Anchors and Anchoring

All cruising sailors have opinions on anchoring, here are some of mine...

Sizing an Anchor

I like a good night's sleep, so we have a big main anchor. From time to time people comment on the size of the anchor sitting on our bow roller. Actually it's the correct size for the boat according to the manufacturer's sizing table (though we're at the bottom end of the boat size range for our anchor) so I think that this demonstrates that a lot of boats are sailing around with under-sized ground tackle.

When someone mentions the size of our anchor the conversation naturally continues onto anchoring incidents and I hear stories of boats needing to let out extra scope to drag less or having to re-anchor somewhere else. Recently we met someone who told us that he tried to avoid anchoring wherever possible because he didn't have confidence in his ground tackle, this was on the west coast of Scotland where there are few marinas and lots of lovely destinations don't have visitor's buoys.

If you sail between marina's with the occasional lunchtime anchorage, or you're a racer who needs to keep weight to a minimum, a small anchor may be fine, but if you're off cruising and want to enjoy exploring more out of the way places then it’s worthwhile investing in a decent anchor.

Choice of Anchor

I'm a big fan of the new generation of anchor designs. We had a 25kg Spade anchor on our Moody s38 and the only time that we ever had to reset it was when another boat dragged across our chain and pulled it out for us in the middle of the night. We liked the Spade so much that we kept it when we sold Ocean Mist but it's too small to use as the main anchor on Speedwell so we needed to buy something bigger. The obvious choice was a bigger Spade, but since we bought our original one some other designs have become available in the UK. The Rocna anchor comes out at least as well as the Spade in sailing magazine anchoring tests and is around 2/3 rds of the price so we decided to go for one of these. We got our 33kg Rocna mail order from Piplers of Poole , it came packaged in bubble wrap (but at least without a “fragile” label) and apparently had the delivery driver wondering what on earth it was as he did his rounds.

We've since found that at least two other Oyster 435s have 33kg Rocna anchors.

Unfortunately the new anchor doesn't line up with the fixing holes in our stemhead fitting so in 2010 we were lashing it down, with some homemade chocks to stop any side to side movement. Whilst this arrangement kept the anchor in place it wasn’t very convenient so during the 2010/11 lay-up we had the stem head metalwork modified to hold the anchor more securely when it’s fully stowed. We’ll see how that works this season and report back.

In 2010 we used our old 25kg Spade as our kedge anchor but it turned out to be cumbersome to lay from the dinghy (probably not helped by 20m of chain connecting it to its warp) so we’ve bought Fortress to use as our kedge. This is remarkably light for its size and gets good write ups for holding power. This style of anchor can trip and not re-set if it gets pulled in the wrong direction (as can happen to a main anchor at the turn off the tide), but as a kedge the pull should always be in roughly the same direction. The Spade is disassembled and stowed in the bottom of the lazerette as a spare.

Using the Rocna

We've anchored a lot this season, on a range of different bottoms in various weather conditions, and been very pleased with the way that our Rocna has performed. We've only had one occasion where the anchor didn't set and hold first time, in Fladday north harbour where holding is notoriously poor we broke it out by reversing too hard as we were setting it. On this occasion the anchor had hooked into kelp growing on a sheet of slate, which stopped it working into the substrate, and when it broke out it pulled the whole lot up with it.

Normally when we retrieve the anchor it comes up with a thick layer of the bottom that needs to be sliced off with the boat hook.

In Canna harbour we set our anchor first time as usual then watched various other boats taking multiple tries to get a good set. The harbour is known to have patches of kelp and each time a boat failed to set it brought up a big bunch of the stuff. One boat had so much difficulty setting their anchor that they sailed off in disgust. When we came to leave our anchor came up with a lot of kelp, but underneath that the anchor was carrying a thick layer of mud, so I think that we had dropped on a patch of weed but our anchor had gone through that and found good holding underneath.

 

Anchor Chain

The anchor chain that came with Speedwell had a number of rather rusty looking links at odd points along its length so we decided to buy new chain for our new anchor and cut the rusty links out of the old chain to give us a few lengths for various uses. Jimmy Green Marine were very helpful in checking measurements to make sure that we bought new chain that matched our anchor windlass.

Our main anchor is on 40m of 10mm chain plus 80m of Anchorplait warp. That gives us plenty of scope for unusual anchoring situations without too much chain in the anchor locker. The weight added by chain helps the anchor to set and hold, but this is most effective near the anchor, chain near the bow is adding little to the system. In extreme conditions the anchor rode will be pulled more or less strait no matter what it's made up of, and warp adds some stretch that reduces shock loading. Tuning an Anchor Rode has much more to say on this topic.

The chain is connected to the anchor with a proof tested galvanised steel shackle (I hope that this gives less scope for dissimilar metal corrosion than a stainless steel shackle). So far I've not seen any need to fit a swivel, I prefer to keep the system simple.

A length of our old anchor chain provides the chain section of the kedge rode. As this is the correct gauge to mate with our anchor windlass it gives us the option of using the windlass to raise the kedge.

