Author Topic: Anchor chain-well "redesign" (Read 10176 times)

Lyra · « **on:** September 19 2016, 20:54 »

I don't know if it is a general problem or only with the Lofrans windlass which I have installed.
The chain drops vertically (ok, that's physics) and starts piling up until it reaches the feed hole and does not let the rest of the chain go through.
This means that every 10m or so I stop pulling the anchor, and using a short tube I push the top of the pile forward to make room for the next 10m etc. etc.
Another thing is that the drain holes are several cm above the well floor so the bottom of the pile is always in water.
Has anyone tried to make a sloping false bottom - one that will force the chain to slide forward and provide drainage? due to the shape and limited access from the top this seems to me like a challenge so if somebody did it and can provide some insight it would be very helpful.

Nigel · « **Reply #1 on:** September 19 2016, 23:12 »

I've bought some perforated rubber matting for the chain-well floor, it's about 22mm thick. Like this

Same problem with the pile-up, but I plan to modify the vertical hole through the GRP, it's meant to be bevelled forwards at 45°

Symphony · « **Reply #2 on:** September 19 2016, 23:14 »

You have just described a common problem to which there is no foolproof solution other than what you are currently doing. Easiest way to raise the chain at the bottom is to use a bit of that plastic grating which will keep the chain out of the water that collects below the drain holes.

landes_h · « **Reply #3 on:** September 20 2016, 08:55 »

Would it make sense to put a layer of insulating foam (from pray can, like for mounting doors & windows) up to the first level of drainage hole. Once dry it could also be fixed with an edge of Sika around.
For the chain I also reach down and throw the pile forward to make room for more chain to come. Maybe some slanted chute would help. Supposedly stainless chain don't pile up, but it's said the are not good for the "warm" Mediterranean water.
What bothers me too is the water filling hole in the anchor well. It is recessed so that dirty water goes in the tank once I open the lid. I intend on having a short pipe (3-5 cm) made to raise the hole, with the same thread measures to fit in the original hole and to take the lid on top.

Yngmar · « **Reply #4 on:** September 20 2016, 11:26 »

I've used two layers of rubber matting similar to what Nigel linked, cut to size. This lifts the chain out of the puddle. My anchor locker already had a sloping floor and I have no problems with chain piling up in there, so that definitely works, although I only have 45m of chain. Bonus, the chain goes in a lot quieter thanks to the rubber

Edit: Oh, if you go for the rubber mat, make sure the holes are smaller than a single chain link, so they can't "fall in".

AFRiCA · « **Reply #5 on:** September 20 2016, 12:24 »

As mentioned this is a common problem. I have a 42ft 2001 Bavaria with a similar issue. My solution to the issue was to purchase large glass marbles and place in the anchor well till the marbles reach a level above the drain holes. This solution has worked well for many years

Lyra · « **Reply #6 on:** September 20 2016, 13:35 »

Thanks to all.
Will most probably tackle the issue this winter.
On first thought I am thinking of epoxying sloping cleats on each side. They will support 2-3 perforated plywood slates (maybe fiberglass reinforced). number of slates will be dictate by the ability to slip them through the well opening. Cleats will be above drain holes so this should solve both piling and draining.

jonrarit · « **Reply #7 on:** September 21 2016, 10:52 »

We have the same issue with the chain piling up. One "solution" I've heard of is placing a small traffic cone underneath where the chain piles, forcing the chain to fall deeper into the locker ....... cheap if it works so worth a shot I reckon

jonathan

Eye Candy · « **Reply #8 on:** December 03 2016, 00:56 »

Hello all,
I have done a very simple modification to our locker setup on our Bav 39C to enable the chain to be distributed more evenly as it is raised.
I fitted a short (300mm) length of poly pipe 2 1/2" dia over the chain immediately under the windlass. ie the chain passes through the pipe. The pipe has 6mm holes in it, two at the top (windlass end) and one at the bottom. The top holes are used to tie the pipe up close to the windlass under the chain outlet with cord but allow articulated movement. The bottom hole is forward and has a piece of cord tied to it and led up to the deck level so the operator can reach it. As the chain is raised the end of the pipe is moved from side to side and back and forth with the cord to spread the chain about. After playing with the geometry (cord lengths), this has worked well for us for 10 years.
I can give more detail if anybody asks. I have no photos here as the boat is in French Polynesia and we are home in Aus.
Andrew

Craig · « **Reply #9 on:** December 03 2016, 04:01 »

We cut down a plastic milk crate to raise the chain out of the water. We found an old plastic milk crate on a beach in Croatia. Just cut down the sides. The chain sits on the up-turned bottom. We also had to chop off a corner to fit our locker.

