Anchor over the bow roller

I was bringing the anchor in last time we were out - not thinking of anything in particular until the anchor chain brought the tip of the anchor shank to the bow roller. At this point the chain is pulling at right angles to the shank and has to pull the anchor (25kg) through 90 degrees (from vertical to horizontal) to get it on board. The winch manages it but it dawned on me what a horrendous strain it must put on the motor and gearbox. Initially the leverage the winch has to work with is virtually nil but it is expected to lift it.

The only thing I could think of was a second roller, forward and down from the existing bow roller which might reduce the angle of direction change from 90degrees to perhaps 45degrees

Am I overthinking this or should I just leave the winch to get on with winching?

they make roller assemblies that do that in various ways for various anchors.

Doesn't your roller dip forward to meet the shank and them come up horizontally with the shank to reduce the stress?

We lift the shank manually.

Another reason is that if I used the winch to do it, the flukes would launch north, bash the underside of our slotted pulpit... whereas I can control speed when I lift it that last little bit myself.

-Chris

I stop my winch just as the shank starts over the roller and points skyward. Then I just bump the motor an inch or two at a time with pauses until the shank flops over and down.

The strain on the motor during that time not a big deal - the "weight" of pulling the anchor around a corner with the axis of rotation at about the halfway point of its length is minimal - Torque and Equilibrium

Lewmar Makes one that helps turn the corner it does minimize the stress but does not eliminate it

siestakey said:

Lewmar Makes one that helps turn the corner it does minimize the stress but does not eliminate it

Click to expand...

Anchorlift makes something similiar that turns the anchor and looks like it would ease the stress. Alas, it won't work on our boat because our windless is too far forward

Seems to me the forces would be very large. The very end of the anchor shank is a short lever pulling the heavy end of the anchor through a 90 degree arc fairly quickly.

This creates a lot of strain on the connection point. If a swivel is used, and the anchor is sideways as the swivel passes over the roller, a bending force is imparted on the swivel. Swivels are designed to be strong in tension - a straight pull when anchor and chain aligned. Not sure how strong a swivel is when it is being bent sideways.

There is a debate about the usefulness of swivels and their real working load strength. I decided to get rid of mine and now connect the anchor with a safety wired shackle.

When the anchor reaches the roller I very carefully inch the shank over the roller, minimizing the big "flip up" as the shank gets horizontal. Have not had any issues with twisted chain. Works for me.

The forces are not all that big compared to what happens when you lift a couple of hundred of feet of chain plus the anchor off the ground. Anchoring in deep water is common here in the PNW.

Lets do a back of the envelope calculation. Say the winch has just raised the anchor to the roller and your anchor is hanging straight down. Which means the anchor's lever arm is zero and the pull the winch sees is just the weight of the anchor. As you raise the anchor further, the center of gravity of the anchor is moving out away from the boat to rotate around the roller. At 45 degrees, your anchor lever arm would be say 10 inches and your winch lever arm say 2 inches. In this case the pull on the winch would be 5 times your anchor weight- not a big deal compared to raising your anchor from the bottom.

Hi,

Anchorlift™ CX help your broblem!

https://www.anchorlift.com/bow-rollers/



Or



or "twist"


NBs

I say let the windlass get on with its job. I`m more worried it will retrieve too strongly and jerk the anchor to a stop. Wouldn`t it have more load once the anchor comes off the bottom? (My Muir has a 1200watt replacement motor).
It could relate to the design of the end of the shank of your anchor. If it is square, or otherwise gets caught at the roller there could be an issue. Ours comes on board easily.My roller axle has a grease nipple(easy tiger!) or zerk, to grease it.

My old, dying windlass would struggle to get the anchor up from the bottom even when it had been liberated from the sand/mud and there was only 5-6metres of vertical chain to lift. Then when the anchor shank was at the bow roller it simply would not come over.

The new Muir windlass would lift the anchor and haul it up, but the clutch would slip when the anchor shank was at the roller. So the force required to get the anchor over the roller is the greatest load i have seen to date with the new windlass. But I have not anchored in dee water yet. Now I have the clutch tight enough to avoid slippage when hauling, but can still get some slippage when backing down to set the anchor. I'm fine with that. But always set the snubber!

When hauling anchor I think momentum helps. My chain counter starts beeping when there is 1.6m of chain to go, so I am ready to let the switch go. But I like to keep it running continuously to get the shank up over the roller. I think that bumping on/off for an inch or so at a time would stress everything to a much higher extent.

