anchor winch dilemmas

Those shiney bits
Jim
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Re: anchor winch dilemmas

Post by Jim » Sat Jan 07, 2012 6:15 pm

Just on anchors, at Orpheus Island one night I had all my chain, 40 meters out and had no idea what the bottom was, late afternoon, and 8 meters of murky water so I couldn't tell. It hooked up quite firmly, (rocks??) and my next thought was "will I ever see that anchor and chain again"? I still had 60 meters of rope as well as a spare anchor with another 80 meters of rope so it wouldn't be a total mess if I lost it. My SCUBA tank was at home in the shed, brilliant, so the thought of cutting the rope and watching many hundreds of $$ going down gave me a few sleepless moments that night. It broke free with less effort than I thought it would the next morning, so it was all good. This time.
Jim.

mahnamahna
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Location: Gosford NSW

Re: anchor winch dilemmas

Post by mahnamahna » Sat Jan 07, 2012 7:00 pm

Its really only one question Jim, with some qualifying information I guess.

How much fall do you have beneath your anchor winch and deck for 40 meters to pile up a bit that you need to push it aside, and do you have 10mm chain, I know a lot of 35ft cats use 8mm. There is quite a difference in size between 8mm and 10mm chain.

And I guess the main question is really the one about having a straight run of chain for the winch, is this better or not. I look at the gypsy and think perhaps if the chain did exit the hawse pipe below the height of the gypsy, the angle that the chain would hit the gypsy would increase the number of teeth of the gypsy gripping the chain before it falls off the back of the gypsy which would promote a better grip, but does the angle mean the windless has to work harder, I would have thought it would prefer to pull in a straight line?

Thanks Jim for the information so far. I guess having the decks clear is more of an aesthetic thing, but I also guess you only have to trip over it once and break something (a bone such as an ankle) on a long passage to wish you had it buried beneath the decks if you could have. I have the option so am just trying to figure what is best given there are a number of variables and each seem to have advantages.

Jim
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Re: anchor winch dilemmas

Post by Jim » Sun Jan 08, 2012 10:12 am

The meter of (8 mm) chain I have on the deck goes straight into the winch, which must be better, as for the fall, maybe 500mm, but the lockers there have a half round front on them which makes everything pile up at the back or deep end of the locker. If the lockers had a flat bottom instead of an angled one the chain would probably stack over a wider area and not be so high. I would advise a good fall into the drain holes and even some sort of plastic mesh at the bottom of the locker to keep the chain as dry as possible.
I have recently switched to an Apple PC and if I can ever work out how to work with photos I will post a couple.
Clear decks are by far a better option, but you do get used to the deck layout on your own boat quite quickly.
Jim.

mahnamahna
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Re: anchor winch dilemmas

Post by mahnamahna » Sun Jan 08, 2012 8:24 pm

Thanks Jim, I will have about a 600mm drop if I put the winch level with the hawse pipe down inside the well, which would be about 300mm into the well, so I could have a 1 meter drop if I continue the deck over the well, and mount the winch at deck level at the top of the D but that would mean and exposed chain to the catwalk and the chain would travel up from the catwalk to a leader or plate on the deck in front of the winch.

Most likely I will mount the winch inside the well so that the chain goes through the hawse pipe from the catwalk, through the D and into the well, its just a question of if I allow the chain to exit the hawse and go up a little to the gypsy and then down through the platform into the well. That would increase the fall and therefore the amount of space in the well. The well bottom is flat and 600mm each way so its pretty big.

The more I think about it the more I am inclined to think that from an angle of attack point of view the winch doesnt know what angle the winch is hitting the gypsy, its a wheel so anywhere it hits is fine, and in fact the earlier it hits the more teeth are in contact and gripping at any given time I guess. But I just feel that having the chain rubbing against the top of the pipe to exit up to the gypsy under tension has to add resistance (in the form of friction) meaning to some extent the winch is working harder, which must shorten its life cycle, the question is by how much. Or another way to look at it is that the winch has a given amount of pull, and any given snag on rocks or coral may have been able to be pulled up by the winch had I not added that extra workload...or not. I just dont know.

As for the bottom of the well, I have a duflex (balsa core) base which I am a bit concerned about having anchor chain crashing into it so I am planing a false floor of 12mm ply elevated by a second layer of ply under it but only around the edges and then many drilled holes in the top layer to drain to the duflex to a single middle drain hole of about an inch in the duflex to the outside, then once the boat is finished I thought a rubber interlocking tile of some kind similar to what they have in play grounds and pre schools to absorb that energy and dampen noise and vibration.

