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What size and type of anchor

I need to buy a new anchor for my narrowboat - 58', 16 tonnes. The question is what type and size of anchor? I have used Danforth anchors on boats in the past but on a narrowboat I find the projecting ends of the cylindrical bar at the bottom of the flukes is a nuisance. A "French" or "grip" anchor is an alternative. Another option is a folding grapple anchor which may be a better option for rivers. Your thoughts please on the type and weight of anchor.
The next question is then what length of anchor chain? I presume that the length will depend largely on the weight of chain and I see that one of the standard sizes which seems to be offered by chandleries is 3/8". Could you please advise me on the length of chain needed for the suggested anchor matched with my boat?
Thank you.

Asked by: Terry  | 4.36am, Thursday 23 October

WW says:

Danforth anchors are commonly used on river craft, as they tend to grip well in soft mud and gravel, which forms the base of most river navigations. They can also work well in sand, though can be compromised by excessive weed growth. A 15kg Danforth would be the minimum size- ideally 20kg, though that can be harder to handle.
Folding grapnel anchors are not very effective, as only one, or possibly two flukes will dig in, and they tend to rely on being a drag weight rather than digging in. They are ok for lightweight boats such as dinghies, but are not suitable for Narrowboats.
# CQR (plough) anchors hold well, but can be difficult to stow; Halls Pattern Stockless anchors (which are popular on barges) are good but quite expensive. Other anchor designs are possible, but can be more expensive and are less common. The Danforth is often chosen as it is a good compromise of price, holding and stowability- though, as you state, the holdfasts can get in the way.
As for chain, and rode, the longer the better. Ideally, 5m of chain and 30m of line (Octaplait polyester or nylon is easy to splice directly into chain) is an absolute minimum for most rivers- if you have to anchor, the longer the better, as it then makes a more shallow angle to the anchor, which gives it more chance of digging in. You need a rode between 5 and 9 times the water depth to ensure good holding. Don't use polypropylene line, as it floats which is counterproductive!
The chain size you mentioned are absolutely fine to use, combined with 14mm line (or 16mm if you can easily handle it).
If you go for an all-chain rode, then you need around 20m of chain at least, which is difficult to stow. Also. Ensure that the end of the chain is secured to the boat by line, rather than chain- unless you have experience, raising an anchor can be problematic and sometimes has to be cut lose- which is impossible with chain under strain.
Let us know if you need any further advice or we can be more specific.

Mark Langley  | 7.33PM, Thursday 23 October

Readers say:

Hello Mark,
Thank you indeed for your detailed and very helpful reply. I had done a search on past issues of WW but could not find anything. Although I've had many years experience with yachts and small craft up to about 300 tonnes (Australia and the Pacific)I've only had 10 years of experience with narrowboats.
A common type of Danforth anchor found in Australia and the region has a slotted shank that the shackle goes through. This is very handy when you are raising your anchor because you can run back over the anchor and the shackle runs down the slot to near the crown and you pull back over the crown which means that you have an easier job disengaging the flukes and you are less likely to damage the flukes. I haven't seen such anchors in the UK but then I haven't visited many yacht or power boat type marinas.
Interestingly, I see you refer to the "holdfast" on the Danforth whereas I would have normally have referred to it using the old term "stock".
To me a holdfast is either a marine organism, an anchor on a work bench or a military anchoring device. But I guess that it's all matter of semantics.
I've had made up a "holdfast" system to use with mooring pins in soft ground for use on our boat. Next time we're out on our boat I'll take some pictures and see if WW is interested in a short article. The holdfast is an adaptation of an old military idea and works very well in soft ground.
Thanks again for your most helpful response.

Terry  | 4.13AM, Friday 24 October

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