Making your own anchor - who has done it?

[JonJo]

Originally Posted by Bestathook

Most arc welding is done with sticks of metal (rods) or wire feed units (wire).

Torch welding is possible but not used as much. I guess if you wanted to be a real purist, you could hammer weld it, but there goes the original tempering.

Sorry - I'd already mentioned that welding was an issue, but Delancy did not think that sufficiently important to merit mention. Even Manson's 800 MPa steel needs careful welding, specific welding rods are demanded, temperatures are critical etc - in fact not a task contemplated by most welding shops (and who are willing to give guarantees).

I was simply checking that there was not another joke in the thread that I had missed

Jonathan

[Bestathook]

I think that the poster who said

mass = strength

was saying that building important parts bigger, would make them stronger, all other things being equal.

I would compare a shank cut from 1/2' plate with one cut from 3/8' plate. not equal weights of different material, like steel, butter, jello, balsa wood, etc.

The photo of the bent Rocna was interesting. I see it being about the value of trip lines as much as metal quality.

[Bestathook]

I have seen the bottoms of repaired steel houseboats suffer major electrolytic damage as the result of badly matched rod and plate, and perhaps mismatching original plate and patching steel.

Most welding shops don't have to deal with their work being submersed in salt water.

As you go to marine welders and marine quality plate, you're getting closer and closer to the Rocna factory.

I am interested in building anchors too. I will make a very light weight one, set it, and pull on it until failure, to see where it proves weak.

An anchor made from available scrap, using rustbuster rod, with zinks, and painted, should last a while if in overkill size. Not good for unattended megayachts, but with scrutiny will work for a while, and teach me more about anchors. and how to build them. I tend to set more than one anchor, anyhow.

[noelex 77]

I don't think stainless steel is such a stupid anchor material for a long distance cruising boat. When you are anchoring full time, as I do, the life of the galvanising on a steel anchor is only in the order of three or four years. With the Heath and safety laws it is getting harder to find companies that will galvanise an anchor. With some anchors such as the Spade its impossible. Although the life of these anchors that cannot be re-galvanised can be extended with paint they are still an expensive proposition in terms of yearly cost for a cruising sailor

The drawbacks of reduced strength have been mentioned, but SS does have the advantages that the leading edge of the flukes can be made very sharp which significantly helps anchor performance (if this is done on a galvanised anchor the galvanising tends to wear quickly).

If the anchor is deformed many manufacturers will replace them. In reality problems are rare especially for cruising sailors that tend to upsize their anchors significantly.

Given the small contribution of the cost of raw material to the finished product SS anchors should be more reasonable cost wise. I don't want bling. Forget the polishing.

Aluminium in many ways should be the ideal anchor material. The lower density enables the balance and toe weight to much better than with a steel anchor. This promises improved performance even before the possibility of utilising a larger blade area is considered. It can be sharpened like SS and should not corrode.

Unfortunately anchor manufacturers have chosen to adapt existing anchor designs sometimes with great results ( like the Fortress), but often with dismal failure (like the aluminium Spade)

It needs a manufacturer to design an anchor to utilise the lower density and higher strength/ weight ratio of aluminium from the ground up (married with lead where weight is needed). It certainly has the promise of a higher performing anchor that is easier on the winch, gives less weight on the bow and never needs re-galvanisng.

[sabray]

My very old Bruce does not agree with your 3 year cycle. My Manson might need a regalvinizing in a few more years. What ever that Bruce is made of is better then most anything.

[noelex 77]

Originally Posted by sabray

My very old Bruce does not agree with your 3 year cycle. My Manson might need a regalvinizing in a few more years. What ever that Bruce is made of is better then most anything.

It does seem to vary considerably. The type of substrate plays the biggest role. Unfortunately sand is one of the most abrasive and is what is present in many of the worlds great cruising grounds. I am taking about full time anchoring, those that cruise only part of the year, or spend time in marinas will get correspondingly longer.

The quality of anchors galvanising is also is a factor with a general deterioration probably due to more stringent H/S laws, but there seems greater difficulty galvanising the higher tensile steels and the durability is consequently less. Your Bruce benefits on both of these scores.

Our Rocna anchor needed re-galvanising at exactly the three year mark.

This was I photo I took of Manson Supreme many years ago (primarily to show the bent tip) but the anchor had not been available for long at this stage so it cannot have been very old when the photo was taken ( even the sticker is still on) and as you can see it is in need of re galvanising.

[Delancey]

Originally Posted by Bestathook

I have seen the bottoms of repaired steel houseboats suffer major electrolytic damage as the result of badly matched rod and plate, and perhaps mismatching original plate and patching steel.

Most welding shops don't have to deal with their work being submersed in salt water.

As you go to marine welders and marine quality plate, you're getting closer and closer to the Rocna factory.

I am interested in building anchors too. I will make a very light weight one, set it, and pull on it until failure, to see where it proves weak.