Our 150lber comes up and over 90degrees.
Never a problem doing the lift , no hint of strain but we have cheap yellow nylon rope woven through the last meter of chain so we can see it coming and then pulse it up and over as mentioned by an earlier poster.

Maxwell 3500 hwc 24v windlass.

Brisyboy said:

I was bringing the anchor in last time we were out - not thinking of anything in particular until the anchor chain brought the tip of the anchor shank to the bow roller. At this point the chain is pulling at right angles to the shank and has to pull the anchor (25kg) through 90 degrees (from vertical to horizontal) to get it on board. The winch manages it but it dawned on me what a horrendous strain it must put on the motor and gearbox. Initially the leverage the winch has to work with is virtually nil but it is expected to lift it.

The only thing I could think of was a second roller, forward and down from the existing bow roller which might reduce the angle of direction change from 90degrees to perhaps 45degrees

Am I overthinking this or should I just leave the winch to get on with winching?

Click to expand...

Brisyboy, as the others have said, it is probably not a huge issue, but one I also felt worth addressing when I bought my Sarca. Although I did not buy the purpose built Sarca roller assembly, the hinged set I did buy is very like it, (only actually a bit better I think, as the hinged part is longer), and the hinged section, that revolves up under the anchor as she comes over, definitely does reduce that load. Probably does lengthen the life of the windlass motor & gears somewhat I'd think. These are available at most chandleries, I think. Also, you might be able to see I was lucky enough to be able to fit it inside the old existing single bronze roller system, now painted white. One mounting bolt slipped neatly into where the bronze roller was mounted. I pull her in so the shank is horizontal when on the move, of course. See pics of mine.

Our Vulcan anchor has a curved shank which seems to be easier to pull up that last little bit as compared to the straight shank anchor it replaced. But as noted by others, the real test of a windlass and its wiring is from a deep hard set.

Also, I will at times use a boat hook to rotate the anchor for a nice final pull over the roller. Easy enough to do with a proper made swivel.

Larger bow rollers are dual roller or have a pivoting anchor cradle. Mine has dual rollers and lifts a 200# anchor w/o noticeable problems.

Be gentle. Bring the anchor slowly (short "ups") the last few feet.

sunchaser said:

Our Vulcan anchor has a curved shank which seems to be easier to pull up that last little bit as compared to the straight shank anchor it replaced. But as noted by others, the real test of a windlass and its wiring is from a deep hard set.

Also, I will at times use a boat hook to rotate the anchor for a nice final pull over the roller. Easy enough to do with a proper made swivel.

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There's a number of other anchors that have the curved shank for a very different reason. Manson Boss, Spade, .....
On second thought I looked at other anchors and see that the curve like on the above named anchors is in the wrong place. To help going over the roller innitially the curve would need to be at the end of the shank where the rode attaches. The Vulcan may be curved there but the others are not. Does the curve go to the very end of the shank Sunchaser?

I pull my smallish anchors over the rail aft of the bow roller and store them on deck or belowdecks.
On anchors that I carry on the bow roller I pull them over the roller by hand and hold my hand high so the angle in question is only 45 degrees or so.

Another thought on this is that the longer the shank is the bigger the problem.

You guys may want to consider the cost of a new windlass long term versus losing your back. Be careful.

menzies said:

You guys may want to consider the cost of a new windlass long term versus losing your back. Be careful.

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Not lot more miserable then pulling err up by hand

On my previous boat, I developed a problem getting the shank up over the anchor roller, seemed like the anchor winch or hydraulics had lost power and could no longer handle the weight. Turns out it was the anchor roller itself. It had stopped spinning freely and was creating enough friction to overcome the winch's power. I replaced the roller and shaft and had the shaft bored and fitted with a grease nipple to keep the roller greased. Never had any more problems after that. Make sure your roller is turning easily and it will do its job in getting the shank up and over.