The piling problem has not occurred in our 2009 Bav 38. even though we have 100m of 8mm chain.

The boats I have seen with the problem appear to be boats that have changed the standard 8mm chain for 10mm chain. I think a number of "Yachties" incorrectly believe that the heavier the chain the better. The Australian Magazine "Cruising Helmsman" had a great article last month explaining why heavier chain is counter-productive.

Craig
"Shirley Valentine"
Gold Coast
Australia

Harveyhall · « **Reply #10 on:** December 03 2016, 07:12 »

Interesting solutions to the problems of an elevated drain hole. I have not tackled this on our new-to-us boat but I was thinking filling the gap with resin to the level of the drain. Hopefully this will eliminate saltwater just sitting in the bottom. I have a 55 m of chain and 60 m of line backing the chain. We sometimes have the need to anchor in deeper anchorages and this may keep the line from being constantly wet.

I am interested in others solutions to the chain piling up as that is a problem with our anchor locker.

Heh Craig your comment about "heavier chain" not being better. Are you referring to not piling up in the locker or not being an advantage to prevent dragging anchor? I can't find that article on-line. Love to hear more to their argument.

Craig · « **Reply #11 on:** December 03 2016, 22:17 »

The reason the drain holes in the anchor locker are not at the bottom of the locker is to allow mud to not clog the drain holes. It is a safety issue.

Do not raise the level of the floor to allow all water to drain out. You are risking the holes being clogged and the anchor compartment filling with water in rough seas.

The basis of the article in Cruising Helmsman is that:-
(a) The catenary effect of heavier chain is limited and almost zero in really strong winds . ( You are better to invest in a larger anchor than in heavier chain)
(b) A thinner cable will allow the anchor to set deeper. (Theoretically piano wire with the appropriate breaking strain would allow the anchor to set deeper. Don't do tis as abrasion resistance is also required.)

Craig
"Shirley Valentine"
Gold Coast
Australia

dawntreader · « **Reply #12 on:** December 04 2016, 08:05 »

Quote from: Craig on December 03 2016, 22:17

The reason the drain holes in the anchor locker are not at the bottom of the locker is to allow mud to not clog the drain holes. It is a safety issue.

Do not raise the level of the floor to allow all water to drain out. You are risking the holes being clogged and the anchor compartment filling with water in rough seas.

The basis of the article in Cruising Helmsman is that:-
(a) The catenary effect of heavier chain is limited and almost zero in really strong winds . ( You are better to invest in a larger anchor than in heavier chain)
(b) A thinner cable will allow the anchor to set deeper. (Theoretically piano wire with the appropriate breaking strain would allow the anchor to set deeper. Don't do tis as abrasion resistance is also required.)

A good point from Craig about blocking the anchor well holes. In order to overcome the issue I have used heavy-duty latticed rubber matting in the bottom of the anchor well. This has been cut to size in triangular shapes and sits securely in the well. It took three pieces and these are cable-tied together.The matting holds the chain above the holes but without filling the (debris) space below them. I would also like to thank the person who threw the perfectly good matting into the skip at my local boatyard allowing me to do this at no cost

Salty · « **Reply #13 on:** December 04 2016, 10:40 »

Quote from: Craig on December 03 2016, 22:17

1. The reason the drain holes in the anchor locker are not at the bottom of the locker is to allow mud to not clog the drain holes. It is a safety issue.

2. Do not raise the level of the floor to allow all water to drain out. You are risking the holes being clogged and the anchor compartment filling with water in rough seas.

3. The basis of the article in Cruising Helmsman is that:-
(a) The catenary effect of heavier chain is limited and almost zero in really strong winds . ( You are better to invest in a larger anchor than in heavier chain)
(b) A thinner cable will allow the anchor to set deeper. (Theoretically piano wire with the appropriate breaking strain would allow the anchor to set deeper. Don't do tis as abrasion resistance is also required.)

