Fabricate spade anchor

[jtsailjt]

Originally Posted by Simi 60

$6000 vs under $500 for a bugel/supreme bolt together hybrid of same size.
I'd rather have a spare anchor or two and a few thousand litres of diesel thanks

$6000 [emoji15] that’ll buy quite a huge SPADE!

But more than just the steel, when you buy one you get the benefit of their testing and resulting refinements, and some of these you can’t see with your eyes. Some features aren’t critical so you could probably change them slightly but other features are very critical so even a small change can have a big impact on the anchors effectiveness. Also, if you build your own anchor and then manage to damage it, you have to take it back to your shop/tools to fix it. If you buy a SPADE and somehow manage to bend it you notify SPADE and send the bent part to them and they send you a new one and you can stay with your boat rather making a pilgrimage all the way back to your machine shop.

My BS degree is in civil engineering with a focus on structures so I think I can do an above average job of understanding the forces involved on certain parts of an anchor, and by closely examining how it was built could understand why each part was as it is. But to understand how the subtleties of each feature interacts with other features and affects the anchors performance in various conditions I’d need to do quite a lot of testing before I’d be able to persuade myself that I really understood everything about all the hows and whys of the anchor as a whole. I don’t have time for all that and the $$$ cost and time cost would be astronomical. Luckily, a few other smart folks have already put themselves through that whole process and I can buy what they learned about what makes a good anchor for pennies on the dollar.

Also, I have nothing against any other anchor such as the Bugel so probably buying one of those would also be smarter than trying to make your own. But the OP mentioned SPADE and it’s the anchor I happen to be most familiar with and trust the most. My primary anchor is one of the things aboard where I consider it’s price less than any other feature. I don’t need the best and most expensive chartplotter or shiniest paint on my top sides but on a moonless night in an exposed anchorage with very strong and shifting winds when all you can do is hope and pray your boat will stay put, an extra few hundred $$ will seem trivial. I’m not trying to make this into an argument about SPADE or any other anchor in particular, just want to make the point that when you REALLY need your anchor to hold, what you paid for it won’t even be part of your consciousness so you want to have whatever anchor YOU think will hold you the best, and that’s not necessarily the anchor you can get for the best price or get the biggest discount on.

[Simi 60]

Originally Posted by jtsailjt

$6000 [emoji15] that’ll buy quite a huge SPADE!

No, that would buy an adequate spade for our vessel

Also, if you build your own anchor and then manage to damage it, you have to take it back to your shop/tools to fix it.

Or bin it because it only cost $500
Pulls out spare 2 piece anchor , quickly assembles and we are good to go

If you buy a SPADE and somehow manage to bend it you notify SPADE and send the bent part to them and they send you a new one and you can stay with your boat rather making a pilgrimage all the way back to your machine shop

.

Really?
Did you not notice it is a single piece anchor, do I simply cut the shank off and send that back?
How do I reassemble on return?
What do I use as an anchor while this one is away being repaired?

Reality is I would not be simply posting back a 200lb anchor.

My BS degree is in civil engineering with a focus on structures so I think I can do an above average job of understanding the forces involved on certain parts of an anchor, and by closely examining how it was built could understand why each part was as it is

And I am trade qualified in welding and manufacture (boilermaker) having experience in pressure vessels, high rise footings, shipbuilding and heavy industrial equipment.
I think I can manage a relatively simple structure such as a bugel/supreme style anchor.

[Paul L]

Originally Posted by Simi 60

....

Really?
Did you not notice it is a single piece anchor, do I simply cut the shank off and send that back?
How do I reassemble on return?

Reality is I would not be simply posting back a 200lb anchor.

I dont think there is any need to further address your reply

Actually a genuine Spade anchor is two part.
A 165lb Spade is specd for up to a 98ft boat that weighs 88,000lbs. At this size you are talking small ship anchors with massive chain. Building yourself might be a lot more cost effective. Just oversize for the job and have a spare.

[Simi 60]

Originally Posted by Paul L

Actually a genuine Spade anchor is two part.
A 165lb Spade is specd for up to a 98ft boat that weighs 88,000lbs. At this size you are talking small ship anchors with massive chain. Building yourself might be a lot more cost effective. Just oversize for the job and have a spare.

