How big is too big?

[Paul L]

Originally Posted by reed1v

The reason for using chain to pull out trucks is to avoid whipping of ropes or cables through the air that can literally remove the truck's body, decapitated nearby folks, and cause all sorts of damages. Chain simply breaks and falls.

Not any more. They use dyneema now adays.
Master Pull - Synthetic Winch Line / Rope, Kinetic Recovery Ropes, Recovery Gear

[Dockhead]

Originally Posted by Guy

Make damn sure it don't come loose at sea. What is your plan for holding it in the bow roller? That is a lot of surface area plowing into a wave. You might consider some chocks on deck to lash it down too.

I don't like the hoop on the Rocnas and some others, but they are actually ideal for lashing the anchor down in the roller. I don't think A64 is going to have any problem with this.

[a64pilot]

Originally Posted by Dockhead

I don't like the hoop on the Rocnas and some others, but they are actually ideal for lashing the anchor down in the roller. I don't think A64 is going to have any problem with this.

He is right though, until I learned the hard way to lash the thing to the railing I did have it come loose, I had it lashed around the shank on the roller and that I guess worked loose.
I think I will for the foreseeable future leave a trip line rigged to it and a little float, so that if it does get buried I can get the thing back.
I have found that if I'm backing even slowly, the Rocna will correctly orient itself to come up on the brow correctly, if I have any forward movement it turns around backward requiring a boat hook to orient it correctly, that is with the 25, Im sure the 40 will be the same, I intend to keep the Mantus swivel as I think it a very good swivel.


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[model 10]

Originally Posted by Dockhead

I don't like the hoop on the Rocnas and some others, but they are actually ideal for lashing the anchor down in the roller. I don't think A64 is going to have any problem with this.

For the occasional wave sure but one after another? Nothing on a regular sized cruising boat bow sprit would hold up, it's too big. Water over the deck is a game changer. This set-up sounds more coastal, which is where you would need it anyway.

[a64pilot]

Originally Posted by Guy

For the occasional wave sure but one after another? Nothing on a regular sized cruising boat bow sprit would hold up, it's too big. Water over the deck is a game changer. This set-up sounds more coastal, which is where you would need it anyway.

It will hold, I weigh 250 and can stand on the rail with little deflection, right there on the bow due I guess to shape and the fact there are two that are welded together, it is stupid strong.
But your right about coastal, I doubt many have use for an anchor in thousands of feet deep water


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[model 10]

[QUOTE=a64pilot;2196068] But your right about coastal, I doubt many have use for an anchor in thousands of feet deep water

That is hardly the point. It's at sea that you don't want the thing coming loose.

[Snowpetrel]

Originally Posted by Jim Cate

Well, his boat's listed displacement is just about the same as our light ship displacement, and with its high freeboard, etc, I doubt if his windage is all that much less... so I dispute your conclusion, Ben!

And when we were replacing the anchor we lost in the Gordon a few months ago, I seriously considered going from 60 to 80 lbs... but it wasn't readily available (actually, neither was the 60, but that was yet to be learned!). I think if I were in A64's place I'd go with the 66 lb if buying a Rocna, but what I would do is not relevant!

Cheers,

Jim

On edit, I see that others have already addressed this issue... sorry for the repetition!

Ha, at the end of the day we both agree that the rocna 33 is about right for his boat. Glad to hear you went for a new manson 60lb though I am sure an 80lb would have suited I2 just fine. It makes me pretty happy having one for my smaller boat.

Windage is a funny thing. I guess without a side by side comparison its going to be hard to say anything definate, and do you measure it head on, 45 deg or beam on? I can see scenarios at anchor where any of these aspects could be the right one to use. I figure mast height is also another big factor as is number and diameter of furlers etc, and amount of rigging, then there is the whole how she sits at anchor. I guess my thinking is that although I2 is much sleeker in comparison to the IP38 she also has a much taller mast, more rigging, longer furler lengths and an extra 8 foot of hull length. The Ip's long keel might also help tame her slightly at anchor?

I still have some genuine concerns about going massively massively oversize on a working anchor. Aside from my prevous points about it being hard to properly set. I can see it being damned tough on windlasses and bowrollers. And getting it firmly imbedded in thick mud could make it very slow to recover, which in some cases could be dangerous.