Thanks again Jim.

Smooth Cruiser
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Re: anchor winch dilemmas

Post by Smooth Cruiser » Sun Jan 08, 2012 9:22 pm

As you say - the winch doesn't care what angle the chain enters it as long as it is in the plane of the gypsy. All the winch provides is a circular turning force - so the chain doesn't need to enter a vettically mounted winch horizontally.

Running a taut chain through a hawse pipe at an angle wiill increase the shock loading on the winch considerably as each link will crash over the tight radius hawse - it would be best to have the chain pass claenly through the hawse so that when it is taut (under load) it is sitting centrally in the hawse and not contacting the sides at all. Normally wherever a chain (or rode) under tension goes round a corner there is either a roller fairlead or a large radius metal bend that would see at least three links of chain in conact with the rounded curve at all times to reduce the tendency for the vertical links to snag.

A couple of other points from your posts - you mention that the winch might need the power to pull the chain off obstructions - this is not how winches whould be used - the winch is only designed to lift the dead weight of the full chain and anchor - while the winch will have some ability to pull the boat to the anchor, it shouldn't be used like this in strong winds or when the anchor is snagged - these high loads will trip your circuit breaker very quickly and burn out the anchor winch contacts or motor if done repeatedly. If the wind is strong then you need to motor the boat up to the anchor - only winching when the chain is slack. If the anchor is caught in coral or rock (or even well buried in thick mud) then you need to secure the chain with a snubbing rope and break the anchor free using the bouyancy of the boat and/or momentum from the engines - the winch will never be able to provide the force required to break the anchor free.

You mention being able to anchor in up to 10m depth - you will need the ability to anchor in up to 25m of water fairly often up the Qld coast and in other volcanic island areas - 50m of chain is enough but you will need at least 30m of rode permanantly attached as well to manage this - you need to ensure that the rope eye and shackle used to attach to the end of the chain can pass around your winch (normally by hand) and then through the hawse and any other fairleads etc - I see a few boats with the anchor chain passing through a nice neat small hole - but this doesn't allow the rope eye to pass through and also perhaps makes it difficult to jettison the chain in an emergency so you really need wide openings that allow this to happen - make sure that your hawse opening is wide enough for this!!

44c
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Re: anchor winch dilemmas

Post by 44c » Mon Jan 09, 2012 7:27 am

A 600x600x600 box will probably fit 50m of 10mm chain, but only if it is packed properly. (I assume you'll be using 10mm - you should be) When you wind chain in with a windlass it tends to stack up under the windlass. Only 600mm of fall will mean you'll have to keep pushing the chain aside as it heaps up. It would be better if you could have more fall. The more fall the better - it puts more pull on the chain, which makes it engage the windlass better, gives more time for the chain to untangle itself when free falling the anchor, and will be less hassle all round.

I wouldn't worry about putting in a false floor to protect the duflex from the chain. Just get some of that rubber matting with holes all over it, and put that in there. Will protect the locker and still allow any water to drain away.

I have my windlass inside the chain locker too. The "wet" issue isn't one so far. The locker seems to stay dry. I do have two large drains in it. Only real downside to me, is that I can't really use the rope drum for the halyards. Although I probably wouldn't anyway, the risk of doing serious damage is pretty high that way.

mahnamahna
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Re: anchor winch dilemmas

Post by mahnamahna » Mon Jan 09, 2012 8:15 am

Guys very handy information thank you. From it I have my solutions.

First Smooth, thank you for reminding us non boaters about the need to motor up onto the anchor, I did actually know this (read it) but had forgotten. Just for further clarification, do you motor back on the anchor until it releases before starting your windless every time or do you often attempt the windlass first and upon feeling that resistance start motoring up on it? The winch I have was given to me in a not working state and I had it repaired, the gearbox was completely stripped and inside it was a mush of bronze filings in a paste, no doubt the electric motor is stronger than the gear case can handle and it gave out before the motor did. The guys at Muir told me the electric motor was as good as new. In effect I got a near new electric winch (which currently sell for over $2500) albeit an old model for the price of a new gearbox ($300) and new switches. But in that damage is the warning to use it properly that you allude to.

And re 50m of chain being enough but needing an 80m rode total, does anyone use full chain rode of 80m, I guess maybe with 8mm chain but surely not with 10mm, that would weight nearly 200kgs.