Other Anchor Gear

Strop

We’ve got a dedicated length or three strand nylon rope that we use as an anchor strop, it’s threaded through a length of plastic pipe to give some chafe protection as it passes over the bow roller. In use we tie it to the rode with a rolling hitch then make the other end off on one of the forward cleats. We don’t use a chain hook for various reasons; a hook places a side load on the chain that it’s not designed to take, a hook may fall off if the load comes off it, you can’t hook onto the rope section or our rode and a rolling hitch is quick to tie in any case.

The stop serves a number of purposes:

Anchor Buoy and Tripping Line

Our anchor buoy has the word “Anchor” and a picture of an anchor painted on it to try to discourage anyone else picking it up and trying to moor to it. We’ve used it a few times but I’ve always been worried that either someone would run over it in the dark or that we’d drift into it and get tangled up if the wind changed, so we tend not to use it now. However it’s good to have for those odd occasions when buoying the anchor is the best option, and when harbour regulations require that require anchors are buoyed.

We do set a tripping line fairly frequently. Rather than buoying this we tie it off to the anchor chain at a point that’s above the water when the chain is strait up and down, and with some slack in the line. If the anchor does foul we’ll only find out when we’re over it and by this point we should have retrieved enough chain to have picked up the end of the tripping line. To date we’ve not got our anchor stuck, maybe we’ve been lucky, but I think that the fact that our Rocna sets very quickly means that it’s got less chance of dragging into an obstruction.

Anchor Ball

At least in the UK many yachts don’t seem to bother with an anchor ball. We do use ours, raising it on the pole up-haul. Partly this is because we hang our anchor light from the ball but in any case it doesn’t take long to set up and if we were unfortunate enough to have someone run into us at anchor we’re in a much better position from an insurance standpoint is we’re complying with the collregs.

Riding Light

During the 2009/10 refit we fitted an LED tri-colour to the main mast but we deliberately didn’t fit one with a combined anchor light. Instead we’ve got an automatic LED light that we hang from the anchor ball. If someone is feeling their way into an anchorage in the dark I think that they’re much more likely to notice a light around deck level rather than one that’s fifteen or twenty meters up in the air.

Fridge

Once the anchor is in and the boat is tidied up we like to open a couple of bottles of beer from the fridge to celebrate our arrival...

Setting the Anchor

Part of the entertainment in an anchorage is watching other boats come and go. We've seen demonstrations of all sorts of anchoring techniques over the years; some people just drop the anchor and a big pile of chain off the bow then go below (presumably hoping for the best), sometimes boats reverse at speed and bounce at the end of their chain, on one occasion we watched a boat change position in an anchorage by simply motoring and pulling their anchor along the bottom (I’d not sleep well if I knew that my anchor could be dragged that easily). We take care setting our anchor, maybe we're more cautions than a lot of people, but as I said earlier I enjoy a good night’s sleep.

When we’ve picked our spot we lower the anchor to the sea floor then pay the chain out as the boat drops back so that we’re laying the chain along the bottom rather than piling it up on top of the anchor. Once most of the scope is out the snubber is attached and paid out to make up the rest of scope then made off on a forward cleat and a little more rode is paid out so that all of the anchoring load goes onto the snubber. We let the boat drop back on the rode (or gently motor back in light conditions) then gradually apply increasing power in reverse to bed the anchor in and check that it’s holding. Our Rocna anchor normally digs in very quickly so it’s best to gently apply power to bed it in than be going backwards at speed and stopping with a jerk as the rode comes tight, also on tricky bottoms a gradual increase in load gives the anchor the best chance of working in.

If we’re anchoring under sail we have to rely on the wind and/or tide to settle the boat back on the ground tackle, but if there’s enough wind to sail up to the anchoring spot then there’s enough to carry the boat back as the anchor is deployed. We can back our mizzen sail to make sternway and apply some load to test the anchor set, though we can’t apply as much force as we can with the engine so if we’re stopping for the night and are concerned about the holding we may well fire up the engine to bed the anchor in.

Retrieving the Anchor

Speedwell has an electric anchor windlass, a first for us, making life much easier for the foredeck crew than it was with the manual windlass on Ocean Mist. Despite having a powered windlass we still like to drive the boat up to the anchor on the engine rather than making the windlass do all of the work, this is kinder to the windlass and remains a workable method in strong winds when the windlass alone may not be able to pull the boat forwards.

If we’re sailing off the anchor into the wind we set the main and mizzen then sail up to the anchor, tacking when the chain is around 90 degrees to the bow and using the windlass to take in the chain as it comes slack. It normally only requires two or three tacks to retrieve the anchor this way. In a wind against tide situation we unfurl sufficient genoa to just make headway then retrieve the chain and anchor as we go. Once again we try to use the windlass to just lift the ground tackle rather than to pull the boat forwards so that the load on the windlass and the power demand from the batteries are kept down (of course we’re not running the engine if we’re sailing off the anchor).

Whoever is on the foredeck has the best view of what’s going on so they signal to the helm to let them know where the boat needs to go.

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