[evm1024]

I'm using a Mantus 85# on the bow of my Gulfstar 50. Currently I'm on the river and San Juan's and Gulf Islands which is sheltered. At some point I'll move to a 105# Mantus when we are on a larger cruise. Here it what it looks like on the bow with 5/16" G70.

[Dockhead]

Originally Posted by a64pilot

Currently I have a snubber that uses the Mantus chain hook and twin 5/8" three strand, three strand cause I think it is very elastic. That attaches to both bow cleats.
I plan on using fire hose for chafe protection, but have read where sanitation hose was used, I do not know which is better.
I have contemplated running 3/4" snubbers back to my primary winches. Before I installed my Windlass I did have to use one to raise my Rocna 25 in about 20 kts of wind once as I didn't want to try screaming back at the wife to motor the boat to the anchor, but I do cheat, I don't have electric winches, but my Milwaukee drill does a decent job of imitating one.
I have heard of tieing off to the mast, but that worries me, my luck and I'd pull the mast off of its step and I can only assume that would not be a good outcome.

I'm open to advice as I'm new to this with little experience and am developing a plan as we speak.

Do not use the snubber as the only attachment to the boat!

Use a chain stopper or strong strop, strongly attached. This system should be as strong as your chain, if you want the chain strength to mean anything (as Uncivil was saying). I use my inner forestay chainplate.

If you use a strop, the strength is easy to achieve with single braid dyneema. If you use a chain stopper, you'll need a massive backing plate and you need to be sure the deck is strong enough. It's probably cheaper and easier to provide a strong enough attachment for a strop, than for a stopper. Uncivil is right that this is not a trivial challenge with a plastic boats.

Don't neglect this issue. Think about it - your ground tackle is only as strong as the weakest element of it. The snubber is no good because it has to be weak, to have the elasticity to fulfill its purpose, unless it is immensely long. But even if it were long enough to have enough nominal strength, remember that nylon loses strength when wet, and is very prone to chafe. The snubber is just fundamentally unsuitable as the main attachment of your ground tackle.

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[Dockhead]

Originally Posted by barnakiel

I have run some numbers thru a catenary formula. It seems, given total weight of the chain constant, a shorter and higher size chain is better than a longer lower size piece.

By better I mean shank angle is lower.

So the mathematics / physics cahoots run contrary to my earlier thin air assumptions.

This could imply when going for stronger chain (G7 vs. G4) one is better off sticking to the original size.

"If you have 10mm chain, if you upgrade to G7, stick with 10mm, do not go 8mm" in plain words.

The function is clearly not linear as the chain size/weight is not linear either. Chain is volume (3d), not area (2d), as simple as that.

Cheers,
b.

Once the chain is bar tight in storm conditions, none of this matters.

That is why Dashew and others have concluded that lighter and higher grade chain is better, allowing you to put more weight in the anchor where it counts.

I think that's all true in theory, but anchoring is not just about ultimate holding in ultimate storm conditions. Anchoring is also about comfort and security in ordinary conditions, and here heavy chain with greater catenary has big advantages. Also with more "meat" in the links, it's more forgiving of minor rust and damage, regalvanizing, etc.



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[Dockhead]

Originally Posted by Guy

For the occasional wave sure but one after another? Nothing on a regular sized cruising boat bow sprit would hold up, it's too big. Water over the deck is a game changer. This set-up sounds more coastal, which is where you would need it anyway.

I don't know about A64s boat, but my bow roller is plenty strong enough for this. My 100 pound Spade is underwater all the time, sometimes at 9 or 10 knots. I don't lash it; just windlass plus chain strop. No problems.

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[model 10]

[QUOTE=Dockhead;2196274]I don't know about A64s boat, but my bow roller is plenty strong enough for this. My 100 pound Spade is underwater all the time, sometimes at 9 or 10 knots. I don't lash it; just windlass plus chain strop. No problems.

He mentioned he has already had a smaller anchor tear off. Our 25kg Rocna is stowed solidly on the end of a 4' bowsprit. I can't do 10 knots but It's quite a ride up there. I would not trust a bolted on roller assembly.