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Installed a helix mooring anchor last weekend...

81K views 75 replies 32 participants last post by  Concrescence 
#1 ·
Just thought i'd share our installation experience with the helix mooring anchor. Originally i was going to install two of these anchors but i decided that one would be sufficiant and i could always add the second one later if i felt the need. Unfortunately we didn't take the camera out on the skiff with us so all i have are prep pictures... but you will get the idea.

There were three of us (My dad, my neighbor and myself) but it could have easily been done by two. As you can see in the pictures we used a 10' joint of 4" PVC schedule 40 pipe to extend the turning position above the water. It worked like a charm; we used an old bumper jack/lug wrench handle to turn the pipe and it was fairly easy to turn and was rigid with no flex in the pipe and relatively light weight. We marked the PVC pipe at one foot increments starting at the anchor eye so we would know how deep the anchor was. We even attached the 1/2" chain to the anchor eye and had it fed through the pipe while we turned it down into the mud. The only dive needed was to take the bolt out that had the eye pinned to the PVC pipe so we could slip it off... easier said than done but not that bad. Visibility in the murky water was about a foot or so. I managed to avoid the jellyfish and bluecrabs while on the bottom taking the bolt out of the anchor eye. :D We decided to sink the anchor 1-2' deeper than the creek bed for a total depth of 8' which meant digging down to take the bolt out of the eye. All installation work was done from our neighbors 12' Carolina Skiff which was anchored three ways to keep it in place. The water was seven ft deep when we placed this one.

These are the anchors...


Photobucket

Here are the prep pictures...

Dad, Bella dog and I...


Heavy with the 1/2" chain attached... but not too bad. You can see the holes drilled at 1' increments for putting the tire tool in place turn turn with.


Closer view...




Different angle...


Here is a better picture that shows the holes for turning... as the anchor sank deeper we would simply pull the tire tool out and move it up to the next hole and continue turning... much like a giant cork screw. The rod in the picture was what we originally planned to use but it ended up being too long to manage so that's when the tire tool came into play.


I wish i had the actual install pics but i think you get the idea. :)
 
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#31 ·
Guys, who or where sells the groundscrews? Haven't seen them in Home Depot or West but obvisouly someone is selling them.<G>

David, if you don't trust the helix there's no reason you can't add a thousand pound mushroom and shackle it on as drag insurance. Bring out the RR car wheels, one at a time, and slip 'em down.

I'd be more concerned that the galvanizing on the shaft would get chewed up and the shaft let go at an inconvenient time. I'd trust a multi-screw setup but I think I'd want to drop 'em off at a galvanizing shop and have them dipped a couple or three extra times before installing them, since they're not intended for salt water use. (And the folks who make the gen-you-whine marine screws, won't sell them retail.)
 
#32 ·
we bought ours at the local ace marine hardware..

if you are looking for a source then go to the helix anchor website and they will direct you to dealers close to you.

the galvanization on these is pretty heavy.... they are made for marine usage.

we added two danforths as a safety factor, one shackled on to the helical..

but as i said earlier.. i have no doubt on the holding strength of the helical, especially after using others on other applications.
 
#35 ·
These are the guys that started the helix stuff (see AB Chance below... I think Helix actually buys their product from them... or so I've been told). The units you buy in hardware stores are really only for very small boats. We have a 38', 12 ton kadey-krogen that we're working on getting an installation done here in Pallm Beach County. The quote I got from the Helix Mooring company was for over $7,000! Anyway, the units the pro's use are 8 - 12 feet long with multiple "flights." There are a few guys along the water front here that install the light weight stuff... but it won't hold on any cruiser size sailboat in a storm.
HomeApplications › Boat Moorings
Boat Moorings

Mooring fields for municipal and private harbors are a cost effective way to safely store your boats.
CHANCE Mooring Screw Anchor can offer a simple, economical mooring for boats requiring holding capacities to 100,000 pounds or even more. These moorings are so effective that in areas subject to hurricanes special incentives are often offered by insurance companies to boat owners who use these moorings.
CHANCE Screw Anchors are installed into the harbor bottom by either work boats or divers using hydraulic rotary installing equipment with anti-torque devices. The bearing plates are installed through the silt to good bearing soils and the chains or lines are connected to the mooring or platforms above. The same anchors are used in the fast growing aqua-culture field holding fish cages securely to the ocean bottoms.
 
#38 ·
just wanted to give an update on the helix system that i installed......
We had a problem with the swivel coming loose a month or so ago, but that was not an issue with the screws...

the screws are holding superbly.... we have had three high wind events with gusts of 50 knots or more. last night we had 50 knot + gusts, and today was a sustained 30 + knots.

i have not added the third screw yet, but will be this fall as i will be leaving the boat in the water in the event of minor hurricanes.
 
#39 ·
thanks for the update. If you wouldn't mind, would you refresh my memory on the diameter and length of your helix screws? I'm really curious on the force required to screw one in.
 
