Help Design my Anchoring System

Here are a couple more pictures.

The rope or chain would fall forward of the 6" deckplate which is a watertight cover.

Behind the deckplate to the bulkhead is about 3 feet.

A drum is nice, but so pricey.


This picture is view to aft and 3 feet where the chain would get messed up, so needs a nest I guess.

 

What size chain and what breaking strength rope for 5 ton/10,000# catamaran

 

I know that I have been beating up a required distance from the bottom of the gypsy to the floor bottom BUT

If there is not enough room and the rope piles up under the deck, even if the rope will go into this, ie somewhat being pushed by the windlass, the problem that has occurred for us is that when spooling the line out the coils could and would occasionally get jambed? into the gypsy which is taking the rope out under power. So the windlass would have to be put on lift, some slack created, a manual separation of the coils, then another start to drop the anchor. Calm seas, large anchorage, no issue. Under poor conditions, it can be an problem

Which brings up another item
Many winches come with a set of (or optional) foot controls right by the winch. When the above problem happens, the foot controls permit the operator to deal with the down and up functions while being close to the rope. Assuming that the winch will some type of plow or claw, often the anchor will not come up in the correct orientation so an operator looking over the bow to the winch, can carefully retrieve the winch but ensure the proper orientation prior to pulling the anchor up
the last bit

Which brings up another item
When an anchor comes up, they often will spin one way or the other and can cause the chain to jump in the gypsy. There is a universal/swivel joint that can be installed between the anchor and the chain which inhibits putting some
pre-twist into the chain.

 

@fallguy I sent a link to this thread to a gentleman called Neeves on the YBW Forum in Britain, and asked him if he might like to contribute his thoughts, as he is very experienced when it comes to setting up and using anchoring systems.
Jonathan and his wife have a sailing catamaran in Australia, and live onboard for extended periods at a time, often at anchor in wild inhospitable places.

Jonathan sent me the very detailed report copied below, along with some photos and PDF's - I shall try to attach the PDF's, but they might be too big.

Jonathan said :

Fallguy, Bajansailor whom I know of old (and trust and respect) introduced me to your anchor dilemma, wondering if I might be able to offer some advice.
I’m reluctant to join the Boat Design Forum, life is too short, and Bajan has offered to post on my behalf.
This is a bit convoluted - but stick with me.
We sail a 38’ x 22’6” cat with a 3’3” draft (sailing cat) as per the photos below. When on a long term cruise we weigh in at about 7t, includes 1t of water and fuel + food for 3 months, 2 kayaks and 2 crew. Our cat is not so different to yours. The cat was originally equipped with 5/16th" chain and a 1000 watt windlass.
We retrieve our rode centrally - through that dark, or black, channel between the forward cross beam and bridge deck, and the chain then disappears under the deck (over a small deck locker) to the chain locker in which the windlass is located.







The supplied windlass was temperamental but we lived with it. But when retrieving by hand, 8mm chain is hard work (even if you are not 75 and still fit). There were other reasons, outlined in the attached articles, and we downsized the chain and upgraded the windlass.
We now use 1/4” chain and still use a 1000 watt windlass. Our windlass is below deck and centrally located (we have good storage forward of the mast but the chain locker is very shallow), as per the photo below.



The chain we use I had made specially (and more cheaply than I could buy), You can source something similar in the US and this is the subject of one of the PDF links below. Our chain was not a one off, a number have been made since and one is in production currently. The windlass has a vertical shaft with the motor offset. Most windlass of this design (there are lots of manufacturers) allow the motor to be in almost any location - in your installation fore and aft. Ours is arranged so that the fall of the chain is away from the motor and the motor is also arranged to minimise the cable run (by a small amount).

Two advantages of 1/4” chain - its takes up less room and its lighter.
In the photo below, the rear 2 drums contain 160’ of 5/16th” chain and the front two drums contains 250’ of 1/4” chain.