So………..I really appreciate all the contributions and thoughtthat everyone has put into this problem.
Let me summarise. Fora brief moment during retrieval, the anchor is suspended vertically at the bow roller. The chain pulls at 90 degrees to the shank. Thinking of it as a lever, the force is applied (by the winch) virtually at the fulcrum point (the bow roller) with the weight of the anchor concentrated at the end of the shank some 2 feet or so away from the fulcrum. In anybodys language, that is a VERY poor mechanical advantage.
During retrieval we have, until this time, a winch that has been raising a chain and anchor at a steady rate (once the anchor is broken out) and with a progressively decreasing load as more chain is hauled on board. Suddenly – whamo – the load is increased exponentially when the anchor hits the bow roller – to my mind a shock load on both the motor and gearbox.
Adding swivels or such to the end of the shank won`t change anything – the only thing that will do this is changing the angle of force from the chain for that over the bow roller moment. Some guys do this by hand pulling (ow my back) or putting in an extra roller forward and below the existing roller- swinging anchor lift style bow roller or a fixed one to get the pull at 45 degrees rather than 90. On the other hand some guys follow the old.. full speed ahead and dam the torpedoes.. approach and believe the winch can cope. Fair enough , although I`m not sure how bumping the winch through the critical stage makes life easier for the winch.
The dam the torpedoes approach has some merit as it has worked on our boat for many years so I think I shall go and stand on the jetty and look up at our bow roller and anchor and maybe devise a cunning plan to add that extra roller without disrupting the neat (and secure) way the Rocna sits stowed on the bow roller .....OR........ decide to do nothing!
I did warn that I was probably over thinking things and Iappreciate everyone joining in with their $.02 worth

Brisyboy said:

Let me summarise. For a brief moment during retrieval, the anchor is suspended vertically at the bow roller. The chain pulls at 90 degrees to the shank. Thinking of it as a lever, the force is applied (by the winch) virtually at the fulcrum point (the bow roller) with the weight of the anchor concentrated at the end of the shank some 2 feet or so away from the fulcrum. In anybody's language, that is a VERY poor mechanical advantage.

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Absolutely right, and the only thing in its favour at that point is for the momentum of the rising anchor/chain combination to help lift it over the brink somewhat, I guess. Because suddenly, the flexible chain round the roller, which therefore means the there is the same longitudinal pull with lightening load on the way up, suddenly meets the rigid shank, which doesn't bend round the roller, and it becomes a whole different set of mechanics.

Brissyboy, if you look at my post 15, you'll see the roller extension actually acts to give more of a lever arm to the winch pull, because the sudden change of direction is about halved, and this allows the end of the shank to protrude above the roller more easily on retrieval, thus adding a lever arm not present when it comes over a roller at right angles as you describe.

So, if you want to mechanically lessen the sudden extra load, that is the only way you can do it. Whether if makes a lot of difference - who knows..? But I suspect it does, as otherwise you tend to have to drag the thing up faster than ideal to lessen the effect by the momentum thing I mentioned. Having said that, it is still a fair question - does it matter..? Over to you on that.

George,I assume we have similar IG original setup. My roller axle has a grease nipple but was seized solid when I bought,took a while to spot that, some WD40, oil and grease,some elbow grease too, and it worked. Solid not turning was bad.
Mine works fine,we do bring it gently over the roller. To be fair, my Muir Cheetah has a newish motor in it which doesn`t fit the cover, I made a spacer under it to accommodate the motor, it is fast on retrieve, and likely the extra power helps get the anchor onboard.
Peter`s set up would help, but my set up works fine without it. If they are similar, yours should too, so check everything is doing its job correctly.

George (Brisboy), thanks for the summary. I am a little late to this thread. Sorry. Attached is a pic of the roller schematic on my boat. The “lower” roller is attached in a slot so I can adjust the position (up or down). I have it secured at its lowest position. The result is I never have a 90’ angle to pull the end of the anchor shank over. Second, I never use my MUIR windlass (for that matter any windlass) to break free the anchor from the seabed. I always use the main engine. In my opinion, the process of breaking free a securely set anchor from the seabed 30’ (or whatever depth) takes more power draw than moving the anchor shank over the roller if the end of the shank is rounded and not inhibiting the movement over the roller even if it is 90 degrees.

I generally stop the windlass right before the moment of contact of the first roller. Need this to hose off the anchor and, if I don’t, the windlass pulls the anchor right over the rollers to fast for my comfort. I “bump” it over. I am not worried about that energy draw because my main engine is on, charging its start battery, before switching to charge the house bank. The windlass is wired to the house bank. By the time I am ready to stop and anchor again, the house bank is 100% charged.

Steve

Think the pic was not added on prior post.

Steve Bedford said:

Think the pic was not added on prior post.

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Still not added Steve. You better read the sticky in the "How to use forum" section re posting pics again.

Okay, thanks. One more time. I thought I followed the directions the first time for the TF process for attachments but obviously I made a mistake. Hopefully will go through this time.

Sorry.
Steve

Anchor retrieval

Speaking of anchors, does anyone have a Rocna or Mantus on a Californian with the standard bow sprit? I like the idea of the roll bar but wonder if it will go over the pulpit and then hang up on deploy. Rocna pushes their Vulcan but I'm looking at the standard or the Mantus. Any experience here??