Can I make my own 'modern' anchor.

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fredrussell

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I'm a practical boat owner, or, if you prefer, a cheapskate. I've been looking at the modern range of anchors (Rocna, Knox, etc) and its occurred to me that it wouldn't be beyond my fabricating/welding skills to make one from, say, 8mm steel plate. Obviously I would get it hot-dipped galvanised.

I'm pretty sure I could make one for a good deal less than the £250 I would spend on the real thing - or am I missing something? The one thing I don't know is the likely cost of getting it hot-dipped. Anyone have an idea of roughly what that might cost. Would mild steel do? Would I be better off with some kind of high tensile steel?
 
fredrussell said:
I'm a practical boat owner, or, if you prefer, a cheapskate. I've been looking at the modern range of anchors (Rocna, Knox, etc) and its occurred to me that it wouldn't be beyond my fabricating/welding skills to make one from, say, 8mm steel plate. Obviously I would get it hot-dipped galvanised.

I'm pretty sure I could make one for a good deal less than the £250 I would spend on the real thing - or am I missing something? The one thing I don't know is the likely cost of getting it hot-dipped. Anyone have an idea of roughly what that might cost. Would mild steel do? Would I be better off with some kind of high tensile steel?
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Why not get the plans for a Bugel - one of the best "modern" anchors and the only one to be in the public domain.
I very much doubt you'll be able to make an effective "copy" of Rocna's et al, and doubt you'll have much change left out of your £250. Certainly my Mantus cost only US$340, delivered from Texas to Greece.
 
Nothing to stop you making your own anchors. Using generous proportions, and a bit of common sense, ordinary mild steel is adequate for most purposes. The easiest to fabricate are the Danforth type, but I've also made several Fishermen, and once, a big heavy CQR copy. My boat is currently lying on a mooring, which was originally for a much bigger boat, consisting of three home made approximately 100kg Danforth types, set out at 120°.

As far as galvanising is concerned, the price is per kilo, but usually with a minimum. It's common for several people to lump their stuff together, to achieve the minimum weight. Fabrications for galvanising must not have any sealed hollow chambers.
 
I think it was Wansworth who put up pics of his DIY anchor. Worth a check.

Unless you really are a certificated welder and steel engineer, there will always be a question mark against a home made copy though, let alone the moral issue of copying a design which has cost a company many hours in the evolution and testing, plus the feedback from users.
 
charles_reed said:
Why not get the plans for a Bugel - one of the best "modern" anchors and the only one to be in the public domain.
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Cheers for that, I'll have a look.

charles_reed said:
I very much doubt you'll be able to make an effective "copy" of Rocna's et al, and doubt you'll have much change left out of your £250.
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You're probably right to be honest, but part of it is the "hey, I can do that" drive. Nice project for the winter anyway. If I'm doing something for the fun of it I tend not to factor in my own hourly labour rate when calculating cost. A few offcuts of 8mm plate would be a few quid, the hot dip would be the main expense I reckon.
 
It's the "modern" part that concerns me. A garden-shed Danforth-pattern will be just as good as a no-name one from the chandler's, but I doubt that something vaguely Spade-shaped will perform as well as a real Spade. Weight distribution matters if you want penetration as good as the real thing, that's why the Spade has a light shank in hollow high-tensile steel and a lead-filled tip.

Nowt wrong with building your own anchors, but I'd go for older designs in large sizes, rather than trying to duplicate the new ones.

EDIT: Bügel sounds like a good choice. Often home-made, and people seem happy with them.

Pete
 
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There was a poster on here (he may still lurk) he was from Portugal and a sculptor, he posted pictures of a home made anchor, at the same time I also posted a picky of one I made. Mine was a small anchor, I cut up a Brittany anchor, then I welded the flukes together, I welded the original bar onto the flukes and made up a hoop out of rebar. Really it was a copy of a Bugel, with a bit of modification it worked very well, far better than the Brittany!
 
Isn't the issue with some types of modern anchor that they require high performance steels to provide the required strength/weight distribution? There was a lot of comment about Rocna when they downgraded the steel for the shank from a very high spec to a lower one. And part of the issue with high performance steels is that they need things like water-jet cutting as they don't take to being heated; the fabrication for a copy that will perform as the original is likely to be beyond DIY capability.
 
I made two "Rocna" style anchors about 8 years ago and they are still on board and the one we use works as well as most other anchors. We anchor almost every night in the summer on our 42ft cat and have sat out 40knts fairly often and occasionally 50knts +. We are currently anchored in Vathy on Serifos with 30knts + forecast for the next couple of days and we expect (or hope) to stay put!!

Our anchors are both around 32kgs each and I think the galvanising cost was about £40 back then.

Due to my job and contacts at the time the steel was basically free so the only other cost was my time, so overall a cheap and satisfactory project.