Most anchor chain is a G30 or G43 quality (this refers to the strength of the wire from which the chain is made) but we are using a high tensile 1/4” chain - so it actually has the same (or similar) strength as the 5/16th” G30 chain that it replaced. The attached articles define the issues with catenary, which you sacrifice when you use smaller chain and we replace catenary with elasticity.
You could use a mixed rode, chain and rope, and most modern windlass will accommodate both. This is the chain wheel/gypsy from our new windlass in the photo below. You can see the pockets for the individual links and the teeth that grip the rope. Ideally you want to try to store the rope separately from the chain as the rope will be damp, and salty damp, and though galvanising protects your chain it will wear and be damaged in use so keeping it as dry as possible (and free draining) will prolong life.



You can locate the windlass at the bow of one hull and retrieve into your forward locker. You will need to add a bow roller. At anchor you will want the rode to act ‘centrally' - this will be achieved using a bridle. I outline our arrangement for a bridle in the attachments.

I note that you are concerned about growing old (aren’t we all!) and want to be able to use your cat when you are 75. Our anchors are primarily aluminium, an 18lb aluminium Excel, an 18lb aluminium Spade and an 18lb FX 16 Fortress. We have been using the Excel as our primary but are now long term trialling a high tensile steel Viking 10, 22lb.
Because we are using 6mm chain we have a long bridle, outlined in the attachments, which we commence at the transom - so we have a bridle that is deck length and only a very short amount of bridle ‘forward’ of the bow. We can extend our bridle if conditions dictate and can add an extra bridle, for storm conditions - easily - and do most of the work from the cockpit.

You can buy Peerless 1/4” G70 chain, similar to ours, for $5.79 through West Marine, or Defender etc.. it has a 3,150lb WLL and UTS of 9,450lbs and weighs 0.66lbs/ft.
Installing ground tackle in one hull is not unique. Nautitech (France) used to install their anchors in the port hull with the bow roller protruding (we looked at one when we were buying). Nautitech were bought out by Bavaria - and I don’t know how they arrange the ground tackle now.

Now….. this is a very brief overview - if you are interested I can provide more detail on our windlass (but there are many suppliers), I can advise how to actually set up the rode, you will need shackles, maybe something to ensure the anchor arrives at your bow roller right way up, you might want more information on our bridle and how to attach to the chain. I’m happy to help - and I’m a journalist - I don’t sell any of the kit nor obtain a commission.

Finally - my view is that your rode should be a ‘device’ that is made up of matching components, windlass, shackles, anchor, chain, bridle, bridle hook - all the devices should match, should fit with the chain being the weakest component - everything else should be stronger - and the chain should be strong enough. I can assure you retrieving 1/4” chain and an aluminium anchor is well within the physical capability of any reasonable fit 75 years old.

Take care, stay safe,
Jonathan

PS - we take ground tackle seriously - re the photo below, that’s our cat in the bottom right hand bay just off the beach. The next land due east is Patagonia and due south Antarctica. This is our summer cruising ground - where we ‘climb’ the hills and fish for crayfish. There are no roads, no houses, no mobile phone coverage and the VHF traffic are commercial fishermen plus the occasional yacht.

 

Here are two of Neeves' articles.

He also sent me one called 'Snubbed in the nicest possible way', but it is 12.7 MB in size, and the Forum told me that it is too big to post here.
However if you let me have an email address by PM, I can email it to you if you like (similarly if anybody else would like to have a copy of this article).

 

Most all the guides for anchor sizing suggest 35-44# anchors.

But the early life of the boat is on the Mississippi River.

I am wondering if I should just get a 35 pound anchor and a 30 foot section of 3/8" chain and a nylon snubber and 200 feet of dyneema for now. Add a bridle and do everything by hand for now. Then when I get the boat closer to Texas, plan upgrading the system. I have found a potential slip that is a bit short and worried the bow pulpit will be too far out into the walkways in the marina.

The boat is headed for a private mooring at our house, so the pulpit can be anything.

