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post #1 of 16 Old 06-07-2013 Thread Starter
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Ground Tackle for an O'day 35

Several people have asked me about my ground tackle setup, so I thought that I would post this here to explain what it is, and how I use it.

Below is a diagram of how I would deploy the anchor if I needed the greatest holding power (storm).



The optional 10' of 1/2" chain weighs about 34lbs, and acts like a kellet, except that it will not chafe the nylon anchor rode. To be honest, I have not had the need to use it in the 3 years that I have hade the boat, and am afraid of having to haul it up with the two arm windlass. The windlass is getting old and creaky...

The usual setup is to deploy the 33lb Rocna on 25' of 5/16" HT chain.

You'll notice that the retrieval line is tied, with a float to the thimble at the end of the 5/8" nylon rode. The float keeps the lightweight line from getting tangled on the bottom, and should the nylon line ever be cut, it would make retrieval easier. I believe that I have a better chance of catching this with a grappling hook. Because I don't usually anchor in more than 30' of water, if I untie the line from the thimble, it would act as an anchor marker.

I tried the anchor a couple of times without the retrieval line. I found that it was hard to break free, and it hauled up about 15 lbs of bottom. Now that I use the retrieval line, the anchor breaks free MUCH easier, and it only brings up about 5lb of muck.

Ya' it's a Chinese made Rocna; but it works fine, fits my bow roller, and sets right every time.

Here are two pictures showing how it fits on the bow;



I use the retrieval line as a safety, in addition to a stainless steel carabiner hooked to the Rocna's rollbar, to keep the anchor secure on the bow roller.

I'm putting this here for my benefit, but if it helps someone else, you're welcome.
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Last edited by eherlihy; 06-08-2013 at 09:07 AM.
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post #2 of 16 Old 06-07-2013
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Re: Ground Tackle for an O'day 35

Thanks for the info. Why not just use the retrieval line as an anchor marker? Whats the
advantage of tying the retrieval line to the thimble?

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post #3 of 16 Old 06-07-2013 Thread Starter
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Re: Ground Tackle for an O'day 35

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Originally Posted by Captainmeme View Post
Why not just use the retrieval line as an anchor marker? Whats the advantage of tying the retrieval line to the thimble?
When I haul the double braid aboard, it automatically brings aboard the chain, and the retrieval line.

As soon as the thimble comes aboard, I know that I have 25' of chain to haul up. I hook the thimble on a cleat, and haul up the retrieval line, which backs the anchor out of the bottom (relatively) cleanly. When the anchor breaks the surface, the chain has enough weight, and is short enough, to stay clear of my prop, so I can tell the person at the helm to go ahead slow. This movement through the water helps wash the whole setup clean.

If I let the marker float (which nobody around here does) I would have to grab a boat hook to bring it aboard. Also, the retrieval line could foul on the bottom as the current changes.
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Last edited by eherlihy; 06-08-2013 at 01:29 PM.
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post #4 of 16 Old 06-10-2013
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Re: Ground Tackle for an O'day 35

Just one note; if you do ever use the 1/2" chain, it should for optimal effect be attached to the anchor, not behind the 5/16". Heavier weight does more good closer to the anchor. (The only reason you wouldn't put a kellet directly next to the anchor is that it has a physical size and you obviously don't want it sitting on the seabed.) However you should also be aware that it really won't have much effect on ultimate holding power at all.

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Re: Ground Tackle for an O'day 35

Thank you Craig.

I'm not sure that I agree with you on this point. By attaching the ½" chain further out from the anchor, I increase the leverage that the increased weight has on the anchor, and thereby the catenary of the anchor rode (see this link; https://en.wikipedia.org/wiki/Catena...marine_objects). My background is Electrical Engineering, so I am open to discussing this point here with the Mechanical Engineers in the crowd. (and please let us keep this discussion on point)

However, I am glad to see that you are still around.


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post #6 of 16 Old 06-10-2013
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Re: Ground Tackle for an O'day 35

Good disusssion.

I use a similar setup bur have a kellet ( a 15 lb. mushroom anchor) which slides down the braided line to a position 5 ft. under the keel depth. This essential keeps the rode perpendicular so it doesn't wrap in a changing tide/

Wouldn't your additional chain just lower the catenary angle of the original set?


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Re: Ground Tackle for an O'day 35

I can see Craigs point, but I can also see how having the heavier chain away from the anchor, would help some in keeping the rest of the rode down in a higher wind. BUT, if it is that windy, more scope will be better than the heavy chain or a really heavy kellet! At least from some of the articles I have read etc.

I'll admit to not having ANY engineering degree's what so ever......