When using mild steel you need to oversize the anchor shank since that is the part that will be subject to side bending loads and is the reason commercial anchors use higher quality steels for that part.

The flukes I made using 6mm plate laminated together, welded and ground smooth. The anchor we use daily was made using 3 pieces laminated together, each one slightly smaller than the first to create a bevelled edge to the fluke. All plates were bent in the middle to create the "concave" shape. The roll bar was 50mm dia tube but I think 25 or 30mm would probably be adequate.
Probably good to maximise the surface area (within reason) since once the anchor is set it is the area that does the holding not the weight. Our anchor is 32kg but has a surface area about the same as a 44kg Bugel. You could try adding an extra lamination to just the tip section to increase the weight on the point to improve setting, however ours performs very well without this.

The shank is welded into a slot in the laminations rather than just welded on the top surface of the fluke. This way it can be welded top and bottom of the fluke to improve strength and rigidity. One of the anchors was designed with a removable shank to ease storage problems but it was probably a bit of overkill and took a good bit of extra time.

There is probably enough information about dimensions, angles, etc to be found on the internet to allow you to design a working anchor. Well worth the effort in my opinion. Provided you don't make an exact copy of a particular anchor, nor sell commercially you are pretty unlikely to run into any copyright problems.
 
Galvanising. You'll need to find others to make up the minimum weight. I did this by walking around the marina, noting the boats with rusty chain/anchor and asking the skippers if they wanted to join the combo.

I said I'd pay up front.

The galvanisers will weigh the stuff however you want, to enable you to allocate appropriate shares in the cost.
 
AntarcticPilot said:
Isn't the issue with some types of modern anchor that they require high performance steels to provide the required strength/weight distribution? There was a lot of comment about Rocna when they downgraded the steel for the shank from a very high spec to a lower one.
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Yes. Mild steel yield point - 250 MPa. Knox steel yield point - 900 MPa.
 
The very very best steel is in farm ploughs and moulding boards for sowing patatoes in ridges. I suggest you buy an old Ransome's plough and unbolt the shank to form into an anchor with the shape of the boards already perfect for a delta type anchor.

Ploughs are tremendously strong , and have to cope with rocks and stones without bending.

Guess : £10.
 
30boat has sent me a series of around 30 photographs illustrating the construction of his latest anchor. It looks superb and will be featured in a book that I have put together. He overcame the shank strength issue by adding a third dimension in the form of L shaped pieces welded on, rather similar to a CQR.
 
fredrussell said:
I'm a practical boat owner, or, if you prefer, a cheapskate. I've been looking at the modern range of anchors (Rocna, Knox, etc) and its occurred to me that it wouldn't be beyond my fabricating/welding skills to make one from, say, 8mm steel plate. Obviously I would get it hot-dipped galvanised.

I'm pretty sure I could make one for a good deal less than the £250 I would spend on the real thing - or am I missing something? The one thing I don't know is the likely cost of getting it hot-dipped. Anyone have an idea of roughly what that might cost. Would mild steel do? Would I be better off with some kind of high tensile steel?
Click to expand...

Two thought occur to me. The first is " if you were a biker, would you fabicate your own crash helmet". I doubt it but an anchor is just as much a piece of safety equipment. The second thought is that we do hear of knock offs of standard anchors that simply dont work that well. Knock off CQR fore example. And that suggests to me that subtle design issues can be important. For example, the Fortress anchor has two different fluke angle for different bottoms. Issues like tip weight matter. I'm sure you could make something that looked like a Rocna but would it work like one?
 
Our knock off anchor cost £25 and works perfectly. I'm so pleased we didn't pay a penny more.

Get on and build it - looks like plenty of other people have managed just fine. Remember, common sense goes a long way.
 
Bosun Higgs said:
Two thought occur to me. The first is " if you were a biker, would you fabicate your own crash helmet". I doubt it but an anchor is just as much a piece of safety equipment. The second thought is that we do hear of knock offs of standard anchors that simply dont work that well. Knock off CQR fore example. And that suggests to me that subtle design issues can be important. For example, the Fortress anchor has two different fluke angle for different bottoms. Issues like tip weight matter. I'm sure you could make something that looked like a Rocna but would it work like one?
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I understand your point, but it's not quite the same. If you drag, it's not the end of the world: you've a good chance to do something about it (including, a day or so later, ditching the home-made hook and buying something 'reputable'.) And some people, not all of them skintflints, just like experimenting.

If your crash helmet fails, the come-back is likely to be on behalf of your estate. Besides, you can't legally use a home-made crash-hat on the road.

Beyond that, I'm saying nothing about The Scottish Player, fake or genuine ;)
 
Glad i spotted this thread, i love DIY and i may well look in to making some myself.

Good post :)

On and i havnt been through all the thread but i would try stainless steel.
 
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