I stand corrected.
They never rated a look here due to cost vs our 150lb supreme.
While it has never let us down , going oversized was our plan if building our own as spares

[Mr B]

Originally Posted by Simi 60

No, that would buy an adequate spade for our vessel


Or bin it because it only cost $500
Pulls out spare 2 piece anchor , quickly assembles and we are good to go
.

Really?
Did you not notice it is a single piece anchor, do I simply cut the shank off and send that back?
How do I reassemble on return?
What do I use as an anchor while this one is away being repaired?

Reality is I would not be simply posting back a 200lb anchor.



And I am trade qualified in welding and manufacture (boilermaker) having experience in pressure vessels, high rise footings, shipbuilding and heavy industrial equipment.
I think I can manage a relatively simple structure such as a bugel/supreme style anchor.

High Rise Footings, Thats a Classic, On Site Boilermakers do it because the Builders, Engineers, Site Foreman, Etc Etc, Cant, Hahahaha
It kept me employed for years,

An anchor is a mere toy to a boilermaker/Welder,
Companys dont make the anchors, The tradesmen do,

[cyan]

Originally Posted by Mr B

An anchor is a mere toy to a boilermaker/Welder,
Companys dont make the anchors, The tradesmen do,

Pretty sure an anchor company would have an engineer on staff who could calculate the tensile strength of the tradesman's mere toy before he guessed at the size and at the welds, hoping it would hold his boat.
You know, math and stuff?

[Simi 60]

Originally Posted by cyan

Pretty sure an anchor company would have an engineer on staff who could calculate the tensile strength of the tradesman's mere toy before he guessed at the size and at the welds, hoping it would hold his boat.
You know, math and stuff?

Pretty sure a decent tradesperson can simply look at what has worked before and go up a size or two to add in some good ol' fashioned belt and braces overbuild.

Has worked with countless structures in the past.

[ctgjerts68]

Owning your own shop should make it a no brainer. Draw it up in cad, waterjet or plasma the material to size and have one of your fabricators weld it up in between jobs. Minimal cost to you (their labor). Everything else is a sunk cost or drop at a minimum it's in your overhead anyway. I'd use SS 316L wire welding it up but beyond that I dont see a reason not to do it if you want to. At my shop we could buy things - yes it's faster but that's about it. Build it yourself you know what's been done. As far as the copy write/patent issue I dont know how applicable that is in this case - personal use first of all, likely modifications to your specific boat and it's a really tough case.

[Mr B]

Originally Posted by cyan

Pretty sure an anchor company would have an engineer on staff who could calculate the tensile strength of the tradesman's mere toy before he guessed at the size and at the welds, hoping it would hold his boat.
You know, math and stuff?

A n Apprentice goes to school to learn all the maths and stuff before he gets an Indentured ticket as a Tradesman, ,

They are quite competant in calculating all stresses and materials to use,
And the means to weld it up,

More so than a theoretical Engineer who only has a book to learn it from,
No practical knowledge in the slightest,

[cyan]

Originally Posted by Simi 60

Pretty sure a decent tradesperson can simply look at what has worked before and go up a size or two to add in some good ol' fashioned belt and braces overbuild.

Has worked with countless structures in the past.

I'll give you that.
However, if you overbuild a structure simply because you did not understand the engineering equations that calculate its strength, you probably wasted time and money and resources.
If you overbuild an anchor for the same reasons, then you might have too much weight in your bow and you still can't answer the question: How many tons of force can this thing survive if it's dug in and a whole gale comes along? Of course, you'll also need a bit of math to calculate your boat's pull on the thing in the first place, in said whole gale.
Or just guess.
Some folks are comfortable with a gut feel.
Pretty sure.

[Simi 60]

Mate, we weigh in a 65000kg.
We carry 12000 litres of fluids
The anchor locker, large enough for my 6ft to stand up in has 160m of chain and 300lb of anchors in it now and we are not yet on our lines.
An extra couple of kg of metal on the bow is neither here nor there

[Paul Elliott]

Originally Posted by ctgjerts68

As far as the copy write/patent issue I dont know how applicable that is in this case - personal use first of all, likely modifications to your specific boat and it's a really tough case.

