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-   -   Round Shaft Helix Mooring (http://www.sailnet.com/forums/living-aboard/53038-round-shaft-helix-mooring.html)

Freerider 04-01-2009 06:32 PM

Round Shaft Helix Mooring
 
Does anybody use one of these for a mooring?

Round Shaft Anchors

I know the more complex type helix are great systems, but I'm not interested in hiring someone to install one. The more simple round shaft helix I can install myself by SCUBA.

I'm concerned with their holding power, I've read their load is around 4000lbs, and sure that is dependent of different factors, including bottom type. My boat will be approx 32', 10' beam, 10000lbs displacement.

I'm not 100% sure what the bottom is like but I will be located in a BC inlet near the mouth of a river.

Do you guys think this type of mooring would be better than say a Rocna 20? I'm not sure if its a good idea to live long term and leave the boat for a week at a time (on rare occasion), and leave her hanging on an anchor.

I feel a permanent mooring would be a better idea however; this mooring can't reset itself if it lets go, a MAJOR disadvantage. I know an anchor should be able to look after my boat, or i should get a new anchor, but the idea of a permanent mooring seems more secure.

I know you guys will know the answer, so which would be better to avoid the price of marinas?

sailingdog 04-01-2009 07:12 PM

A Rocna 20 is probably capable of holding with greater force than 4000 lbs., since the Rocna 15 was generating loads of over 5000 lbs. in the Sail magazine anchor test a couple years ago. However, a permanent mooring is a far better idea for a long-term solution.

How well a round shaft helix will work depends a lot on what the bottom composition is like and how deeply you can screw the helix anchor into the bottom. Without knowing what the bottom consists of, you're basically shooting in the dark. If it can hold 4000 lbs. of force, then it is probably sufficient for your boat, but you'd also have to size the chain and pendant properly.

See this page from the Hamilton Marine catalog regarding that:

http://www.hamiltonmarine.com/images/0128.jpg

Freerider 04-01-2009 09:26 PM

Great diagram thanks!!

I guess if I thought 1 wouldn't hold, 2 wouldn't be such a bad idea.

Its just when i find them online, it says they're for "small" craft. "Small" could mean anything.

Bene505 04-01-2009 09:45 PM

If the helix achors are easy to put in, then they come out easily too. The professional installers use a machine that has (IIRC) 40 times the torque of a post hole digger. You can't come near that with scuba and a self-install.

sailingdog 04-01-2009 09:57 PM

The real key is what is the bottom in the location you'll be using it in. If the bottom type is wrong, you won't be able to use a helix mooring. I would also highly recommend that you talk to the company about the usage and the loads your boat will impose. While 32' LOA is a relatively small boat, yours is relatively heavy for a boat of that size.

Freerider 04-01-2009 11:04 PM

Quote:

Originally Posted by Bene505 (Post 469651)
If the helix achors are easy to put in, then they come out easily too. The professional installers use a machine that has (IIRC) 40 times the torque of a post hole digger. You can't come near that with scuba and a self-install.

I agree with that to an extent, I would be screwing it in using a bar for leverage, but when its pulled its not being unscrewed.

You guys are both right on the bottom type, I guess I'll go dive on the site and then I'll know if its even a viable option.

Thanks

By the way, does anyone know of any charts that show the correlation between wind speed, and force exerted on an anchor/mooring? I'm sure it would complicated due to the variables in aerodynamics of different vessels.

Freerider 04-02-2009 01:09 AM

I found this using google, I wonder why it didn't come up when i searched on here.

Anyways lots of questions answered.

http://www.sailnet.com/forums/genera...t-weekend.html

sailingdog 04-02-2009 09:05 AM

Cause Sailnet's search function sucks... :)
Quote:

Originally Posted by Freerider (Post 469742)
I found this using google, I wonder why it didn't come up when i searched on here.

Anyways lots of questions answered.

http://www.sailnet.com/forums/genera...t-weekend.html



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