An anchor made from available scrap, using rustbuster rod, with zinks, and painted, should last a while if in overkill size. Not good for unattended megayachts, but with scrutiny will work for a while, and teach me more about anchors. and how to build them. I tend to set more than one anchor, anyhow.

Don't be dissuaded by naysayers, question their motives and why they would tell you you cannot do something.

In the case of an anchor manufacturer it is quite obvious, however ironic, because as has been mentioned their product is essentially a commodity only distinguished by design from any other.

While they can/have to pay if they want to protect their design by fighting other manufacturers for piracy, there is little they can do to prevent the individual from benefiting from their design without paying.

Totally understandable why they would discourage you. I only say it is also ironic because they were once upon a time likely a sailor or fisherman who was also a fabricator or maybe an engineer who decided he can do better himself.

It's not some secret mystery, you can't go to school and get a degree in the black art of anchor making. It's cutting out material and connecting it together to make something that looks like an anchor and is strong enough to do what you want it to do.

You can go to school for engineering, you can go to school for welding. You don't have to do either to develop the necessary skills to make a successful anchor.

I would point to the entire history of mankind as an example that a successful anchor doesn't have to be made from some exotic ballistic armor made by robots in a zero gravity factory either and is otherwise beyond the reach of the individual.

Anyone can educate themselves and learn how to measure square area and perform the calculations required for a finite element analysis of the loads and materials.

You don't have to do FEA to have a great idea and mock it up and see if it works. You can always spend the time and money on that later if your idea works.

Who knows, maybe someday people on this forum will debate how much better your anchor is than the current generation?

[transmitterdan]

Originally Posted by Delancy

While they can/have to pay if they want to protect their design by fighting other manufacturers for piracy, there is little they can do to prevent the individual from benefiting from their design without paying.

If they have a patent where the individual lives they can sue for infringement. They can also sue anyone that helps the individual copy their product or method. It may cost them but if they win the loser may have to repay those coats. Most important, it's just plain wrong to steal the intellectual property of another.

[transmitterdan]

Why is it impossible to regalvanize a Spade anchor?

[colemj]

The Spade has a lead-filled tip. While not impossible to regalvanized, the lead would need to be removed before and replaced after.

Mark

[Delancey]

Originally Posted by transmitterdan

If they have a patent where the individual lives they can sue for infringement. They can also sue anyone that helps the individual copy their product or method. It may cost them but if they win the loser may have to repay those coats. Most important, it's just plain wrong to steal the intellectual property of another.

Good artists copy, great artists steal. Funny how at a glance a Manson Supreme and a Rocna look pretty similar. I guess they kinda look like a Detla, which kind of looks like a CQR.

No one is going to sue an individual if they chose to take inspiration from someone else's design. Not saying it right or wrong, just sayin.

[noelex 77]

Originally Posted by transmitterdan

Why is it impossible to regalvanize a Spade anchor?

The lead creates problems, it melts in the zinc bath. The lead needs to be be removed and then replaced. This is very difficult to do with the Spades construction.
Almost anything is possible, but it have never met any one that has managed to do it despite many trying. Spade themselves say something like the "the spade anchor cannot be re-galvanised", but they don't publicise this for obvious reasons.
They sell a kit to refinish the anchor but its nothing more than an epoxy/cold gal paint system which has a short life on a well used anchor.

Unfortunately the bottom of the slot where the shank enters the fluke tends to be one of the first areas to corrode. On some anchors this loss of material looks unsafe to my eyes in this structural part of the anchor. It is a spot that tends to be hidden from casual observation when using the anchor, so check from underneath if you have a Spade. Try to keep this area clean and free from wet mud etc when the anchor is not in use. Some Spades do seem to have a different design in this area so perhaps they have made an alteration to address this problem? I seem to vaguely remember an early recall. (Beyond the change in bolt design)

On the positive side the Spades galvanising does seem one of the best. It should also be remembered that the 3 year life of my Rocna's galvanising was about 1000 days and nights at anchor and this will take a lifetime to accumulate for the casual user. My Rocna is now at the 2+ year post galvanising stage and seems to holding up a bit better than the factory finish despite identical usage. My guess is that I will get 4 years out of this finish.

Happy to be corrected if anyone has re galvanised one. An engineer that specialised in this field (and a steel boat owner ) suggested "flame galvanising" was possible. I understand molten zinc is sprayed at the prepared steel. I would have expected a shorter life than hot dip galvanising, but he felt this was not the case. Galvanising is not an area where I have any expertise.

[transmitterdan]

Flame galvanizing (aka stick galvanizing) can be used to touch up a weak spot in galvanizing. In simple terms it's just a stick of zinc and a torch. Heat the bad spot with the torch and melt the zinc over the surface. Easier said than done properly.

[wsmurdoch]

When I had my Delta regalvanized, they suspended it in the galvanizing kettle with the hole in the tip up so the lead in the tip would not drain out. I did lose about an ounce of lead.

[noelex 77]

This is an example of a Spade shank/fluke joint.The rest of the anchor was in reasonable condition with only slight surface rusting around the underside edges.