I have plenty of room for the drop; it is probably 32" inside the locker deck to base.

But I would be buying a windlass and wiring it all and using it nearly not at all. Huck Finn down the Mississippi and maybe 20-30 anchoring events in shallow water. I have lotsa anchors here for stern ties to stop swing in the river as well.

maybe this needs to be in phases..

otoh, if the boat is heavy to starboard, 300-450 pounds of anchor stuff to port might be darn near perfect

 

@bajansailor , that post is brilliant. Your friend is a gentleman and a scholar. Please send him my regards.

 

The immersed weight of this will be about 70 pounds, plus mud or kelp, so not too much of a pull. Your whole set up out of water would weight about 84 ish pounds, give or take, with 1/4 inch Dyneema. For the future I wonder if there is a gypsy that will grab the Dyneema. (1/4 inch strength 8700 pounds +/-)(specific gravity close to 1)
Re your pulpit, you may be able to make one that hinges/flips forward for or to the side, for retrieving so that you do not have to lean over the boat edge to retrieve the winch/rode. This will save the side of the boat from chain and rope scrapes

I was able to find a recommendation for the space from the TOP OF THE ROPE PILE to the bottom of the winch of 12 to 15 inches. So you would have 20 inches to store say a 1/2 inch 3 strand in the future. This seems tight to me for rope and chain, but?
All chain will distribute itself lower.

 

Re @fallguy post #36 - Jonathan has just sent me this comment in response to it, and asked me to post it for him :

Modern anchors are NOT about weight but about design.
A 35lb steel anchor sounds about the right size, its the weight we used originally (but have replaced with half the weight in aluminium). By all means use a 44lb version but if you are buying it will simply cost you unnecessary money and you need to retrieve unnecessary weight - you were suggesting a concern about weight as you get older.
You could use a Danforth of 35lb or you could use a Fortress of half the weight and in every test the aluminium Fortress out performs a steel Danforth of the same physical size. Instead of the 35lb steel anchor you could use an aluminium anchor of the exact same design and have the same holding capacity but it will be half the weight.
The alternative, and also weight saving, is the high tensile steel Viking. I don’t know the Mississippi and assume the river bed is largely mud - a Fortress will be ideal for this.
Once you move from river mud then a Spade, Excel or Viking will serve you well. All of these anchors are highly rated in independent tests. All are available in the US but I think the Viking might only be available mail order.

Larger anchors do not produce more hold for a given vessel. The hold developed is dictated by the vessel (not the anchor). If the tension in your rode from wind or your engine is 500lb - then that is the hold of your anchor - big or small. A bigger anchor does not, somehow, produce more hold.
If your anchor is ridiculously small it will not hold that 500lb of tension but a 35lb anchor will develop about 2t of ultimate hold - you will never, ever, be subject to 1t of tension - but you need a safety factor and 2:1 is about right.
Having conducted the tests I can assure you that at 1,200lb of tension you and the crew will be scared witless - it will not happen!

So if the focus is on weight saving to allow easier manual retrieval - go for design - in aluminium or high tensile steel. If you have bottom less pockets and a resilient back go for weight - but you are wasting your money (which I might invest in a few decent bottles of whisky - or put toward a windlass).
I’d strongly recommend a windlass - you will be reluctant to get up in the middle of the night to move when the forecast or location is wrong if you need to hand retrieve the anchor. Its so much easier pressing a button, you don’t get covered in mud and you can retrieve and clean, simultaneously, if you have a windlass and decent deck wash.
Dyneema floats and there is a danger it will be a hazard to other vessels or your own. Having a length of dyneema round a propeller will spoil your day and that of the unfortunate person whose propeller is locked into your rode.