Please don't make me launch into another rant: "personal use" makes no difference whatsoever when it comes to violating a patent.

[cyan]

Originally Posted by Simi 60

Mate, we weigh in a 65000kg.
We carry 12000 litres of fluids
The anchor locker, large enough for my 6ft to stand up in has 160m of chain and 300lb of anchors in it now and we are not yet on our lines.
An extra couple of kg of metal on the bow is neither here nor there

Well THAT changes everything. Sorry. I was thinking cruiser+anchor = sailboat (typically GRP) averaging 40 something feet, 60 if super fancy. I have certainly never anchored next to you. Perhaps we sail in different areas?

A Spade for your boat might be a model 380, at the top end of their normal production run. In that case, doubling up on the 110Kg weight for a home made version might indeed be no-worries. Still, the math might be interesting. If someone measured the Spade 380 copied the clever curve of the shank, increased the dimensions a bit, employed a tradesperson... Wouldn't you still like to know the bending moment of the steel or the maximum bending tensile stress at the critical cross section? Could you be sure of the alloy and hardening process? More specifically, wouldn't you want to know what load your big boat could put on it before it failed? I would.

What is the Safe Working Load of your anchor chain? For us smaller folks, 10mm chain's SWL can be 1200Kg or 2600Kg... depending upon the alloy and hardening. These numbers are not really so important until the wind blows.

[cyan]

Originally Posted by Mr B

A n Apprentice goes to school to learn all the maths and stuff before he gets an Indentured ticket as a Tradesman, ,

They are quite competant in calculating all stresses and materials to use,
And the means to weld it up,

More so than a theoretical Engineer who only has a book to learn it from,
No practical knowledge in the slightest,

That's good to know. This sounds much different than the tradespeople I know, who do indeed study enough math to read prints and calculate welding parameters and apply formulas, but that is the extent. If such a person is also calculating shear and tensile forces in order to size materials and make design decisions, then I would say that they are practicing engineering, in addition to fabrication. If this person can come up with the calculus needed to determine where on the curved Spade shank is the critical cross section, then they are beyond a tradesperson. (in all fairness, the math is nasty, but FEA engineering software makes the answer easy)
Anyway, THIS type of person is the one you want on your boat!

[Simi 60]

Originally Posted by cyan

Well THAT changes everything. Sorry. I was thinking cruiser+anchor = sailboat (typically GRP) averaging 40 something feet, 60 if super fancy. I have certainly never anchored next to you. Perhaps we sail in different areas?

If you care to look to the left to the avatar you will see the boat and area we are in

A Spade for your boat might be a model 380, at the top end of their normal production run. In that case, doubling up on the 110Kg weight for a home made version might indeed be no-worries.

I doubt we need to get that carried away
I run 68 kg Supreme now and if making my own version of would do a larger, 80 to 90 kg version just for the hell of it.
Steels cheap, hours to build would be close enough to the same

Still, the math might be interesting. If someone measured the Spade 380 copied the clever curve of the shank, increased the dimensions a bit, employed a tradesperson...

I really have no interest in a spade.
I prefer surface area working for me, not a lump of lead in the tip.
Plus lead in the tip is an over-complication that is not needed.

Wouldn't you still like to know the bending moment of the steel or the maximum bending tensile stress at the critical cross section? Could you be sure of the alloy and hardening process? More specifically, wouldn't you want to know what load your big boat could put on it before it failed? I would.

As I said, I currently run a 68 lb supreme.
This was suggested as an overkill anchor by manson themselves when I sent boat picture and weight to them.
I said I was happy to go bigger, they said no need.

That anchor has seen multiple 50+knot and an 80+knot storm with no issues apart from getting it back.
Simple logic says if I use the same steel, same thickness or up a size I am good to go.

What is the Safe Working Load of your anchor chain? For us smaller folks, 10mm chain's SWL can be 1200Kg or 2600Kg... depending upon the alloy and hardening. These numbers are not really so important until the wind blows.

13mm grade L has a SWL / WLL of 1.7 tonnes.
As mentioned earlier the anchor, therefore the chain has seen multiple 50+knot and an 80+knot storm with no issues.
Clearly it is adequate for the job at hand.