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Old 14-09-2012, 00:29   #1
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What system should i use to anchor with

Hi everyone,

i have a few questions for those more knowledgeable than me.

I have a 28 foot 5.5 ton steel yacht 1.5 mtr draft, that will go in the water shortly.

I have just finished the building the bow roller and installing the anchor winch which is a vetus alexander III with a 10mm gypsy on it.

Now I'm wondering about what amount of chain and anchor rode that is a good feasible amount to keep forwards in the chain locker.

Currently i have 2 x 10mm pieces of chain at 30 mtrs long (total of 60 mtrs, ideally i was going to keep one in the locker and one hidden elsewhere, under mast etc.

But i was wondering from you guys, would i be better off changing those chains for one that is slightly smaller and keeping it all in the forward locker

For instance i can get a 8mm gypsy for the winch that i have.

Does 8mm chain take up that much difference in space to 10mm?

Or should i just keep the chain that i have and extend it with a nylon rode when anchoring deeper?

If so whats a good style of rode to use, brand, name? If possible i would like to build a roller system for it too that will either sit at the base of the mast or hide in the anchor locker so a rode that coils well would be an advantage

Ideally once I'm in the water I'm going to try and get to remote spots and stay on the water for quite a while exploring so the type of tackle and the amount will be important.

On a side note (not sure if it matters) i already have anchors that i will use, 1 plough, 2 sand, 1 fushermans. More can be purchased later if i feel that i need them

Thanks in advance for any information passed back to me regarding my questions

Matthew
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Old 14-09-2012, 02:45   #2
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What are your anchoring conditions most likely going to be, soft bottom with good holding. Rocky or sharp bottoms? I think you have plenty of chain either way. Unless your anchoring in very deep very harsh conditions. Be sure to use a good snubber if your not using a nylon rode. Also I am sure know how much scope to use...as for how much total rode to keep on board I prefer two or three times the amount im likely to need. In case you lose one or have a bad storm need it for towing, tying the wife etc....
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Old 14-09-2012, 03:50   #3
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Re: What system should i use to anchor with

Rocna's inventer, Peter Smith, argues that a rode longer than 8:1 is unnecessary since it becomes the rule of diminishing results. So how deep is the water? Figure 8:1 as max. In general, the heavier the anchor the better. Smith (and others) argue that any anchor you have should be at least twice as heavy as the manufacturers recommend. But this, of course, is dependent on the conditions you expect to anchor in. The above sized anchors will probably hold in almost anything.

Do use a nylon snubber - a lot of it if the conditions are heavy. Forget anchor kettles - they don't add anything. In general,. increasing the weight of your anchor and decreasing the size of your chain and going to high tensile chain is a good idea. Why? Because when the wine gets up to 20+ knots, your chain will be taut as a rod and you will have no catenary effect. Now the anchor has to do all the holding.

see:

PeterSmith.net.nz: anchors & anchoring, photos from Patagonia & Antarctica

Lot's of good advice there -just remember he invented the Rocna and therefore is a bit biased there.
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Old 14-09-2012, 04:19   #4
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Re: What system should i use to anchor with

60 meters of chain in a boat with 1.5 meters draft should be plenty, unless you think you might need to anchor in places with steeply sloping bottom or with some huge tidal range.

I have 100 meters of chain on board my 2.5 meters draft boat, and I sail in the English Channel which has some of the biggest tidal ranges in the world. I do need all or nearly all of those 100 meters of chain sometimes, if I'm anchored say in the Channel Islands at springs. That's because 6 meters of water at low tide suddenly becomes 18 meters at high tide. So to maintain adequate scope you will need at least 80 meters of chain out, and maybe more.

If you don't have a big range of tide, then this won't apply. You can definitely anchor in 40 feet of water with 60 meters of chain, and probably more -- less and less scope is needed as you get into very deep water.

I agree with Carsten that Peter Smith's stuff is the best single source on anchoring you will find. See also: Main Page (Rocna Knowledge Base)

You will see that he recommends a 15kg anchor for a boat of your size and displacement, and that an 8mm "high test" (G40) chain is fine for that. If I were you, I would probably not use a 10mm chain on your boat if it creates difficulties in stowing it (and it might create trim problems as well). I would use probably 60 meters of 8mm and keep it all in the forward chain locker where you can use it easily.

I agree with Carsten also about the extremely great importance of using a snubber. It's very dangerous, actually, to anchor without a snubber, because the snatch loads in even fairly benign weather can break your stem fitting or even your chain. It's also important to take the load off your windlass with another rope or a chain stopper. There's plenty of information on CF about anchoring technique if you'll search the archives.

Good luck!
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Old 14-09-2012, 05:49   #5
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Re: What system should i use to anchor with

Another source is Evans Starzinger and Beth Leonard. Check out their site at:

Beth & Evans

Evans has written a series of articles on anchoring. They know what they are doing
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Old 14-09-2012, 06:04   #6
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Re: What system should i use to anchor with

Quote:
Originally Posted by Dockhead View Post
60 meters of chain in a boat with 1.5 meters draft should be plenty, unless you think you might need to anchor in places with steeply sloping bottom or with some huge tidal range.

I have 100 meters of chain on board my 2.5 meters draft boat, and I sail in the English Channel which has some of the biggest tidal ranges in the world. I do need all or nearly all of those 100 meters of chain sometimes, if I'm anchored say in the Channel Islands at springs. That's because 6 meters of water at low tide suddenly becomes 18 meters at high tide. So to maintain adequate scope you will need at least 80 meters of chain out, and maybe more.

If you don't have a big range of tide, then this won't apply. You can definitely anchor in 40 feet of water with 60 meters of chain, and probably more -- less and less scope is needed as you get into very deep water.

I agree with Carsten that Peter Smith's stuff is the best single source on anchoring you will find. See also: Main Page (Rocna Knowledge Base)

You will see that he recommends a 15kg anchor for a boat of your size and displacement, and that an 8mm "high test" (G40) chain is fine for that. If I were you, I would probably not use a 10mm chain on your boat if it creates difficulties in stowing it (and it might create trim problems as well). I would use probably 60 meters of 8mm and keep it all in the forward chain locker where you can use it easily.

I agree with Carsten also about the extremely great importance of using a snubber. It's very dangerous, actually, to anchor without a snubber, because the snatch loads in even fairly benign weather can break your stem fitting or even your chain. It's also important to take the load off your windlass with another rope or a chain stopper. There's plenty of information on CF about anchoring technique if you'll search the archives.

Good luck!
Because you are operating out of Townsville in great Barrier reef waters all chain is way to go.

Dockheads suggestion of 60 - 80m of 8mm chain (with snubber) would be the way I would go.
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Old 14-09-2012, 23:19   #7
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Re: What system should i use to anchor with

I agree that all chain is the way to go, but if you end up using rope and chain an anchor kettle( a weight run down your nylon on a snatch block) helps to keep the snap out of the rode coming to its limits. Nylon is streachy, but the kettle helps. If you go with all chain(my choise) a snubber is required to keep from breaking things.___Grant.
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Old 15-09-2012, 00:00   #8
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Re: What system should i use to anchor with

Cool,

thanks for the replies so far, it has helped me realize that keeping my existing chain is the way to go, ooh and it was also helped by me being able to scrounge 70 mtrs of 16mm nylon anchor rode this morning for a neat $20

Guess my anchoring concerns are now mists on morning waters.

Matthew
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