There is simply no logic at all in using 3/8th” chain, its heavy and lifting it and a 44lb anchor will do your back no good - but maybe you know a good and sympathetic chiropractor. 3/8” chain is strong - but you do not need that strength. The maximum tension you are ever likely to experience will be well below 1,000lb - what exactly are you planning for?
You need chain as it is abrasion resistant (and relatively easy to clean) - use a smaller chain and it will give you protection from abrasion and if you use sufficient it will offer a horizontal pull for the anchor. More and lighter chain is better as you enjoy a longer part of the rode that is a abrasion resistant and you ’spread’ the load. If, as you suggest, the anchorages are shallow - then if you have a decent length of lighter chain - you might never need to deploy the rope portion.

If you use a mixed rode I'd recommend you use nylon as it will offer some snubbing.
To attach a rope bridle (which should also be nylon and not very beefy), which you will need, to cordage in the rode means you need to learn how to make a rolling hitch or Prussic knot - neither are difficult. You need the bridle to centre the tension, assuming your bow roller is at one bow, and a bridle will steady the vessel from veering.
If you use 1/4” chain you will need some form of chain hook for the bridle - which you can slip on in seconds - much easier than a knot.

Personally as you eventually intend adding a windlass I’d bite the bullet now and buy the rode you will want and need then - or the rode you buy now will be simply wasted. A windlass capable of handling 3/8th” chain will be more expensive and use more power than one designed for 1/4” chain. The wiring for a bigger windlass will need to be of a larger size than the wiring for 1/4” chain. Windlass last decades - they are a good investment. Our new windlass is designed for 5/16th” chain and 5/16” is the conventional size for your and our yachts. We have downsized the chain to 1/4” and have a gypsy and chain wheel to suit and the chain is the same strength as 5/16”. We have replaced catenary with elasticity in the bridle. It merits note - at about 30 knots of wind (think a thunderstorm) there is no catenary left - your rode is bar tight - elasticity will be available until your snubber fails (which if you plan correctly will not happen).

I note you mention you have plenty of fall for the chain. Ideally your windlass will primarily be installed below the deck (and it will look nicer and neater if below deck). You will lose some of the ‘fall’ because the windlass protrudes ‘down’. Having it below the deck protects the ‘electrics'.
I’d look at the cost of 3/8th” chain and that of G70 1/4” chain and mull over if spending the same amount of money, on 1/4”, might not be a better option - saves that back! Longer term you can join the chain, when you buy the windlass (using a Crosby ‘C’ link) - I’d buy the length of G70 I will need then, now - and save money long term.

Lots of options but buying the windlass, chain and a decent anchor seems within the budget you mentioned. Longer term you will need an anchor of a different design (to a Fortress) but a good Fortress makes an excellent kedge, stern or emergency anchor.
I have noted your concern about balancing the weight - I’d suggest don’t get hung up - carry a few jerry cans of emergency fuel is a good idea, a spare rode for the stern lines and anchor you mention will help, you will carry an outboard, which will need fuel - I can assure you extra weight materialises very quickly.
Our pulpit at the extreme bow is vertical and set slightly aft of the bow itself - we have no overhang. I don’t see how the pulpit will add to LOA. Our problem is the prodder/bowsprit, but it can fold up.
However we don’t use marinas - we anchor out exclusively.

Take care, stay safe.

 

How does one build a vertical pulpit aft of a knife bow?

would you bridle to the tow hooks or an eye bolt in the netting beam socket? The tow hooks are just set in 4# density corecell and so the pull is supposed to be mostly forward and the reason for the butterflied stainless tubing is to spread the lateral loads on the tow eye..the eye bolts are 10" long and custom machined; I hate to mention what they cost; too much let's say

a serious overpull of the eye bolt on the netting beam would be stopped by the beam socket backer or eventually the beam itself if it were to break, but the hole is 3/16" and the tensile rating of the eye bolt is probably 70-100,000 psi or say 5,600 per eye@2 eyes or about 11,200#..while the tow hooks need to be that, I'd never put a 5600 pound lateral pull on them without cringing

 

Jonathan also sent me today the following observations and thoughts :

Decisions on choice of anchor is increasingly based on the fear of dragging and the idea that weight is the panacea to provide security.
The reality is that with modern anchors the incidence of dragging has almost disappeared - except for bad luck (catching a beer can in the toe of an anchor) and even this can be mitigated by power setting.
But the public’s mindset is devoted to the idea of big anchors to the exclusion of the idea that maybe design plays a role.

