Making an anchor for a mooring line

[Darnold9999]

Something to consider. Anything like a pair of anchors, or an engine block with chain through without a buoy on the surface marking it is a hazard for boaters that might anchor nearby. Ask how I know

Spent a good couple of hours once trying to unsuccessfully retrieve my anchor. Finally geared up and went down to find it entangled in an engine block and cable someone had left on the bottom with no marker. Had I not had dive gear on board I would have had to abandon the anchor.

 

[Fred Tagge]

The first rule of Ocean Engineering is that Mother Ocean is a hungry bitch who will be fed. The Engineers job is to delay her meal as long as possible.
The second rule is to never put anything into seawater you absolutely have to get back. This includes your ass.

 

[wetb4igetinthewater]

View attachment 776218

From creative anchoring by Gary(cptn fatty) goodlander

I did find his book here:
I also ran across this: https://support.jamestowndistributo...ing-Basics-How-to-install-a-permanent-mooring

This part surprised me:
When it comes to metal finish, "hot dip" galvanized steel works best in salt water. While stainless steel is preferable on deck, it's not best for below the water. Stainless steel needs oxygen to breathe. Constantly submerged, the lack of oxygen is thought to cause stainless steel to corrode. Steel that is "hot dip galvanized" into a bath of zinc at over 800° yields a very corrosion-resistant metal. But even so, wear is unavoidable, meaning you will need to replace any chain after a few years mooring service regardless. Even the best stuff will wear away with time so it's more cost effective to replace less expensive chain frequently. For all the above reasons, the most common chain for mooring use is a hot dipped galvanized Grade 30 proof coil.

Does this sound right to you? How about you @Fred Tagge ?

 

[GiraffeMarineSalvage]

Personally I would strongly recommend all galvanized chain/shackles instead of stainless steel for anchoring and mooring (with stainless steel wire to sieze all shackles being the only exception). In addition to simply having better places to spend money (such as bigger gear for same cost), it's worth considering crevice corrosion, work hardening and regardless of metal used who made the chain/shackles.
Also while enough concrete is certainly tried and true for moorings, the denser the material the more efficient the weight will be (such as a clean used engine block from a piece of heavy equipment since steel is much denser than concrete the weight of surrounding water reduces the relative effective weight less..).
Lastly, I personally would be very diligent about maintenance and inspections but wouldn't bother with seasonally removing quality galvanized chain unless there is a local theft concern. A pretty common practice in Maine is to use a "winter stick." In short, simply swap the mooring buoy out for a brightly painted small rot resistant (but NOT pressure treated..) log and a suitable length of crab pot line (which factors in highest winter tides plus swell since it needs to stay visible at all times for the sake of other boaters...) between the log and the last link of chain. That way the chain can all rest on the bottom (where there's little oxygen, which is fine for galvy and terrible for stainless..) so there is no meaningful wear over winter but it will be easy to retrieve in the spring.

 

[wetb4igetinthewater]

wouldn't bother with seasonally removing quality galvanized chain unless there is a local theft concern.

I wish I took a picture of my neighbors "oyster farm" growing on his line. He pulled in his line at the end of last summer. When I see him when summer starts, I'm going to ask him if he cashed in and bought a new truck and boat! These waters are nutrient rich and oysters/mussels/barnacles grow like crazy.

If you miss a season, you are going to have a lot of crap growing on the line.

 

[GiraffeMarineSalvage]

I wish I took a picture of my neighbors "oyster farm" growing on his line. He pulled in his line at the end of last summer. When I see him when summer starts, I'm going to ask him if he cashed in and bought a new truck and boat! These waters are nutrient rich and oysters/mussels/barnacles grow like crazy.

If you miss a season, you are going to have a lot of crap growing on the line.

Oysters/everything else should be pretty dormant over winter but in the case you give it may very well be easier to pull your chain in that circumstance, especially if have luxury of a pressure washer..

 

[wetb4igetinthewater]

Oysters/everything else should be pretty dormant over winter but in the case you give it may very well be easier to pull your chain in that circumstance, especially if have luxury of a pressure washer..

Oysters are MUCH tastier in winter!

 

[NW Dive Dawg]

I’d just sign you off.

There are no skills in the solo class you haven’t learned.

But I am no longer active.

Oysters are MUCH tastier in winter!

And also much safer from paralytic shellfish poisoning resulting from red tide...... We have our own boat up here in the PAC NW and love harvesting our own bivalves..... Nothing beats a nice load of fresh oysters and clams during football season! We also love the pectin "singing" scallops and they are prolific on the SE side of Deception Island....

In the old days before testing was available....the general rule was to only harvest oysters in months that contain the letter "R".

 

[Fred Tagge]

It is all about the $s. Galvanized steel is is less expensive than stainless, but galvanizing prices are based on the pounds of raw steel in the batch with a pretty significant minimum charge. If doing a 10,000 pound batch Galvanizing is less expensive, if doing a 100 pound welded fixture welded stainless may be the way to go, especially if it may need to be unbolted from something a time or 2 during it's life. Stainless steel needs to be at least 316 with a fair component of moly in it to keep it from pit and inter-granular corrosion and a rather low carbon content. Not all stainless even close to similar in potentially low oxygen environments.
Chain anodes are a pretty good cost effective way to protect chain that is not attached to anything else with a conductive connection. OTOH load bearing insulated connections can be right pricey on a onesy twosey basis. In lot sizes of 200 or more utilizing near net castings to minimize machining time the price can be held down to something reasonable. Be aware that a galvanized surface should never come in contact with a non-galvanized one, including fasteners.
The most cost effective thing for a permanent one-of anchor is to figure how long you want it to last, then use your worst expected corrosion rate and double it to determine how much of what size steel is necessary to come home from the junkyard with to fabricate what you need. What is inexpensive is going to a local thing, so it pays to spend a bit o time browsing the yard before starting the project.

I did find his book here:
I also ran across this: https://support.jamestowndistributo...ing-Basics-How-to-install-a-permanent-mooring

This part surprised me:
When it comes to metal finish, "hot dip" galvanized steel works best in salt water. While stainless steel is preferable on deck, it's not best for below the water. Stainless steel needs oxygen to breathe. Constantly submerged, the lack of oxygen is thought to cause stainless steel to corrode. Steel that is "hot dip galvanized" into a bath of zinc at over 800° yields a very corrosion-resistant metal. But even so, wear is unavoidable, meaning you will need to replace any chain after a few years mooring service regardless. Even the best stuff will wear away with time so it's more cost effective to replace less expensive chain frequently. For all the above reasons, the most common chain for mooring use is a hot dipped galvanized Grade 30 proof coil.

Does this sound right to you? How about you @Fred Tagge

 

[GiraffeMarineSalvage]

if doing a 100 pound welded fixture welded stainless may be the way to go, especially if it may need to be unbolted from something a time or 2 during it's life.

I respectfully don't think the original poster needs to get into any customer fabrication though. If going concrete there is a very solid way to simply use a metal rod (a picture is worth a thousand words so check out picture of 1.25" steel rod at Habitat Mooring | A Mooring That Provides Marine Habitat, with one key detail being strength of concrete...) or even simpler still put chain through where pistons of a large engine block normally are and make sure the chain is shackled tight so no excessive wear from movement (and I'm only referring to BIG blocks, some engine castings may be unsuitable for this approach if strength of casting/brittleness is a concern).