#41 ·
another update

we have had several significant storms here... many with gusts of 60 knots plus...
Tuesday night we had a front come through... sustained 30-40 knott winds with gusts of 60 knots plus recorded.

mooring is still sound and in perfect position....

we had a house boat moored near me break loose three times recently and drag all over the place. He has a small >30 foot houseboat on aluminum pontoons... not much mass, but still broke a 50 lb danforth loose three times now.
 
#43 ·
I don't think that doubling up on the helix anchors gives you twice the holding power, depending on how you rig the bridle. With a fixed length of chain to each eye, you're only going to be loading one helix anchor at a time, in almost all circumstances, just like with two regular anchors.
 
#46 ·
I concur, so consideration of a sliding pennant, or some sort of bridal, could be of some logic, but an interesting physics issue. Continuous equal distribution of the load is the challenge.

Funny but true, over here on the West Coast, it seems Helical Mooring is largely unknown. I've been studying this subject now -and the industrial construction applications that spawned it- for a couple weeks now. Very, very interesting.

Anyone like to update this thread with their more current Helical Anchor/mooring experiences?
 
#44 ·
Can anybody give me some guidance on how to calculate what the minimum pullout force of a system should be for a given boat. Mine is a Bristol29.9.

The original displacement was 8650lb. I would like to install a system that will securely anchor my boat in a protected bayou, but it is the Emerald Coast area of FL, so prone to hurricanes, although a storm surge is more frequent in this area (Panama City).
 
#47 ·
equal pulls

Scurvysailor wrote: I concur, so consideration of a sliding pennant, or some sort of bridal, could be of some logic, but an interesting physics issue. Continuous equal distribution of the load is the challenge.

You would need 2 anchors to have equal pulling in two directions, 3 for 3 directions...ect. What hasn't been mentioned is something to keep the helix shaft from being pulled sideways when it's in a strain as the scope of the rode will try to pull it out sideways, not straight up. House trailer helixs use a side plate to take the lateral strain. For a marine helix, a 12" diameter steel pipe cap about 12" long welded near the top of the shaft might work. It would turn as the helix turns and would hinder lateral movement of the shaft.
 
#48 ·
Great Post! Thanks to the original poster for taking the trouble to take the photos and provide the detailed instructions.

I am researching how to place a Helix for my 23.5' Hunter sailboat in about 10ft of water on the northern Chesapeake Bay. My problem is that I don't have any help and would like advice on how this could be done by one person. I don't mind getting wet because the water is about 80 degrees right now. The location is only about 30 feet off the beach so I could easily walk/swim out.

Do you think I could use the ingenious PVC pipe method and turn it while floating in the water in my PFD, or would I need the traction of standing on the bottom? On some days the tide goes out so far that I could probably stand on the bottom and a snorkel would reach the surface. I am a certified diver but don't have any gear any more. Would it be smarter to rent gear and do it from below? I'm trying to keep costs and complexity to a minimum. Am I crazy?
 
#49 ·
Tri Anchor

Read in Chapman's that 3 anchors 120 degrees apart was way superior to massive mushroom anchors.
That proved itself correct when I used 3 Delta's which held my 4000# 25' Cape Dory 25 in an infamous nor'easter that devastated much of the Chesapeake several years back.

It follows therefore that 3 helix's at 120 degrees apart connected with chain would always have at least 2 of them holding regardless of the wind direction.

That would be my approach for anything short of a major hurricane.

Dick
 
#50 ·
Reef, you will not be able to install the mooring by simply swimming as you won't be able to exert enough force if the bottom is any good. You either need good traction on the bottom (note- I have personally never installed one in deep enough water that I have had to suit up and dive) or you need to have a boat very firmly anchored in place to work from. If you have a way to extend the shaft of the helix so that it is long enough to be reached from above the water's surface, this works decently well but you do need to spend some time getting the anchor lines adjusted right (or you need to rent a spud barge). Anytime you do this, you should make sure that the soil is appropriate for the anchor type.

Flybyknight, putting 3 helix anchors at 120 degrees apart is very different than putting 3 danforths or similar in the same arrangement. In this arrangement, each anchor has to be able to independently take all of the load from the boat (imagine 1 anchor being directly upwind, the other two won't do anything). A helix makes a great boat anchor not only because of its holding power but because it doesn't need to reset or rotate if the direction of pull changes. If you take the examples of danforths, 3 anchors is necessary so that the anchors always see a relatively straight line pull. There is way more to the 3 anchor arrangement than most people realize, the lengths of chain are very critical to really minimize the load. The arrangement does work quite well but a lot of people install them improperly because they don't understand the important of the geometry.

It is possible to rig up a load sharing arrangement between multiple anchor points so that they will have relatively equal loading independent of wind direction but this is not standard to my knowledge. The problem is that you need to allow for moving parts which tend not to work well over long periods of time underwater. The way that most systems are setup, in most wind directions, one anchor will be doing all of the work and the other one will simply be there for backup.
 
#51 ·
Hey, thanks Klem. I thought so, about getting enough torque while treading water. I guess I'll try to catch it at maximum low tide and see if I can do it without SCUBA gear. If not, I guess I'll go rent gear. Still much cheaper than hiring someone.