There are some issues I have with Craig's posting, particularly at point 3 above in regard to the article mentioned from the "Cruising Helmsman," but dealing with them in turn:-
1. Correct, but on my B36 (2002) the drain holes are located port and starboard, and in particular are at different heights above the bottom of the chain locker. So using the benefit of "seamanship," surely the thing to do would be to squirt a hose into the chain locker periodically, and investigate if water only came out of the upper drain hole with nothing exiting the lower one. Okay, not all boats have two drain holes, but surely that is easily remedied, and secondly on some boats the drain holes are both at the same level so it would take a little more time and effort to make one significantly higher or lower than the other.

2. Fair enough, but Dawntreader's system should work well and has the benefit of keeping the chain out of the water, thereby helping to slow down any corrosion. And remember that even stainless steel, will corrode in the stagnant seawater that resides in the area below the bottom drain hole of your pride and joy while it sits quietly at a marina berth for weeks on end.

3a. If you anchored in really strong winds, it is more likely that you will damage the fittings on the bow than loose the catenary in the chain. Don't take my word for it, just get hold of a ten metre length of chain, secure it firmly at one end a couple of metres off the ground and pull the other end until the catenary has been lost and the chain is straight and tight. Yeah, right !!
3b. Is there any chance Craig that you can convey the Cruising Helmsmans thinking on this, because it doesn't make any sense at all to me. A heavier chain will help to ensure that the pull on the anchor is as near horizontal as possible where that would be the best situation to ensure that the anchor digs in deep. With a lighter chain, there is a greater possibility of loosing that catenary which in strong winds or current flow, would tend to raise the anchor stock above the horizontal thereby allowing a tendency for the anchor to break free. So some explanation of the Cruising Helmsmans thinking on this matter would be appreciated, and until then I most certainly would not change to a lighter chain.

Lastly when I was at sea, it was always recommended that in a blow or strong current, that you put out more chain because as much as anything it was reckoned that the length of chain laid on the bottom did more good at holding the ship than did the hook on the end !!

Yngmar · « **Reply #14 on:** December 04 2016, 11:56 »

Catenary research by Peter Smith (the Rocna designer): http://www.petersmith.net.nz/boat-anchors/catenary.php

Well worth reading to clear out any false notions about catenary.

Salty · « **Reply #15 on:** December 04 2016, 18:20 »

Quote from: Yngmar on December 04 2016, 11:56

Catenary research by Peter Smith (the Rocna designer): http://www.petersmith.net.nz/boat-anchors/catenary.php

Well worth reading to clear out any false notions about catenary.

Thanks Yngmar, an interesting article that tries to get the reader to question the old tried and tested methods, but does not entirely dismiss them. Am I going to change the way I anchor? Well I've not seen a good enough for me reason yet, so probably not this side of very old age or ill health and a wooden box consequent (hopefully) only to those factors👹

Craig · « **Reply #16 on:** December 04 2016, 22:03 »

Guys,

The article supplied by Yngmar gives clear evidence for the need to increase scope to hold anchors and clearly shows the limitation of the catenary effect in anything but "light" winds. This is backed up by a number of other , properly researched articles.

The "Cruising Helmsman" article agrees with the above article and also raised an additional point against heavy chain:-
Where the seabed is soft and the anchor needs to be buried deep, a large heavy chain will lie on the surface of the seabed and hold the shank of the anchor at the level of the seabed, rather than let the shank dig deep as well. As the flukes dig deep, but the shank is kept at seabed level, the angle of the anchor changes and is prevented from digging deeper. I will try to scan in the article in the next week and post.

Basically, I would always invest in a larger ( or better designed) anchor than in heavier chain.