Anchors are sold by weight, not by surface area and not by performance. All the spread sheets are derived on the basis of vessel length and weight of anchor.
If we look at chain - all the spread sheets are on the basis of link size (which effectively means weight - as well as strength) and LOA.
This results in the market place considering that more weight is thus better.
This is then compounded by the Dashew theory that your anchor is not big enough until people start to laugh about how big it is.
This latter comment is constantly repeated on virtually every anchor thread - but there is no evidence behind it.

There is grudging acceptance that the Fortress is a good anchor (and it has a hold factorially better than any steel anchor of the same size) - though people don’t go as far as to say its as good as a genuine Danforth.
But credit to Fortress that they have some acceptance at all. Spade and Anchor Right with their aluminium anchors have an uphill battle. Viking are equally facing an immense task to overcome the prejudice. The acceptance of ‘weight’ is widespread and all embracing.

I note that many people use oversized chain and equally many people blindly follow the advice and buy a bigger anchor than recommended by the anchor maker (and in the next breath complain about how expensive marine components are).
The Classification Societies allow a reduction in weight of a modern anchor vs one from the previous generation by 30% - but the market place knows better and blindly buys an anchor as big as the one they retire - or bigger still (and then marvel at how good the new anchor is!)
This is the problem with an anchor that is too big. In the photo below, the smaller Fortress FX 16 is quite well buried, except for the crown. The larger FX 37, set under a similar tension to the FX 16 sits proud - all ready to be tripped in a change of tide when the rode gets under the stock. The anchors were set under water and then photographed after the tide had receded (a bit contrived - but near reality).



This phenomena is not restricted to Fortress. This anchor, below, looks well set - but there is enough of the anchor protruding to allow it to be tripped with a change of tide or wind. A slightly smaller anchor would have set more deeply.



This article Deep Anchors Stay Put in Moderate Yawing - Practical Sailor https://www.practical-sailor.com/sails-rigging-deckgear/deep-anchors-stay-put-in-moderate-yawing concludes that a deep set anchor has greater resistance to yawing.
A smaller anchor can be more deeply set than one larger. If the anchor is ridiculously small - all bets are off.
Chain suffers under a similar mindset - that catenary is essential. Elasticity can replace catenary - or work in conjunction with catenary.
Testing and simple maths (actually the maths is quite complex) underline that catenary has a finite limit - commonly around 30 knots - unless you have a lot of chain.
Elasticity from nylon, if you have a storm snubber as well as an every day snubber, will work the full range of winds you are likely to experience.
By broadening your mind and accepting that catenary has a finite range you can downsize chain size, save weight and space and replace some catenary with elasticity.
No-one objects to the comfortable ride of their automobile, which incorporates a number of devices to smooth out irreularities in the road, tyres, springs, shock absorbers, foam in the upholstery - why object to the idea that your rode can minimise snatch loads using complimentary devices?

Everyone when considering a new rode has constraints - money often being high on the list. There are so many options, we are spoilt for choice.
There is a large range of anchor designs today made from a range of materials, we have reliable chains or different strengths and weights, we have access to cordage and methods of manufacture that was simply just a dream 30 years ago.
Many of us are locked into what we can buy - because our windlass accepts only one chain size (and buying a new gypsy can be an expense we don’t need).
To have a new yacht - you can consider all the options and come up with a much better combination then the conventional standard answer.
We should not be restricted to what our fathers and grandfathers did - technology and knowledge has moved on.
In Patagonia where anchors are still important but shore lines are de rigour - think outside the box. Snubbers, if used, were a short strop to keep the tension off the windlass - ours are now 30m long.

 

Absolutely brilliant stuff!