General Anchorage Anchor

[transiberian]

I am planning to (park) my 27' O'Day at general anchorage since its free, and I can use money to invest in anchor. I need a very good anchor, what would you recommend for my 27'? I need to be sure my boat will not move with this anchor.

[boatman61]

Search anchors..... we've enough going in circles threads already mate....

[Pete7]

Can you lay a permanent mooring? if so a nice big tractor engine block would do. If not, well have a search on here for Delta /Rocna / Spade / Manson / fortress. That should keep you busy for a while. The alternative and cheaper option would be a huge great secondhand Bruce.

The manufacturers will state the sizes on their websites and there is nothing stopping you over sizing a bit too.

Pete

[beneteau-500]

cant you just drop a slab of concrete and chain and ball

[John A]

Originally Posted by beneteau-500

cant you just drop a slab of concrete and chain and ball

That's called a mooring.

[S/V_Surya]

What kinda bottom are you dealing with, sand, rocks, mud, grass....? I would also go with two whatever you use.

[transiberian]

Sorry guys I only had a very little time to search then I went to work. I don't think I can do something permanent there, I like an idea about two anchors.

[Adelie]

Originally Posted by transiberian

I am planning to (park) my 27' O'Day at general anchorage since its free, and I can use money to invest in anchor. I need a very good anchor, what would you recommend for my 27'? I need to be sure my boat will not move with this anchor.

25# CQR or 22# Bruce on 50-100' of 5/16" BBB chain, with 7/16" nylon rode past that.

These 2 anchors should be available second hand to hold costs down. They are oversized for your boat in that they would be appropriate for use in a gale or for longer term anchoring, but you probably wouldn't want to daysail or coastal sail with them. Storm sizes would be 35# CQR or 33# Bruce, with same chain and rope.

On deck you want a roller leading the chain over the bow. It needs to have pin across the top to keep the chain and rope from jumping out of the roller when it is bumpy.

Install a chain pawl with a big backing plate, this allows you to bring up the anchor more easily by hand before you can afford a windlass. Once you have the windlass continue using the pawl as it takes the anchoring load off the windlass. Windlasses are only designed for hauling loads (ie raising the anchor), not the anchoring loads that can be 5x-10x higher in a blow.

If you are anchoring in water shallow enough that you don't get to the rope part of the rode before you have enough scope out, then you want a couple of chain grabbers with nylon rope leaders. In a blow the chain doesn't do a good job of absorbing shock loads from waves, nylon stretches a lot and will do this just fine.

Make sure your bow cleats are a bit oversized and have big backing plates.

[klem]

What you really need to do is set up a permanent mooring but since that is not allowed, you need to set up an anchoring system that imitates a permanent mooring.

Permanent moorings are generally either deadweight anchors, mushroom anchors or screw anchors (there are others like Dor-Mor but they are not as common). With the exception of the mushroom anchor, all of these will work on very short scope provided that the anchor is made large enough, something that is not true of any anchor that you might be looking at. Additionally, they allow for the direction of pull to change without requiring the anchor to pivot or reset. The chain in permanent moorings is quite heavy so that it will provide some shock absorption, weight to cancel out the vertical component of the rode tension and so that it will last longer before rusting out. The pendants are there to attach the boat to the chain and they must be strong enough even with severe chafing while still providing some stretch.

To start, you need to figure out the loads that the system must handle. ABYC has a chart which suggests you should be prepared for loads of over 2000lbs. If you are in an exposed area or an area with bad storms, you will want to use a higher load. This is never a place to start skimping and is a good place to put an extra safety factor on. Next, you need to find an anchor that will reliably hold greater than this amount, will pivot in the seabed without coming out and that you trust to reset if it ever does come out.

When selecting chain, you need to select chain that has a WLL greater than your maximum load. Keep in mind that the chain will degrade rapidly so either you need to change it pretty often or you need to seriously oversize it. Since you won't be using a massive permanent mooring anchor, you will need to have sufficient scope (~6:1) for your worst case water depth (high tied + storm surge). The necessary scope will mean that your boat will take up a lot of real estate. You will also need to include a swivel so that your chain does not kink up and shorten itself.

The pendants should be the equivalent of what you would use in a permanent mooring (probably 3/4") since they will need to be strong enough even when badly chafed. They also need to be long enough to provide shock absorption which probably means >15'.

Note: doing this is not something that I would recommend and it may well violate the local rules where you are. It certainly can be done and is done in many places. If you are going to do it, do not use the general ground tackle sizing recommendations that are geared toward weekend warriors, this will not work in a big storm. Getting an anchor that you trust to stay embedded in a wind shift would be my greatest concern and may be an argument for a 3 anchor system.

[Free Agent]

Plow anchors in the ocean,, box anchors on lakes and rivers.
Lots and lots of quality chain with both, no matter what the MFG says.

Our rules are we try and not anchor in more that 60 ft of water if at all possible, and have 5 times the line/chain extended than the depth.

Every sailor should be good at anchoring because ya never know when weather conditions or mechanical problems put you in a bad situation.

Moorings and slips are a nice way to roll, but they aren't always available when ya really need one. Hell, they usually aren't available when ya need one.

[transiberian]

I decided to go with mooring, it wasn't that bad... $1500 for a season. Thanks everyone!

[klem]

I am glad to hear that you made the right choice. The cost is painful but coming down to see your boat on the beach has to be a lot more painful.