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Re: Ground Tackle for an O'day 35

I find that my similar Manson Supreme (and the Lewmar Claw that I had before it) break free pretty easily if I get to 1:1 scope, let the boat sit there for a minute, then haul in the rest.

Your float plus trip line might be better for tight anchorages though!

Interesting discussion on where to put the extra length of heavier chain.

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Re: Ground Tackle for an O'day 35

Because I threw this out for analysis by the collective, I thought that I should look at it a little more closely myself.

First of all I mis-stated the weight of the ½" chain above. It is actually 2.6 lb/ft.
The weight of the 5/16" chain is 1 lb/ft, and the weight of the anchor is 33 lbs.

I do not mean to speak for Craig, but I believe that the source of his info is here; Kellets or Anchor Angels / Sentinels: Uses and Applications and here; Catenary & Scope In Anchor Rode: Anchor Systems For Small Boats. Craig - please feel free to correct.

The conclusion of both papers is that rather than increasing weight of the rode, it makes more sense to increase the size of the anchor. I'll tell you now, that the 33lb anchor is as big an anchor as I am going to haul up; so that ain't happening.

Peter does allow the following regarding Kellets;
Quote:
The ideal placement of the kellet is different according to the application. This is an unfortunate fact, as it means the desired benefit must be selected – the best of all worlds cannot be had.

To achieve the supposed increased anchor performance already dismissed, the kellet should be placed as close to the anchor as possible. This is so its weight exerts the maximum leverage on the rode. It pays to note that a kellet is not a point on a graph, but a physical object which hangs below the rode. Therefore, it cannot be placed directly next to the anchor, otherwise it will simply rest on the bottom and its weight will have no effect.
I believe that this is the point that Craig is referencing. Again, Craig, set me straight if necessary.

My counterpoint is that by adding the heavier chain, it is not the same as a kellet, which hangs beneath the rode, but becomes a (heavier) part of the rode. By spacing the heavier load away from the anchor, it has more leverage, and should help keep the load on the anchor horizontal, rather than vertical.

Continuing the quote from Peter;
Quote:
To provide the best shock absorption, the kellet should be placed halfway along the rode. (Shock absorption is a point not elaborated on above, as it is closely related to the idea of increasing anchor performance). Since one may wish to both increase one’s holding power and benefit from shock absorption, one could compromise and place the kellet one quarter along the rode from the anchor. Neither is ideal, as, like the lowered pull angle, this quasi “spring” disappears in bad conditions when it is most needed.

To minimize swinging radius, the kellet should be positioned down the rode from the boat a distance equal to that of the vertical distance to the seabed (depth plus height to bow-roller). This allows the gravitational potential of the kellet to work to its full potential. (Nb. while effective in light conditions, this technique is questionable in any case; if the anchorage is empty, swing radius is unlikely to be important, whereas if it is crowded, it is desirable to swing similarly with the other boats).
I believe that my technique is a good compromise to both of these points.

Further, consider the weight of hauling the damn thing aboard. If I were to anchor in 20' of water, allowing 5' of freeboard;
  • As illustrated above I am lifting 15' * 1lb/ft (15lbs) + 10' * 2.6lb/ft (26lbs) = 41lbs of ground tackle when hauling chain, and then 25' * 1lb/ft (25lbs) + 33lbs (anchor) = 58lbs max as I haul the anchor itself.
  • Putting the heavier chain next to the anchor would increase the max load (20' of water, plus 5' of freeboard) to; 33lbs (anchor) + 10' * 2.6lb/ft (26lbs) + 15' * 1lb/ft (15lbs) = 74lbs


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Re: Ground Tackle for an O'day 35

I think my usage is the actual kellet as I previously explained..

I cannot draw here,

As I explained before I have a 15 lb mushroom on a large double jaw swivel shackle
Double Jaw Swivel Shackle 3 1/2" by Suncor

Pin from one swivel shackle goes through the mushroom anchor shank hole and a 1/4 inch line is attached

The other pin is removed, shackle is placed around the anchor rode and the pin is replaced.

I let the mushroom anchor slide down the anchor rode to a position at least 5 ft below the depth of the keel. This way the mushroom anchor is hanging off the rode dropping it mostly perpendicular to the anchor roller. Then cleat the line off. It also decreases the catenary angle on the Rocna by having the rode "weighed down" further below water so the angle starts there as opposed to the bow roller.

When retrieving the kellet slides back up the anchor rode easily.

I would suggest you simplify and put the chain on a double jaw swivel like I have it would be the same as the mushroom anchor and you'd have a kellet. You could slide it down the rode after setting your anchor. You could retrieve the weight first so you wouldn't have to add a heavier anchor, but youd have the weight lowering the angle of the rode..


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Last edited by chef2sail; 06-10-2013 at 10:54 PM.
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