And I completely agree with your analysis of the anchor trilogy. Anchors are designed for directional forces. Helix are non-directional. You could plant 3 Helix right next to each other and have the same amount of redundant protection. If the 1st one pops out the load then goes to the second, etc. As for load, the 8" Helix could hold my boat if the world turned upside down and the boat was hanging from the anchor. No competition as far as holding power of a Helix. Plus they're about 1/10th the cost!
 
#52 ·
i wanted to give an update on the helix system.
I have had it in for a while now and dove down to check it after we had a direct hit from hurricane irene... helix anchors are fine and dandy. We are getting some corrosion on the first few feet of chain that connects to the stainless cable.. i am thinking about adding some zincs to see if that will help with that issue.

I did not have boat on my mooring in the storm, but three boats got hung up on my mooring and it held a 24 foot sailboat, a 22 foot sailboat and a 31 foot motorboat all broadside in direct eyewall winds for several hours. the float pendant finally chafed through letting the boats go...

the only two boats that made it through the storm in my area were on helix anchors as well. there was a 30 Catalina that chafed a pendant and went wandering about, but the helix held.. no issues.

I am now a die hard fan of these systems... we had a tropical storm come through last fall... no problems.... several high wind events with gusts over 80 mph. several boats have come loose, but mine, and all the other helix anchors have held solid.
 
#54 ·
Not surprising, Sean. That was the situation in the US a short few years ago, you could only buy one from a gen-you-whine certified installer who came along to install it.

Utility companies apparently use them to secure guy wires for poles, and the heavy galvanized products they use seem to be up to marine use. You've probably got them in that market.
 
#56 ·
Sean, there are also helical mixing "screws" used in industrial mixers. To mix up paints, foods, cement mortar type products, all sorts of things in huge quantities.

Most of that stuff is fabricated in stainless steel, so if you can find a local shop that fabricates stainless for large machine parts, for industrial customers, food service, etc. they may also be familiar with fabbing up "helixes". Except in the anchor, you just need the bottom disc of the helix, not a whole screw of it.
 
#57 ·
HelloSailor. I've spoken to engineer(s) about making a helix anchor. Their response is "Yes it can be very easily done" but thats as far as they go. I'm definitely not a 'difficult' customer and cannot understand why somebody will not take the job on.

I think part of the problem is that I cannot specify exactly what I need; in terms of pull-out strength, windage of the boat and soil cohesion of the swamp marsh it will be screwed into because I do not have the expertise. I have gathered lots of data but need to find someone to pull it all together. It's not rocket science but it's not something they want to take on.

Thanks for you input. Perseverence furthers.
 
#58 ·
goodone1, Hello Mate! Helix's are still pretty unusual in my area, too. You mention a Helix around here and people look at you funny. Most Hillbillies where I live will throw an old engine block or something in the water and call that a mooring!

Anyway, here are a couple of links that might help you, the first is the maker of Helix. The fellow there always replies to my emails very quickly. He might be able to work out shipping for you. The second link is where I bought mine. Good Luck to you!

Helix Mooring
ANCHORS
 
#60 ·
New to forum. Tried to provide a link but wasn't permitted. If you google Octopus or Wombat mooring and have a look, I'd be very interested in what you think about this helix anchor (Wombat) and the attached springer system (Octopus) designed and sold in Western Australia. Any thoughts?

Harry
Tasmania
 
#61 ·
Harry Tams,

I googled the anchor/mooring system that you mentioned and here is my take on it. These helix anchors are pretty small meaning that the holding power per helix is going to be pretty low. In a relatively hard bottom, this would be okay for a smaller boat but not a larger one. The trick with helix anchors is that you need to match them to the bottom. The professional installers will often take a sample from the bottom to analyze so that they can estimate the holding power from the different size helix's. Also, the stated weight is pretty light which makes me think that these are lightly constructed. It is quite possible that they are plenty strong to resist bending, my concern would be the reduction in strength related to corrosion because thin pieces lose a greater percentage of their strength for the same amount of corrosion.

Regarding the Octopus mooring system, I really dislike mooring systems where multiple anchors are put together to increase the holding power of the system. The problem is that until you have 5 or greater anchors in a star pattern, there are directions of loading where a single anchor will take all of the loading. If the force on this single anchor is too great, then it will pull out and the next anchor in line will be shock loaded with all of the load and likely pull out. Therefore, every anchor needs to be sized to carry the entire load so there is no need for multiple. There are ways to load equalize in all directions but I am unaware of any that I would trust for a permanent mooring because they are prone to chafe, fouling and sticking. The major advantage of setting multiple anchors in a star pattern is that the direction of loading does not change so that you can use anchors like danforths. Since the helix is symetrical about its vertical axis, the direction of pull does not matter.

In the right circumstances, I feel that a well engineered helix install is one of the best mooring systems possible. However, I feel that a single helix should be used which means that it must be pretty large for a reasonably sized boat.
 
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