And 44, your advise has convinced me to mount the winch higher in the well to avoid having to continually push the piled up chain aside. Glad also to hear that you have your winch inside the well, I had not found any pics of it and wondered if I was making a mistake in doing so. But I have the depth to have the winch under the hatch lid and mounting it inside the hatch not only looks better but is much less work. Mounting at deck level requires me to scallop the cabin sides out, inside the well just means cutting a hatch out.

The solution I have come up with, bearing in mind Smoothes advice re chains relationship to the hawse, and 44'c advice re space needed for 10mm chain is to mount the winch as high as I can but have a fairly large diameter rubber roller aft of the hawse pipe exit that directs the chain upward whilst maintaining the chain at the centre of the hawse pipe under tension.

Pretty obvious solution now that it has presented itself and I feel a bit silly now that it has been flushed out. Thanks guys. But do let me know of any potential pitfalls in this idea.

Smooth Cruiser
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Re: anchor winch dilemmas

Post by Smooth Cruiser » Mon Jan 09, 2012 10:27 pm

mahnamahna wrote:Just for further clarification, do you motor back on the anchor until it releases before starting your windless every time or do you often attempt the windlass first and upon feeling that resistance start motoring up on it?
It is really a combination of motoring and winching. The best approach requires two people - the person on the bow signals the way the anchor chain is leading allowing the person helming to motor up slowly keeping the chain falling close to vertically - this allows the winch to be used continuously pulling in the slack and only lifting the chain weight. This requires good communication (with hand signals preferably - nothing worse than a boat with people shouting from one end to the other in an otherwise serene anchorage!!). Then if the anchor itself is caught you snub it off so that the load is removed from the winch and drive forward with the engines using the upwards bouyancy of the bows and the boats momentum to break the anchor free before winching again once the load has gone. With only one person this is obviously more difficult - you can get the feel for the engine revs needed vs wind strength to take the load off the winch but sometimes you can over-run the anchor or start heading off at an angle so there may be a few instances where you snub the anchor off again and go back to the helm to reposition the boat. No dramas - just adds a bit of time to the exercise. With one person you will tend to pull the boat to the anchor with the winch a bit more, but you still can't use it to take shock loads or to break the anchor free.

While on the topic - I refer to snubbing the anchor off - in my opinion every boat should have a short strong rope cleated off with a chain hook on the end forward of the winch - set up so the hook can quickly be thrown on the chain to take the load and leave slack chain to the winch. This is essential in many scenarios - a jam of the winch itself, the boat blowing back quickly on a slack chain with a reslting massive shock load when the chain comes tight, breaking anchors free, resetting winch circuit breakers etc etc. Saves many a tricky situation from turning nasty and removes almost all risk of shock loading the winch with resultant often serious damage.
mahnamahna wrote:And re 50m of chain being enough but needing an 80m rode total, does anyone use full chain rode of 80m, I guess maybe with 8mm chain but surely not with 10mm, that would weight nearly 200kgs.
50m of chain is plenty - the rest as rode is fine. In sand or mud you can let out as much rode as you like, in rock or coral only the chain should contact the bottom so you should let out the depth at low tide as rode only. An anchor and nearly 50m of chain sitting on the bottom will hold you whatever the depth.

Finally
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Re: anchor winch dilemmas

Post by Finally » Mon Jan 09, 2012 10:56 pm

Paul

The cat I usually sail on has 100m of 8mm short link chain through a Muir Cheetah (an excellent piece of kit by the way). His anchor lockers are the deepest I have seen - a little under 1.5m deep on a 40' cat - so he never has any problem with the chain stacking on him.

For the section of chain from the anchor shank up to the gypsy he replaced the gal chain with 13mm stainless steel chain. This achieves a couple of things - it helps set the anchor by holding the shank down when lying on the sea bed (because of its heavier weight compared to the 8mm chain) and stops the rust stains on the catwalk / protector strip usually associated with gal chain (the anchor spends more time "up" in the marina than "down").

I do have a question to ask for the readers. The monos and tris I have sailed on didn't use bridles (only snubbers) and because my experiences to date with bridles has been solely on a boat which has all chain where you just hook the bridle onto a chain link - how do you attach a bridle to a rope rode to stop the boat from "searching" which would be one of the jobs of a bridle on a cat?

David

44c
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Re: anchor winch dilemmas

Post by 44c » Tue Jan 10, 2012 6:58 am

Rolling hitch

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