Key points are:-
1, Although there are usually two drain holes in the bottom of an anchor locker, I would not compromise safety by raising the floor. Periodically hosing out the anchor locker will remove any mud and remove salt water from contact with the chain.
2. The chain can be kept out of the water/mud by using the mats or cut down crates mentioned in the posts.
3. The lighter the chain the better, provided that abrasion resistance is not compromised.
4. The longer the chain (rode) the better the angle to the anchor. Catenary effect is useless in winds over 35knts. There is benefit in anchoring ratios up to 10:1 but the benefit of more rode after 10:1 is limited.
5. A smaller chain ( or rode) is less likely to hold the shank above the seabed and should allow the anchor to dive deep in soft bottoms.
6. Replacing anchor chain with a larger chain is expensive and more likely to clog the anchor compartment, requiring broom handles ( or similar) to poke the chain down.

Craig
"Shirley Valentine"
Gold Coast
Australia

Craig · « **Reply #17 on:** December 07 2016, 01:47 »

Salty,

I've managed to retrieve my copy of the Cruising Helmsman article.

The copy of the article is attached.

Craig
"Shirley Valentine"
Gold Coast
Australia

Salty · « **Reply #18 on:** December 07 2016, 09:46 »

Thanks Craig, it's a well written easy to read and seems to me to be well researched article, I'm almost convinced ! However, I'm old school and will not be changing either my anchor or chain. One thing which the article does discuss, albeit not in any great depth is that of chain wear where it lays across a rocky sea bed, and where thinner chain would have less to wear through before it breaks under load, and thereby warranting more frequent and closer inspection.
As for anchoring in the strong wind speeds suggested in both this and the article written by Peter Smith, well I don't yet howl at the moon !!

Craig · « **Reply #19 on:** December 07 2016, 22:06 »

After spending 3 days in the Bora in Pula, Croatia in 2010, where the winds reached 75knts. ( Cat 2 or 3 Cyclone) on the third day, I can personally testify that catenary is a myth. With 80m of chain out in 4m of water, the chain looked dead straight and did not touch the water for at least 3 boat lengths in front of the boat.

Without boring you guys with the proof, the other anchoring myth is that if 2 anchors are deployed, they are placed in a V pattern. The best option is to deploy the main anchor on a long chain and the second anchor on a shorter rode, much closer to the boat, both anchors directly in front of the boat.

After 6 years our 8mm chain shows no abrasion damage except for the first link where it joins the anchor. We chopped this link out.

Craig
"Shirley Valentine"
Gold Coast
Australia

landes_h · « **Reply #20 on:** December 12 2016, 13:17 »

Quote from: Craig on December 03 2016, 22:17

The basis of the article in Cruising Helmsman is that:-
(a) The catenary effect of heavier chain is limited and almost zero in really strong winds . ( You are better to invest in a larger anchor than in heavier chain)
(b) A thinner cable will allow the anchor to set deeper. (Theoretically piano wire with the appropriate breaking strain would allow the anchor to set deeper. Don't do tis as abrasion resistance is also required.) . . . .

. . . . is all this also valid for the northern hemisphere

landes_h · « **Reply #21 on:** December 12 2016, 13:23 »

Quote from: Eye Candy on December 03 2016, 00:56

Hello all,
I have done a very simple modification to our locker setup on our Bav 39C to enable the chain to be distributed more evenly as it is raised.
I fitted a short (300mm) length of poly pipe 2 1/2" dia over the chain immediately under the windlass. ie the chain passes through the pipe. The pipe has 6mm holes in it, two at the top (windlass end) and one at the bottom. The top holes are used to tie the pipe up close to the windlass under the chain outlet with cord but allow articulated movement. The bottom hole is forward and has a piece of cord tied to it and led up to the deck level so the operator can reach it. As the chain is raised the end of the pipe is moved from side to side and back and forth with the cord to spread the chain about. After playing with the geometry (cord lengths), this has worked well for us for 10 years.
I can give more detail if anybody asks. I have no photos here as the boat is in French Polynesia and we are home in Aus.
Andrew

easy explanation:
...this is like peeing your Name in the snow. Very good !

Trundletruc · « **Reply #22 on:** January 29 2017, 12:56 »

Our B36 had the same problem of the chain/rope always sitting in water. I solved the problem by cutting the drain hole on the one side lower - level with the bottom of the chain locker (about 1cm) and angling the plastic cover outside downwards. This also gets rid of the water that is likely to seep into the glass fibre in time. You just need to make sure that, where you have cut the edge of the glass fibre, it is well covered with resin.

Great idea with the plastic tube - I will try this.