slanted bottoms, THEN build your statistics.

99% of sailors are smart people, what does this tell us about PILOTS?

Cheers,
b.

[s/v Jedi]

Okay Barna, 99% of all situations, okay?

[Don C L]

Well, in case I missed it, sorry, but my first and strong gut reaction is no anchor, chain or no, will hold on a significant downslope. Not only will it pull out as soon as the rode goes taught (and I doubt 25 kts is enough for that in the tri described, and if you are hung up on some coral or rocks I would not trust that either,) slopes are often loose or untsable material. Pulling an anchor UP a slope is great though. I'm one of the 1%ers, I'd set a full sized anchor, a Danforth 20H is a good choice in this case I'd bet, off the stern in the shallows but not quite as shallow as you have described. Can you move out a bit so your stern anchor is set in water deep enough to retrieve safely regardless of tide? Then I'd either set it up Bahamian as Jedi says or leave it on the stern. Not a great anchorage but with two anchors like that, I could sleep.
Oh, and I am a no-swivel guy too, they are not as strong as a shackle and are they necessary?